Note: Descriptions are shown in the official language in which they were submitted.
1323814
2B410/717
AZB/dmc
6818B
GUIDE WIRE EXTENSION
FIELD OF THE INVENTION
This invention relates to guide wires used in
vascular catheterization procedures, and to
techniques for performing catheter exchanges.
BACKGROUND OF THE INVENTION
In vascular catheterization procedures it often
is necessary for the physician to use different
catheters in the diagnosis or treatment of a
particular blood vessel. For example, when
performing a coronary angiographic study, a
physician commonly will use a series of catheters,
to be inserted into the patient. Each of the
catheters is provided with a different shape, size
or configuration suited for a specific purpose.
Angiographic studies typically include the use of at
least three cardiac catheters including a right
coronary artery catheter, left coronary artery
catheter and a pigtail catheter. The three
catheters each have different shapes and
. , ,
~ . i
. .
,' 2B410/717
AZB/dmc
~, 6818B
~ i323814
'3 2
configurations at their distal tips. The right and
left coronary artery catheters aee shaped to
facilitate placement of their distal outlet tips at
the entries to the right and left coronary arteries,
respectively. The pigtail catheter is provided with
a special pigtail-shaped tip intended to reduce
trauma as the catheter is advanced through the
patient's tricuspid valve into the ventricle for
ventricular studies. By way of further example,
other types of catheters may include balloon
dilatation catheters which are intended to be placed
within a stenosed portion of an artery and then
inflated under high pressure to expand the lumen of
the artery so as to improve blood flow through the
artery. In some dilatation procedures it may be
desirable to use a series of dilatation catheters
having different sizes or balloon configurations.
It has long been common practice in the
placement of catheters to use a guide wire which is
placed in the patient's artery and which is
receivable in lumen of the catheter. With a guide
wire in place, a catheter can be advanced over the
guide wire and thereby guided to the intended
vascular site. The guide wire serves to center the
catheter within the blood vessel and reduces the~
risk of trauma to the blood vessel by the advancing
catheter. The use of a guide wire reduces the risk
2~410/717 1323814
AZB/dmc
68~8~
that the distal end of the catheter might become
caught on the inner surface of the blood vessel
lumen. The use of a guide wire also enables the
catheter to be advanced through the blood vessel
relatively ~uickly, thereby reducing the time
required for the procedure.
A standard guide wire typically is slightly
longer than the catheter with which it is to be
- used. For example, with an angiographic catheter of
the order of 130 centimeters long, the guide wire
typically may be of the order of 145-175 centimeters
long. When the catheter is in place over the guide
wire, a relatlvely short portion of the guide wire
protrudes proximally from the catheter. That
enables the guide wire to be manipulated, if
desired, from its proximal, protruding end. In that
regard, it may be noted that the guide wire may be a
steerable construction in which a bend is formed in
its distal tip and the direction in which the bent
distal tip extends it controlled by rotating the
guide wire from its proximal end. For example, the
guide wire may be of the type described in
Canadian Patent 1,208,096, issued July 22,
1986.
When it is necessary to change catheters, it
usually is preferred that the catheter be removed in
a manner which enables a guide wire to remain in
2B410/717 ~814
AZB/dmc
6818B
place in the blood vessel so that the next
succeeding catheter in the procedure can be inserted
into the blood vessel, over the guide wire, and will
be guided to the intended site in the blood vessel.
In order to maintain a guide wire in place while
withdrawing the catheter, the guide wire must be
gripped at its proximal end to prevent it from being
pulled out of the blood vessel together with the
catheter. The catheter, however, is longer than the
proximal portion of the guide wire which protrudes
out of the patient. Thus, before the catheter is
fully withdrawn it completely covers the proximally
extending end of the guide wire. As a result, there
i8 no means by which a standard guide wire can be
held in place to prevent it from being withdrawn
together with the catheter. If, as is often the
case, it is desired to place the next succeeding
catheter by advancing it over a guidewire, a new,
longer guide wire is inserted in to the blood vessel
and advanced into a position to provide a guide for
the next catheter.
It is recognized generally as undesirable to
insert, advance and withdraw a series of guide wires
through a patient's blood vessels. To do so greatly
increases the risk of trauma and puncture to the~
patient and also extends the duration of the
procedure. It also requires exposure of the patient
2B410/717
AZB/dmc
6818B 1 a~ol~
to additional radiation because of the additional
fluoroscopy which would be required to place the
successive guide wires. In order to reduce the risk
of puncture or trauma it has become a long time
practice to use an exchange wire when performing
catheter exchanges. The exchange wire typically is
about 300 centimeters long, much longer than the
typical standard guide wire. The structure of the
standard and exchange wires typically is the same
except for the length. The additional length of the
exchange wire results in a long proximally
protruding portion which is longer than the ca~heter
to be removed. When a catheter is removed some part
of the proximally extending portion of the exchange
wire will always be exposed to provide a means by
which the exchange wire can be gripped and its
position in the blood vessel maintained. Use of the
exchange wire reduces the risk of trauma to the
patient because it is placed while the first
catheter remains in the patient. Thus, the
procedure involves initially, removal of the
standard guide wire from the catheter while the
catheter remains in place in the patient. Then the
exchange wire is advanced through the catheter to
replace the original guide wire. Because the
exchange wire is guided through the patient's blood
vessel by the first catheter, it does not contact
, . . .
2B410/717 132381~
AZB/dmc
6818B
the lumen of the blood vessel except, perhaps, for a
small portion which protruded distally of the first
catheter. The original catheter then is withdrawn
over the exchange wire, which is maintained in place
in the blood vessel. The next succeeding catheter
then can be inserted into the patient over the
exchange wire.
The foregoing system and technique of using a
long exchange wire has been conventional practice
for many years. The use of an exchange wire during
catheter exchanges, however, is not free from
difficulty. The proximally extending end of the
exchange wire is quite long and cannot be
manipulated easily, should it be desired to
manipulate the distal end of the exchange wire.
Additionally, the placement of the exchange wire
must be performed under fluoroscopy to assure that
it is placed propeely in the patient's blood
vessel. The use of an exchange wire also adds to
the time and the complexity of the procedure.
Notwithstanding these difficulties, the use of
exchange wires has continued to be common practice
in making catheter exchanges.
It is among the general objects of the invention
to provide an improved guide wire system and
technique by which catheter exchanges can be
2B410/717
AZ~/dmc 3 2 3 814
6818B
performed without the use of separate exchange wire
and in a manner which avoids the foregoing and other
difficulties.
SUMMARY OF THE INVENTION
The present invention enables a catheter
exchange to be made wlthout requiring any guide wire
exchanges. In accordance with the present invention
a guide wire extension is attached to the proximally
extending end of the guide wire while the guide wire
remains in place in the patient. The guide wire
extension effectively increases the length of the
guide wire. After the extension is attached to the
guide wire, the catheter can be withdrawn over the
guide wire and its extension. The extended length
enables the proximal end of the combined guide wire
and extension to be exposed at all times so that its
position can be maintained during removal of the
catheter. Once the first catheter has been removed,
the new catheter can be inserted over the combined
guide wire and extension. The technique
substantially shortens the duration of the procedure
because the extension can be attached to the
proximal end of the guide wire much faster than a
conventional wire exchange can be performed.
Additionally, there is a further reduction in risk
s
2B410/717 13 2 3 814
AZB/dmc
681BB
of puncturing the blood vessel. There also is less
exposure to fluoroscopic radiation which is required
each time a guide wire is inserted.
In accordance with the invention the proximal
end of the guide wire includes a connector
arrangement which may be in the form of a tubular
socket. The socket is receptive to a mating tip
formed at the distal end of the extension wire.
When the extension wire and guide wire are mated,
the joint is secured, as by crimping with a special
crimping tool. In the preferred embodiment, the
crimp is a trapezoidal shape and is formed to have a
low profile so that it will not adversely interfere
with the advancement of the catheters over the
crimped joint. After a successful catheter
exchange, the joint can be broken to separate the
extension to allow for easy manipulation of the
guide wire, from its proximal end.
It is among the objects of the invention to
provide a new and improved technique for performing
catheter exchanges.
Another object of the invention is to provide a
guide wire system which enables catheter exchanges
to be performed without the use of an exchange wire.
Another object of the invention is to providè a
technique for performing catheter exchange which is
quick and requires no fluoroscopic exposure.
r
2B410/717
AZB/dmc ~ Q1 A
6818B 1~ ao 1~
A further object of the invention is to provide
method and apparatus for attaching an extension on
to the proximal end of the guide wire while the
guide wire is in place thereby to facilitate
catheter exchanges over the combined guide wire
extension.
Another object of the invention is to provide a
system of the type described in which the extension
wire can be separated from the guide wire after the
catheter exchange has been completed.
DESCRIPTION OF THE DRAWING
The foregoing and other objects and advantages
of the invention will be appreciated more fully from
the following further description thereof, with
reference to the accompanying drawings wherein:
PIG. 1 is a diagrammatic illustration of a
patient undergoing catheterization with a catheter
inserted percutaneously into the femoral artery and
showing, diagrammatically, the catheter and guide
wire which protrude proximally, and illustrating
further, in phantom, the relative length of an
exchange wire;
FIG. 2 is a composite fragmented and partly
sectional unscaled illustration of the proximal end
of a guide wire of conventional length in accordance
28410/717
AZB/dmc
6818B
~ ~23814
-- 10 --
with the present invention and the guide wire
extension, showing the distal end of the extension
aligned with the proximal end of the guide wire in
readiness to be mated;
FIG. 3 is an unscaled illustration of the
proximal and distal ends of the guide wire and
extension wire of the invention when mated but
before being crimped:
FIG. 4 is an unscaled illustration of the
crimped connection of the guide wire an extension
wire;
FIG. S iS a partly fragmented and partly
sectioned illustration of the crimping tool:
FIG. 6 is a side elevation of the jaw end of the
crimping tool with the jaws closed to a wire
gripping position;
FIG. 7 is a sectional illustration as seen along
the line 7-7 of FIG. 6 illustrating the jaws
gripping the proximal end of the guide wire in
readin0ss to receive the guide wire extension;
FIG. 8 is an illustration similar to FIG. 7 with
the extension wire and guide wire connected and with
the jaws of the crimping tool in a crimped
configuration; and
FIG. 9 iS a side elevation of the jaws of the
crimping tool in crimped configuration as seen along
the line 9-9 of FIG. 8
2B410/717
AZB/dmc
681~B 1~2~81~
-- 11
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 illustrates, in highly diagrammatic form,
the catheter 10 and guide wire 12 which have been
inserted into the patient's femoral artery and have
been advanced to the region of the patient's heart
where the desired procedure will be performed. The
guide wire 12 and catheter 10 will have been
inserted and placed in the artery in accordance with
well known procedures.
When it is desired to exchange the catheter for
another, it is important that the guide wire be
maintained within the patient's artery so that it
may guide the next succeeding catheter quickly and
efficiently to the intended site in the patient's
vascular system. Typically, the clearances between
the guide wire 12 and inner lumen of the catheter
10, coupled with the bends which the catheter 10 and
guide wire 12 must follow along the patient's
vascular system are such that withdrawal of the
catheter 10 tends to drag the guide wire 12 out with
the catheter 10. In order to maintain the guide
wire 12 in place while the catheter 10 is withdrawn,
it is necessary to hold the guide wire 12 by its
proximal end 16 while withdrawing the catheter 10
over the guide wire 12. Because the proximal end 16
of a conventional guide wire only extends proximally
2B410/717
A8l/8dmC 1323814
- 12 -
beyond the proximal end 18 of the catheter by an
amount which is substantially less than the length
of the catheter 10, there is no means for retaining
the conventional guide wire 12 in position while the
catheter 10 is removed.
In order to effect a catheter change, it has
bean the practice fo~ many years to use an exchange
wire. The exchange wire is substantially longer
than the conventional length of guide wire 12 and
may be of the order of 300 cm long. The additional
effective length o the exchange wire as compared to
the conventional length guide wire 12 is represented
by the phantom line 20 in FIG. 1. The length of the
exchange catheter is such that its tip, represented
by the reference character 22, is spaced from the
proximal end 18 of the catheter by a distance which
is greater than the length of the catheter 10.
In performing the exchange, the guide wire 12 is
removed from the catheter 10 while the catheter 10
remains in the patient. The exchange wire then is
inserted into and advanced along the catheter 10
until its distal tip is located at the intended site
within the patient's vascular system. The
additional length of the exchange wire which
protrudes proximally of the proximal end 18 of the
catheter 10 provides a sufficiently long means by
which the exchange wire may be gripped so that its
2B410/717
6A8l/dBmc 132~814
- 13 -
position may be maintained in the patient while the
catheter 10 i-Q withdrawn. Thus, the catheter 10 may
be withdrawn over the exchange wire, and the next
catheter may be placed in the patient by advancing
it over and along the exchange wire. After the next
catheter has been placed, it may be desirable to
remove the exchange wire and replace it with another
standard length guide wire, depending on the type of
catheterization procedure which is to be performed.
For example, if the procedure requires use of a
steerable guide wire which must be manipulated from
its proximal end, such a guide wire will have to be
exchanged for the exchange wire after the catheter
exchange has been made.
In accordance with the present invention,
catheters may be exchanged without requiring removal
of the guide wire 12 and without requiring the
involvement attendant to the use of an exchange
wire. In accordance with the present invention, the
guide wire 12 is connected, at its proximal end, to
an extension wire 24 while the guide wire 12 and
catheter 10 remain in the patient. The extension
wire 24 is attached securely to the proximal end of
the guide wire 12 and serves to extend the effective
length of the guide wire 12 sufficiently to permit
the catheter 10 to be withdrawn over the guide wire
12 and extension 24.
2B410/717 1323~1~
AZB/dmc
6818B
As shown in FIG. 2, the guide wire 12 iS
provided with a hollow tubular connective fitting 26
which is attached to and extends proximally of the
proximal end of the guide wire 12. In the
S illustrative embodiment, the guide wire 12 is
illustrated as having a proximal end formed from a
Qolid wire such aR the type of guide wire
illu-~trated in the aforementioned Canadian
Patent 1,208,096. It should be
understood, however, that the general principles of
the present invention may be applied to any guide
wire by modifying the proximal end of the guide wire
to include a means for attaching the proximal end of
the guide wire to an extension wire.
In the illustrative embodiment, the proximal end
of the guide wire is provided with a reduced
diameter projection 28 which is received within an
end of the tube which forms the connective fitting
26. The tube 26 is secured to the guide wire 12
such as by brazing as indicated at 30 at the
junction of the end of the tube 26 with the shoulder
32 defined at the transition of the guide wire 12 to
the reduced diameter projection 28. Alternate
construction may have tapered portion to form the
transition from the guide wire to the projection~
28. The outer diameter of the tube 26 preferably is
the same as the outer diameter of the guide wire
;~,
"
2B410/717 13 2 3 814
AZ3/dmc
6818B
- 15 -
12. The tube 26 thus defines an elongated socket 34
which is receptive, as will be described, to the
distal end of the extension wire 24 The tube 26
may be formed from stainless steel, as may be the
S guide wire 12. The tube 26 may be fabricated from
reaqlly available hypodermic tubing. The wall
thlckness of the tube 26 should be selected so that
it can be crimped easily, as will be described, but
it also must be capable of ~roviding sufficient
rigidity to maintain a secure connection to the
guide wire extension 24. By way of dimensional
example, with a guide wire of the type described in
the aforementioned Canadian Patent 1,208,096,
the-proximal end of the guide wire may
have an outer diameter of the order of .016 inches
and the tubing 26 will have the same outer
diameter. A wall thickness for the tubing of the
order of .0015 to about .003 inches has been found
to be satisfactory. The length of the tubing 26 may
20- be of the order of about four inches and the socket
may be of the order of about three inches deep.
The guide wire extension 24 also may be formed
from stainless steel and preferably is of comparable
diameter to that of the guide wire 12 and extension
26. -The distal end of the extension 24 has a
reduced diameter tip 36 which is insertable into the
socket 34 of the fitting 26. The guide wire
2B410/717 13 2 3 81~
6818B
- 16 -~
extension 24 may be provided with a tapered
transition region 38 between its main body and the
tip 36. By way of dimensional exa~ple, in the
illustrative embodiment, the tip 36 may be of the
order of about four cm long having an outer diameter
of .008-.009 inches so that it may be received
within the socket 34. The tip 36 and socket 34
should be sufficiently long so that the full length
of the tip 36 extends into the socket 34.
FIG. 3 illustrates the manner in which the guide
wire 12 and guide wire extension 24 mate. The
distal tip of the extension simply is inserted into
the socket 34 of the fitting 26. The connected
members then are deformed, preferably in a
configuration illustrated in FIG. 4, to secure the
wire 12 and extension 24 together. once secured,
the effective length of the wire 12 will have been
extended and the catheter 10 can be removed over the
combined effected extended length without requiring
removal of the guide wire 12.
The mechanical attachment is effected preferably
by deforming the connected tube 26 and tip 36 by
displacing a segment of them laterally of the common
axis X of the combined guide wire 12 and extension
24. The extent of lateral displacement, howeverj is
limited by the flexibility of the catheters with
which the device is to be used. The extent of
2B410/717 1 3 2 ~ Q~ A
AZB/dmc
6818B
lateral displacement should not be so great or sharp
so as to require so sharp a bend in the catheter
that it will interfere with smooth advancement of
the catheter 10 over the joint. In accordance with
the present invention, it has been found that a
trapezoidal shaped deformation seems to provide the
best results, although other non-trapezoidal shapes
might be employed. As shown in FIG. 4, the
preferred shape of the crimp includes a central
segment 40 and a pair of spaced segments 42 which
are formed between the ends of the tube 26.
Preferably the crimp is formed in a manner which
leaves a short proximal segment 44 of the tubing 26
which remains in coaxial alignment with the
extension wire 24. In the preferred embodiment, the
spaced segments 42 are arranged at an angle A of
about 30 to the central axis of the guide wire 12
and extension 24. The central crimped segment 42 is
displaced transversely of the axis X but extends
substantially parallel to it. Preferably, the
central segment 40 can be displaced about .060
inches from the common axis X. The overall length -
of the crimp including the end segments 42 and
central segments is of the order of about .60 inches.
It has been found that such a connection can~be
made quickly and easily. It maintains sufficient
tensile strength of the order of about one to two
2B410/717 13 2 ~ 81~
- 18 -
pounds force so as not to come apart during use, yet
it does not interfere with advancement of the
catheter as it is snaked over the crimped portion.
Additionally, it should be noted that the connection
also maintains sufficient compressive strength so
that when the catheter is advanced over the guide
wire and extension, the connection between the guide
wire and guide wire extension will not collapse or
otherwise become adversely deformed as a result of
the compressive force resulting from pushing the
catheter along the guide wire extension.
Additionally, the connection may be broken easily
and quickly should it be desired to separate the
guide wire extension 24 from the guide wire 12. The
guide wire 12, fitting 26 and guide wire extension
24 preferably all are coated with a thin film of
low-friction material such as polytetrafluoro-
ethylene to enhance the ease with which the catheter
may slide over the guide wire and connected
extension.
Although the principals of the invention may be
applied to a wide range of sizes of guide wires and
catheters, the configuraton in the illstrative
embodiment is useful particularly with smaller
diamter guide wires for use with relatively small
diameter flexible catheters. For example, the
illstrative embodiment of the invention is
AZ~/dmc 13 2 3 8 1~
6818B
-- 19 --
particularly advantageous when used with guide wires
of the order of ,025 diameter and smaller which, in
turn, may be used with catheters of the order of 6
French and smaller.
The invention also provides a device for
facilitating connection and crimping of the
connected guide wire 12 and extension wire 24. As
shown in FIGS. 5-9, the crimping device indicated
generally at S0 may be molded from a suitable
plastic such as for example, Delrin (trade name for
acetal). The crimping device 50 is somewhat in the
form of pliers having a pair of handle members 52,
54 which are connected to each other at a pivot pin
56 and slot 58 formed integrally with the members
lS 52, 54. The members 52, 54 thus are pivotable with
respect to each other and define a pair of jaw
members 60, 62 which are movable toward and away
from each other. The jaws 60, 62 are arranged to
hold the connective fitting 26 at the proximal end
of the guide wire 12 in a position to receive the
tip 36 of the extension wire 24. The jaws 60, 62
also include an arrangement for guiding the tip 56
of the extension wire 24 into the socket 34 of the
fitting 26 and, when the extension wire and fitting
26 are mated, for effecting the crimp illustrated in
FIG. 4.
~ .
_
2B410/717
AZ~/dmc
6818B 132381~
-- 20 --
One of the jaw ~embers 60 has an inner face 64.
The jaw 60 is molded to include a platform 66 which
extands away from the jaw face 64. The platform is
of trapezoidal configuration and includes an upper
face 68 which is parallel to the inner face 64 of
the jaw 60, and a pair of sloping side faces 70.
The transversely extending groove 72 is formed
transversely along the upper face 68 of the platform
66. The groove 72 is intended to receive and
cooperate in holding the connective fitting 26. The
opposing jaw 62 is formed with a trapezoidal shaped
indentation 74 having surfaces corresponding to and
paralleling those of the platform 66, including
surfaces 70 and 72. The jaw member 62 also includes
lS a pair of transversely extending members 76, 78
which have surfaces 80, 82. The surfaces 80, 82
extend parallel to the surface 64 of member 52 when
the jaws 60, 62 are mated. AS will be described in
further detail, the fitting 26 may be positioned in
the device by placing it along the channel 72 and
then closing the jaw 62 to cause jaw surfaces 80 and
82 to engage the fitting 26 and hold it in place,
ready to receive the tip 36 of the extension wire
24. The surface 82 of the jaw member 62 is provided
with a transversely extending groove 84 which
receives the end of the fitting 26 in a manner and
2B410/717
68l/8BmC 132381~
for a purpose which will be described. The outer
end of the groove 84 is formed to include an
upwardly and transversely diverging funnel-shaped
channel 86.
The jaw end of the handle member 52 includes an
integrally formed elongate finger 88 which is
separated from the main portion of the jaw member 60
by a slot 90. The finger i~ formed so that it may
flex and bend with respect to the jaw 60 and handle
52. The outer end of the finger 88 is formed to
include a platform 92 having an upper surface 94.
The platform 92 includes a transversely extending
groove 96 which communlcates with transversely
opening funnel-shaped channel 98. The platform 92
is located with respect to the transverse portion 78
of the jaw 62 so that when the jaws 60, 62 are
brought together, the surfaces 82 and 94 will butt
against each other with the grooves 84, 96
cooperating to define a guiding passage and the
channels 86, 98 cooperating to define a funnel
leading into the guiding passage.
As shown in FIGS. 6 and 7 the connective fitting
26 is held between the jaws 60, 62 with the fitting
26 being engaged by the channel 72 on the platform
66 and by the surfaces 80 and groove 84 of-the jaw
member 62. The fitting 26 thus is held securely and
its socket 34 is in alignment with the guiding
2B410/717
AZB/dmc
6818B 1323814
pa-Rsage defined by the cooperating geooves 84, 96.
The distal tip 36 of the extension wire 24 then may
be passed through the funnel 86 and into the aligned
socket 34. The funnel defined by the channels 86,
98 serves to facilitate entry of the tip 36 into the
socket 34.
Once the distal tip 36 of the extension wire has
been inserted through the funnel and guiding passage
into the socket 34, the crimping tool is operated to
draw the jaws 60, 62 together and effect the
crimping operation. During the crimping operation,
the finger 88 flexes downwardly as shown in FIG. 7
to maintain the axial alignment of the guide wire 12
and extension wire 24 which are located proximally
and distally of the crimp. After the crimp has been
completed, the jaws 60, 62 are opened to release the
connected wires 12, 24. The guide wire 12 thus has
been effectively extended so that the catheter 10
may be removed without requiring withdrawal of the
guide wire 12 and insertion of a new exchange wire.
After the extension has been attached and the
catheter has been withdrawn, the next succeeding
catheter is advanced over the extension and the
guide wire into and through the patient's blood
vessel. Depending on the technique involved and the
physician's preference, the extension may be
2B410/717
AZB/dmc
6818B 13238~4
- 23 -
permitted to remain attached to the guide wire or
may be separated easily. Separation can be effected
by cutting the guide wire distally of the crimp.
From the foregoing, it will be appreciated that
the invention provides a technique and devices by
which catheter exchanges may be made in a manner
which shortens the time required for the procedure,
reduces the amount of radiation exposure to the
patient and reduces further the risk of trauma to
the patient, It should be understood, however, that
the foregoing description of the invention is
intended merely to be illustrative thereof and other
embodiments and modifications may be apparent to
those skilled in the art without departing from its
spirit.
Having thus described the invention, what I
desire to claim and secure by Letters Patent is:
