Note: Descriptions are shown in the official language in which they were submitted.
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Apparatus aIld Method for Engrafting a ~ Blood
Vessel
Technical Field
The present invention relates to medical prostheses and to a
method and apparatus for performing aneurysm repair, and more
particularly to a method and apparatus for performing aneurysm
repair by placing a graft percutaneously via an insertion catheter
0 having a controllable inflatable balloon disposed about and
integral with its distal end.
Background Art
Aortic aneurysms, or ruptures, are a very common type
deteriorating disease which tend to affect blood vessels.
Aneurysms often affect the ability of the lumen to conduct fluids
and in turn may at times be life threatening. The standard
treatment for aneurysms is to surgically remove the aneurysm
and graft a replacement prosthetic section into the lumen.
However, such surgery is generally postponed until the aneurysm
has grown to a diameter greater than five cm. With aneurysms
over five cm in diameter, the risk of complications is greater than
the risks inherent in surgical excision and grafting of the
aneurysm. Consequently, aortic aneurysms, or those that show a
rapid increase in size, or those greater than five cm in diameter
are generally surgically removed and grafted as a matter of
course, before rupture occurs.
The typical procedure for repairing an aortic aneurysm
requires one or two days of preparing the large and small
intestines prior to hospitalization. The operation itself will
generally take one to three hours, and necessitate several units of
~ blood transfusion. The patient commonly remains hospitalized for
several days following surgery, and requires as much as three
~ 35 months recuperation time before returning to work. Even for
surgical e~cision and grafting of an aneurysm, there remains
significantly high rates of mortality and morbidity. The mortality
rate is as high as eight percent (8%). The morbidity rate includes
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incident complications such as blood loss, respiratory tract
infections, wound infections, graft infections, renal failure, and
ischemia of the bleeding intestine. The mortality and morbidity
rates for this type of major surgery are also often influenced by
the fact that the typical aortic aneurysm patient is elderly and
therefore less able to withstand major surgery and a major
anesthesia.
Another surgical procedure for repairing an aneurysm is to
excise part or all of the aneurysm and replace the aneurysmal
0 lumen section with a man made tubular section, sutured end-to-
end to the severed lumen at a site proximal to the origination of
the aneurysm.
Other methods of repairing aneurysms involve placing graft
within the vascular system via catheters through the femoral
artery. Conventional tubular aortic replacement sections, however,
are generally considerably larger in diameter than the femoral
artery and therefore cannot be inserted through the femoral
artery lumen. Also, where such devices have been proposed, as in,
for example, the devices of U.S. Patent Nos. 4,140,126 and
4,562,596 by Choudhury and Kornberg, respectively, the
expanding structure of the devices are cumbersome, and difficult
to operate.
U.S. Patent No. 5,104,399, to Lazarus discloses an artificial
graft and implantation method. Graft is of a preselected cross
section and length and is capable of being substantially deformed
so as to accommodate the interior surface of the blood vessel as
well as stapling means for securing it to the blood vessel. The
system further includes a capsule for delivering graft, thereby
overcoming s o m e of the complications of the prior art.
The majority of other grafting systems, such as U.S. Patent
Nos. 5,304,220 to Maginot and 5,151,105 to Kwan-Gett, employ a
variety of insertion means, but they require additional suturing or
other methods for securing graft. Furthermore, once a graft has
been placed inside the lumen, adjustment usually requires a major
surgical procedure. The difficulties involved with traditional
surgical procedures and additional complexities associated with
securing grafts make the treatment of aneurysms a very
expensive and lengthy procedure.
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Thus, there exists a need for a treatment for aneurysms
which requires minim7Jl preparation and outpatient care while
providing a safe and percutaneous method for implanting grafts
which do not require additional suturing or stapling for security.
Disclosure of Invention
The present invention relates to a method and apparatus for
0 performing rupture sizing and repair. The system is characterized
by a graft which can be placed percutaneously via an insertion
catheter having two controllable, inflatable and deflatable
balloons, as well as a plurality of interior tracks for utilizing a kink
resistant nitinol core wire, a guide wire, and a condensing spring
15 push rod to provide enhanced pushability and support, and for
fluid injection into the balloons and the lumen of the blood vessel.
Such placement is facilitated by a standard sheath introducer
which is equipped with a hemostasis valve to prevent leakage of
blood from the system. The sheath introducer may further include
20 a side port and may be as small as 14FR. The graft is comprised of
at least two nitinol springs which are embedded in graft material
at each end and covered completely by the material so as to
prevent direct exposure to bodily fluids or tissue. Furthermore,
the graft contains a nitinol wire mesh extension to allow bedside
25 sizing with standard operating room scissors. Nitinol connecting
bars are laser welded to the nitinol springs, or crimped fit with
nitinol or steel hypodermic tubing in order to place the springs in
physical communication with each other, inhibit twisting or
bunching of graft material, and secure fixation of the graft to the
30 blood vessel wall. The nitinol connecting bars also provide extra
security during deployment and positioning of graft.
Nitinol is a biologically inert alloy which possesses special
shape-memory properties. The alloy consists of roughly equal
portions of nickel and titanium. The shape-memory properties of
35 nitinol allow a wire coil spring which is initially fabricated with a
desired shape and configuration to be reshaped into a temporary
compressed configuration, which is more suitable for transluminal
placement. The alloy composed is typically stable at room and
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body temperature, but can be forced to lose its malleability and
permanently revert to its initially fabricated configuration. This
thermally induced reversion occurs due to a crystalline transition
from the martensitic to austenitic phase. The transition
5 temperature of the alloy can be controlled by varying its
composition and processing.
Prior to the selection and placement of a graft, the ruptured
blood vessel must be sized. The method for sizing the diameter of
a blood vessel and length of an rupture to determine the
10 necessary size of a graft involves, generally, the use of a
controllable, inflatable and deflatable balloon sizing catheter. The
sizing catheter is generally comprised of an embedded kink
resistant nitinol core wire and four (4) lumens, one for the
condensing spring push rod; one for injection of fluid into the
5 sizing balloon for sizing balloon inflation, preferably contrast
media to enhance visual communication; one for injection of fluid
into the tip balloon for the balloon inflation, and one for the guide
wire and injection of fluid, again, preferably contrast media, into
the lumen of a blood vessel to enhance visual communication. A
20 syringe is the preferred means for injection of the fluid into the
balloons of the sizing catheter as well as into the lumen of a blood
vessel. The syringe is equipped with a means for measuring the
amount of fluid injected, such as measuring lines, as well as a
pressure gauge to track resistance to sizing balloon inflation. The
25 pressure gauge will react when the balloon expands to the size of
the diameter of the lumen of the blood vessel and thereby makes
contact with the blood vessel wall. Such contact creates a sudden
increase in resistance to the injection of contrast media, or other
fluid, into the balloon. When the balloon makes such contact with
30 the blood vessel wall, the pressure gauge indicates a significant
increase in pressure by sudden deflection, associated with
injection of the fluid into the balloon. The sudden increase in
pressure will be an indication to the operator that the balloon is of
a size consistent with the diameter of the blood vessel, and
35 measurement of the diameter of the blood vessel is then based
upon the amount of fluid injected into the balloon. The
measurement will then dictate the selection of size of the diameter
of graft at full expansion.
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The current apparatus allows placement of the graft through
a smaller entry puncture than the prior art allows. The distal end
of an insertion catheter (the distal end is the end farthest from the
point of entry into the human body, and not the end farthest from
5 the heart) is placed within the lumen of the graft with its tip
balloon extending beyond the distal end of the graft, then the
graft is compressed and pre-loaded with the insertion catheter
within a standard teflon sheath introducer. The sheath, graft, and
insertion catheter are then introduced percutaneously into a blood
10 vessel, such as the femoral artery of the patient and directed to
the site of the aneurysm, such as an aortic aneurysm, using
fluoroscopy .
During movement of the graft through the blood vessel the
vessel is dilated by a balloon tip at the distal end of the insertion
5 catheter. Once inserted and placed appropriately at the rupture
site, the sheath which is disposed tightly about the graft is slowly
and firmly pulled back across the length of graft toward the point
of entry by the operator, thus releasing the graft and leaving the
graft deployed in the lumen of the blood vessel. The operator
20 must e~ert some inward force to the insertion catheter and
condensing spring push rod while pulling the sheath back toward
the point of entry so as to support the release of graft. Without
such force, the sheath may not release the graft.
The pre-loaded insertion catheter, partially disposed within
25 graft, contains an inflatable and deflatable balloon at the tip of its
distal end, the tip balloon, and a second inflatable and deflatable
balloon near its distal end, the graft balloon. When pre-loaded
within graft, the distal nitinol spring is directly disposed about the
graft balloon of the insertion catheter. At the same time the
30 sheath is pulled back toward the point of entry, the distal nitinol
spring of graft is caused to be released from the sheath and
expand in the blood vessel. Inflation of the graft balloon near the
distal end of the insertion catheter as the sheath is being pulled
back and the distal nitinol spring is released supports the release
35 of the graft and stabilizes graft while the sheath is being removed
from its position about the graft. The graft is further stabilized by
the constant force exerted by the nitinol springs against interior
wall of the blood vessel. Such constant force, approximately 340
,
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grams, exerted the top portion of each spring also pre~ents blood
from flowing between the springs and the inner wall of the blood
vessel. Furthermore, inflation of the balloon during deployment of
the distal end of the insertion catheter assures several things;
provides even deployment of graft material; and reduces the risk
of vessel rupture from the catheter tip itself while the tip balloon
is in its deflated position. Moreover, once the distal nitinol spring
has been deployed, inflation of the graft balloon of the insertion
catheter in the center of the distal nitinol spring provides extra
0 strength to the friction fit of the nitinol spring against the blood
vessel wall.
The graft balloon of the insertion catheter may also be used
to determine whether or not the nitinol spring is against a strong
portion of the blood vessel wall. Moreover, the additional force
provided by the graft balloon upon the distal nitinol spring
ensures that the distal nitinol spring will not move from its
original position while the sheath is moved back toward the point
of entry during the release of the proximal nitinol spring.
Additionally, by maintaining the balloon in the inflated position
during placement, the operator can prevent blood flow through
the blood vessel and therefore, prevent blood flow through the
open distal end of the graft which may disrupt placement.
The proximal nitinol spring is released in a manner similar
to that for releasing the distal nitinol spring; that is by pulling the
sheath introducer back toward the point of entry while the graft
balloon of the insertion catheter is inflated and inward force is
exerted upon the graft by pushing the condensing spring push rod
and the insertion catheter.
If for any reason the graft is mispositioned after its
deployment, the Taheri string system may be used to partially
collapse the nitinol springs and reposition the graft. Once both
nitinol springs have been released and proper placement of graft
has been verified, the graft may be permanently secured by
means of an intravascular stapling system such as the one
described in U.S. Patent No. 4,872,874 to Taheri. It should be
noted that use of the stapling system need not be immediate and
is in many cases optional. Such use, however, is appropriate when
the patient is lacking strong vessel wall segments, to prevent
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further expansion of the rupture or aneurysm along the length of
the blood vessel, or to provide extra security to prevent blood
from flowing between the exterior of the graft and interior of the
blood vessel wall. Such blood flow may upset graft placement.
Once the graft is in place, the graft balloon may be slowly
deflated in order to gently introduce blood flow through graft to
avoid a sudden rush of blood which is capable of moving the
position of the deployed graft. The balloon may also be partially
deflated after both springs have been released, then dragged
0 through the length of the graft in order fully un-ravel and open
the graft and further to remove any wrinkles and twists. The
sheath and catheter can then be safely removed; and the arterial
and skin incisions may be closed.
As mentioned above, the present invention further
comprises a method for partially collapsing the nitinol springs
after placement of the graft for movement of the graft within the
blood vessel or for removal of the graft from the blood vessel.
Such movement must be effected prior to implementation of
stapling procedures. Such collapsing of the graft is facilitated by
the looping of one or more strings around the V-portions of the
proximal spring, or the proximal and distal springs, during pre-
loading of the graft within the sheath introducer. The strings
must be of a length sufficient to reach from the graft at the
rupture site to the exterior of the body through the blood vessel
for manipulation by the operator. Furthermore, the strings must
be of a sufficient strength to withstand the pulling force during
the collapsing of the spring(s). ~fter placement of the graft, if it is
determined that the graft must be moved or removed from the
blood vessel, the operator may merely pull both ends of each
string until the proximal or proximal and distal springs have
collapsed, then pull the graft through the lumen of the blood
vessel. If placement is secure after movement or without
movement, the operator may merely pull one side of each string
to remove the strings completely from the graft and blood vessel.
The present invention further provides an additional means
for stopping or slowing the blood flow during placement of the
graft so as to prevent misplacement of the graft due to such blood
flow. The additional means comprises either a separate double
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balloon blocking catheter containing two inflatable and deflatable
balloons or two separate single balloon blocking catheters, each
containing one inflatable and deflatable balloon.
The separate double balloon blocking catheter is inserted
5 into the jugular vein or another vein leading to the superior vena
cava, then passed through the superior vena cava, into the inferior
vena cava, until the two balloons are positioned, when inflated, so
as to fully or partially block the superior and inferior vena cava
points of entry to the right atrium and, therefore, reduce or
10 prevent blood from flowing into the heart and throughout the
body .
The separate single balloon blocking catheters are inserted
simultaneously into the inferior and superior vena cava, and
positioned, again, to enable inflation of the catheter balloons for
5 stoppage or slowing of blood flow into the right atrium.
B lood flow may be slowed or stopped during placement of
the graft. The catheter balloons may then be deflated slowly after
the graft placement so as to gently re-introduce blood flow to the
area of the graft. This means may be utilized alone or in
zo conjunction with the balloon of the insertion catheter for such
gentle re-introduction of blood flow.
After placement of the graft, the graft position may be
strengthened by utilizing a tissue adhesive substance which may
be applied to the exterior of the graft material prior to placement
25 thereof. Small packets containing such tissue adhesive substance
may be comprised partially of a biologically insert material such
as corn starch which will dissolve over time, preferably after
three days, thus providing a time release. The tissue adhesive
substance contained therein is preferably Isobutyl 2
30 cyanoacrylate.
The invention further comprises a method and apparatus
engrafting bifurcated blood vessels without multiple points of
entry. The present invention contains many features which are
not taught in the prior art. For example, the present invention is
35 the only current system which may be easily repositioned or
removed after the initial deployment. The present system also
provides a very low entry profile of less than l~FR, thus two the
grafts at 1 3FR would still be lower in profile than a typical 26FR to
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28FR single the graft of the prior art. The present system also
provides a method for sizing the blood vessel diameter and
obtaining information necessary for accurate selection of the
appropriate the graft size for blood vessel rupture repair.
5 Furthermore the present invention provides an insertion catheter
with superior pushability and a controllable inflatable and
deflatable balloon to assure even displacement and less risk of the
graft and vessel damage, as well as a controllable inflatable and
deflatable tip balloon to lead the graft through a blood vessel and
o provoke advanced dilation thereof. Moreover, it provides a
nitinol spring system which does not lock in place, but rather
continuously presses against the vessel wall with a force of
between 240 and 340 grams in order to hold the graft in place
while conforming to the shape and size of the blood vessel and
15 prevent blood flow between the graft and the interior wall of the
blood vessel. The nitinol springs also flex so as not to create any
erosion of the vessel wall at the mounting sites. Additionally, it
provides connecting bars to support the graft and substantially
decrease the likelihood of twisting and bunching of the graft
20 material. Moreover, the graft material completely covers the
springs and connecting bars to prevent nitinol contact with blood
or tissue. Additionally, the end portions of the graft are
comprised of material arranged on the springs with the web
portions cut away in such a way to allow for expandability of the
2~ springs to a diameter in excess of the middle portion of the graft
for enhanced flexibility in sizing.
The present invention is further distinguished from the
prior art by the tissue adhesive substance applied to the graft
material exterior and by utilizing the Taheri means for slowing or
30 stopping blood flow during placement of the graft.
The present invention is further distinguished from the
prior art by its ability to provide engrafting of bifurcated blood
vessels with one point of entry and therefore on incision.
-
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Industrial Applicability
Industrial applicability is defined by the objectives of the
invention. Each objective defines unto itself and in combination
with other objectives industrial applicability.
It is therefore an object of this invention to provide an
improved method for implanting the graft prostheses in patients.
It is another object of this invention to provide a method of
implanting the graft prostheses which is less invasive than
0 traditional surgical methods.
It is yet another object of this invention to provide a method
of implanting the graft prostheses having a low mortality and
morbidity risk to patients.
It is yet another object of this invention to provide a method
of implanting the graft prostheses which provides less hospital
and outpatient care than that of normal surgical grafting
procedures .
It is yet another object of this invention to provide a graft
prostheses capable of being inserted with minim~l incision.
It is yet another object of this invention to provide a method
for sizing the blood vessel diameter.
It is yet another object of this invention to provide an
improved spring assembly.
It is yet another object of this invention to provide a spring
assembly which is flexible and yet capable of retaining its shape
and not collapsing or folding.
It is yet another object of this invention to provide a graft
prostheses capable of being secured without the use of staples or
sutures .
It is yet another object of this invention to provide a graft
prostheses capable of being easily removed or adjusted after
being implanted.
It is yet another object of this invention to provide a method
and apparatus for engrafting a bifurcated blood vessel with on
incision.
It is another object of this invention to provide multiple
means for slowing or stopping blood flow during placement of a
graft
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BRIEF DESCRIPTION OF DRAWINGS
Figure 1 is a side elevational view of a graft with a view of
two nitinol springs and connecting bars, with nitinol mesh
5 extensions connected to each spring.
Figure 2 is a side elevational view of a preferred
embodiment of a graft within a ruptured blood vessel with a view
of the nitinol springs, connecting bars, nitinol mesh extensions and
10 the smaller, nondistensible middle portion, and the strings of the
Taheri string system.
Figure 3 is a side elevational view of a graft and insertion
catheter, pre-loaded within a sheath.
Figure 3a is a cross sectional view of a graft and insertion
catheter, pre-loaded within a sheath introducer.
Figure 3b is a side elevational view of the sheath introducer
20 pre-loaded with graft and insertion catheter, with tip balloon of
insertion catheter in the inflated position.
Figure 4 is a side elevational view of a blood vessel
containing the expanded distal nitinol spring and distal nitinol
25 mesh extensions with the inflated graft balloon of the insertion
catheter positioned therein with a metal ring positioned
therebeside, as well as the sheath covering the proximal nitinol
sprlng.
Figure 5 is a side elevational view of a blood vessel
containing a graft with expanded proximal and distal nitinol
springs and nitinol mesh extensions, and an inflated graft balloon
therein .
Figure 5a is a side elevational view of a blood vessel
containing a graft with expanded proximal and distal nitinol
springs and nitinol mesh extensions, and a partially deflated graft
balloon therein.
1 1
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Figure 6 is a side elevational view of a sizing catheter, its
multiple interior tracks, and metal rings disposed about the distal
portion near sizing balloon and tip balloon.
Figure 7 is a side elevational view of a double balloon
blocking catheter in the inferior and superior vena cava.
Figure 8 is a side elevational view of two single balloon
0 blocking catheters positioned in the superior and inferior vena
cava.
Figure 9 is a chart demonstrating the relationship between
volume of fluid injected into the sizing balloon and the diameter of
5 the blood vessel.
Figure l 0 is a chart demonstrating the sizing of a graft based
upon the size of the blood vessel diameter.
Best Mode for Carrying Out the Invention
For the purposes of promoting an understanding of the
principles of the invention, reference will now be made to the
25 embodiments and methods illustrated in the drawings and specific
language will be used to describe the same. It will nevertheless
be understood that no limitation of the scope of the invention is
thereby intended; such alterations and further modifications in
the illustrated devices and methods, and such further applications
30 of the principles of the invention as illustrated therein being
contemplated as would normally occur to one skilled in the art to
which the invention relates.
As shown in FIG. l graft l 5 is comprised of an expandable
material l 0, particularly for both end portions, preferably Dacron~
35 or Gortex(É), two nitinol springs l l, l2 embedded in proximal 11
and distal l 2 ends of material l 0 to provide continuous pressure
to a blood vessel wall, between 240 and 340 grams of outward
pushing force, and simultaneously conform to the specific
12
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diameter of a blood vessel.
As shown in FIG. 1 a graft l S is further comprised of nitinol
mesh extensions 1 1 a, 1 2a extending outward in a cylindrical
shape from each nitinol spring 11, 12. The nitinol mesh
extensions 1 la, 12a provide approximately 30 grams of outward
pushing force, and enable sizing flexibility by allowing for the
cutting away of portions of the nitinol mesh extensions 1 la, 12a
with ordinary scissors. The nitinol mesh is preferably covered
with Dacron or PTFE. Preferably, material 10 completely covers
both nitinol springs 1 1, 12 and nitinol mesh extensions, thereby
preventing direct contact between the nitinol and the blood or
tissue .
As shown further in FIG. l distal 12 and proximal 1 1 nitinol
springs are connected by connecting bars 13. The material l O
provides complete coverage of connecting bars 13 as well,
thereby, again, preventing direct contact between the nitinol and
the bodily fluids or tissue. Connecting bars 13 are preferably
crimped fit with steel or nitinol hypodermic tubing or laser
welded to each of the inner portions 14 of proximal 11 and distal
12 nitinol springs to inhibit the twisting or bunching of graft
material 10. For example, without the connecting bars 13, and the
associated communication between proximal 11 and distal 1 2
nitinol springs, the middle area of graft 15 may twist or bunch
and collapse, thereby shrinking or eliminating the passage for
blood flow. Furthermore, the connecting bars 13 provide extra
security during the deployment and positioning of graft l S . For
example, if distal nitinol spring 12 is against a weak portion of the
blood vessel wall and proximal nitinol spring 11 is against a strong
portion, then the connecting bars 13 will help to stabilize distal
nitinol spring 12.
As shown in further Fig. 1 a, in its most preferred
embodiment, graft 15 contains cut away web portions wherein the
material covering distal 1 2 an proximal 11 springs is cut away
within the V portions to enhance flexibility in sizing.
As shown in FIG. 2 in its most preferred embodiment, the
middle portion 10' of graft 15 is smaller in diameter when graft
15 is deployed in the lumen of a blood vessel 34, than both end
portions. This smaller diameter middle portion 10' provides
13
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greater flexibility in sizing than would a graft 1 ~ having a middle
portion 10' of equal or greater maximum diameter to the end
portions. For example, if the full diameter of both end portions is
equal to the full diameter of the middle portion 10' of graft 15,
and if graft 15 is inserted into a blood vessel 34 of smaller
diameter than of the middle 10' and end portions of graft 15,
proximal 11 and distal 12 springs of the end portions would
sufficiently compensate by expanding only to a diameter size
consistent with the diameter of the lumen of the blood vessel 34.
o The middle portion 10', however, does not contain springs. It,
therefore, would not have the sizing flexibility of the end portions
and would be too large. Wrinkling or bunching of the material
covering the middle portion 10' could result. This result could,
again, substantially impair blood flow through graft 15, and may
cause clotting. A graft 15 containing a smaller diameter middle
portion 10' allows graft 15 to fit within a blood vessel 34 of equal
or greater diameter than the middle portion 10' as long as the
diameter of the blood vessel 34 is not in excess of that of the fully
expanded end portions.
As shown in FIG. 3, Insertion catheter 31 with balloon 32
are pre-loaded within graft 15, prior to its introduction into blood
vessel 34. Graft 15 is then compressed and loaded within sheath
introducer 21, preferably a teflon sheath introducer 21, for
delivery to the damaged region of blood vessel 34. An inflatable
and deflatable graft balloon 32 and an inflatable and deflatable tip
balloon 32a, preferably polyurethane balloons, are disposed about
and integral with the distal end of insertion catheter 31. Sheath
introducer 21 may also be comprised of material such as
polyurethane, silicone, polyethylene, or other similar materials.
As shown in Fig. 3a, sheath introducer 21, after pre-loading,
is disposed radially about, but not affixed to graft 15, and graft 15
is disposed radially about but not affixed to insertion catheter 31.
As shown in Fig 3b, after pre-loading, the portion of the insertion
catheter having the tip balloon 32a extends outward from graft 15
and the distal end of sheath introducer 21. Tip balloon 32a is
inflated as the pre-loaded sheath introducer is passed into and
through the blood vessel 34 toward the rupture site for the
purpose of provoking advanced dilation of blood vessel 34.
14
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- As shown further in FIG. 3, sheath introducer 21i is most
preferably equipped with a homeostasis valve 22 and a side port
23. The homeostasis valve 22, most preferably comprised of latex,
grips around the surface of insertion catheter 31 to prevent blood
5 from leaking out of the patient at the entry site 35. The side port
23 provides a means for injecting contrast media into the blood
~ vessel 34. Insertion catheter 31 is preferably comprised of a
length sufficient to extend into the blood vessel beyond the site of
rupture, while having a length sufficient at the proximal end for
0 manipulation by the operator.
As shown further in FIG. 3, insertion catheter 31 is further
comprised of four inner tracks; track one 41 having an opening at
the distal end and all three tracks having an opening at proximal
end of insertion catheter 31. Track one 41 is utilized in
conjunction with a guide wire to guide insertion catheter 31
through blood vessel 34. Track one is further utilized for injection
of contrast media or other fluid into blood vessel 34 to enhance
visual communication with graft 15. Moreover, track two 42
opens intot and therefore communicates with graft balloon 32 of
insertion catheter 31 to allow for injection of fluid, gaseous or
liquid, from the opening at the proximal end. Additionally, track
three 43, while having an opening at the proximal end, is closed at
the distal end. Track three 43 is preferably used to facilitate the
use of a condensing spring push rod for application of force to
graft 15 during deployment of graft lS into the lumen of blood
vessel 34. The condensing spring push rod is flexible to enable it
to maneuver through blood vessel 34 and most preferably
contains a plunger at its tip to prevent outflow of blood through
sheath introducer 21. Track four 44 opens into and therefore
communicates with tip balloon 32a to allow for injection of a fluid,
preferably a contrast media, into tip balloon 32a from the opening
at proximal end of insertion catheter 31. Insertion catheter also
most preferably contains an embedded kink resistant nitinol core
wire and a conical shaped tip at its distal end.
As shown in FIG. 4, insertion catheter 31 contains a balloon
control means for inflation and deflation of graft balloon 32 and
tip balloon 32a. The preferred means for inflating balloons 32 and
32a is by injecting a fluid, preferably a radiopaque dye, into
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balloons 32 and 32a with a syringe 46 through track two 42 and
track four 44 of insertion catheter 31. The radiopaque dye
provides not only for the inflation of balloons 32 and 32a, but also
provides for visual communication with balloons 32 and 32a,
thereby enabling the user to determine the location of balloons 32
and 32a relative to positions within graft 15.
As shown further in Fig. 4, for an alternative means of
creating such visual communication a metal ring 45 may be
positioned around insertion catheter 31 on either or both sides of
o graft balloon 32 and tip balloon 32a. The metal ring 45 would,
thereby, replace the need for a radiopaque dye within balloon 32,
thus allowing for the use of another fluid for inflation and
deflation of balloons 32, 32a.
As shown further in Fig. 4, balloon 32 is inflatable to a size
consistent with an ability to provide force against the interior of
distal nitinol spring 12 during its expansion, after its release from
sheath introducer 21, thereby providing additional support to
distal nitinol spring 12 during placement of graft 15 within blood
vessel 34 and removal of sheath introducer 21 from its position
about graft 15. Furthermore, as also shown in Fig. 4, balloon 32 is
inflatable to a size consistent with an ability to, at the same time,
block blood flow through graft 15 during placement of graft 15.
Moreover, as shown in Fig. 5, balloon 32 is inflatable for a
duration consistent with the time period necessary to support
distal nitinol spring 12 after it is released from sheath introducer
21 and particularly while proximal nitinol spring 11 is being
released therefrom. Additionally, balloon 32 is inflatable for a
duration consistent with the time period necessary to verify that
graft 15 is secured in the appropriate position within and against
the lumen wall; a time-period of at least 5 seconds.
As shown in FIG. 5a, balloon 32 is also deflatable and
inflatable to a size consistent with an ability to pass through graft
15 after complete placement of graft l S within the lumen of blood
vessel 34, and thereby provide the means for unraveling and fully
opening graft 15, and for smoothing out wrinkles and twists that
may be present in graft 15 after placement. As shown further in
Fig. 5a, when balloon 32 is in the deflated position, insertion
catheter 31 is movable within the length of graft 15 while at least
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partiall-y deflated, for smoothing out any wrinkles and -twists
formed during the placement.
As shown further in FIG. 4, once graft 15 and sheath
introducer 21 are positioned appropriately within the lumen of
5 the blood vessel 34, sheath introducer 21 is slowly and gently
pulled back across the length of graft 15 toward the point of entry
~ 35 until it is removed from the lumen of the blood vessel 34. The
sheath action of moving sheath introducer 21 toward the point of
entry 35 causes distal nitinol spring 12 of graft 15 to be released
and therefore, expanded into the lumen of the blood vessel 34. As
shown further in FIG. 4, as distal nitinol spring 12 is deployed,
balloon 32 of insertion catheter 31, pre-loaded within graft 15, is
inflated in the center of distal nitinol spring 12 to support
insertion catheter 31 in its connection to graft 1 5 so that force
applied to nitinol core wire, condensing spring push rod, and
insertion catheter 31 will communicate with graft 15 and aid in
the release of graft 15 from sheath introducer 21. Furtherrnore,
balloon 32 to provide extra strength to the friction fit of distal
nitinol spring 12 against blood vessel wall 36 after distal spring
12 is released from sheath introducer 21. Balloon 32 is then used
to determine whether distal nitinol spring 12 is positioned against
a strong portion of the blood vessel wall 36. For example, if
balloon 32 inflates without a sudden increase in resistance at a
pre-determined point representing the pre-determined size, it is
an indication that distal nitinol spring 12 is not deployed in the
correct position, in that it is likely positioned within and against
the ruptured portion of the blood vessel, and must be moved. If
balloon 32 meets sudden, and appropriate resistance, this is an
indication that graft 15 is placed with its distal nitinol spring 12
against a strong portion of the blood vessel wall 36.
As shown further in Fig. 4, the preferred inflation and
deflation means for balloons 32, a syringe 46, is equipped with a
means for measuring the amount of fluid injected into balloon 32
and a pressure gauge. As each unit of fluid is injected into balloon
32 and as balloon 32 inflates, pressure gauge will indicate steady
resistance associated with the inflation of said balloon 32. When
balloon 32 inflates to a size consistent with the diameter of the
lumen of the blood vessel 34 and therefore, makes contact with
17
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the blood vessel wall 36, the resistance to further inflation of
balloon 32 will suddenly increase. The sudden increase in
resistance will be shown by an attached pressure gauge and
represent graft's 15 contact with the blood vessel wall 36. The
operator may then continue to pull sheath introducer 21 across
the length of graft 15 toward the point of entry 35 and at the
same time apply force to the nitinol core wire, condensing spring
push rod, and insertion catheter 31. As shown further in FIG. 5,
this sheath pulling action and force to graft lS causes the release
o of proximal nitinol spring 11, thereby enabling its expansion
within the lumen of the blood vessel 34. Balloon 32 may remain
inflated to maintain communication of such force to graft 15 and
support the position of graft 15 until after sheath introducer 21
releases proximal nitinol spring 11 . As sheath introducer 2 1 is
moved across proximal nitinol spring 11, thus releasing proximal
nitinol spring 11, the additional resistance provided by balloon 32
secures distal nitinol spring 12 in its original placement position.
As shown further in FIG. Sa, after placement is complete,
balloon 32 may be deflated slowly to gently introduce blood flow
through graft 15 thereby preventing displacement of graft l S
which might be caused by a sudden rush of blood. The partially
deflated balloon 3 2 may be moved throughout the length of graft
15 to unravel and fully open graft lS, and further to smooth out
any wrinkles that may have formed in graft 15 during placement.
Insertion catheter 31 may then be removed and if graft is
appropriately positioned, incisions may be closed.
As shown further in FIG. 2, when graft 15 is fully deployed
within the lumen of the blood vessel 34, the outer V portions l 4
of both springs exert significant force against the blood vessel wall
36. Between 240 and 340 grams of force is exerted at that point
to prevent leakage of blood to the outside of graft 15 between
graft l S exterior and the wall of the blood vessel 36, so as to
prevent disruption of graft l S placement. This will allow for a
period of time to pass prior to stapling graft 15 to the blood vessel
wall 36. Such stapling will permanently prevent such leakage and
the growth of the rupture.
As shown further in FIG. 2, a string system may be used to
partially collapse proximal nitinol spring 11 or distal nitinol spring
18
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12, or both after sheath introducer 21 has been removed and graft
l S has been placed. The string system will facilitate repositioning
graft lS if graft lS has been misplaced. The most preferred
means for partially collapsing graft 15 for such repositioning is to
5 utilize a string system which is comprised of two or more strings
17 pre-loaded in a position looped around two or preferably all of
the outer V-shaped portions 14 of proximal nitinol spring 11 or
inner V-portions 14a of distal nitinol spring 12, or most
preferably both. Strings 17 must be of a length sufficient to reach
10 from outside the body at the point of entry 35 and through the
blood vessel 34 to the position of distal nitinol spring 12 after
initial placement so as to allow for manipulation by the operator.
If movement is required after placement, it may be effected by
pulling strings 17 until the proximal 11 or distal 12 or both
proximal 11 and distal 12 springs have partially or fully
collapsed. Graft l S may then be pulled by such strings 17 within
the lumen of the blood vessel 34 to a more appropriate position
therewithin or be pulled completely from the lumen of the blood
vessel 34 out through the initial point of entry 35, then re-
20 inserted. Strings 17, therefore, must be of a sufficient strength tocollapse proximal 11 and distal 12 nitinol springs, and pull graft
lS through the blood vessel 34. When the operator is satisfied
with the new position of graft 15 within the lumen of the blood
vessel 34 he may pull one side of each string 17 until strings 17
25 are completely removed from the blood vessel 34.
Once distal 12 and proximal 11 nitinol springs have been
released and proper placement of graft l S is made, graft l S may
be permanently secured by means of an intravascular stapling
system such as that disclosed in U.S. Patent No. 4,872,874 to
30 Taheri. It is most preferred to utilize a stapling system to add
more permanency to the placement of graft 15 after a sufficient
period of time has elapsed and it is determined that no further
movement of graft l S is required. Furthermore, the stapling will
aid in the prevention of further expansion of the rupture site, and
35 prevention of leakage of blood between graft lS and blood vessel
wall 36.
As shown in Fig. 7, another means for slowing or stopping
blood flow during placement of graft lS, comprises the use of a
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double balloon blocking catheter 5 l containing two inflatable and
deflatable balloons 52 spaced sufficiently along the length of
double balloon blocking catheter 5 l to, when inflated and
positioned appropriately, partially or fully block the blood flow
into the right atrium at the points of entry associated with the
superior 54 and inferior vena cava 54a. As with insertion
catheter 3 l, double balloon blocking catheter 5 l preferably
contains a plurality of interior tracks. Track one SS provides a
means for utilizing a guide wire; and tracks two 56 and three 57
0 provide a pathway for fluid injection for inflation and deflation of
balloons 52. Double balloon blocking catheter S l is most
preferably inserted into the jugular vein prior to or
contemporaneous with the entry of the pre-loaded insertion
catheter 3 l . Double balloon blocking catheter S l is then passed
through the superior vena cava 54 and into the inferior vena cava
54a.
As shown further in FIG. 7, metal rings 45 may be, again,
placed on each side of the balloons 52 of double balloon blocking
catheter S l to enhance visual communication for positioning of
balloons 52 at each point of entry into the right atrium 53.
Furthermore, a radiopaque dye may be used as the fluid for
inflation and deflation of balloons 52 to further enhance visual
communication .
After double balloon blocking catheter S l is positioned as
described hereinabove, and sheath introducer 2 l is positioned for
placement of graft l 5 as also described hereinabove, balloons 52
of blocking catheter 5 l may be inflated to partially or fully block
the blood flow into the right atrium while graft l 5 is released
from the sheath introducer 2 l and placed appropriately within
the blood vessel 34. Such inflation is preferably effected with a
syringe. During inflation of balloons 52 of blocking catheter 5 l,
blood flow must be monitored to determine the point when blood
flow has ceased or slowed to an acceptable rate for placement of
graft l 5 . It is most preferred to reduce the mean arterial pressure
from normal which is 85-9Smm Hg to 30mm Hg, and to reduce the
pulmonary artery blood pressure from a normal which is 35mm
Hg to Smm Hg. After placement of graft 15, balloons 52 of
blocking catheter 5 l may be slowly deflated so as to gently
CA 0223~67~ 1998-04-23
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reintroduce blood flow through the body. Such gentle~
reintroduction of blood flow will prevent dislodging graft 15 from
a sudden rush of blood. Furthermore, blocking catheter 51 may
be used in conjunction with balloon 32 of insertion catheter 31 for
introduction of blood flow through graft 15.
As shown in Fig. 8, another means for slowing or stopping
blood flow during placement of graft 15 comprises two single
balloon blocking catheters 60, each containing one balloon 61
disposed about its distal end, and in fluid communication with an
0 interior track of blocking catheter 62. Each single balloon blocking
catheter 60, as with the double balloon blocking catheter 51 and
insertion catheter 31, contains one or more interior tracks for the
guide wire or core wire and the fluid injection into balloon 61.
The single balloon blocking catheters 60, however, must be
inserted separately into the superior vena cava 54 and inferior
vena cava 54a, then passed through the respective veins until the
balloon of each is positioned at its respective point of entry into
the right atrium. The same blocking method is performed as
described hereinabove.
With regard to sizing graft 15 prior to insertion and
placement, as shown in Fig. 6, a sizing catheter 70 is used to size
the diameter of the lumen of the blood vessel 34 prior to selection
of the appropriate graft 15. As shown further in Fig. 6, a sizing
catheter 70 is comprised of a plurality of interior tracks each
25 running along the length of sizing catheter 70, preferably four
interior tracks, a sizing balloon 75 and a tip balloon 75a, each
disposed about and integral with its distal end. All four tracks of
the sizing catheter 70 have openings at the proximal end. Track
one 71 of the sizing catheter 70 has an opening at the distal end
30 and thereby provides an unobstructed pathway for injection of
fluid through the sizing catheter 70 into the lumen of the blood
vessel 34. Track two 72 of the sizing catheter 70, at its distal end,
opens into sizing balloon 75 of the sizing catheter 70. Track three
73 of sizing catheter 70 opens into tip balloon 75a to facilitate
35 inflation and deflation thereof.
Track one 71 of sizing catheter 70 is preferably utilized as a
pathway for injection of contrast media into the blood vessel so as
to enhance the visual communication with the sizing catheter 70
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in its location within the blood vessel 34. Such injection is
preferably effected with the use of a syringe at the proximal
opening of the sizing catheter 70. As shown further in Fig. 6, a
metal ring 45 may be placed around the sizing catheter 70 at a
5 point on either or both sides of balloons 75 and 75a to further
enhance visual communication. Track one 71 is further utilized
for movement of sizing catheter along a previously placed guide
wire through blood vessel 34.
Track two 72 of sizing catheter 70 is preferably utilized as a
0 pathway for injection of fluid, preferably contrast media such as a
radiopaque dye, into balloon 75 of sizing catheter 70 for inflation
and deflation of balloon 75. Again, it is preferable to use a syringe
for injection of the fluid. The injection means is preferably
equipped with a means for measuring the amount of fluid injected
5 into balloon 75 of sizing catheter 70.
As shown in Fig. 9, the infused volume multiplied by 1.50
equals balloon diameter and vessel diameter. The injection
means is preferably equipped with a pressure gauge. As a balloon
inflates, the resistance to such inflation remains constant until
20 balloon 75 inflates to a size consistent with the diameter of the
lumen of the blood vessel 34 and makes contact with the blood
vessel wall 36. When such contact occurs between balloon 75 and
the blood vessel wall 36, the pressure gauge will indicate a sudden
increase in resistance to further inflation. At the point the
25 pressure gauge indicates a sudden increase in resistance, a
measurement of the amount of fluid injected will indicate the
diameter of balloon 75, and therefore, the diameter of the lumen
of the blood vessel 34.
The most preferred method of utilizing the sizing catheter
30 70 for sizing of a blood vessel 34 is to first place the sizing balloon
75 of the sizing catheter 70 at a position proximate to the site of
the aneurysm. This can be determined by injecting a small
amount of the radiopaque dye into balloon 75 or by obtaining
visual communication utilizing metal rings 45 on either or both
35 sides of balloon 75. Second, the operator, by utilizing the visual
communication provided by the radiopaque dye or metal rings 45
must determine the location of the sizing balloon 75 in relation to
the site of the aneurysm. When the sizing balloon 75 is positioned
22
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on the-proximate side of the aneurysm, balloon 75 may~ be inflated
until a sudden pressure increase from increased resistance is
indicated by the pressure gauge. At the movement of sudden
pressure increase, the operator must record the amount of fluid so
injected, and convert that number to the increased diameter of
balloon 75. The operator must then deflate balloon, advance the
catheter 2 cms forward, and repeat procedure. Depth marks on
the catheter surface may be used to verify depth position. The
rupture site is easily identified by this sizing method during
0 balloon 75 inflation. After one measurement is complete, the
point of increased resistance is predictable. When sizing catheter
70 moves into the ruptured areas, balloon inflation will continue
well beyond the predicted size. This, therefore, indicates to the
operator that the rupture site has been reached. The length of the
rupture site is determined by utilizing the sizing catheter depth
marks. Radiopaque image photos should be taken every 2 cms.
Such measurements at each 2 cm interval will enable the operator
to determine not only the diameter of the lumen of the blood
vessel 34, but the length of the rupture as well. After the size of
the diameter of the blood vessel lumen and the length of the
rupture have been determined, an appropriate graft may be
selected for insertion.
As shown in FIG. 10, a graft size is determined after sizing a
blood vessel by multiplying the blood vessel size by 1.33 then
rounding up to the nearest 2mm size from the following; 10, 12,
14, 16, 18, 20, 22, 24, 26, 28, 30, 32.
