Note: Descriptions are shown in the official language in which they were submitted.
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DEVICES AND METHODS FOR TREATING EDEMA
Cross-Reference to Related Applications
This application claims benefit of U.S. Provisional Application No.
62/810,653, filed
February 26, 2019; U.S. Provisional Application No. 62/810,658, filed February
26, 2019; U.S.
Provisional Application No. 62/810,660, filed February 26, 2019; U.S.
Provisional Application
No. 62/810,668, filed February 26, 2019; and U.S. Provisional Application No.
62/810,672, filed
February 26, 2019, the contents of each of which are incorporated herein by
reference.
Technical Field
The disclosure relates to devices and methods for the treatment of edema.
Background
Congestive heart failure occurs when the heart is unable to pump sufficiently
to maintain
blood flow to meet the body's needs. A person suffering heart failure may
experience shortness
of breath, exhaustion, and swollen limbs. Heart failure is a common and
potentially fatal
condition. In 2015 it affected about 40 million people globally and around 2%
of adults overall.
As many as 10% of people over the age of 65 are susceptible to heart failure.
In heart failure, the pressures in the heart ventricles and atria are
excessively elevated. As
a result, the heart works harder to eject blood, leading to a buildup of blood
pressure, which may
result in edema forming within interstitial compartments of the body. Edema
refers to the
abnormal accumulation of fluid in tissues of the body and results when
elevated blood pressure
prevents lymphatic fluid from draining from the interstitium. The additional
work of the heart,
with time, weakens and remodels the heart thus further reducing the ability of
the heart to
function properly. The fluid accumulation leads to dyspnea and acute
decompensated heart
failure (ADHF) hospitalization. Those conditions may result in severe health
consequences
including death.
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Summary
The invention provides devices and methods for treatment of edema that use an
indwelling catheter with an impeller to lower pressure at an outlet of a
lymphatic duct and a
balloon on the impeller to guide and to restrict blood flow. The balloon
restricts return flow from
the jugular and guides that flow into the impeller cage. By funneling the flow
into the impeller
cage, a rate of flow down the vessel may be increased, resulting in a lateral
pressure decrease
effecting the lymphatic outlet. Because the lymphatic outlet is subject to a
pressure decrease,
fluids in the lymphatic system drain to the outlet and into the circulatory
system. These effects
can be optimized by having the balloon disposed on or around the impeller cage
and, in some
embodiments, the balloon may be connected directly the impeller cage,
surrounding the cage,
and forming a torus that funnels fluid flow into the impeller cage. A shape of
a balloon in a
deployed state directs and facilitates blood flow into an inlet of an
impeller. By using the
impeller in conjunction with the balloon on the catheter, the ability of the
device to lower
pressure at the lymphatic outlet is optimized.
The geometry of the combined impeller cage and toroidal balloon employ flow
dynamics
to drain the lymphatic system. The impeller cage in combination with the
balloon creates a local
constriction (or choke) in the cross-sectional area of flow through the vessel
(e.g., the innominate
vein). This flow constriction results in a Venturi effect, in which fluid
pressure is reduced as
applicable to the outlet of the lymphatic duct. Due to the pressure decrease
experienced by the
lymphatic outlet, lymph drains from the lymphatic system to the circulatory
system. Thus
devices and methods of the disclosure use a balloon mounted to an impeller to
exploit the laws of
fluid mechanics to drain lymph. Since operating an impeller in an innominate
vein near a
lymphatic outlet with a balloon connected to the impeller cage is effective to
reduce pressure at
the lymphatic outlet and drain lymph, devices and methods of the invention are
useful to relieve
the symptoms of edema. Accordingly, the invention provides methods and devices
that use a
balloon mounted to an impeller cage to treat edema and congestive heart
failure.
In certain aspects, the disclosure provides a device for treating edema. The
device
includes a catheter having a proximal portion and a distal portion, an
impeller housing attached
to the distal portion of the catheter with an impeller disposed therein, and
an expandable member
(e.g., a balloon) aligned over an outside of the impeller housing. An exterior
surface of the
expandable member may be physically coupled to an exterior surface of the
impeller housing.
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Preferably, the exterior surface of the expandable member is physically
coupled directly to the
exterior surface of the impeller housing, i.e., without any membrane, sheath,
or device between
the exterior surface of the expandable member and the exterior surface of the
impeller housing.
The expandable member may surround the impeller housing.
Where the expandable member is a balloon, the balloon may inflatable and may
surround
the impeller housing. In some embodiments, the impeller housing comprises a
metal and a
portion of the expandable member is fixed to a surface of the metal by an
adhesive. At least a
portion of the surface of the metal may be impregnated with a polymer to
promote bonding to the
adhesive. Embodiments of the device may include a motor housing connected to
the proximal
portion of the catheter with a motor disposed within the motor housing. A
drive cable may
extend through the catheter from the motor to the impeller with an inflation
lumen extending
along the catheter to the expandable member. Related embodiments provide a
method of using
the device for treating edema. The method includes inserting the distal
portion of the catheter
into an innominate vein of a patient, operating the impeller, and expanding
the expandable
member to thereby decrease pressure at a lymphatic duct.
Aspects of the invention provide an edema treatment device that includes a
catheter with
a proximal portion and a distal portion, the distal portion dimensioned for
insertion into a lumen
of a patient and comprising a pump, and an expandable member connected to the
pump. When
expanded, the expandable member comprises a toroidal shape, in which a
proximal surface of the
toroidal shape directs fluid into the pump. Preferably an inner radius of the
toroidal shape is
substantially the same as a radius of the proximal end of the pump. The
expandable member may
include an inflatable balloon mounted on the pump. In some embodiments, the
pump comprises
an impeller housing with an impeller therein, with the balloon mounted around
at least a portion
of a proximal end of the impeller housing. In certain embodiments, the
impeller housing has a
distal portion and a proximal portion, in which an external diameter of the
proximal portion is
smaller than an external diameter of the distal portion, such that the
expandable member, when
not expanded, is disposed around the proximal portion of the impeller housing.
The impeller may
have one or more blades on a shaft, with a radius measured from an axis of the
impeller to an
outer edge of the blades decreasing from a distal to a proximal portion of the
impeller. The outer
edge of each blade may include a dogleg defining a step-down in radius located
adjacent a
transition between the distal portion and the proximal portion of the impeller
housing. In
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preferred embodiments, the distal portion of the impeller housing has outlets
and the impeller
shaft flares outwards near a distal end of the impeller such that when the
impeller is rotated, the
impeller pumps blood through the impeller housing and out of the one or more
outlets.
The pump may include an impeller disposed within an impeller housing and the
expandable member may include an inflatable balloon connected to an exterior
surface of the
impeller housing. In certain embodiments, when the balloon is inflated, it
defines a torus. When
the balloon is inflated, a surface of the torus may be attached to a surface
of the impeller housing.
Preferably, when the expandable member is not expanded, the distal portion of
the catheter may
be passed through a 12 Fr introducer sheath.
Aspects of the disclosure provide a device and associated method that use a
restrictor for
compensation to pressure changes resulting from flow induced by a pump. In the
restrictor for
flow compensation aspects, the invention provides a method for treating edema.
The method
includes operating a pump to increase flow through an innominate vein of a
patient and¨
subsequent to the operating step¨deploying a restrictor upstream of the pump
to thereby restrict
flow from a jugular vein to the innominate vein in order to balance pressure
downstream of the
pump. The method may include operating the pump and then restricting the flow
once the
increased flow through the innominate vein affects pressure in the jugular
vein. The method may
further include sensing, with a pressure sensor, an increase in pressure in
the jugular vein that
results from the increased flow and restricting the flow in response to
sensing the increased
pressure in the jugular vein. Restriction of the flow may be adjusted
according to the sensed
pressure. Preferably, the method includes placing a device comprising the pump
within
vasculature of a patient prior to the operating step. The device comprises a
catheter dimensioned
to be at least partially implanted within the vasculature and the pump
comprises an impeller
assembly disposed at a distal portion of the catheter. In some embodiments, a
proximal portion
of the catheter is connected to a motor housing and the device includes a
pressure sensor and a
deployable restrictor attached to the catheter proximal to the pump.
Preferably, the restrictor
includes an inflatable balloon and restricting the flow includes inflating the
restrictor. The
sensing may be performed using a computer system communicatively connected to
the pressure
sensor. The inflation of the restrictor may be periodically or continually
adjusted according to the
sensed pressure.
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Other aspects of the invention provide a method for treating edema. The method
includes
operating a pump to increase flow through an innominate vein of a patient,
sensing a pressure
change in a jugular vein of the patient that results from the increased flow,
and adjusting a
restrictor to restrict flow from the jugular vein to the innominate vein based
on the sensed
pressure. The method may further include inserting a catheter into the
innominate vein, wherein
the catheter comprises the pump, a pressure sensor, and the restrictor.
Preferably, the restrictor
includes an inflatable balloon and adjusting the restrictor includes at least
partially inflating the
balloon. The sensing may be performed using a pressure sensor. The method may
include
periodically or continually adjusting inflation of the restrictor according to
the sensed pressure.
Preferably, the method includes adjusting the inflation in order to balance
pressure downstream
of the pump. Optionally the pump comprises an impeller assembly disposed at a
distal portion of
the catheter. A proximal portion of the catheter may be connected to a motor
housing having a
motor therein operably coupled to the impeller assembly. In some embodiments,
the catheter is
coupled to a computer system operable to read the pressure or control the
inflation.
Aspects of the invention provide a purge-free system, device, and method for
treatment
of edema. For example, aspects provide a purge-free device that includes a
catheter with a
proximal portion and a distal portion, an impeller connected to the distal
portion of the catheter, a
motor connected to the proximal portion of the catheter, a drive cable
extending through the
catheter from the motor to the impeller, and an impermeable sleeve extending
through the
catheter over the drive cable. The sleeve features a distal seal at the
impeller and a proximal seal
at the motor such that fluid external to the sleeve is prevented from entering
the sleeve and
contacting the drive cable. The sleeve and at least the distal seal exclude
fluid from the drive
cable. Either seal (or both) may include one or more 0-rings. The device may
include a first
lumen and a second lumen, both extending through the catheter, in which the
first and second
lumen have respective first and second proximal ends accessible outside of the
motor housing.
Preferably the first lumen and the second lumen are symmetrically disposed
about the drive cable
to impart balance to the device. The catheter preferably does not include a
purge system or a
purge fluid. In some embodiments, the impeller sits in an impeller housing and
the device also
has at least one expandable member connected to the distal portion of the
catheter. The
expandable member may be connected to the impeller housing, and the device may
also include
a second expandable member disposed along the catheter. Preferably, the first
expandable
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member comprises a toroidal balloon connected directly to a surface of the
impeller housing. The
device may also include at least one pressure sensor disposed along the
catheter proximal to the
impeller.
In some embodiments, the proximal seal comprises a fitting between the
impermeable
sleeve and a portion of the impeller, such that the fitting excludes fluids
and allows the impeller
and drive cable to rotate within the device.
A related aspect provides a method using the purge-free device. The purge-free
device
may be used in a method of treating edema. The method includes inserting into
an innominate
vein of a patient a distal portion of a catheter and driving an impeller
connected to the distal
portion of the catheter by means of motor at a proximal portion of the
catheter. The motor is
connected to the impeller by a drive cable extending through the catheter.
Driving the impeller
decreases pressure at a lymphatic duct. An impermeable sleeve extends through
the catheter over
the drive cable such that body fluid external to the impermeable sleeve is
prevented from
entering the impermeable sleeve and contacting the drive cable. The method may
further
comprise inflating a restrictor disposed along the distal portion of the
catheter to restrict flow
from a jugular vein into the innominate vein, wherein the inflating uses an
inflation lumen
extending through the catheter outside of the impermeable sleeve. The
decreased pressure at a
lymphatic duct promotes drainage from a lymphatic system into a circulatory
system.
Preferably, the impermeable sleeve has a proximal seal at a housing of the
motor and a
distal seal at the impeller. The proximal seal prevents the blood and bodily
fluid from escaping
the patient through the motor housing or the proximal portion of the catheter.
The distal seal may
include a fitting between the impermeable sleeve and a portion of the
impeller, in which the
fitting excludes fluids and allows the impeller and drive cable to rotate
within the device. The
impermeable sleeve may be made of a polymer such as Teflon.
The method may include inflating at least one balloon disposed along the
catheter by
means of an inflation lumen having a proximal end accessible outside of the
motor housing while
the distal portion of the catheter is inserted into the innominate vein. Blood
and bodily fluid is
preferably excluded from the drive cable without the use of a purge fluid or
purge system.
Other aspects of the disclosure related to methods and devices that use and
deliver an
anticoagulant to promote effective operation of a device of treatment of
edema. For example,
aspects of the disclosure provide a device that includes an intravascular pump
with built-in
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delivery mechanism for an anticoagulant (i.e., to deliver the anticoagulant to
moving parts of the
pump). Thus the invention provides an edema treatment device that includes a
catheter, an
impeller assembly mounted at a distal portion of the catheter, and a
medicament lumen extending
through the catheter and terminating substantially at an inlet of the impeller
assembly such that a
medicament released from the medicament lumen flows through the inlet and
impeller assembly.
Preferably, the catheter and impeller assembly are dimensioned for insertion
through a jugular
vein of a patient. The device may further include a reservoir in fluid
communication with the
medicament lumen. The impeller assembly may comprise an impeller housing with
an impeller
rotatably disposed therein. The device may include a motor connected to a
proximal end of the
catheter and operably connected to the impeller via a drive cable extending
through the catheter.
Preferably, the port is located at the impeller housing, proximal to the
impeller.
In some embodiments, the catheter comprises a tube with a drive cable
extending
therethrough, with a cap connected around a terminal portion of the tube. The
impeller housing is
mounted to the cap by a plurality of struts to define inlets into the impeller
housing. The cap
seals a terminus of the flexible tube to a shaft of the impeller, and the port
may be located in the
cap. The impeller housing may have one or more outlets around a distal portion
of the impeller,
such that operation of the impeller within a blood vessel drives blood into
the impeller assembly
via the inlets and out of the impeller assembly via the outlets.
The device may include an anticoagulant (e.g., tirofiban, heparin, warfarin,
rivaroxaban,
dabigatran, apixaban, edoxaban, enoxaparin, or fondaparinux) in the reservoir.
When the device
is inserted into a blood vessel of a patient and the impeller is operated, the
anticoagulant is
released from the port in the impeller cage and the released anticoagulant
mixes with blood and
washes over the rotating impeller.
Related aspects of the invention provide a method for treating edema. The
method
includes operating a pump to increase flow through an innominate vein of a
patient and releasing
an anticoagulant at or adjacent an inlet of the pump. The pump may include an
impeller in a cage
at a distal portion of a catheter and the anticoagulant may be released from a
port in or adjacent a
proximal portion of the cage. Optionally, a proximal end of the catheter
terminates at a housing
comprising a motor, with the motor operably coupled to the impeller by a drive
cable extending
through the catheter. The catheter may include a medicament lumen extending
therethrough and
terminating at the port. The method may include the steps of providing the
anticoagulant in a
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reservoir in fluid communication with the medicament lumen; inserting the
catheter into
vasculature of the patient to position the impeller in the innominate vein;
operating the motor to
drive the impeller; and washing the anticoagulant over the impeller by
releasing the
anticoagulant from the port. Preferably, operating the pump decreases pressure
at a lymphatic
duct, thereby draining lymph from a lymphatic system of the patient.
In certain embodiments, the pump includes an impeller on a distal portion of a
catheter
and the anticoagulant is released from a port at a proximal portion of the
impeller.
By the release of the anticoagulant, clotting or thrombosis is prevented from
interfering
with operation of the impeller. Optionally, the method may include restricting
flow from a
jugular vein to the innominate vein to thereby promote flow from a subclavian
vein to the
innominate vein.
The invention provides devices and methods useful for treating edema by means
of an
indwelling catheter that is placed in a blood vessel of a patient and used to
pump blood to cause a
decrease in pressure at an outlet of a lymphatic duct. The catheter pumps
blood by means of an
impeller but is purge-free in that the catheter does not include a system for
purging or flushing
catheter components with a purge fluid. The purge-free catheter avoids blood-
related mechanical
complications such as clotting or thrombosis by means of an impermeable sleeve
or shroud that
protects moving parts of the impeller drive system. For example, a drive cable
to the impeller
may be protected by an impermeably sleeve that is closed a distal end by a
distal seal near the
impeller and may also be closed at a proximal end (e.g., outside of the
patient) by a proximal
seal, such as by 0-rings fitted to a motor housing and/or catheter handle used
to navigate the
impeller into place and drive the impeller. The impermeable sleeve or shroud
and appropriate
seals exclude blood and bodily fluid from entering operable parts of the
catheter system. Thus
the impermeable sleeve or shroud and any associated seal provide a purge-free
system that
maintains smooth and reliable operation of the catheter by excluding blood or
bodily fluid from
operable parts of the catheter.
Edema may be treated by accessing a blood vessel such as a jugular vein and
navigating
the catheter therethrough. The catheter is navigated to position the impeller
near an outlet of a
lymphatic duct. For example, the impeller may be located in an innominate
vein. A substantial
length of the catheter as well as the impeller may be positioned to sit within
blood vessels and
thus may be surrounded by, and operating within, blood. To avoid problems that
would result
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from blood clotting within moving parts of the impeller or hemolysis induced
by those moving
parts, the catheter includes a sealed sleeve or shroud that excludes blood
from the impeller and
associated moving parts. The catheter may further include a proximal seal at
the external motor
housing the prevent blood from backing up and flowing outside of the patient.
The sealed sleeve
or shroud is much simpler in operation and maintenance than elaborate purge
systems that use a
purge fluid delivered by a purge lumen to prevent blood from interfering with
device operation.
Also, the purge-free system of devices and methods of the invention by not
using a purge fluid
do not effect blood chemistry or osmolality because they do not release an
external fluid into the
blood stream. Accordingly, the invention provides devices and methods that use
a sealed sleeve
or shroud on an intravascular catheter with blood pump or impeller to reduce
pressure at an
outlet of a lymphatic duct while also preventing adverse effects such as
clotting or hemolysis.
Because devices and methods of the invention reduce pressure at a lymphatic
outlet, they
promote drainage of lymph from the lymph system. Thus, devices and methods of
the invention
may be used to treat edema or congestive heart failure.
The invention provides devices and methods for treating edema that use an
indwelling
catheter to place an impeller in a blood vessel of a patient, near an outlet
of a lymphatic duct.
Operating the impeller creates a local depression in blood pressure, which
promotes drainage of
lymph from the lymphatic system. The catheter is also used to release an
anticoagulant such as
heparin to wash and lubricate the impeller. Specifically, the anticoagulant
inhibits clotting,
hemolysis, or thrombosis from occurring and interfering with smooth operation
of the impeller.
The anticoagulant may be released using a medicament lumen that extends along
the catheter to
release port that is just upstream of, or just proximal to, the impeller. A
suspension or solution of
the anticoagulant may be flowed down the lumen and released such that washes
over moving
parts of the impeller, such as the impeller blades, drive cable, and bearing
faces between the
impeller and surrounding impeller housing. The anticoagulant prevents blood
from clotting at
those locations and surfaces and thus avoids an adverse effects of thrombosis
or hemolysis.
By releasing anticoagulant to the impeller, devices of the invention operate
smoothly and
reliably within a blood vessel of a patient. By using the impeller to drive
blood flow and relieve
pressure at the lymphatic outlet, devices of the invention promote the
drainage of lymph from the
lymphatic system to the circulatory system. Preferably, the impeller is
provided by a catheter that
releases an anticoagulant such as heparin at or near an inlet of the impeller
cage. Due to the
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drainage of lymph, devices and methods of the invention are useful for
treating edema and
congestive heart failure. Since those devices use an anticoagulant to maintain
smooth and
reliable operation of the impeller, the devices avoid being adversely effected
by blood clotting or
other effects. Thus devices and methods of the invention are useful for
treating edema and
congestive heart failure.
The invention provides devices and methods for treating edema that use an
intravascular
pump to pump blood through the circulatory system in such a manner as to
relieve pressure at an
outlet from the lymphatic system into the circulatory system. Devices and
methods of the
invention further use a flow-restrictor in the circulatory system, upstream of
the pump, to balance
pressure changes induced by the pump and to compensate for downstream flow.
The device may
be provided as an indwelling, intravascular catheter with a mechanical pump
such as an impeller
and a selectively deployable restrictor such as an inflatable balloon.
Congestive heart failure or
edema is treated by inserting the catheter and operating the pump in the
circulatory system (e.g.,
in an innominate vein), just downstream of an outlet of a lymphatic duct.
Pumping blood away
from the outlet of the lymphatic duct tends to lower pressure at the outlet.
Methods of the
invention further use the restrictor for flow compensation, to restrict the
upstream flow and thus
amplify or maintain pressure reduction at the lymphatic outlet.
Access may be made through a jugular vein and the catheter may be navigated
into
position (e.g., under radiographic imaging) to position the pump just
downstream of the
lymphatic outlet. A proximal end of the catheter may house a motor connected
to the impeller by
a drive cable. Once the impeller is positioned in the innominate vein,
operating the motor to
drive the impeller pumps blood towards the heart and away from the lymphatic
outlet, reducing
the pressure at the lymphatic outlet. Absent methods and devices of the
invention, blood return
or blood flow through the jugular may simply increase, to restore hydrostatic
equilibrium. To
compensate for that effect, the catheter includes a selectively deployable
restrictor, such as a
balloon inflatable via an inflation lumen extending along the catheter. When
the balloon in
inflated, it inhibits return flow through the jugular vein, thereby
maintaining the local pressure
depression at the lymphatic outlet. Due to the low pressure at the lymphatic
outlet, lymph flows
out of the interstitial spaces within bodily tissue, relieving pressure there,
and thus relieving
edema and protecting against congestive heart failure.
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Thus, device and methods of the invention use an intravascular pump and a flow
restrictor to decrease lymphatic pressure and compensate for increased
circulation, respectively.
Those means are effective to drain lymph from the lymphatic system and thus
relieve edema.
Accordingly, devices and methods of the invention are useful for preventing
congestive heart
failure.
The invention provides an impeller assembly with a structure that facilitates
flow without
recirculation. When the impeller is operated, structural features of the
impeller assembly channel
flow and function as vanes that guide smooth flow of fluid through the
impeller. Due to the vane-
like features making up the structure of the impeller assembly, fluid flow
through the impeller
assembly is guided along smooth and continual flow lines such that the overall
flow patterns
exhibit no vortices or recirculation. The impeller assembly may be connected
to a distal portion
of an intravascular treatment catheter and may be used for treating edema.
By navigating the catheter into a jugular vein of a patient suffering edema
and operating
the impeller in a vicinity of a lymphatic duct, the device promotes and
increases blood flow
along the jugular vein, which by Bernoulli's principle decreases pressure at
an output of the
lymphatic duct. Because pressure is decreased at an output of the lymphatic
duct, lymph drains
from the lymphatic system and into the circulatory system, thereby providing
relief from adverse
effects and symptoms of edema.
Moreover, the impeller assembly can include specialized combinations of
structures to
promote flow therethrough. For example, the impeller assembly may have an
inflatable balloon
disposed thereon. An inflation lumen extends down the catheter and passes
through a rigid strut
that extends from the catheter to the impeller housing. Several of those rigid
struts collectively
support the housing with respect to the catheter. One or any number of those
rigid struts may
each have an inflation lumen running therethrough. But a lumen need not be
disposed
concentrically within the strut and in preferred embodiments is eccentric as
the struts¨relative
to the lumen¨bears an excess of material standing into the inner space of the
impeller housing.
That excess of material extending inward from each strut functions as flow-
guiding vane that
channels the flow into smooth patterns without vertices or recirculation.
Since a primary benefit
of an intravascular impeller is its ability to efficiently pump blood
therethrough, efficient
operation without recirculation or vortices provides an optimized treatment
tool for relieving
effects and symptoms of edema.
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In certain aspects, the invention provides a device for treating edema. The
device
includes a catheter with a proximal portion and a distal portion. An impeller
assembly is
connected to the distal portion. The impeller assembly has an impeller
operably disposed within
it. A proximal portion of the impeller assembly is configured to facilitate
flow into an inlet of the
impeller assembly without recirculation. When the impeller operates within a
blood vessel, blood
flows through a housing of the impeller assembly without recirculation.
The impeller assembly may include a cap secured to the distal portion and one
or more
struts extending from the cap to the housing. The housing may have a diameter
greater than a
diameter of the cap, such that a proximal base of the housing, the cap, and
the one or more struts
define the inlet. In some embodiments, the strut includes an inflation lumen
extending
therethrough for inflating a balloon mounted on the impeller assembly.
Preferably, the strut is
substantially parallel to an axis of the impeller and protrudes radially
inward from at least a
portion of an inner surface of the impeller housing. Such a strut may define a
vane within the
impeller assembly that channels fluid flow when the impeller operates to
thereby prevent the
recirculation or vortices. The strut may include a fluidic lumen extending
therethrough, in which
the fluidic lumen is non-concentric with at least a portion of the body of the
strut due to material
of the strut forming the vane within the impeller assembly. The device may
have several, e.g.,
three, of the struts, wherein each of the several struts defines a vane within
the impeller assembly
that channels fluid flow when the impeller operates to thereby prevent the
recirculation or
vortices. The device may optionally include a medicament lumen extending
through the catheter
and terminating substantially within a proximal portion of the impeller
assembly such that a
medicament released from the medicament lumen flows through the inlet and
impeller assembly.
In certain embodiments, the catheter includes a tube with a drive cable
extending there
through with a cap connected around a terminal portion of the tube, with the
impeller housing
mounted to the cap by a plurality of struts that define vanes that promote
laminar flow of fluids
through the impeller assembly. The impeller housing may have one or more
outlets around a
distal portion of the impeller, such that operation of the impeller within a
blood vessel drives
blood into the impeller assembly via the inlets and out of the impeller
assembly via the outlets
such that the blood exhibits smooth laminar flow without the recirculation or
vortices.
Aspects of the invention provide a method of treating edema. The method
includes
inserting into an innominate vein of a patient a distal portion of a catheter.
The catheter includes
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an impeller assembly on the distal portion. Driving an impeller disposed
within the impeller
assembly decreases pressure at a lymphatic duct. A proximal portion of the
impeller assembly is
configured to facilitate flow into an inlet of the impeller assembly without
recirculation.
The catheter may include a cap secured to the distal portion and one or more
struts
extending from the cap to support a housing of the impeller assembly. The
housing may have a
diameter greater than a diameter of the cap, and a proximal base of the
housing, the cap, and the
one or more struts may define the inlet. The struts may extend substantially
parallel to an axis of
the impeller and protrude radially inward from at least a portion of an inner
surface of the
impeller housing. The struts may define vanes within the impeller assembly
that channel fluid
flow when the impeller operates to thereby prevent the recirculation or
vortices. One or more of
the struts may include a fluidic lumen that is non-concentric with at least a
portion of the body of
the strut due to material of the strut forming the vane within the impeller
assembly.
The method may include inflating an inflatable flow restrictor mounted on the
impeller
assembly by delivering an inflation fluid to the restrictor via an inflation
lumen extending
through the catheter. The impeller housing may include one or more outlets
around a distal
portion of the impeller, such that operation of the impeller within a blood
vessel drives blood
into the impeller assembly via the inlets and out of the impeller assembly via
the outlets such that
the blood exhibits smooth laminar flow without the recirculation or vortices.
Brief Description of the Drawings
FIG. 1 shows a device for treatment of edema.
FIG. 2 gives a detail view of the impeller assembly.
FIG. 3 shows the expandable member in a deployed state.
FIG. 4 shows a motor housing connected to the catheter.
FIG. 5 shows steps of a method of using the device for treating edema.
FIG. 6 is a detail view of the impeller assembly with the expandable member in
a
deployed state.
FIG. 7 diagrams a method for treating edema that uses a restrictor to balance
pressure and
compensate for downstream flow.
FIG. 8 shows the restrictor and a pressure sensor for the balance and
compensation
method.
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FIG. 9 shows a device inserted into vasculature of a patient.
FIG. 10 diagrams a related method for treating edema using a restrictor for
balance/compensation.
FIG. 11 is a detail view of features that provide for a purge-free system.
FIG. 12 diagrams a method of treating edema using a purge-free device.
FIG. 13 illustrates a portion of an intravascular device for treatment of
edema that
releases an anticoagulant at an intravascular pump.
FIG. 14 is a cross-sectional view through an impeller assembly.
FIG. 15 shows results of a computerized flow model.
FIG. 16 is a partial cutaway view of an impeller assembly.
FIG. 17 is a side view of an impeller assembly.
FIG. 18 shows an exemplary inlet region of an impeller assembly.
FIG. 19 shows an inlet region with an internal inflation lumen.
FIG. 20 is a detailed view of a proximal inlet.
FIG. 21 shows a side view of an impeller assembly with rectangular proximal
inlets.
FIG. 22 shows an impeller assembly with arcuate proximal struts.
FIG. 23 shows a side view of a proximal portion of an impeller assembly.
FIG. 24 illustrates an impeller assembly.
FIG. 25 shows an elongated impeller assembly.
FIG. 26 shows a cross-sectional view of an impeller assembly.
FIG. 27 is a cross-sectional view of an impeller assembly inside a vein.
FIGS. 28A-F illustrates attachment and folding of an expandable member.
FIG. 29 shows an impeller assembly with an expandable member having an
elongated
surface for interfacing with a wall of a blood vessel.
FIG. 30 shows an impeller assembly with a two-part expandable member.
FIG. 31 is a partial cross-sectional view of a distal portion of a catheter.
FIG. 32 is a partial cross-section of a self-expanding impeller assembly.
FIG. 33 shows a partial cross-section of an impeller assembly.
FIG. 34 shows an inlet of an impeller assembly.
FIG. 35 is an exemplary catheter system.
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FIG. 36 shows a catheter with an expandable member slidably mounted along a
shaft of
the catheter.
FIG. 37 shows a fluid channel across an expandable member that allows a
controlled
amount of blood flow.
FIG. 38 shows a catheter with an alternative bypass channel.
FIG. 39 shows a patient interface with a sheath in situation.
FIG. 40 shows a patient interface with a sheath held in situation by an
adhering
membrane.
FIG. 41 shows a flow control sheath.
FIG. 42 shows a proximal portion of a catheter system.
FIG. 43 illustrates a locking mechanism for fixing a catheter shaft to a hub
of a sheath
during therapy.
FIG. 44 shows the locking mechanism engaged with the catheter shaft.
FIG. 45 shows a schematic of a push lock mechanism.
FIG. 46 shows an alternative locking mechanism.
FIG. 47 is a partial cutaway of a jugular vein showing a flow control sheath
inserted
therein.
FIG. 48 shows an indwelling catheter system.
FIG. 49 is a cross-section taken along line A-A of FIG. 48.
FIG. 50 is an indwelling catheter.
FIG. 51 is an expanded view of dotted circle B of FIG. 50 according to an
embodiment of
the invention.
FIG. 52 is an expanded view of dotted circle B of FIG. 50 according to another
embodiment of the invention.
FIG. 53 is an expanded view of dotted circle B of FIG. 50 according to a
different
embodiment of the invention.
FIG. 54 illustrates a distal flush of an indwelling catheter.
FIG. 55 illustrates distal flush of an indwelling catheter according to a
different
embodiment.
FIG. 56 shows an indwelling catheter with a purge system.
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FIG. 57 shows a cross-section of the central lumen taken along line A-A of
FIG. 56
according to one embodiment of the invention.
FIG. 58 shows a cross-section of the central lumen taken along line A-A of
FIG. 56
according to a different embodiment of the invention.
FIG. 59 shows a cross-section of the central lumen taken along line A-A of
FIG. 56
according to another embodiment of the invention.
FIG. 60 shows an optimized guide surface of a cage inlet.
FIG. 61 shows a suboptimal guide surface.
FIG. 62 shows a cage inlet.
FIG. 63 shows a suboptimal inlet configuration.
Detailed Description
The disclosure relates to devices and methods for treating edema or congestive
heart
failure. Devices of the disclosure include catheters dimensioned for insertion
through a jugular
vein, in which the catheters use or include various features each alone or in
combination as
described herein. Embodiments of the devices include treatment devices in
which a flow
restrictor such as a balloon is mounted to a cage or housing of an
intravascular pump or impeller.
In some of those embodiments, a shape of a balloon in a deployed state directs
and facilitates
blood flow into an inlet of an impeller. In certain embodiments, devices of
the disclosure include
an impeller that has a smaller diameter proximal end as compared to a distal
end to compensate
in size for positioning of a balloon on an impeller cage. Aspects of the
invention relate to a
purge-free system, or purge-free intravascular treatment catheters that do not
use a purge fluid to
protect an impeller from thrombosis or clotting. In certain embodiments,
devices and methods of
the disclosure use the release of an anticoagulant such as heparin at an inlet
of an impeller cage.
Other embodiments of the disclosure relate to devices and methods that use a
restrictor such as a
balloon to balance pressure and to compensate for downstream flow when an
impeller is
operated to drain a lymphatic duct. Features and embodiments of the disclosure
include edema
treatment devices that include an arrangement of lumens that is symmetrical
about a drive shaft
to impart balance to the drive shaft. In some embodiments, those lumens have a
proximal
terminus outside of a motor housing and extend down to a distal portion of a
catheter. Device of
the disclosure may include an atraumatic tip with a thread therein to allow
for a smooth material
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transition. Embodiments of the disclosure may include a guidewire running
through an impeller
cage. Those embodiments are described and shown in greater detail herein and
may be present in
any suitable combination in a device of the disclosure.
FIG. 1 shows a device 101 for treatment of edema. The device 101 includes a
catheter
105 comprising a proximal portion 109 and a distal portion 115. An impeller
housing 203 is
attached to the distal portion 115 of the catheter 105 with an impeller
disposed therein. An
expandable member 301 may be aligned over an outside of the impeller housing
203. The
expandable member 301 is depicted in a collapsed configuration, and thus
appears as little more
than a smooth continuation of the impeller housing 203.
The device 101 may include a restrictor 801 and at least one pressure sensor
805. In the
depicted embodiment, the restrictor 801 is proximal to the expandable member
301. Preferably,
each of the restrictor 801 and the expandable member 301 is independently
selectively
deployable to restrict, impede, guide, or direct fluid flow around the
relevant portion of the
device 101. In preferred embodiments, each of the restrictor 801 and the
expandable member 301
sits in fluid communication with a dedicated inflation lumen that runs along a
length of the
catheter 105.
One feature of the device 101 is the impeller 205, which is preferably
provided within an
impeller assembly 201 that provides the impeller housing 203 and other
mechanical features
such as ports and openings useful to pump blood and fluid within blood vessels
of a patient.
FIG. 2 gives a detail view of the impeller assembly 201. The impeller assembly
201
includes an impeller housing 203 with an impeller 205 rotatably disposed
therein. An expandable
301 member is aligned over an outside of the impeller housing 203. The
expandable member is
represented in FIG. 2 using dashed lines (ghosted lines to aid in seeing other
features of the
device 101). The dashed lines represent the location and disposition of the
expandable member
301 in its collapsed or un-deployed state. The impeller housing 203 is
attached to the distal
portion 115 of the catheter 105 with an impeller disposed therein. An
expandable 301 member is
aligned over an outside of the impeller housing 203. The expandable member is
represented in
FIG. 2 using dashed lines (ghosted lines to aid in seeing other features of
the device 101). The
dashed lines represent the location and disposition of the expandable member
301 in its collapsed
or un-deployed state.
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As shown, the impeller comprises 205 has blades 206 on a shaft 207. A radius
measured
from an axis of the impeller 205 to an outer edge of the blades 206 decreases
from a distal to a
proximal portion of the impeller. This can be seen in that an outer edge of
each blade 206
includes a dogleg 209 defining a step-down in radius located adjacent a
transition between the
distal portion and the proximal portion of the impeller housing 203.
When the distal portion 115 of the device 101 is inserted into vasculature of
a patient and
a motor in the motor in the motor housing 401 is operated, the impeller 205
rotates and drives
fluid (i.e., blood) through the impeller housing 203. To that end, a proximal
end of the impeller
housing 203 includes one or more inlets 255 and a distal portion of the
impeller housing 203
comprises one or more outlets 227. The impeller shaft 207 flares outwards near
a distal end of
the impeller 205 such that when the impeller 205 is rotated, the impeller
pumps blood through
the impeller housing 203 and out of the one or more outlets 227.
FIG. 14 is a cross-sectional view through the impeller assembly 201 on the
distal portion
115 of the device 101. The impeller assembly 201 includes an impeller housing
203 with an
impeller 205 rotatably disposed therein.
The impeller assembly 201 is connected to the distal portion 115 of the
catheter. The
impeller assembly has the impeller 205 operably disposed within the assembly.
The cutaway
view of the impeller assembly 201 shows a proximal portion of the impeller
assembly is
configured to facilitate flow into an inlet of the impeller assembly without
recirculation.
When the impeller 205 operates within a blood vessel, blood flows through a
housing 203
of the impeller assembly 201 without recirculation.
As illustrated by the cross-sectional view, in the depicted embodiment, the
impeller
assembly 201 comprises a cap 249 secured to the distal portion 115 and one or
more struts 1405
extending from the cap 249 to the housing 203. Any one or more of the struts
1405 may include
a lumen 415. The housing 203 has a diameter greater than a diameter of the cap
249. It can be
seen that structurally, a proximal base of the housing 203, the cap 249, and
the one or more struts
105 define one or more inlets into the impeller housing 201.
In the depicted embodiment, the strut 1405 has an inflation lumen 415
extending
therethrough for inflating a balloon mounted on the impeller assembly. The
strut 1405 is
substantially parallel to an axis of the impeller 205 and protrudes radially
inward from at least a
portion of an inner surface of the impeller housing 203. When structured as
such, each strut 1405
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defines a vane within the impeller assembly 201 that channels fluid flow when
the impeller 205
operates to thereby prevent the recirculation or vortices.
As shown, the strut 1405 has a fluidic lumen 415 extending therethrough. The
fluidic
lumen 415 is non-concentric with at least a portion of the body of the strut
1405 due to material
of the strut 1405 forming the vane within the impeller assembly 201. With
reference to, e.g.,
FIG. 3, it can be seen that the device 101 may include a plurality, e.g., at
least three, of the struts.
Together, the struts define vanes within the impeller assembly that channels
fluid flow when the
impeller operates to thereby prevent the recirculation or vortices.
The impeller housing 201 includes one or more outlets 258 around a distal
portion of the
impeller 205. Operation of the impeller 205 within a blood vessel drives blood
into the impeller
assembly 201 via the inlets 255 and out of the impeller assembly 201 via the
outlets 258 such
that the blood exhibits smooth laminar flow without the recirculation or
vortices.
FIG. 15 shows how blood flows through the impeller assembly 201 via the inlets
255 and
out of the impeller assembly 201 via the outlets 258 such that the blood
exhibits smooth laminar
flow without the recirculation or vortices. The image depicts results of a
computerized flow
model. The flow model shows that flow through an impeller assembly with a
structure of the
invention is smooth and does not exhibit recirculation.
Because the model test results show smooth and efficient flow, a device of the
invention
pumps blood more efficiently than other devices that lack structures as shown
herein.
The computer model test results show that flow is smooth and that there are no
vortices
or recirculation within the flow.
Because devices of the invention are more efficient than other devices and
pump blood
without vortices or recirculation, devices of the invention are beneficial for
treating patients with
edema. Thus, using a device of the disclosure, a clinician may perform a
method for treating
edema. The method includes inserting into an innominate vein of a patient a
distal portion 115 of
a catheter. The catheter has an impeller assembly 201 on the distal portion
115. The method
includes driving an impeller 205 disposed within the impeller assembly 201 to
thereby decrease
pressure at a lymphatic duct. A proximal portion of the impeller assembly 201
is configured to
facilitate flow into an inlet of the impeller assembly without recirculation
as clearly shown in the
depicted computer flow model. The catheter may have any of the other features
disclosed herein
(e.g., a cap secured to the distal portion with one or more struts extending
from the cap to
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support a housing of the impeller assembly in which the housing has a diameter
greater than a
diameter of the cap, and in which a proximal base of the housing, the cap, and
the one or more
struts define the inlet).
As shown by the image of results from the computer flow model, the struts
define vanes
within the impeller assembly that channel fluid flow when the impeller
operates to thereby
prevent the recirculation or vortices. The flow lines appearing in the
computer flow model clear
avoid any loops that would appear if the flow had recirculation or vortices.
Because flow through
the impeller assembly 201 has no recirculation or vortices, the image from the
computer flow
model shows only flow lines that do not have loops, circles, spirals, etc.
The impeller housing includes one or more outlets around a distal portion of
the impeller.
When the impeller is operated within a blood vessel, the impeller drives blood
into the impeller
assembly via the inlets and out of the impeller assembly via the outlets such
that the blood
exhibits smooth laminar flow without the recirculation or vortices.
Devices and methods of the disclosure may include other features.
A device 101 of the disclosure may further include a medicament lumen 251
extending
through the catheter 105 and terminating substantially at an inlet 255 of the
impeller assembly
201. In some embodiments, the impeller assembly 201 also includes an
atraumatic tip 231 with a
threaded fitment 237 therein to allow for a smooth transition of material
properties between the
rigid impeller cage 203 (e.g., a metal) and the softer material of the
atraumatic tip 239. The tip
239 preferably includes a suitable soft material such as a polymer. The
material may include, for
example, polyether block amides such as those sold under the trademark PEBAX
by Arkema Inc.
(King of Prussia, PA). Although polyether block amides are mentioned in
detail, the polymer can
comprise any number of other polymers such as polytetrafluoroethylene (PTFE),
fluorinated
ethylene propylene (FEP), polyurethane, polypropylene (PP), polyvinylchloride
(PVC),
polyether-ester, polyester, polyamide, elastomeric polyamides, block
polyamide/ethers, silicones,
polyethylene, Marlex high-density polyethylene, linear low density
polyethylene,
polyetheretherketone (PEEK), polyimide (PI), or polyetherimide (PEI). The
threaded fitment 237
may include a threaded post (e.g., of metal or a plastic such as a
polycarbonate) threadingly fitted
to both the impeller housing 203 and the atraumatic tip 231. By including a
long post for the
fitment 237 (e.g., longer than its own maximal diameter, preferably at least
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longer), the tip 231 can deform but is prevented from assuming or exhibiting
any kinks or
discontinuities. Further, as shown, the tip 231 may include a guidewire lumen
239.
The expandable member 301 on the impeller assembly 201 is depicted in the
collapsed
configuration with dashed lines. The impeller assembly 201 operates as a pump
and includes the
impeller 205 disposed within the impeller housing 203. In preferred
embodiments, the
expandable member 301 comprises an inflatable balloon connected to an exterior
surface of the
impeller housing 203.
FIG. 3 shows the expandable member 301 in a deployed state. In the depicted
embodiment, the expandable member 301 is provided as a balloon. As shown, when
the balloon
is inflated, it defines a torus. An exterior surface of the expandable member
301 is physically
coupled to an exterior surface of the impeller housing 203 (e.g., the balloon
may be cemented to
the housing 203 with an adhesive).
Preferably, the exterior surface of the expandable member 301 is physically
coupled
directly to the exterior surface of the impeller housing 203 without any
membrane, sheath, or
device 101 between the exterior surface of the expandable member 301 and the
exterior surface
of the impeller housing 203. The expandable member 301 may partially or fully
surround the
impeller housing 203. The expandable member 301 may be provided as an
inflatable balloon that
surrounds the impeller housing 203.
Devices of the disclosure may include feature to facilitate bonding of the
balloon to the
impeller housing 203. For example, the impeller housing may include metal
(e.g., stainless steel,
steel, aluminum, titanium, a nickel-titanium alloy, etc.) and a portion of the
expandable member
301 may be fixed to a surface of the metal by an adhesive. To facilitate
bonding, at least a
portion of the surface of the metal may be impregnated with a polymer. In some
embodiments,
the metal surface at least at the exterior, proximal portion of the impeller
cage 203 is
impregnated with polyurethane to a depth of at least 3 p.m.
Using the expandable member 301 mounted to the impeller cage 203, the device
101 is
configured for placement in a body vessel. The impeller housing comprises an
axis that may be
placed substantially parallel to an axis of the vessel. Preferably, the
expandable member 301 is
impervious to flow across the expandable member. The expandable member 301 is
configured in
use to appose the wall of a blood vessel and in so doing direct fluid flow to
an inlet of the
impeller housing 203.
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In use, the expandable member 301 anchors or holds the impeller assembly 201
in a
fixed position relative to the axis of the vessel. In that anchored state, the
expandable member
301 conforms to the vessel wall at a region of apposition and the region of
apposition comprises
a substantially cylindrically segment of the vessel wall. The central axis of
the expandable
member and the central axis of the impeller housing are preferably
substantially the same.
The expandable member is configured, in use, to allow the axis of the impeller
housing to
articulate relative to the axis of the balloon. The articulation of the
impeller relative to the
balloon preferably comprises two degrees of freedom.
In some embodiments, the expandable member 301 comprises a balloon and the
membrane of the balloon comprises an omega shape in cross-section.
The impeller housing 203 may include a tubular member and a wall of the
tubular
member may include a hole extending through the wall of the tubular member to
at least partially
define an inflation port for the balloon. Preferably, the inflation port is
connected via the catheter
to an inflation system exterior of the patient. The connection may include a
shaped metal tube or
tubing that couples to, and forms a seal with (i.e., "sealingly coupled to")
the inflation port. In
certain embodiments, the coupling of the expandable member to the impeller
housing comprises
at least one circumferential seal around the outside diameter of the housing.
More preferably, the
coupling of the expandable member to the impeller housing comprises a first
circumferential seal
around the outside diameter of the housing and a second circumferential seal
around the outside
diameter, with the second circumferential seal spaced apart axially from the
first circumferential
seal. In some embodiments, the circumferential seal has an axial length and a
part of the seal
surrounds an inflation port that extends across the walls of the impeller
housing and the
expandable member. The impeller housing may include an inflation port
positioned between the
first circumferential seal and the second circumferential seal.
Referencing back to FIG. 2 and FIG. 3, preferably, the balloon has a collapsed
state (FIG.
2) for delivery and retrieval and an expanded state (FIG. 3). In some
embodiments, in the
collapsed state at least a portion of the balloon material can slide relative
to an axis of the
impeller housing (i.e., is axially slidable relative to the impeller housing).
For example, at least a
portion of the balloon material may be configured to slide proximally during
delivery and to
slide distally during retrieval. It may be provided that the balloon comprises
a toroidal shape with
a first neck and a second neck coupled to the impeller housing. Preferably, a
distance between
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the first neck and the second neck is smaller than the circumference of the
toroidal shaped
balloon.
A coupling between the expandable member 301 and the impeller housing 203 may
include an interfacial layer. For example, the interfacial layer may include
an interpenetrating
layer. In certain embodiments, the impeller housing comprises interstices and
the
interpenetrating layer comprises an interpenetration of material of the
membrane into the
interstices of the impeller housing. The interpenetrating layer may include a
tie layer, which may
include an acrylate material.
In some embodiments, the expandable member 301 is configured to apply a radial
outward force to the vessel wall. The device may be configured such that said
application of said
outward radial force substantially fixes at least a portion of the impeller
housing 203 to a central
axis of the vessel. The impeller housing comprises an inner lumen extending
from a proximal
section of the impeller housing to a distal section of, or outlets of, the
housing, the inner lumen
configured to house the impeller 205. The impeller housing comprises a first
diameter adjacent
the proximal section and a second diameter adjacent the distal section. In
certain embodiments, a
diameter of the inner lumen of the impeller housing varies between said
proximal section and
said distal section. Similarly, a radial dimension of the impeller blades 206
may vary between
said proximal section and said distal section. The diameter of the variation
of impeller housing
inner lumen diameter may define a tapered, a step, a plurality of steps, a
plurality of tapers, a dog
bone, a parabola or a combination of these. The impeller blades are configured
to be in fluidic
engagement with the inner lumen of the impeller housing. Preferably, the
impeller blades 206 are
configured to be in clearance with the inner lumen of the impeller housing.
The impeller
assembly 201 has at least one inlet opening and at least one outlet opening.
The at least one inlet
opening and the at least one outlet opening may be separated by a distance of
between 1-40
millimeters. Preferably, the at least one inlet opening and the at least one
outlet opening are
approximately 5 millimeters apart and may position a proximal end of the
impeller 205
approximately 0.5 millimeters from a distal edge of the inlet. This
configuration is preferable
because it helps minimize recirculation at a transition from inlet to impeller
205. In some
embodiments, discussed herein, for example, in FIG. 25, the distance between
the inlet and outlet
may be extended to the approx. 25 ¨ 30 millimeters. This configuration
provides a more laminar
flow into the impeller 205. In other embodiments, the at least one inlet
opening and the at least
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one outlet opening may be approximately 3 millimeters apart to bring the
impeller 205 nearer or
just inside the inlet. The at least one inlet opening comprises a proximal end
and a distal end. A
proximal part of the torus extends proximally of the distal end of the
proximal inlet opening to
define an entry funnel into the inlet opening. The distal portion 115 of the
catheter 101 is
configured for insertion into a vessel of a patient and the proximal portion
109 of the catheter is
configured to extend exterior of the patient.
The proximal portion 109 of the catheter 101 may terminate at the motor
housing 401.
FIG. 4 shows a motor housing 401 connected to the proximal portion 109 of the
catheter
105. A motor 405 is disposed within the motor housing 401. A drive cable 411
extends through
the catheter 105 from the motor 405 to the impeller. In preferred embodiments,
an inflation
lumen 415 extends along the catheter 105 to the expandable member 301. The
drive cable 411
preferably extends through a sleeve within the catheter 101, such as an
impermeable sleeve 121.
In purge-free embodiments, the impermeable sleeve 121 may include a seal at
one or both ends
to exclude fluids from the drive cable 411. The impermeable sleeve 121 meets
the motor housing
401 at the proximal seal 433.
In certain embodiments, the motor 405 includes a rotor operable to rotate at
high speed
and the catheter 101 includes a drive cable 411 to transmit said rotational
speed through the
catheter 101 to the impeller 205. The drive cable 411 may be able to transmit
a rotational speed
of greater than 5,000 rpms to the impeller 205 (e.g., >10,000 rpm, >15,000
rpm, or >20,000
rpm). Most preferably, the catheter is configured for heatless operation while
transmitting high
rotational speeds to the impeller.
The impermeable sleeve 121 may include a material such as
polytetrafluoroethylene
(PTFE). For example, the impermeable sleeve 121 may be provided by thick-
walled PTFE
tubing. The thick-walled PTFE tubing may have a wall thickness of greater than
75 micrometers,
preferably >100 microns, >125 microns, or greater than 150 microns.
Optionally, the drive shaft
has a second moment of area with a value. The drive cable 411 may include a
cylindrical super-
elastic member over at least a portion of the length of the drive shaft. The
clearance between the
drive shaft may be less than a certain number of micrometers. In some
embodiments, the
impermeable sleeve 121 comprises hydrophobic material. The impermeable sleeve
121 may
include a material with a Hildebrand solubility parameter (6) of less than 16
MPa^(0.5). The
impermeable sleeve 121 may include a material with a Hildebrand solubility
parameter of less
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than 14 MPa^(0.5). For example, 6 of nylon is about 15.7 Mpa^0.5; 6 of
polytetrafluoroethylene
(PTFE) is about 6.2 MPa^0.5. The impermeable sleeve 121 may include a PTFE
material, and
the drive cable 411 may include a nitinol rod and a gap between the rod and
the sleeve may be
less than a few microns. Preferably, a concentricity of the rod is greater
than 95%. The drive
cable may have a first diameter and a second diameter, with the first diameter
being slightly
larger than the second diameter. The impermeable sleeve may include a polymer
material with a
dynamic coefficient of friction of less than 0.08, or less than 0.07, 0.06, or
0.05.
Devices of the disclosure are useful for treating edema or congestive heart
failure. Using
a device of the disclosure, one may operate a pump to promote flow in an
innominate vein,
resulting in a decrease in pressure at an output of a lymphatic duct, which
drains lymph from the
lymphatic system. To compensate for what would otherwise be changes in
pressure in the
circulatory system that would result from operating the pump, the disclosure
provides methods to
compensate for a pressure change.
FIG. 5 shows steps of a method 501 of using the device 101 for treating edema.
The
method 501 includes inserting 510 the distal portion 115 of the catheter 105
into an innominate
vein 939 of a patient, operating 515 the impeller, and expanding 517 the
expandable member 301
to thereby decrease pressure at a lymphatic duct 907.
The method 501 may include the use of a device 101 that includes a catheter
105 with a
proximal portion 109 and a distal portion 115, the distal portion 115
dimensioned for insertion
into a lumen of a patient. The device 101 includes a pump (e.g., an impeller
assembly 201) and
an expandable member 301 connected to the pump. When expanded, the expandable
member
301 comprises a toroidal shape, in which a proximal surface of the toroidal
shape directs fluid
into the impeller housing 203. Preferably, an inner radius of the toroidal
shape is substantially
the same as a radius of the proximal end of the impeller housing 203. In some
embodiments, the
expandable member 301 comprises an inflatable balloon mounted on the pump. The
pump
comprises an impeller housing 203 with an impeller therein, with the balloon
mounted around at
least a portion of a proximal end of the impeller housing 203. The impeller
housing 203 may
include a distal portion and a proximal portion, with an external diameter of
the proximal portion
being smaller than an external diameter of the distal portion. The expandable
member 301, when
not expanded, is disposed around the proximal portion of the impeller housing
203. When the
balloon is inflated, a surface of the torus is attached to a surface of the
impeller housing 203.
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When the expandable member 301 is not expanded, the distal portion 115 of the
catheter 105
may be passed through a 12 Fr introducer sheath.
FIG. 6 is a detail view of the impeller assembly 201 with the expandable
member 301 in
a deployed state. The impeller 205 sits substantially within and/or just
downstream of the
deployed restrictor. An inflation lumen 415 extends through the distal portion
115 of the catheter
and terminates at port 601 into the expandable member 301. Visual inspection
of a surface of the
expandable member 301 on a proximal side and an inner surface of the impeller
housing 203
reveals that those surfaces form a smooth continuous surface that funnels
fluid, under an
impelling power of the impeller, through the impeller housing 203. This drives
blood through
blood vessels and modulates fluid pressure in the vicinity. When operated
substantially within an
innominate vein, pressure at an outlet of a lymphatic duct decreases, which
promotes the
drainage of lymph and relief from edema.
FIG. 7 diagrams a method 701 for treating edema. The method 701 includes
operating
710 a pump to increase flow through an innominate vein 939 of a patient
and¨subsequent to the
operating step¨deploying 717 a restrictor upstream of the pump to thereby
restrict flow from a
jugular vein to the innominate vein 939 in order to balance 729 pressure
downstream of the
pump. The method 701 may include operating the pump and then restricting the
flow once the
increased flow through the innominate vein 939 affects pressure in the jugular
vein.
The method 701 preferably includes sensing 715, with a pressure sensor 805, an
increase
in pressure in the jugular vein that results from the increased flow and
restricting the flow in
response to sensing the increased pressure in the jugular vein.
FIG. 8 shows the restrictor 801 and a pressure sensor 805. In fact, as shown
in FIG. 8, the
device 101 includes pressure sensors 805 along the catheter 105 at locations
both proximal and
distal to the restrictor 801. In the depicted embodiment, the pressure sensors
805 include pressure
sensing lumens extending along the catheter 105 and terminating at the skive-
cut sensing
apertures along the side of the catheter 105. The sensing lumens extend
proximally along the
catheter to the motor housing 401, where the sensing lumens preferably exit
the housing 401 and
make fluidic contact with a mechanical pressure sensor device such as a
piezoelectric pressure
sensor. The interior of the pressure sensing lumens preferably establish at
least substantial
hydrostatic equilibrium from the skive-cut sensing apertures along the side of
the catheter 105 to
the mechanical pressure sensor devices such that a reading from the sensing
device(s) is
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informative of pressure in an area around the restrictor 801. Thus the
pressure sensors 805
provide information that can feedback into the method 701 and be used as
information to control
deployment 717 of the restrictor 801. The method 701 preferably includes
inserting 705 the
device 101 comprising the pump into vasculature of a patient prior to the
operating 710 step.
FIG. 9 shows a device 101 inserted 705 into vasculature of a patient. The
device 101
comprises a catheter 105 dimensioned to be at partially implanted within the
vasculature and the
pump comprises an impeller assembly 201 disposed at a distal portion 115 of
the catheter 105.
The distal portion 115 is inserted through the jugular vein and down and into
the innominate vein
939. Preferably a proximal portion 109 of the catheter 105 is connected to a
motor housing 401
and the device 101 one or more pressure sensor 805 and the deployable
restrictor 801 attached to
the catheter 105 proximal to the pump.
Once the impeller assembly is at least partially within the innominate vein
939, the
impeller 205 is spun, which pumps blood through the impeller housing 203. This
causes a
decrease in pressure around an outlet of a lymphatic duct 907. The decrease in
pressure causes
lymph to drain from the lymphatic duct 907 and into the circulatory system.
That drainage of
lymph relieves edema or alleviates congestive heart failure. The method 701
further includes
deploying 717 a restrictor 801 upstream of the impeller assembly 201 to
thereby restrict flow
from a jugular vein to the innominate vein 939 in order to balance 729
pressure downstream of
the impeller assembly 201. The method 701 may further include sensing 715
pressure and
adjusting 735 restriction of the flow according to pressure sensed 715 via one
or more of the
pressure sensors 805.
In some embodiments, the restrictor 801 includes an inflatable balloon and
restricting 717
the flow includes inflating the restrictor. Optionally the sensing 715 is
performed using a
computer system communicatively connected to the pressure sensor(s) 805. The
method 701
may include periodically or continually adjusting 735 inflation of the
restrictor according to the
sensed pressure.
FIG. 10 diagrams a related method 1001 for treating edema. The method 1001
includes
inserting 1005 a pump into an innominate vein and operating 1010 the pump to
increase flow
through an innominate vein 939 of a patient. A pressure change in a jugular
vein of the patient
that results from the increased flow is sensed 1015, and a restrictor 801 is
adjusted 1029 to
restrict flow from the jugular vein to the innominate vein 939 based on the
sensed pressure.
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Preferably, the method 1001 includes inserting 1005 a catheter 105 into the
innominate vein 939.
The catheter 105 comprises the pump, a pressure sensor 805, and the restrictor
801. The
restrictor may include an inflatable balloon and adjusting 1029 the restrictor
may include at least
partially inflating and/or deflating the balloon. The sensing 1015 may be
performed using the
pressure sensor 805. The method 1001 preferably includes periodically or
continually adjusting
inflation of the restrictor according to the sensed pressure. The method 1001
may include
adjusting 1029 the inflation in order to balance pressure downstream of the
pump. In preferred
embodiments, the pump comprises an impeller assembly 201 disposed at a distal
portion 115 of
the catheter 105. A proximal portion 109 of the catheter 105 is connected to a
motor housing 401
having a motor 405 therein operably coupled to the impeller assembly. In
certain embodiments,
the catheter 105 is coupled to a computer system operable to read the pressure
or control the
inflation.
Aspects and embodiments of the disclosure relate to a purge-free system, which
may be
understood to refer to or include methods and devices for the treatment of
edema that do not use
a purge system or a purge liquid.
FIG. 11 is a detail view of features that provide for a purge-free system. The
purge-free
system may be provided by a device 101 that includes a catheter 105 comprising
a proximal
portion 109 and a distal portion 115, an impeller 205 connected to the distal
portion 115 of the
catheter 105, a motor 405 connected to the proximal portion 109 of the
catheter 105, a drive
cable 411 extending through the catheter 105 from the motor 405 to the
impeller 205, and an
impermeable sleeve 121 extending through the catheter 105 over the drive cable
411.
The sleeve 121 has a distal seal 435 at the impeller. With reference back to
FIG. 4, the
sleeve 121 may have a proximal seal 433 at the motor 405. Due to the sleeve
121 and at least the
distal seal 435, a body fluid external to the impermeable sleeve 121 is
prevented from entering
the impermeable sleeve 121 and contacting the drive cable 411. The sleeve 121
and at least the
distal seal 435 exclude fluid from the drive cable 411.
With reference back to FIG. 4, the proximal seal 433 (see FIG. 4) may include
one or
more 0-rings. Similarly, the distal seal 435 between the sleeve 121 and the
drive cable 411 may
be provided by an 0-ring, or a collar or press-fit, or extended, friction-fit
tube. Any suitable seal
may be included that prevents blood or bodily fluid from entering the sleeve
and making contact
with the drive cable 121. The drive cable 121 may be provided by any suitable
material
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including, for example, a nickel-titanium alloy or a braided steel cable.
Contact with blood
would present a risk of hemolysis or clotting that could interfere with an
ability of the drive cable
411 to rotate freely (e.g., at > 5,000 rpm) within the sleeve 121 and within
the catheter 105. The
sleeve excludes blood and thus obviates concerns about clotting or hemolysis,
allowing the drive
cable 411 and impeller 205 to operate freely without impediment.
Embodiments of the device 101 may include multiple lumens. For example, the
device
101 may include a first and second inflation lumen 415 (or a single inflation
lumen 415). The
device may include a medicament lumen 251 extending through the catheter 105.
In preferred
embodiments, the device 101 includes at least a first inflation lumen 415 and
a second inflation
lumen 415, both extending through the catheter 105. The first inflation lumen
415 and the second
inflation lumen 415 have respective first and second proximal ends 416 (see
FIG. 1) accessible
outside of the motor housing 401. The first lumen and the second lumen are
preferably
symmetrically disposed about the drive cable 411 to impart balance to the
device 101. As shown,
the catheter 105 does not include a purge system or a purge fluid.
With reference back to FIGS. 1 and 3, the device 101 may include an impeller
205 sitting
in an impeller housing 203. The device 101 includes at least a first
expandable member 301
connected to the distal portion 115 of the catheter 105. The first expandable
member 301 may be
connected to the impeller housing 203, wherein the device 101 further
comprises a second
expandable member 801 disposed along the catheter 105. The first expandable
member 301 may
use a toroidal balloon connected directly to a surface of the impeller housing
203. The device
101 may further include at least one pressure sensor 805 disposed along the
catheter 105
proximal to the impeller. In purge-free embodiments, the distal seal 435 may
be provided using a
fitting 1107 between the impermeable sleeve 121 and a portion of the impeller
205, in which the
fitting 1107 excludes fluids and allows the impeller 205 and drive cable 411
to rotate within the
device 101. The depicted device 101 is useful for the treatment of edema, and
may be
characterized as a purge-free device. The purge-free device may be used in a
method of treating
edema.
FIG. 12 diagrams a method 1201 of treating edema using a purge-free device.
The
method 1201 includes inserting 1205 into an innominate vein 939 of a patient a
distal portion
115 of a catheter 105 and driving 1210 an impeller 205 connected to the distal
portion 115 of the
catheter 105 by means of motor 405 at a proximal portion 109 of the catheter
105. The motor
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405 is connected to the impeller 205 by a drive cable 411 extending through
the catheter 105, to
thereby decrease pressure 1217 at a lymphatic duct 907. An impermeable sleeve
121 extends
through the catheter 105 over the drive cable 411 such that body fluid
external to the
impermeable sleeve is prevented from entering the impermeable sleeve and
contacting the drive
cable. The impermeable sleeve 121 and at least the distal seal 435 exclude
1215 fluid from
entering into the impermeable sleeve 121 and making contact with the drive
cable 411.
The method 1201 may include inflating 1229 a restrictor disposed along the
distal portion
115 of the catheter 105 to restrict flow from a jugular vein into the
innominate vein 939. The
inflation 1229 may be performed using an inflation lumen 415 extending through
the catheter
105 outside of the impermeable sleeve 121. In some embodiments, blood and
bodily fluid is
excluded 1215 from the drive cable 411 using a repulsive gap between the drive
cable 411 and
the impermeable sleeve 121. For example, the repulsive gap may include a
hydrophobic material
(PTFE) on one side of the gap, a smooth metallic shaft 411 on the other and a
gap dimension that
prevents influx of blood components. For example, a gap dimension of about 0.5
p.m should
prevent influx of red blood cells, leukocytes, and platelets. It may be found
that a gap dimension
of 0.1 p.m excludes 1215 all blood and bodily fluid. The drive cable 411 may
not lie concentric
with the sleeve 121 so preferably the gap dimension is the largest gap between
the two.
The decreased pressure at a lymphatic duct 907 promotes drainage from a
lymphatic
system into a circulatory system. Preferably, the impermeable sleeve 121
comprises a proximal
seal 433 at a housing of the motor 405 and a distal seal 435 at the impeller
205. The proximal
seal 433 prevents the blood and bodily fluid from escaping the patient through
the motor housing
401 or the proximal portion 109 of the catheter 105. In some embodiments, the
distal seal 435
comprises a fitting between the impermeable sleeve and a portion of the
impeller, wherein the
fitting excludes fluids and allows the impeller and drive cable to rotate
within the device 101.
The method 1201 may include inflating at least one balloon 301, 801 disposed
along the
catheter 105 by means of an inflation lumen 415 having a proximal end
accessible outside of the
motor housing 401 while the distal portion 115 of the catheter 105 is inserted
into the innominate
vein 939. In various embodiments, the proximal seal 433 uses an 0-ring; the
impermeable sleeve
121 comprises PTFE; the drive cable 411 comprises a metal such as a nickel-
titanium alloy;
either or both of balloon 301 and restrictor 801 may comprises polyvinyl
chloride, cross-linked
polyethylene, polyethylene terephthalate (PET), or nylon; or any combination
of the those
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materials are included. Employing the method 1201, blood and bodily fluid are
excluded 1215
from the drive cable 411 without the use of a purge fluid or purge system.
Other features and benefits are provided by or within the scope of the
disclosure.
Methods and devices of the disclosure avoid problems with thrombosis or
hemolysis that
may otherwise interfere with the functioning of mechanical systems or form
surface irregularities
that lead to other complications. For example, mechanical system may be most
beneficial
medically when blood clots or other coagulation-related phenomena are avoided.
Accordingly,
embodiments of devices and methods of the disclosure are provided that inhibit
coagulation,
thrombosis, hemolysis, or other issues that may present when treating edema.
Certain embodiments provide a device that operates with benefit from an
anticoagulant.
The device may include a pump (e.g., an impeller assembly) that is washed with
a solution or
suspension that comprises an anticoagulant such as, for example, heparin.
Where the pump or
impeller assembly is provided via a catheter, the catheter may include a
lumen, reservoir, port, or
other such feature to release the coagulant at or near the pump.
FIG. 13 illustrates a portion of an intravascular device 101 for treatment of
edema that
releases an anticoagulant at an intravascular pump. The device 101 includes a
catheter 105, an
impeller assembly 201 mounted at a distal portion 115 of the catheter 105, and
a medicament
lumen 251 extending through the catheter 105 and terminating substantially at
an inlet 255 of the
impeller assembly 201. When the device 101 is used (e.g., when the impeller
205 is operated
within a blood vessel of a patient), a medicament released from the medicament
lumen 251 flows
through the inlet 255 and impeller assembly 201. Preferably, the catheter 105
and impeller
assembly are dimensioned for insertion through a jugular vein of a patient The
device 101 may
include a reservoir in fluid communication with the medicament lumen 251. The
reservoir may
be, for example, a solution bag (aka an "IV bag") on a rack near the treatment
gurney and in
fluid communication with the medicament lumen 251 (e.g., via a Luer lock).
In certain embodiments of an anticoagulant delivery device 101, the impeller
assembly
201 has an impeller housing 203 with an impeller 205 rotatably disposed
therein. The device 101
preferably includes a motor 405 connected to a proximal end of the catheter
105 and operably
connected to the impeller 205 via a drive cable 411 extending through the
catheter 105. The
medicament lumen 241 preferably extends through the catheter 105 (e.g.,
outside of a sleeve 121
surrounding the drive cable 411) and may terminate at a port 252 such that an
anticoagulant
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released therefrom washes the impeller 205 or impeller assembly 201.
Preferably, the port 252 is
located at the impeller housing 203, proximal to the impeller.
To define the inlets 255, the catheter 105 may include a tube with a drive
cable extending
there through with a cap 249 connected around a terminal portion of the tube,
with the impeller
housing 203 mounted to the cap by a plurality of struts to define inlets 255
into the impeller
housing 203. In some embodiments, the cap 249 seals a terminus of the flexible
tube to a shaft of
the impeller, and the port 252 is located in the cap 249. Preferably, the
impeller housing 203
includes one or more outlets 258 around a distal portion 115 of the impeller,
such that operation
of the impeller 205 within a blood vessel drives blood into the impeller
assembly 201 via the
inlets 255 and out of the impeller assembly via the outlets 258.
The device 101 may include an anticoagulant in the reservoir. When the device
101 is
inserted into a blood vessel of a patient and the impeller 205 is operated,
the anticoagulant is
released from the port 252 in the impeller cage 201 and the released
anticoagulant mixes with
blood and washes over the rotating impeller 205. Any suitable anticoagulant
may be used. For
example, the anticoagulant may include one or any combination of heparin,
tirofiban, warfarin,
rivaroxaban, dabigatran, apixaban, edoxaban, enoxaparin, and fondaparinux. Due
to the
anticoagulant, the device 101 may be used for the treatment of edema, using
the impeller to
cause drainage of a lymphatic duct or vessel.
Using such a device, aspects of the invention provide a method for treating
edema. The
method includes operating a pump to increase flow through an innominate vein
939 of a patient
and releasing an anticoagulant at or adjacent an inlet of the pump. The pump
may include an
impeller 205 in a cage 203 at a distal portion 115 of a catheter 105 and the
anticoagulant is
released from a port 252 in or adjacent a proximal portion of the cage.
Preferably, a proximal end
of the catheter 105 terminates at a housing comprising a motor 405, and the
motor 405 is
operably coupled to the impeller by a drive cable extending through the
catheter 105. In this
method, the catheter 105 includes a medicament lumen extending therethrough
and terminating
at the port. This method may include providing the anticoagulant in a
reservoir in fluid
communication with the medicament lumen; inserting the catheter 105 into
vasculature of the
patient to position the impeller in the innominate vein 939; operating the
motor 405 to drive the
impeller; and washing the anticoagulant over the impeller by releasing the
anticoagulant from the
port. Preferably, this method includes operating the pump decreases pressure
at a lymphatic duct
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907, thereby draining lymph from a lymphatic system of the patient. The pump
may include an
impeller on a distal portion 115 of a catheter 105. This method may include
releasing the
anticoagulant from a port at a proximal portion 109 of the impeller,
preventing clotting or
thrombosis from interfering with operation of the impeller by the release of
the anticoagulant, or
both. The anticoagulant may include heparin, warfarin, rivaroxaban,
dabigatran, apixaban,
edoxaban, enoxaparin, or fondaparinux. Using a restrictor 801, 301, the method
may include
restricting flow from a jugular vein to the innominate vein 939 to thereby
promote flow from a
subclavian vein to the innominate vein 939.
FIG. 16 is a partial cutaway view of an impeller assembly 1601. The impeller
assembly
1601 includes an impeller housing 1603 with an impeller 1605 rotatably
disposed therein. An
expandable member 1607 is attached to an outside of the impeller housing 1603.
The expandable
member 1607 is depicted in an expanded state.
The impeller assembly 1601 is may be designed to facilitate a blood flow
through the
impeller housing 1603. To facilitate blood flow, the impeller housing 1603 may
include proximal
inlets 1655. Preferably, the impeller housing 1603 includes at least four
proximal inlets 1655.
The proximal inlets 1655 may be substantially rectangular and may include
rounded corners. The
impeller assembly 1601 may also include distal outlets 1658. For example, the
impeller assembly
1601 may include four to five distal outlets 1658. Preferably, the proximal
inlets 1655 and distal
outlets 1658 include substantially rounded features, such as, rounded corners.
Rounded features
are preferable because rounded features provide smooth contact surfaces for
blood that flows
through the impeller housing 1603. This may reduce incidences of damage to
particles in blood,
e.g., blood cells, that occurs when blood strikes a sharp surface.
In preferred embodiments, an expandable member 1607 is attached to an outer
surface of
the impeller housing 1603. The expandable member 1607 may comprise a shape
that facilitates a
flow of blood into the impeller housing 1603 when the expandable member 1607
is in an
expanded state. In some embodiments, the expandable member 1607 forms a D
shaped ring
around a circumference of the impeller housing 1603. In other embodiments, the
expandable
member 1607 forms an Omega shaped ring around a circumference of the impeller
housing
1603. In other embodiments, the expandable member 1603 forms a substantially
circular ring
around the impeller housing 1603.
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In an expanded state, a proximal face 1613 of the expandable member 1607 may
be
substantially aligned with a distal portion 1615 of the proximal inlets 1655.
A distal face 1617 of
the expandable member 1607 may be substantially aligned with the proximal
extent 1619 of the
distal outlets 1658.
In preferred embodiments, the expandable member 1607 comprises an elastomeric
membrane, for example, a polyurethane membrane. The expandable member 1607 may
be a
balloon. The balloon may comprise a low durometer material, for example, a
durometer of <80
shore D hardness, or <70 shore D hardness, or less than 60 shore D hardness,
or between 60
shore A hardness and 60 shore D hardness.
The expandable member 1607 may include a fluidically sealed space, i.e., an
inflation
space 1623, that is radially expandable relative to the impeller housing 1603.
The impeller
assembly 1601 may include an inflation tube 1627 connecting the inflation
space 1623 to a
lumen of the catheter 1602. The inflation tube 1627 may extend between the
catheter 1602 and
the inflation space 1623, for example, parallel to a proximal strut 1633. The
inflation tube 1627
may extend exterior of the proximal strut 1633 (as shown). Alternatively, the
inflation tube 1627
may extend interior to the proximal strut 1633. The inflation tube 1627 may
connect with the
inflation space 1623 by extending through a wall of the expandable member
1607. Alternatively,
the inflation tube 1627 may connect with the inflation space 1623 by extending
through an
interface between the expandable member 1607 and the impeller housing 1603, or
by extending
through a wall of impeller housing 1603. The fluidically sealed space 1623 may
comprise an
inflation port for expanding the expandable member 1607.
The inflation tube 1627 may comprise an outer surface and a lumen. The
inflation tube
1627 preferably provides a sealingly penetrate into the inflation space 1623.
The penetration of
the inflation tube 1627 into the inflation space 1623 may comprise a seal of
the region of
penetration. The seal may comprise a melting or bonding operation.
FIG. 17 is a side view of an impeller assembly 1701. An expandable member
1707, e.g.,
a balloon, is attached to an outer surface of an impeller housing 1703. The
expandable member
1707 may be substantially torpid in shape. The expandable member 1707 is
depicted with muted
lines to reveal structures beneath the expandable member 1707. A proximal face
1713 of the
expandable member 1707 extends over a distal inlet region 1715. In this
configuration, the
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proximal face 1713 of the expandable member 1707 provides a funnel to converge
blood flow
towards inlets of the impeller housing 1703 thereby facilitating blood flow
through the device.
The impeller assembly 1701 is dimensioned for inserting into an innominate
vein. The
expandable member 1707 is dimensioned such that in a deployed state, the
expandable member
1707 opposes walls of the innominate vein to impede, guide, or direct a flow
of blood into the
impeller housing 1703. In some embodiments, an inner diameter of the
expandable member 1707
is substantially equivalent to the outer diameter of the impeller housing
1703. The inner diameter
of the expandable member 1707 may extend over a portion of the proximal
inlets. This
arrangement helps funnel blood into the impeller assembly 1701 without the
distal edge of the
inlets disrupting blood flow. In some embodiments, the proximal inlets are
substantially D
shaped with rounded features to prevent shearing of blood cells.
The expandable member 1707 may comprises a bonded region, the bonded region
comprising a substantially cylindrical section where the expandable member
1707 is bonded to
the impeller assembly 1701. In some embodiments, the inlet region may comprise
a conical
element 1737 coaxial with the impeller. The conical element 1737 may be
proximal to the
impeller and may be configured to minimize flow recirculation regions.
FIG. 18 shows an exemplary inlet region 1855 of an impeller assembly 1801. The
inlet
region 1855 comprises a conical element 1837 with flow directing features
projecting radially
outward from a surface of the conical element 1837. The flow directing
features may be aligned
with proximal struts. A drive element 1839 may extend through the conical
element 1837 and
connect with an impeller disposed inside the impeller assembly 1601. In the
shown embodiment,
an inflation lumen 1827 is exterior of the impeller assembly 1801.
FIG. 19 shows an inlet region 1955 with an internal inflation lumen. The
inflation lumen
is internal to the impeller housing 1903. The inflation lumen may connect to
and extend through
the conical element 1937. The inflation lumen may, for example, extend through
a wall of the
impeller housing 1903. Alternatively, the inflation lumen may be interiorly
located within the
impeller housing 1903.
FIG. 20 is a detailed view of a proximal inlet 2055. The proximal inlet 2055
is defined by
proximal struts 2033. The proximal struts 2033 extend parallel to one another
connecting a
proximal portion 2041 of the impeller housing 2003 to a distal portion 2043 of
the impeller
housing 2003. The proximal struts 2033 are designed such that when the
catheter is operating
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inside a patient's body, the proximal struts 2033 may separate and direct a
flow of blood into the
impeller housing 2003 without inducing a recirculation flow pattern. The
proximal struts 2033
may include a proximal and distal rim 2045, 2047. The proximal struts 2033 and
rims 2045,
2047 may, for example, define a generally rectangular inlet region 2055. In
some embodiments,
the generally rectangular inlet region 2055 comprises a curved rectangular
inlet. The curved
rectangular inlet may have, for example, a bevel around at least a portion of
a rim 2045, 2047 of
the inlet 2055. The bevel may provide a gentle transition region for blood to
flow into the
impeller housing 2003.
In some embodiments, the proximal struts 2033 comprise a substantially
constant width
along a length of the proximal strut 2033. In other embodiments, the width of
the proximal struts
2033 may vary, for example, the width of the proximal struts 2033 may be
greater at a proximal
end than at a distal end, or vice versa. The proximal struts 2033 may comprise
a first wall
thickness and a second wall thickness, wherein said first wall thickness is
greater than said
second wall thickness. In some embodiments, the proximal struts 2033 may
comprise a tapered
wall thickness.
Preferably, the impeller housing 2003 is substantially cylindrical in shape
for easy
passage through an innominate vein. The impeller housing 2003 may comprise a
plurality of
inner diameters for manipulating a flow of blood through the impeller housing
2003 and such
that the flow of blood experiences minimal disturbances such as recirculation
or vortices within,
or near, the impeller assembly 2001. For example, the impeller housing 2003
may comprise a
first inner diameter D1 and at least a second inner diameter D2 wherein the
first inner diameter is
greater than said at least second diameter. In some embodiments, the impeller
housing 2003 may
comprise stepped portions defined by changes in inner diameters. In some
embodiments, the
impeller housing 2003 may comprise, for example, a tapered diameter, defined
by a diminished
or reduced internal diameter along the length of the impeller housing 2003
toward one end.
FIG. 21 shows a side view of an impeller assembly 2101 with rectangular
proximal inlets
2155. This configuration may reduce recirculation of blood at a proximal area
of the impeller
assembly 2101 by providing a larger inlet area at the distal-most region of
the inlet 2147.
FIG. 22 shows an impeller assembly 2201 with arcuate proximal struts 2233. The
arcuate
proximal struts 2233 extend longitudinally and radially. In some embodiments,
the arcuate
proximal struts 2233 comprise tubular members. The tubular members may be
welded to the
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impeller assembly 2201, connecting a proximal portion 2241 of the impeller
housing 2203 to a
distal portion 2243 of the impeller housing 2203. The arcuate proximal struts
2233 may connect
to a proximal portion 2241 of the impeller housing 2203 integral with the
catheter shaft. The
arcuate proximal struts 2233 may comprise a monolithic structure. The
monolithic structure may
comprise a 3D printed structure.
The impeller assembly 2201 may be distally mounted to a catheter shaft (not
shown)
comprising a plurality of lumens and at least one of the lumens sealingly
connected to an
expandable member 2207 attached to an outer surface of the impeller housing
2203.
FIG. 23 shows a side view of a proximal portion of an impeller assembly 2301.
The
proximal portion of the impeller assembly 2301 includes a proximal hub 2383, a
proximal inlet
2355, and a body section 2385. The proximal hub 2383 may be configured to
facilitate a smooth
flow pattern as fluids, e.g., blood, are directed into the proximal inlet
2355. The hub 2383 may
comprise a substantially circular outer geometry in axial cross section for
easy movement within
a vein. The hub 2383 may comprise a tapered geometry. For example, a cross-
sectional diameter
of the hub 2383 may decrease along a length of the hub 2383 from a first end
to a second end.
The hub 2383 may have a tapered outer geometry that may comprise a proximal
diameter, an
intermediate diameter, and a distal diameter wherein the intermediate diameter
is greater than
either the proximal diameter or the distal diameter and the transition between
proximal,
intermediate, and distal diameters is substantially smooth. The curve between
the proximal,
intermediate, and distal diameters may be without an inflection point.
FIG. 24 shows an impeller assembly 2401. The impeller assembly 2401 includes
an
impeller housing 2403 with an impeller 2405 rotatably disposed therein. An
expandable member
2407 depicted with ghosted lines is attached to an outer surface of the
impeller housing 2403, the
expandable member 2407 is shown in an expanded state.
The impeller assembly 2401 is designed to facilitate the flow of blood through
the
impeller housing 2403. The impeller assembly 2401 may include fillets 2435
under the proximal
end of the proximal struts 2433 to provide mechanical support and prevent
recirculation of blood
in these regions when the catheter is inside a vein. In some embodiments, the
proximal struts
2433 taper towards their distal ends.
FIG. 25 shows an elongated impeller assembly 2501. The elongated impeller
assembly
2501 includes an expandable member 2507 spaced apart from a proximal inlet
region 2555. The
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expandable member 2507 may be, for example, approximately 1-25 cm from the
proximal inlet
region 2555. Preferably, the expandable member is at least 1 cm from the
proximal inlet region
2555.
FIG. 26 shows a cross-sectional view of an impeller assembly 2601. The
impeller
assembly 2601 includes an impeller housing 2603 with an impeller 2605
rotatably disposed
therein. The impeller assembly 2601 includes a distal portion 2645. The distal
portion 2645 may
include a tip 2647 that is substantially disc shaped. The distal portion 2645
may have at least a
partially flat surface. The disc-shaped tip 2647 may be spaced apart from a
proximal surface of
the distal portion 2645.
The impeller 2605 may comprises a substantially fixed axial position relative
to the
impeller housing 2603. The distal portion 2645 may comprise a substantially
fixed axial position
relative to the impeller housing 2603. The fixed axial positions of the
impeller 2605 and the
distal portion 2645 may define a distal gap 2651 between the distal portion
2645 and the impeller
2605. The gap 2651 is preferably greater than Sum. The gap 2651 may be greater
than 10um or
20um. The gap 2651 may be preferably less than 150um, 120um, or 100um.
Ideally, the gap
2651 is between 25um and 50um.
FIG. 27 is a cross-sectional view of an impeller assembly 2601 inside a vein
2756. The
impeller assembly 2701 comprises an impeller housing 2703 with an impeller
2705 inside. The
impeller housing 2703 has an expandable member 2707 attached to an outer
surface of the
impeller housing 2703.
The impeller 2705 includes at least one blade 2753. The blade 2753 comprises a
proximal
end and a distal end. A core diameter of the impeller 2705 comprises a
proximal end and a distal
end. The core diameter proximal end is proximal of the proximal end of the
blade 2753. The
core diameter distal end and the blade distal end terminate substantially at
the same axial region.
The core diameter is smallest at the proximal end of the impeller 2705 and
largest near the distal
end of the core diameter. The core diameter may comprise a curved tapered
surface.
The proximal end of the impeller 2705 core diameter may be spaced apart from
the distal
end of a cuff 2761. The proximal end of the impeller 2705 core diameter and
the distal end of the
cuff 2761 comprise a controlled proximal gap. The gap 2751 is preferably
greater than Sum. The
gap 2751 may be greater than 10um or 20um. The gap 2751 may be preferably less
than 150um,
120um, or 100um. Ideally, the gap 2751 is between 25um and 50um.
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The impeller 2705 may comprise an inner diameter, the inner diameter extending
through
at least a portion of the length of the impeller 2705 and being coaxial with
the impeller 2705.
The impeller 2705 may comprise a bearing arrangement distal of the distal
surface. The bearing
surface may include a ball bearing arrangement, for example, a ceramic bearing
arrangement or a
PTFE or PEEK bearing surface arrangement.
FIGS. 28A-F illustrates attachment and folding of an expandable member 2807.
In
particular, these drawings detail attachment of the expandable member 2807 to
an outer surface
of an impeller housing 2803 as wells as folding of the expandable member 2807
when the
expandable member is inflated or when the catheter is being delivered or
retrieved.
FIG. 28A is a partial cross-sectional view of an impeller assembly 2801. A
portion of the
cross-section demarcated by dashed lines and labeled B shows a portion of the
expandable
member 2807 and is enlarged in FIG. 28B. The expandable member 2807 includes
at least one
coupling 2863 attaching the expandable member 2807 with the impeller housing
2803. The
coupling 2863 may create a sealed annular space in the expandable member 2807.
The coupling 2863 may comprise a laser weld joint, a solvent weld joint, an
adhesive
weld joint, a hot air or heated surface weld joint, or any other similar type
of attachment. The
coupling 2863 may comprise a prepared outer surface of the impeller housing
2803 onto which
the expandable member 2807 is attached. For example, the impeller housing 2803
may be
prepared such that the impeller housing 2803 includes at least one of a primed
surface, a
chemically activated surface, a plasma activated surface, a mechanically
abraded surface, a laser
ablated surface, an etched surface, or a textured surface. The prepared outer
surface of the
impeller housing 2803 may comprise a surface roughness, a patterned surface,
or a high energy
surface.
Referring to FIG. 28B, the expandable member 2807 may include at least one
neck 2867,
the neck 2867 may be dimensioned for joining with the impeller housing 2803.
The expandable
member 2807 may comprises a joint distal end 2831 and a joint proximal end
2832. The shape of
the distal end 2831 may be configured to change as the expandable member is
inflated/deflated
(compare FIGS. 28B, 28D, and 28E) or when the catheter is moved inside a vein.
In particular,
the joint distal end 2831 may comprise a distal neck segment joined to the
impeller housing 2803
and a distal transition segment 2845 that is integral with the neck 2867 but
not attached to the
impeller housing 2803. As the expandable member 2807 is inflated, the distal
transition segment
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2867 may fold inward. The joint proximal end may comprise a neck 2832 joined
to the impeller
housing 2803 and a proximal transition segment that is integral with the neck
but not joined to
the impeller housing. The expandable member 2807 may be configured to be
substantially rigid
in the expanded configuration. The expandable member 2807 may be configured to
be
conformable in the expanded configuration. The expandable member 2807 may be
made from a
polyurethane, or pebax or nylon material. The expandable member 2807 may be
made from
polytetrafluoroethylene.
FIG. 28C is a partial cross-sectional view of the impeller assembly 2801 in
which the
expandable member 2807 is partially inflated. The portion of the partial cross-
section showing
the expandable member 2807 (labeled D) is enlarged in FIG. 28D. Notably, the
shape of the
distal neck changes as the expandable member 2807 is inflated (compare FIG.
28D in which the
expandable member is partially inflated to FIG. 28B in which the expandable
member is fully
inflated).
FIG. 28E is a partial cross-sectional view of the impeller assembly 2801 with
moderately
inflated expandable member 2807. The portion of the partial cross-section
showing the
expandable member 2807 (labeled F) is enlarged in FIG. 28F.In particular, the
expandable
member 2807 is inflated more than the expandable member 2807 illustrated in
FIG. 28D. Upon
inflating the expandable member 2807, the distal transition segment 2845 may
fold outward
eliminating a potential recirculation zone at the interface between the
balloon and housing 2803.
FIG. 29 shows an impeller assembly 2901 with an expandable member 2907 having
an
elongated surface 2974 for interfacing with a wall of a blood vessel. The
elongated surface 2974
increases an interaction between the blood vessel and the impeller assembly
2901 to restrict
movement of the impeller assembly inside the blood vessel. The expandable
member 2907 may
comprise a compliant material. The compliant material may be a polyurethane or
silicone. The
compliant material may stretch 100% to 800%, thus creating an elongated
surface 2974. In other
embodiments, the expandable member 2907 may comprise a non-compliant material,
which may
expand to one specific size or size range, even as internal pressure
increases.
FIG. 30 shows an impeller assembly 3001 with a two-part expandable member
3007. The
two-part expandable member 3007 includes a first part 3065 comprising a
compliant material
and a second part 3066 comprising a non-compliant material. The first part
3065 and second part
3066 may be attached to each other and to the impeller housing 3003 to define
an annular space
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for inflation. Preferably, the first part 3065 of the expandable member 3007
comprises a portion
of the expandable member 3007 that interacts with a wall of a blood vein
during operating of the
catheter.
FIG. 31 is a partial cross-sectional view of a distal portion of a catheter
3101. The distal
portion of the catheter 3101 is attached to an impeller housing 3103 with an
expandable member
3107 mounted to an outer surface of the impeller housing 3103. The impeller
housing 3103 is
connected to a distal portion of a catheter 3101 by a plurality of proximal
struts 3133. The
proximal struts 3133 preferably comprise a flexible material, for example,
latex, silicone, or
Teflon, to provide for easier navigation inside a vein of a patient. The
proximal struts 3133 may
be configured to conform to anatomical curvatures. A drive shaft 3139
connecting a motor to an
impeller disposed inside the impeller housing 3103 may comprise a flexible
drive cable.
FIG. 32 is a partial cross-section of a self-expanding impeller assembly 3201.
The
impeller assembly 3201 comprises an impeller housing 3203 with an impeller
3205 disposed
therein. An expandable body 3207 is attached to a surface of the impeller
housing 3203 between
proximal inlets 3255 and distal outlets 3258.
In an expanded configuration, the expandable body 3207 is configured to oppose
a wall
of a vein over a longitudinal segment of the vein. The longitudinal segment of
apposition extends
proximal of the proximal inlets 3255. The longitudinal segment of apposition
extends distal of
the distal inlets 3258. The expandable body 3207 is configured to provide a
proximal flow
directing funnel that extends from a region of apposition with the vessel wall
to the distal end of
the inlets 3255. The proximal flow directing funnel is configured to promote
converging flow
pattern at the entrance to the proximal inlets 3255. The expandable body 3207
may be configured
to provide a distal flow directing funnel that extends from a proximal region
of the outlets 3258
to a region of apposition with the vessel wall to the distal end of the
outlets 3258. The distal flow
directing funnel may be configured to promote diverging flow pattern distal of
the exit of the
outlets 3258. The diverging flow pattern may be configured so as to impart a
gradual
deceleration of fluid distal of the outlets and maintain a larger proportion
of the pressure gain
developed by the impeller 3205 by reducing recirculating or negative velocity
flow patterns.
The expandable body 3207 may comprise a nitinol membrane, a non-compliant
membrane, or a porous membrane. The longitudinal segment of the expandable
body 3207 may
comprise a compliant material. Preferably, the flow directing funnels of the
expandable body
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3207 comprise a relatively less compliant material (or a semi compliant
material or a non-
compliant material).
The catheter 3200 may comprise a plurality of pull wires 3279 attached to the
expandable
body 3207 and configured to facilitate collapse of the expandable body 3207 in
preparation for
the removal of the catheter 3200 from the body.
FIG. 33 shows a partial cross-section of an impeller assembly 3301. The
impeller
assembly 3301 comprises proximal struts 3333 attaching a proximal portion 3341
of the impeller
assembly 3301 to a distal portion 3343 of the impeller assembly 3301. At least
one proximal
strut 3333 comprises an inflation lumen, i.e., an integrated inflation
channel, extending through
the proximal strut 3333 to an interior of an expandable member 3307 that is
attached to an outer
surface of the impeller assembly 3301. The inflation lumen provides a
structure for inflating the
expandable member 3307. The inflation lumen is preferably terminated within
the inlet to
minimize disruption to the flow inside the housing. This is facilitated by the
more proximally
positioned expandable member 3307.
FIG. 34 shows an inlet 3433 of an impeller assembly 3401. The inlet 3433 is
configured
to provide easier fluid flow into the assembly 3401. This configuration
includes a proximal hub
3480 with at least one flow basin 3481. The flow basin 3481 extends from a
proximal region of
the proximal hub 3480 and terminates at the inlet 3433. The flow basin 3481
extends between a
first and second strut 3433, 3434. The flow basin 3481 may be configured to
modulate a flow of
blood upstream of the inlets. For example, the flow basin 3481 may
progressively slope inwards
along the length of the flow basin 3481 towards the inlet 3433.
FIG. 35 is an exemplary catheter system 3500. In particular, FIG. 35
illustrates a catheter
3500 according to aspects of the invention to show interactions between an
impeller assembly
3501 of the catheter 3500 and a blood vessel wall 3556. The catheter 3500
includes the impeller
assembly 3501, a catheter shaft 3581, a proximal expandable member 3508, a hub
3583 and a
motor (not shown).
The impeller assembly 3501 is dimensioned for placement inside a blood vessel
with a
shaft 3581 extending from the impeller assembly 3501 to a position exterior of
the patient. The
shaft 3581 may comprise a multilumen shaft. A first proximal expandable member
3508 is
attached to the shaft 3581 and may be configured to restrict a flow of blood
to the impeller
assembly 3501.
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A motor may be connected to an impeller housed within the impeller assembly
3501 and
may be configured to drive the impeller at high RPMs. The impeller assembly
3501 may
comprise a distal expandable member 3507 mounted onto an outer surface of an
impeller
housing 3503 and wrapping around the impeller housing 3503, for example, like
an expandable
ring. The distal expandable member 3503 may be configured to appose a vessel
wall 3556 during
operation of the catheter.
The proximal expandable member 3508 may be mounted on the catheter shaft 3581
proximal of the impeller assembly 3501. The proximal expandable member 3508
may be spaced
apart from the impeller assembly 3501. For example, the proximal expandable
member 3508
may be a distance of 1-10 cm upstream of the impeller assembly 3501,
preferably about no more
than about 5 cm.
The proximal expandable member 3508 may be dimensioned for placement
(inflation)
between the vessel access site and an outflow port of a thoracic duct 3585.
The expandable
members 3507, 3508 are preferably configured to atraumatically contact a
vessel wall.
In some embodiments, a proximal expandable member 3508 may be configured to
reduce
a volume of blood flowing in the vessel by impeding a flow of flood. The
proximal expandable
member 3508 may be configured to adjust the volume of blood flowing in the
vessel by
impeding, restricting, guiding, or directing the flow of blood. For example,
the proximal
expandable member 3508 may include an orifice for fluid to flow across the
expandable member
3508 while the expandable member 3508 is in an expanded state. For example,
the orifice may
substantially comprise one of an annular ring or a crescent shape with a lumen
through a body of
the expandable member 3508. The orifice may comprise a valley or a recess in
the outer surface
of the expandable member 3508. The orifice may comprise a channel underneath
the expandable
member 3508. The expandable member 3508 may comprise a shape that defines the
orifice. For
example, the expandable member 3508 may be shaped at least partially as a
spherical, conical, or
cylindrical shape and the orifice comprises an annular ring or a crescent. The
expandable
member 3508 shape may comprise, for example, a double D shape and the orifice
may be
defined by surfaces between the two joining shapes. The expandable member 3508
may
comprise a helical shape wrapped around the catheter shaft 3581 and the
orifice may comprise a
channel defined by a space between adjacent spirals.
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The proximal expandable member 3581 may comprises a compliant material and the
compliant material may comprise a compliance-pressure relationship. The
expandable member
3581 may be processed so the compliance pressure relationship is repeatable.
The expandable
member 3581 may comprise an annealed member. The expandable member 3581 may be
configured to achieve a precise diameter at a given pressure. The expandable
member 3581 may
be configured to have minimal hysteresis when inflated, deflated and inflated
again.
The hub 3583 may be configured to facilitate inflation of a distal expandable
member
3507, and may be configured to at least partially inflate the proximal
expandable member 3508.
For example, the hub 3583 may include access to one or more lumens that extend
through the
catheter shaft 3581 and connect to a proximal and/or distal expandable member
3508, 3507. The
expandable members can be inflated by infusing a fluid into the lumens at the
hub 3583. The hub
3583 may be configured to inflate the proximal expandable member 3508 into
apposition with an
innominate vessel.
The device may comprise a connector cable 3585 configured to connect the
catheter to a
console (not shown), the console may comprise a computer with hardware,
software and a user
interface. The console can be configured to operate the device.
FIG. 36 shows a catheter 3600 with an expandable member 3608 slidably mounted
along
a shaft 3681 of the catheter 3600. The catheter 3600 comprises a first
catheter shaft 3681 and a
second catheter shaft 3682. The catheter 3600 includes an impeller assembly
3601 attached to a
distal end of the first catheter shaft 3681. The proximal expandable member
3608 mounted near
a distal end of said second catheter shaft 3682.
The first catheter shaft 3681 may comprise a multilumen tubing wherein a first
lumen is
configured to facilitate inflation of a distal expandable member 3607 and a
second lumen is
configured to transmit mechanical or electrical energy to facilitate the
operation and control of an
impeller disposed within the impeller assembly 3601.
The second catheter shaft 3682 may comprise a multilumen tubing wherein a
first lumen
is configured to encapsulate the first catheter shaft 3681 and a second lumen
is configured to
inflate the proximal expandable member 3608. The first and second catheter
shafts 3681, 3682
may be configured to facilitate relative axial movement (indicated by arrows)
between the distal
expandable member 3607 and the proximal expandable member 3608. The relative
axial
movement may be limited distally. The relative axial movement may be is
limited proximally.
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The catheter 3600 may include a first stop and a second stop and axial
movement of second shaft
3682 may be limited by the first and second stops. The first and second stops
may be mounted on
the first shaft 3681, exterior of the patient (inside or around the hub). The
axial movement may
comprise fine movements. The fine movements may comprise, for example, a
thread or ratchet
mechanism.
Relative axial movement between the distal expandable member 3607 and the
proximal
expandable member 3608 may provide better anatomical placement, i.e., accurate
placement of
the distal expandable member 3607 in the innominate vein and then accurate
placement of the
proximal expandable member 3608 between the vessel wall access site and the
thoracic duct.
The first and second shafts 3681, 3682 may extend exterior of the patient. The
second
shaft 3682 may be coupled and decoupled to the first shaft during use. In a
collapsed state, the
catheter may be dimensioned for advancement through a valve and lumen of a
sheath. The
second shaft 3682 may comprise a distal segment and a proximal segment. The
distal segment
may comprise a tubular member and an inflation lumen with the proximal
expandable member
sealingly welded (bonded) to a distal segment so as to create an inflation
space in the expandable
member 3607 that is in fluid communication with the inflation lumen.
The proximal segment of the second shaft may comprise an inflation lumen and a
member configured to transmit axial push and pull forces to the distal segment
of the second
shaft 3682. The proximal segment of the second shaft may be concentric or
eccentric with the
first shaft. The inflation lumen of the proximal segment may be integral with
a wall of the
proximal segment of the second shaft.
FIG. 37 shows a fluid channel across an expandable member 3708 that allows a
controlled amount of blood flow. The proximal expandable member 3708 may be
configured to
oppose a wall of a vessel. The proximal expandable member 3708 may comprise a
flow channel
3706, the flow channel 3706 defining a lumen through the body of the
expandable member 3708.
Flow is indicated by black arrows. The flow channel 3706 may comprise a
collapsed state and an
expanded configuration. The flow channel 3706 may be configured to expand when
the
expandable member 3708 is inflated. The expandable member 3708 may comprise at
least one
inner membrane, the inner membrane may be configured to support the body flow
channel 3706
in the expanded state. The proximal expandable member 3708 may be configured
to allow 100m1
or more fluid to cross the expandable member 3708 per minute.
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FIG. 38 shows a catheter 3800 with an alternative bypass channel 3806. A
second shaft
3882 comprises a tubular member with a distal end and a proximal end and a
lumen 3883
extending through both distal and proximal ends. The lumen 3883 may be sized
to provide a
fluid flow pathway underneath the inflated expandable member 3808 in a distal
segment. The
second shaft 3882 may comprise an entry port 3885 at the proximal end of the
distal segment of
the second shaft 3882, the entry port may be configured to facilitate blood
flow into said fluid
flow pathway.
FIG. 39 shows a patient interface 3900 with a sheath 3904 in situation. A
proximal
expandable member, a flow entry port, and pressure sensor, may be on the
sheath. The catheter
system may comprise a catheter and a flow control sheath 3904, the catheter
comprising an
impeller assembly at a distal end of an elongated shaft, the flow control
sheath 3904 comprising
a flow restrictor, a fluid channel and a pressure sensor.
The system may be configured for transdermal insertion into a vein of a
patient 3908.
Insertion of the catheter comprises transdermal insertion in a region of the
neck. The flow control
sheath 3904 may be configured for placement so as to provide an access
platform for other
components of the system. The flow control sheath 3904 may comprise a flow
restrictor adjacent
a tip. The flow restrictor may comprise an expanded state and a collapsed
state. In the collapsed
state the flow restrictor may be configured to collapse completely onto the
shaft of the sheath. In
the collapsed state, the OD of the flow restrictor may be substantially the
same as the shaft of the
sheath. The restrictor may sit in an annular recess in a diameter of the shaft
of the flow control
sheath in the collapsed configuration. In the expanded configuration, the flow
restrictor may be
configured to at least partially restrict fluid flow through the jugular vein.
The flow restrictor
may be configured to control the rate of flow through the jugular vein. The
flow restrictor may
be configured to prevent inadvertent displacement of the flow control sheath
during the
procedure.
The flow control sheath may comprise a pressure sensor, the pressure sensor
may be
configured to measure pressure in a vein upstream of the restrictor. The
sheath may comprise a
lumen in a wall of the sheath and the pressure sensor may be positioned in
said lumen. The
pressure sensing lumen may comprise a port, the port may be configured to
establish a
hydrostatic connection between blood in the vein and the pressure sensor. The
pressure sensor
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and the pressure sensing lumen may be sized to prevent blood flow ingress into
the pressure
sensing lumen.
FIG. 40 shows a patient interface 4000 with a sheath 4004 held in situation by
an
adhering membrane 4010. The adhering member 4010 helps maintain a sterile
region around an
access site and secures a hub 4080 of the sheath 4004 to the skin. This
reduces irritation to the
patient by movement of the hub 4080 made by accidental forces. The membrane
4010 may be
shaped so as to allow second or tertiary layers to be added to tie all of the
various system
elements of the sheath 4004 or catheter together or to the skin.
FIG. 41 shows a flow control sheath 4150. Shown are various features of the
flow control
sheath 4150 according to some preferred embodiments. In particular, the flow
control sheath
4150 may include a restrictor 4151 (shown in an inflated state), a sheath tip
4152, a port 4153, a
pressure sensor 4154, a sheath shaft 4155, and a hub 4159, the hub 4159
including a pressure
sensor lead 4156, an inflation side port 4157, a flushing and infusion side
port 4158. At least one
suturing hole may be added to the hub 4159 to facilitate fixation to the
patient.
FIG. 42 shows a proximal portion of a catheter system 4200. A catheter 4269
that is
similar to the catheter described in FIG. 40 is disposed within a catheter
sheath 4280. The
catheter 4269 includes a shaft 4270, a proximal expandable member 4271
(depicted in an
expanded state), and a catheter pressure sensor 4273. The sheath 4280 includes
a sheath tip 4272,
a sheath pressure sensor 4274, a sheath shaft 4275, a pressure sensor lead
4276, an inflation side
port 4277, and hub 4278.
FIG. 43 illustrates a locking mechanism 4300 for fixing a catheter shaft 4392
to a hub
4391 of a sheath 4390 during therapy. The locking mechanism 4300 includes an
arm 4396 with a
catheter shaft grip 4395 attached to a distal end of the arm 4396. When
engaged, the catheter
shaft grip 4395 attaches to the catheter shaft 4392 preventing movement. The
locking mechanism
4300 is advantageous because it prevents migration of a distal expandable
member of the
catheter system, described above, during therapy. The locking mechanism 4300
is configured to
lock the catheter shaft 4392 to the sheath 4390 during at least a portion of
the procedure.
The locking mechanism 4300 may be configured for easy engagement and
disengagement. The locking mechanism may be configured to prevent relative
movement
between the catheter distal balloon and the access sheath 4390. The locking
mechanism 4300
may comprise a clip 4395 on locking mechanism 4300; the clip on mechanism 4300
may be
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configured to be clipped onto the catheter shaft 4392 from one side of the
shaft 4392. The
locking mechanism 4300 may be pre-mounted on the catheter shaft 4392 such that
the locking
mechanism 4300 may slide into position when fixation is required.
The locking mechanism may be integral with the sheath. The locking mechanism
may
optionally attach to the sheath. Preferably, the locking mechanism may be a
Tuohy Borst type
locking mechanism.
FIG. 44 shows the locking mechanism 4300 engaged with the catheter shaft.
FIG. 45 shows a schematic of a push lock mechanism 4500.
FIG. 46 shows an alternative locking mechanism 4600. The locking mechanism
4600
includes an arm 4696 attached to a hub 4691 of a sheath 4690. The arm 4696
includes a catheter
shaft grip 4695 attached to a distal end of the arm 4696. When engaged, the
catheter shaft grip
4695 attaches to the catheter shaft 4692 preventing movement. A further
embodiment of a
locking system may include a C shaped shaft which may be secured over the
catheter shaft
proximal to the sheath. The shaft would be configured so that when the shaft
is slid into the
sheath hub it creates an interference lock between the catheter shaft OD and
Sheath ID.
FIG. 47 is a partial cutaway of a jugular vein 4752 showing a flow control
sheath 4750
inserted therein. The restrictor 4751 of the sheath 4750 is shown in a
deployed state with the
restrictor 4751 opposing a wall of the jugular vein 4752. In a preferred
position, the shaft 4755 of
the sheath 4750 terminates adjacent to a junction of the subclavian vein 4753
and the thoracic
duct 4756. The hub 4759 is external to the jugular vein 4752.
FIG. 48 shows an indwelling catheter system 4800 according to aspects of the
invention.
The indwelling catheter system 4800 includes a catheter shaft 4851 with an
impeller assembly
4861 mounted to a distal portion thereof. The catheter shaft 4851 includes a
proximal expandable
member 4850 attached to an outer surface of the catheter shaft 4851. The
proximal expandable
member 4850 comprises a flow channel 4854 that allows fluid to bypass the
proximal
expandable member 4850 at a controllable rate.
FIG. 49 is a cross-section taken along line A-A of FIG. 48 to reveal internal
lumens of
the catheter shaft 4851. The internal lumens extend internally through the
catheter shaft 4851.
Shown is a proximal expandable member lumen 4901 for delivering fluids, i.e.,
gas or a liquid,
used to inflate the proximal expandable member 4850. A separate distal
expandable member
lumen 4902 is provided for delivering fluids to inflate the distal expandable
member 4862. The
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separate lumens allow the proximal and distal expandable members 4850, 4862 to
be
manipulated independently of one another during therapeutic treatments. A
pressure sensor
lumen 4966 is provided for sending and receiving electrical signals with one
or more pressure
sensors disposed on the catheter system 4800. One or more reinforcement lumens
4930 may be
provided to reinforce the catheter 4800 so that the catheter 4800 can be more
easily navigated
through the body.
FIG. 50 is an indwelling catheter 5000. The catheter 5000 includes mechanical
components, e.g., an impeller 5005 and/or drive shaft 5007, and a purge
system. The purge
system operates to exclude biological fluids and materials from the catheter
5000 and mechanical
components operating within the catheter 5000. In that manner, body fluids are
prevented from
entering the crevasses of the catheter 5000, ensuring smooth and efficient
operation of the
mechanical parts, e.g., impeller 5005 and drive shaft 5007, within the
catheter 5000 while also
preventing the patient's body fluid from travelling to a proximal portion of
the catheter 5000
outside of the patient's body, where it could leak out of the catheter. The
purge system would
further prevent air entering the vein though the same channels.
The catheter 5000 may be used to reduce pressure in a region of a venous
system. The
catheter 5000 includes an impellor assembly 5009 mounted at the distal end of
the catheter 5000.
The impellor assembly 5009 comprises an expandable member 5013, a cage 5015
with an inlet
region 5017 and an outlet region 5019 and an impellor therein. The impellor
5005 may rotate at
high RPMs within the cage 5015. The impellor 5005 may further include a distal
surface, a
proximal surface and an impellor blade surface. The distal surface, proximal
surface and impeller
blade surface configured to rotate in close proximity to adjacent surfaces
inside the cage, but
without contacting said adjacent surfaces.
The impellor assembly 5009 may further comprise a cuff 5023. The cuff 5023 may
include a distal surface 5025 and a proximal surface 5027. The impeller 5005
rotates in clearance
of the distal surface of a cuff 5023.
The clearance between the cuff distal surface 5025 and the impeller 5005
comprises a
proximal gap 5029 and the proximal gap 5029 is configured to remain fixed
during operation.
The proximal gap 5029 is configured to define a transition between a static
cuff and a rotating
impeller 5005. The proximal gap 5029 is configured to allow blood to flow
across the proximal
gap 5029 without flow disturbance, flow recirculation, or vortices. The
proximal gap 5029 may
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be in fluid communication with a catheter lumen which is in fluid
communication with a fluid
reservoir exterior of the patient. The proximal gap 5029 may be configured to
prevent blood flow
from entering the proximal gap 5029.
In preferred embodiments, the proximal gap 5029 includes a resistive fluid
pressure
configured to prevent blood from entering the proximal gap. For example, the
resistive fluid may
be a purge fluid delivered from a fluid reservoir external to the patient. The
purge fluid can be
used to purge or flush the proximal gap 5029 clearing debris; for example, as
described in co-
owned U.S. Provision Application 62/629,914, which is incorporated herein by
reference. The
resistive fluid pressure may comprise a hydrostatic fluid pressure, which may
include a pulse of
fluid pressure. The fluid pressure comprises a solution that may include
saline, dextrose or a
heparin solution.
The viscosity of the purge solution may be tailored to effectively purge small
gaps and
orifices. The solution may also be immiscible with blood to prevent blood
contact with the
purges surfaces. For example, the solution may be a hydrophobic solution. In
some
embodiments, the proximal gap 5029 may include a seal, such as, for example, a
spring loaded
seal.
A clearance between a distal-most surface of the impellor 5005 and a tip 5031
comprising
a bearing housing 5033 may comprise a distal gap 5041 and the distal gap 5041
may be
configured to remain fixed during operation. The distal gap 5041 may be
configured to define a
transition between a rotating impeller 5005 and a static tip 5031. The distal
gap 5041 may be
configured to allow blood to flow across the distal gap without flow
disturbance, recirculation, or
vortices.
In preferred embodiments, the distal gap 5041 is in fluid communication with a
catheter
lumen which is in fluid communication with a fluid reservoir exterior of the
patient. The distal
gap 5041 may be configured to prevent blood flow from entering the distal gap,
for example, by
providing a purge from the fluid reservoir as discussed above. The distal gap
5041 may comprise
a resistive fluid pressure configured to prevent blood from entering the
distal gap. The resistive
fluid pressure comprises a hydrostatic fluid pressure. The resistive fluid
pressure comprises a
pulse of fluid pressure. The fluid pressure comprises a solution, for example,
a saline, dextrose or
a heparin solution. The viscosity of the purge solution may be tailored to
effectively purge small
gaps and orifices. The solution may also be immiscible with blood to prevent
blood contact with
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the purges surfaces. The solution may be a hydrophobic solution. The distal
gap 5041 may
comprise a seal, such as, for example, a spring loaded seal.
FIG. 51 is an expanded view of dotted circle B of FIG. 50 according to an
embodiment of
the invention. In this embodiment, fluid is delivered from a purge channel
5101 extending along
a central lumen of the device. The purge channel may be external to a PTFE
liner that surrounds
a central lumen of the catheter.
FIG. 52 is an expanded view of dotted circle B of FIG. 50 according to another
embodiment of the invention. In this embodiment, purge fluid is delivered from
the reservoir
exterior of the patient via a purge channel 5201 that travels through a lumen
used for inflating
the expandable member 5013. The purge channel 5201 is external to a PTFE liner
of a drive
cable.
FIG. 53 is an expanded view of dotted circle B of FIG. 50 according to a
different
embodiment of the invention. In this embodiment, purge fluid is delivered from
a purge channel
5301, the purge channel 5301 extending through a PTFE liner that surrounds a
drive lumen.
FIG. 54 illustrates a distal flush of an indwelling catheter 5400. The flush,
i.e., purge
fluid, is delivered via a lumen 5403 of the expandable member 5407. The purge
travels through
the lumen 5403 and through a distal bearing housing 5411, preventing blood
flood flow into
bearings of the catheter. The purge fluid flows into the distal gap 5431
flushing and preventing
blood from filling the distal gap 5431. The purge fluid travels down a second
lumen 5437 to a
proximal gap 5439 and flushes blood from the proximal gap 5439.
FIG. 55 illustrates distal flush of an indwelling catheter 5500 according to a
different
embodiment. In this embodiment, the purge fluid is delivered via a purge lumen
5505 that is
separate and distinct of the lumen for inflating the expandable member 5507.
The purge travels
through the purge lumen 5505 and into a distal bearing housing 5511, thereby
preventing blood
flood flow into bearings of the catheter. The purge fluid flows into the
distal gap 5531 flushing
and preventing blood from filling the distal gap 5531. The purge fluid then
travels down a
second lumen 5537 to a proximal gap 5539 to flush blood from the proximal gap
5539.
FIG. 56 shows an indwelling catheter 5600 with a purge system. The catheter
5600
includes a central lumen 5603 optimized for transporting purge fluid and
maintaining
concentricity of the catheter 5600 assembly. The internal structures of the
central lumen 5306
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can have various configurations some of which are detailed below in cross-
sections taken
through a cuff 5606 along line A-A.
FIG. 57 shows a cross-section of the central lumen 5603 taken along line A-A
of FIG. 56
according to one embodiment of the invention. In this embodiment, a purge
channel 5709 is
external to a drive shaft 5711 that connects a motor to an impeller of the
device. Between the
purge channel and the drive shaft 5711 is a profiled extrusion 5713. The
profiled extrusion 5713
includes a number of projections 5715, for example, at least two projections
5715, and preferably
three projections 5715, the projections 5715 extend outward from a central hub
5717 that encases
the drive shaft 5711. The profiled extrusion 5713 optimizes a purge cross
sectional area and also
helps to maintain assembly concentricity.
FIG. 58 shows a cross-section of the central lumen 5603 taken along line A-A
of FIG. 56
according to a different embodiment of the invention. In this embodiment, a
purge channel 5809
is in association with the drive shaft 5711 connecting the motor to the
impeller of the device. The
purge channel 5809 is defined by a profiled extrusion 5813. The profiled
extrusion 5813 includes
a number of projections 5815, for example, at least two projections 5815, and
preferably three
projections 5815, the projections 5815 extending inward from an outer hub 5817
that encases the
drive shaft 5711. The profiled extrusion 5813 defines and optimizes a purge
cross-sectional area
and maintains assembly concentricity.
FIG. 59 shows a cross-section of the central lumen 5603 taken along line A-A
of FIG. 56
according to another embodiment of the invention. In this embodiment, the
central lumen 5603
houses a coil drive shaft 5905 connecting the motor to the impeller of the
device. A purge
channel 5909 surrounds the coil drive shaft 5905. The purge channel 5909 is
defined by an outer
hub 5911 that encases the coil drive shaft 5905.
FIG. 60 shows an optimized guide surface 6001 of a cage inlet 6003. With
reference to
FIG. 27, the optimized guide surface 6001 comprises a portion of a cuff 6007
that tapers towards
the impeller 6011 in harmony with an outer boundary surface 6015. The
optimized guide surface
6001 maintains axial momentum and prevents recirculation of fluid 6017 flowing
into the cage
assembly 6021. In particular, the optimized guide surface 6001 tapers in a
manner that creates a
flow field convergence and minimizes fluid divergence in the inlet region
6003. The optimized
guide surface 6001 may comprise a curved tapered section. The optimized guide
surface 6001
may be configured to smoothly reduce the cross sectional area along the length
of the inlet 6003.
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For example, the change in cross sectional area of the optimized guide surface
6001 along the
length of the inlet 6003 may be less than or equal to about 1 mm2. The
optimized guide surface
6001 may comprise a curved taper. The optimized guide surface 6001 may
comprises a
cylindrical section. The optimized guide surface 6001 may comprise a
substantially conical
section.
In some embodiments, the outer boundary surface 6015 tapers over at least a
portion of
the inlet region 6003. With reference to FIG. 17, the outer boundary surface
6015 may comprise
a proximal surface of an expandable member. Alternatively, the outer boundary
surface 6015
may comprise an inner surface of the cage.
FIG. 61 shows a suboptimal guide surface 6105. The suboptimal guide surface
6105 may
cause disturbances in flow 6107 of fluid flowing into the inlet region 6111.
In particular, the
suboptimal guide surface 6105 comprises a steeper profile as compared to the
optimized guide
surface 6017 of FIG. 60. The steeper profile causes changes in axial momentum
and fluid
divergence of blood flowing into the inlet region 6111. These disturbances in
flow 6107 are
prevented by with the optimized guide surface 6017.
FIG. 62 shows a cage inlet 6201. Illustrated is an optimal configuration where
fluid flow
6207 is aligned with the inlet 6201 along an optimized guiding surface 6017.
The flow 6207 is
primarily in the X-direction with no rotational component which promotes a
smoothly flowing
inlet 6201.
FIG. 63 shows a suboptimal inlet 6301 configuration. This suboptimal
configuration
includes a steep guide surface 6105 that causes recirculation and stalls the
flow in the inlet. A
rotational component of the velocity dominates and carries the flow underneath
the inlet struts
6215. This phenomenon creates disrupted flow 6217 in the inlet 6301 and
reduces the
effectiveness of the inlet 6301 to guide flow towards the impeller.
Incorporation by Reference
References and citations to other documents, such as patents, patent
applications, patent
publications, journals, books, papers, web contents, have been made throughout
this disclosure.
All such documents are hereby incorporated herein by reference in their
entirety for all purposes.
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Equivalents
Various modifications of the invention and many further embodiments thereof,
in
addition to those shown and described herein, will become apparent to those
skilled in the art
from the full contents of this document, including references to the
scientific and patent literature
cited herein. The subject matter herein contains important information,
exemplification and
guidance that can be adapted to the practice of this invention in its various
embodiments and
equivalents thereof. The scope of the present invention is not intended to be
limited to any one
exemplary embodiment shown or described herein. Rather, any one or more
features of any
exemplary embodiment shown or described may be combined with any other
embodiment so
long as the combination does not render the invention inoperable.
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