U.S. patent application number 14/135357 was filed with the patent office on 2014-06-26 for tissue penetrating catheters having integral imaging transducers and their methods of use.
This patent application is currently assigned to MEDTRONIC VASCULAR, INC.. The applicant listed for this patent is MEDTRONIC VASCULAR, INC.. Invention is credited to John Y. Chang, Philip C. Evard, Christopher J. Flaherty, Joshua Makower, David R. Tholfsen, Jason B. Whitt.
Application Number | 20140180098 14/135357 |
Document ID | / |
Family ID | 27555502 |
Filed Date | 2014-06-26 |
United States Patent
Application |
20140180098 |
Kind Code |
A1 |
Flaherty; Christopher J. ;
et al. |
June 26, 2014 |
Tissue Penetrating Catheters Having Integral Imaging Transducers
and Their Methods of Use
Abstract
A catheter device that is useable to penetrate from a blood
vessel in which the catheter device is positioned to a target
location comprises a flexible catheter advanceable into the first
blood vessel, a tissue penetrator lumen adapted to receive an
operative tissue penetrator which is usable to penetrate from the
blood vessel to the target location when properly aimed. Further
said catheter including an imaging transducer fixedly mounted on or
within the catheter body to provide an imaging signal from which an
image of the target location can be obtained. The catheter device
may include an imageable marker on the catheter to form on the
image obtainable from the imaging signal a penetrator path
indication that indicates the path that will be followed by the
tissue penetrator when the tissue penetrator exits from the
catheter. Alternatively, or addition thereto, the imaging
transducer may comprise a plurality of imaging elements which are
located so that the penetrator path indication can be obtained. A
method of utilizing such a catheter device to bypass an arterial
obstruction is also disclosed.
Inventors: |
Flaherty; Christopher J.;
(Los Altos, CA) ; Whitt; Jason B.; (San Francisco,
CA) ; Chang; John Y.; (Mountain View, CA) ;
Tholfsen; David R.; (San Francisco, CA) ; Evard;
Philip C.; (Palo Alto, CA) ; Makower; Joshua;
(Santa Rosa, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MEDTRONIC VASCULAR, INC. |
SANTA ROSA |
CA |
US |
|
|
Assignee: |
MEDTRONIC VASCULAR, INC.
SANTA ROSA
CA
|
Family ID: |
27555502 |
Appl. No.: |
14/135357 |
Filed: |
December 19, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13114987 |
May 24, 2011 |
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14135357 |
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12634916 |
Dec 10, 2009 |
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13114987 |
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10714155 |
Nov 14, 2003 |
7637870 |
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12634916 |
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10033836 |
Dec 26, 2001 |
6660024 |
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10714155 |
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09282774 |
Mar 31, 1999 |
6375615 |
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10033836 |
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08730496 |
Oct 11, 1996 |
5830222 |
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09282774 |
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60080196 |
Mar 31, 1998 |
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60005164 |
Oct 13, 1995 |
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Current U.S.
Class: |
600/439 |
Current CPC
Class: |
A61M 25/0152 20130101;
A61M 2025/0076 20130101; A61B 17/11 20130101; A61B 2018/00392
20130101; A61B 2018/1425 20130101; A61F 2/90 20130101; A61F
2210/009 20130101; A61B 2017/1139 20130101; A61B 8/4488 20130101;
A61F 2/2493 20130101; A61F 2002/30079 20130101; A61M 2025/018
20130101; A61B 90/40 20160201; A61B 17/3496 20130101; A61B 8/12
20130101; A61B 2017/00247 20130101; A61B 17/3207 20130101; A61B
8/445 20130101; A61B 2017/306 20130101; A61B 18/1492 20130101; A61B
2017/22069 20130101; A61B 2090/3784 20160201; A61F 2/07 20130101;
A61F 2/95 20130101; A61B 2017/12127 20130101; A61B 2017/00455
20130101; A61B 2017/3488 20130101; A61B 2017/1107 20130101; A61B
2018/00869 20130101; A61M 29/02 20130101; A61B 17/12172 20130101;
A61B 90/39 20160201; A61B 18/1477 20130101; A61B 2017/00243
20130101; A61B 2017/00252 20130101; A61M 29/00 20130101; A61B
17/3403 20130101; A61B 90/361 20160201; A61B 18/00 20130101; A61B
2090/378 20160201; A61K 31/195 20130101; A61B 2090/3925 20160201;
A61B 18/1445 20130101; A61B 2090/3958 20160201; A61B 2017/22038
20130101; A61B 2017/003 20130101; A61B 2090/3929 20160201; A61B
2017/22072 20130101; A61B 2017/22077 20130101; A61B 17/12109
20130101; A61B 17/320725 20130101; A61F 2002/8486 20130101; A61M
2025/1052 20130101; A61B 2017/00504 20130101; A61B 18/24 20130101;
A61M 25/0133 20130101; A61B 17/3417 20130101; A61B 1/3137 20130101;
A61B 2017/347 20130101 |
Class at
Publication: |
600/439 |
International
Class: |
A61B 17/34 20060101
A61B017/34; A61B 8/12 20060101 A61B008/12 |
Claims
1. A percutaneous, transluminal method for creating a flow channel
between a first blood vessel that has a wall and a lumen and a
second blood vessel that has a wall and a lumen, said method
comprising the steps of: A) providing a catheter device that
comprises: i. a catheter having a proximal end and a distal end,
said catheter being advanceable into the lumen of the first blood
vessel; ii. a tissue penetrator that is advanceable in a lateral
direction from the catheter, said tissue penetrator being operative
to penetrate from the lumen of a first blood vessel, through the
walls of the first and second blood vessels and into the lumen of a
second blood vessel when the catheter is positioned and
rotationally oriented within the first blood vessel such that the
tissue penetrator is aimed at the second blood vessel; iii. an
imaging transducer fixedly mounted on the catheter to provide an
imaging signal from which an image of the second blood vessel and
other anatomical structures located adjacent the first blood vessel
can be obtained, said imaging transducer comprising a plurality of
transducer elements at radially spaced-apart locations, one of said
transducer elements being a penetrator path indicating element
which creates an image that is enhanced or otherwise visually
discernible from the images produced by the other transducer
elements, thereby providing a penetrator path indication which
indicates the lateral direction in which the penetrator will
subsequently advance from the catheter body; B) percutaneously
inserting and transluminally advancing the catheter into the first
blood vessel; C) actuating the imaging transducer and moving the
catheter within the first blood vessel until the penetrator path
indication is aimed at the lumen of the second blood vessel; and,
D) advancing the tissue penetrator from the catheter, through the
walls of the first and second blood vessels and into the lumen of
the second blood vessel.
2. A method according to claim 1 wherein the tissue penetrator is
an elongate member that has a lumen extending longitudinally
therethrough and wherein said method further comprises the step of:
E) advancing a first crossing guidewire through the lumen of the
tissue penetrator and into the lumen of the second blood
vessel.
3. A method according to claim 2 wherein the method further
comprises: F) retracting the tissue penetrator into the catheter
leaving the first crossing guidewire in place such that it extends
from the lumen of the first blood vessel into the lumen of the
second blood vessel.
4. A method according to claim 3 wherein the catheter device
provided in Step A has a main guidewire lumen that extends
longitudinally through at least a portion of the catheter and
wherein the method further comprises the steps of: G) moving the
first crossing guidewire from the lumen of the tissue penetrator,
and reintroducing a crossing guidewire into the main guidewire
lumen of the catheter; and, H) re-advancing the catheter over the
first crossing guidewire to a position wherein the catheter extends
through the lumen of the first blood vessel, through the openings
created in the walls of the first and second blood vessels by
advancement of the tissue penetrator in Step D, and into the lumen
of the second blood vessel.
5. A method according to claim 4 wherein the method further
comprises the steps of: I) actuating the imaging transducer and
moving the catheter within the second blood vessel as required to
cause the penetrator path indication to be aligned with the lumen
of the first blood vessel; and J) advancing the tissue penetrator
from the catheter, through the walls of the first and second blood
vessels and into the lumen of the first blood vessel.
6. The method of claim 5 further comprising the step of: K)
advancing a second crossing guidewire through the lumen of the
tissue penetrator and into the lumen of the first blood vessel.
7. A method according to claim 6 wherein the method further
comprises: L) retracting the tissue penetrator into the catheter
leaving the second crossing guidewire in place such that it extends
from the lumen of the first blood vessel into the lumen of the
second blood vessel and back into the lumen of the first blood
vessel.
8. A method according to claim 7 wherein the method further
comprises the steps of: M) providing a connector delivery catheter
accompanying a radially expandable connector; and N) advancing the
connector delivery catheter over the second crossing guidewire and
implanting the radially expandable connector such that the
connector extends from the lumen of the first blood vessel, through
the openings created in the walls of the first and second blood
vessels in Step D, through the lumen of the second blood vessel,
through the openings created in the walls of the first and second
blood vessels in Step J and back into the lumen of the first blood
vessel.
9. A method according to claim 5 wherein the method is carried out
to bypass an obstruction in the first blood vessel and wherein the
openings created in the walls of the first and second blood vessels
in Step D are proximal to the obstruction and the openings created
in the walls of the first and second blood vessels in Step J are
distal to the obstruction.
10. A catheter device comprising: a catheter having a proximal end
and a distal end, said catheter being advanceable into the lumen of
the first blood vessel; a tissue penetrator that is advanceable in
a lateral direction from the catheter, said tissue penetrator being
operative to penetrate from the lumen of a first blood vessel,
through the walls of the first and second blood vessels and into
the lumen of a second blood vessel when the catheter is positioned
and rotationally oriented within the first blood vessel such that
the tissue penetrator is aimed at the second blood vessel; and an
imaging transducer fixedly mounted on the catheter to provide an
imaging signal from which an image of a target location located can
be obtained, said imaging transducer comprising a plurality of
transducer elements at radially spaced-apart locations, one of said
transducer elements being a penetrator path indicating element
which creates an image that is enhanced or otherwise visually
discernible from the images produced by the other transducer
elements, thereby providing a penetrator path indication which
indicates the lateral direction in which the penetrator will
subsequently advance from the catheter body.
11. A catheter device according to claim 10 wherein the imaging
transducer comprises a radial phased array ultrasound
transducer.
12. A system comprising a catheter device according to claim 10 in
combination with a display having a screen on which there is
displayed the image of the target location and the penetrator path
indicator received from the imaging transducer.
13. A system according to claim 12 wherein hash marks appear on the
display screen to divide the display screen into quadrants and the
imaging transducer is fixedly mounted within the catheter such that
its penetrator path indicating transducer element is in the 12
o'clock position and aligned with a top vertical hash mark on the
display screen such that the top vertical hash mark thereby
functions as the penetrator path indicator.
14. A system according to claim 13 wherein the catheter is
rotatable within a blood vessel in which it is positioned so that,
if the top vertical hash mark is not initially aimed at the target
location, the catheter may be rotated to an orientation within the
blood vessel that causes the top vertical hash to be aimed at the
target location, thereby indicating that subsequent advancement of
the penetrator will cause the penetrator to advance toward the
target location.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of copending U.S. patent
application Ser. No. 13/114,987 filed May 24, 2001, which is a
continuation of U.S. patent application Ser. No. 12/634,916, now
abandoned, which is a division of U.S. patent application Ser. No.
10/1714,155 filed Nov. 14, 2004, now U.S. Pat. No. 7,637,870, which
is a continuation of U.S. patent application Ser. No. 10/033,836
filed Dec. 26, 2001, now U.S. Pat. No. 6,660,024, which is a
continuation of U.S. patent application Ser. No. 09/1282,774 filed
Mar. 31, 1999, now U.S. Pat. No. 6,375,615, which claims benefit of
U.S. Provisional Patent Application No. 60/1080,196 filed Mar. 31,
1998 and is a continuation-in-part of U.S. patent application Ser.
No. 08/837,294 filed Apr. 11, 1997, now U.S. Pat. No. 6,302,875,
which itself is a continuation-in-part of two-earlier filed
applications, namely; U.S. patent application Ser. No. 08/1730,327
filed Oct. 11, 1996, now U.S. Pat. No. 6,190,353 and Ser. No.
08/1730,496 filed Oct. 11, 1996, now U.S. Pat. No. 5,830,222, both
of which claim priority to earlier-filed U.S. Provisional Patent
Application No. 60/005,164 filed Oct. 13, 1995 and Application No.
60/010,613 filed Feb. 2, 1996, the entire disclosures of all such
related applications being expressly incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to medical devices
and methods, and more particularly to catheter devices and methods
that are useable to form channels (e.g., penetration tracts)
between vessels such as arteries and veins and vessels and other
anatomical structures, in furtherance of a therapeutic purpose such
as bypassing an arterial blockage, delivering therapeutic agents,
or performing other interventional procedures.
BACKGROUND OF THE INVENTION
[0003] Atherosclerotic cardiovascular disease remains a major cause
of premature death and morbidity, in most regions of the world.
Various transluminal, catheter-based interventional techniques have
been used, or proposed for use, to dilate or otherwise treat
atherosclerotic obstructions that occur in coronary and/or
peripheral arteries. These therapies have traditionally focused on
treating the disease intraluminally, or from "within" the vessel
lumen.
[0004] Included among the newer interventional techniques are
certain percutaneous, transluminal techniques for bypassing
obstructions in coronary or peripheral arteries through the use of
the adjacent vein(s) as in situ bypass conduit(s); (e.g. using
catheters to perform extra luminal procedures outside the diseased
vessel lumen. These procedures are described in U.S. Pat. No.
5,830,222 (Makower) and in published PCT Applications WO 98/16161
and WO 98/46119. As described therein, in some instances, these
procedures may be performed by a venous approach wherein a tissue
penetrating catheter is inserted into a vein and the desired
passageway or puncture is initially formed by facilitating the
passage of a tissue penetrator (e.g., a flow of energy or an
elongate penetration member) from a catheter, through the wall of
the vein in which the catheter is positioned, and into a target
location such as the lumen of an adjacent vessel (e.g. the artery).
Alternatively, some of these procedures may be performed by an
arterial approach wherein the catheter is inserted into an artery
and the desired passageway or puncture is initially formed by
facilitating the passage of a tissue penetrator (e.g., a flow of
energy or elongate penetration member) from the catheter, through
the wall of the artery in which the catheter is positioned, and
into the target location such as the lumen of an adjacent vessel
(e.g. a vein). It is typically necessary for the tissue-penetrating
catheter to be placed in proper rotational orientation within the
blood vessel, prior to facilitating the passage of the tissue
penetrator therefrom, to ensure that the tissue penetrator is aimed
or positioned to enter the target. To facilitate such aiming of the
tissue penetrator, some of the previously described tissue
penetrating catheters have included a penetrator direction marker
that indicates the direction in which the tissue penetrator will
pass from the catheter and an imaging catheter lumen through which
a separate intravascular ultrasound imaging catheter (IVUS
catheter) can be advanced. After the separate IVUS catheter has
been advanced into the imaging lumen of the tissue penetrating
catheter, the IVUS is used to image the target and the penetrator
direction marker. The catheter can then be rotated within the blood
vessel until the penetrator direction marker is aligned with the
target, thereby indicating that subsequent advancement of the
tissue penetrator from the catheter will result in the formation of
the desired penetration tract between the blood vessel in which the
catheter is positioned and the target.
[0005] Applicant has determined that, in cases where the
tissue-penetrating catheter is to be placed in a relatively small
blood vessel such as branches of the coronary artery, carotid
arteries, or smaller vessels located in the peripheral vasculature
(e.g. vessels in the arms or legs), it is desirable for the tissue
penetrating catheter to be of reduced profile while still having
sufficient column strength and torque transfer properties to allow
the operator to rotate and maneuver the distal end of the catheter
within the patients body by twisting, pushing and pulling the
proximal end of the catheter that remains outside of the patient's
body. Thus, because the provision of a separate imaging catheter
lumen substantially increases the required diameter of the tissue
penetrating catheter, it is desirable to devise new tissue
penetrating catheter designs that do not include an imaging
catheter lumen while still maintaining the capability of imaging
from a vantage point near the catheter's distal end to facilitate
proper rotational orientation of the tissue penetrating catheter to
facilitate aiming of the tissue penetrator.
SUMMARY OF THE INVENTION
[0006] This invention facilitates accurate and reliable orientation
of a tissue penetrating catheter in a blood vessel so that an
adjacently located blood vessel or other anatomical target can be
accurately penetrated, while eliminating the need for formation of
a separate imaging lumen within the tissue penetrating catheter.
Thus, because the need for an imaging lumen has been eliminated,
the tissue penetrating catheters of this invention may be of
reduced profile (e.g., 5-7 French diameter).
[0007] In accordance with the invention, there is provided a tissue
penetrating catheter device that comprises an elongated catheter
having an instrument lumen to facilitate the passage of a tissue
penetrator, a penetrator direction marker, and an integral imaging
transducer (e.g., an IVUS transducer). To facilitate orientation,
the imaging transducer is useable to provide an imaging signal from
which an image of the target structure and other adjacent
anatomical structures can be obtained. The imaging transducer is
fixedly mounted on or within the catheter, thereby eliminating the
need for a separate imaging lumen which requires sufficient
clearance in the lumen to allow a separate imaging transducer to be
advanced and retracted in the lumen. This in turn enables the
catheter to be of smaller cross sectional area. In addition, by
fixedly mounting the imaging transducer on the catheter, its
orientation relative to the catheter and certain components on the
catheter can be specifically known.
[0008] One advantageous approach to imaging is to employ an imaging
transducer which includes a plurality of imaging elements fixedly
mounted on the catheter to provide an imaging signal from which an
image of adjacent structures can be obtained. The imaging elements
are mounted on the catheter at known circumferential locations
relative to the path that will be followed by the tissue penetrator
as the tissue penetrator exits from the catheter. The image
obtained from the imaging signal from the imaging transducer is
useable by the operator to rotationally orient the catheter such
that, when the tissue penetrator subsequently exits the catheter,
the tissue penetrator will extend into the desired target. In
addition, the imaging transducer is useable to image other
structures to allow several diagnostic functions such as assessing
calcification of a vessel, distance of the target location to the
vessel in which the catheter is positioned, and the presence of
other devices.
[0009] Another advantageous approach to imaging is to provide an
imaging marker on the catheter to form, on the image obtainable
from the imaging signal from the imaging transducer, a penetrator
path indication. This penetrator path indication is indicative of
the path that will be followed by the tissue penetrator when the
tissue penetrator exits from the catheter. The imaging transducer
and the marker are useable in cooperation with each other to enable
the operator to rotationally orient the catheter until the
penetrator path indicator is aimed at the target thereby indicating
that when the tissue penetrator exits from the catheter it will
extend to the target as desired. The imaging elements fixedly
mounted on the catheter at known circumferential locations can also
be used to orient the catheter without any imageable markers.
[0010] When an imageable marker is used, it preferably includes a
structure formed on the catheter including at least one
longitudinal member disposed circumferentially about a hollow
interior space. When a plurality of longitudinal members is
employed, said longitudinal members are disposed at
circumferentially spaced apart locations about a hollow interior
space thereby forming a cage. At least one of such longitudinal
members is located at a circumferential position that is axially
aligned with the path or plane of the path that will be followed by
the tissue penetrator as it exits from the catheter.
[0011] The tissue penetrator may be any instrument for penetrating
the target of interest. For example, the tissue penetrator may be
or include a laser beam, flow of energy, or an instrument which
will itself puncture or penetrate the target of interest. One
preferred form of tissue penetrator includes a needle member formed
of resilient material that is biased to a preformed curved
configuration with the needle member being initially disposed in a
retracted position within the catheter and subsequently advanceable
from the catheter to an extended position wherein the needle member
assumes its preformed curved configuration.
[0012] The imaging transducer of the current invention is
preferably an ultrasound imaging transducer and more preferably a
phased array transducer. Because the phased array transducer can be
fixed in a permanent manner on or within the catheter body, said
phased array transducer has the advantage of being useable with or
with out an imageable marker to obtain reliable and accurate
orientation. Moreover, the nature of the imaging elements and the
fact the imaging signal can be transmitted by multiplexing numerous
signals on fewer lead wires contribute to the small profile of the
catheter.
[0013] The catheter may include an elongated catheter body having a
proximal end, a distal end and a peripheral wall with at least a
distal region of the catheter body being flexible enough to
navigate through the coronary vessels. The catheter body has an
penetrator lumen that terminates distally at an exit location on
the peripheral wall and contains or is adapted to receive an
instrument or other tissue penetrator for penetrating the blood
vessel in which the catheter body is received ("resident blood
vessel") to a target adjacent to the resident blood vessel. The
phased array transducer is preferably an onboard transducer which
is mounted on or within the catheter body and is inseparable or not
removable from the catheter body. The phased array transducer is
carried by the catheter body in fixed relationship to the catheter
body and in some instances, in a known orientation relative to the
exit location. The phased array transducer provides an imaging
signal for use in locating the target and identifying the angular
orientation of the exit location. Accordingly, with the penetrator
received in the penetrator lumen the catheter body can be rotated
to properly orient the exit location so that the penetrator can
penetrate the resident blood vessel into which the catheter body is
receivable and into the target. The catheter body is of
sufficiently small profile so that it can be received within a
coronary artery, branch or peripheral vessel if desired.
[0014] The catheter may be considered as including an imageable
marker which may include a plurality of circumferentially spaced
imageable members carried by the catheter body in a known
circumferential orientation relative to the exit location. The
imageable markers can be sensed by the phased array transducer and
used to locate the target and in identifying the angular
orientation of the exit location.
[0015] The phased array transducer may comprise a plurality of
imaging elements arranged on the catheter body with at least one of
the elements being at a known circumferential location relative to
the exit location so that such at least one element is useable to
identify the angular orientation of the exit location.
Alternatively or in addition thereto, the at least one element may
form an image region that defines an acceptable zone of penetration
for the tissue penetrator.
[0016] In a preferred construction, the catheter body includes a
major section which includes a proximal end and the exit location
and a distal tip section extending from the major section to the
distal end. The distal portion of the distal tip section has a
smaller cross sectional area than the adjacent region of the major
section. An active imaging apparatus is carried by the catheter
body and includes imaging elements fixedly mounted on the distal
tip section and a lead or leads extending proximally from the
imaging elements along the catheter body. Accordingly, the reduced
diameter portions of the catheter body are used to mount the
imaging elements, to thereby minimize the profile of the catheter
at this region of the catheter. Although various constructions are
possible, in one preferred form of the invention, the major section
terminates distally in a distal opening and a proximal portion of
the distal tip section is received in the distal opening and a
distal portion of the distal tip section extends distally of the
distal opening.
[0017] The method of this invention includes inserting and
transluminally advancing the catheter of this invention into a
first blood vessel, actuating the imaging transducer and moving the
catheter within the first blood vessel until the penetrator path
indication is aimed at the target, and thereafter facilitating the
exit of the tissue penetrator from the catheter through the wall of
the first blood vessels and into the target. Thereafter various
procedures may be performed such as the delivery of therapeutic
agents or diagnostic devices.
[0018] In procedures where it may be advantageous to perform
subsequent procedures over a guidewire, such as the formation of
passageways between a first blood vessel and a target, the method
may also include advancing a first crossing guidewire through the
lumen of the tissue penetrator and into the target, such as the
lumen of the second blood vessel or other target and retracting the
tissue penetrator into the catheter leaving the first crossing
guidewire in place.
[0019] In some procedures, such as those novel procedures more
fully described in U.S. Pat. No. 5,830,222 and in U.S. patent
application Ser. Nos. 08/730,496, 09/048,147 and 09/048,147, and
other means of revascularizing oxygen starved tissues or delivering
therapeutic substances to vessels, tissue and other organs, it may
be advantageous to obtain a second point of access to the same
vessel into which the catheter was initially introduced at some
point distal of the first crossing. However, this access may be
limited due to the presence of calcium or other vessel disease
blocking the lumen of the vessel. To obtain catheter access to a
second point, distal of a diseased section in the same blood
vessel, the first crossing guidewire is removed from the lumen of
the tissue penetrator and reintroduced into the main guidewire
lumen of the catheter and the catheter may be readvanced over the
first crossing guidewire to a position wherein the catheter extends
through the lumen of the first blood vessel, and through the
openings created in the walls of the first and a second blood
vessel. Thereafter, the catheter can be advanced distally in the
lumen of the second blood vessel. To gain access back to the first
blood vessel at a different location (e.g. past the disease or
obstruction), the imaging transducer is actuated and the catheter
is moved within the second blood vessel as required to cause the
penetrator path indication to be aligned with the lumen of the
first blood vessel. The tissue penetrator is advanced from the
catheter through the wall of the second blood vessel and through
the wall and into the lumen of the first blood vessel. To obtain
guidewire access to the first blood vessel, a second crossing
guidewire is advanced through the lumen of the tissue penetrator
and into the lumen of the first blood vessel. The tissue penetrator
is retracted into the catheter leaving the second crossing
guidewire in place such that it extends from the lumen of the first
blood vessel into the lumen of the second blood vessel and back
into the lumen of the first blood vessel.
[0020] As part of the invention envisioned herein, a radial
expandable connector can be used to provide a blood flow passageway
between the blood vessels. For example, a connector delivery
catheter can be advanced over the second crossing guidewire and the
connector implanted such that the connector extends from the lumen
of the first blood vessel through the openings created in the walls
of the first and second blood vessels through the lumen of the
second blood vessel through the openings created in the walls of
the first and second blood vessels and back into the lumen of the
first blood vessel.
[0021] The invention together with additional features and
advantages thereof may best be understood by reference to the
following description taken in connection with the accompanying
illustrated drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is schematic illustration showing the catheter of
this invention in use on a human patient.
[0023] FIG. 2 is an elevational view of one form of catheter
constructed in accordance with the teachings of this invention.
[0024] FIG. 3a is an enlarged fragmentary elevational view
partially in section showing a distal portion of the catheter.
[0025] FIG. 3a' is an enlarged, cut-away view of the wire braid
formed within the distal section of the catheter body.
[0026] FIG. 3a'' is a diagram of a catheter braid illustrating the
braid angle and pick count of the braid.
[0027] FIG. 3b is an enlarged elevational view showing the distal
tip section of the catheter.
[0028] FIGS. 3c, 3d and 3e are cross sectional views taken
generally along lines 3c-3c, 3d-3d, and 3e-3e of FIG. 3
respectively.
[0029] FIG. 3f is a perspective view of the marker structure of the
catheter embodiment shown in FIGS. 3a-3b.
[0030] FIG. 3g is a cross sectional view through FIG. 3g-3g of FIG.
3a.
[0031] FIG. 4 is an elevational view similar to FIG. 3a
illustrating a second embodiment of the catheter.
[0032] FIGS. 4a and 4a' are schematic diagrams of a annular phased
array transducers that may be mounted within catheters of the
present invention.
[0033] FIG. 4b is a schematic diagram of an alternative single
element transducer that is rotatable within or in conjunction with
the catheter.
[0034] FIGS. 5a and 5b are elevational views of the screen of the
imaging apparatus showing standard quadrant-indicating hash marks
on the screen, and illustrating the manner in which the
fixed-transducer catheter of FIG. 4 can be rotationally oriented
within the blood vessel to cause a penetrator-path-indicating
element (and hence the penetrator) to become aimed at a target
location to which the penetrator is intended to travel.
[0035] FIGS. 5c and 5d are elevational views of the screen of an
imaging apparatus whereon a line has been marked to denote the
location of the particular penetrator-path-indicating element of
the fixed-transducer catheter of FIG. 4, and illustrating the
manner in which the line can be used to facilitate rotational
orientation of the catheter within the resident blood vessel such
that the penetrator-path-indicating transducer element (and hence
the penetrator) are aimed at the target location.
[0036] FIGS. 5e and 5f are elevational views of the screen of an
imaging apparatus displaying an image from a fixed-transducer
catheter as in FIG. 4 wherein the penetrator-path-indicating
element(s) of the imaging transducer is/are electronically modified
to produce an image that is i) visually distinct from the images
produced by the other elements of the transducer array, or ii)
modified to produce multiple lines that define a path region, and
illustrating the manner in which the visually distinct image of the
penetrator-path-indicating transducer can be used to facilitate
rotational orientation of the catheter within the resident blood
vessel such that the penetrator-path-indicating transducer element
(and hence the penetrator) are aimed at the target location or
conversely, the path region incorporates the target location within
its scope.
[0037] FIGS. 6a and 6b are views similar to FIGS. 5a and 5b
respectively illustrating how the catheter embodiment of FIG. 3a
can be rotationally oriented within the blood vessel to cause the
image created by the penetrator-path-indicating member of the
marker structure (i.e., the particular strut member of the marker
structure that is aligned with the path that will be followed by
the tissue penetrator when the penetrator is advanced from the
catheter body) to be aimed at the target location to which the
penetrator is intended to travel.
[0038] FIGS. 7a-8d illustrate the triangle of Brock-Moscheau (a
name given to the formation bounded by the relationship between the
arterial and venous system on the heart) and show by way of example
as preferred method that can be carried out in accordance with the
teachings of this invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0039] Set forth herebelow are detailed descriptions of certain
embodiments and examples of the catheter devices and methods of the
present invention.
A. First Embodiment
Catheter with Phased Array (or Rotatable) Imaging Transducer and
Marker Structure for Indicating Penetrator Path
[0040] FIG. 2 shows a catheter 11 constructed in accordance with
the teachings of this invention, while FIG. 1 shows the catheter 11
in use on a human patient. In the embodiment illustrated, the
catheter 11 includes an elongated catheter body 13 having a
proximal end 15, a distal end 17, a handle 19 and a hub 21 coupled
to the proximal end of the catheter body 15 and to the handle. The
handle 19 may also serve as a controller for use in advancing and
retracting the penetrating instrument, such as a tissue penetrator
85 described more fully below.
[0041] The Catheter Body:
[0042] The catheter body 13 includes a relatively rigid proximal
section 23 shown in FIGS. 2 and 3a which may be constructed, for
example, of a metal hypo tube and an elongated flexible distal
section or region 25 suitably joined to the proximal section. A
hand piece 19 is attached to the proximal end of the proximal
section 23, as shown. In the preferred embodiment the hand piece 19
and proximal section 23 are approximately 100 cm in length. The
flexible distal section 25 may incorporate a reinforcement member
such as a wire braid 400 as shown in FIGS. 3a and 3a' and, in the
preferred embodiment is approximately 30 cm in length. The braid
400 terminates approximately 3 cm from the distal end 17.
[0043] It has been determined that material expansion and changes
in the physical properties of certain materials may occur after the
catheter 11 is inserted into the patient's body and warmed from
room temperature to body temperature. This material expansion and
changes in the physical properties of certain materials can result
in variation in the tolerances and sizing of the catheter 11 (e.g.
elongation or shrinking) and can thus give rise to an unwanted
modification of the position of the tissue penetrating member 85.
This could, in at least some cases, interfere with the precise
aiming and advancement of the tissue penetrating member as desired.
FIG. 3a'' illustrates the braid angle A and pick count PC of the
catheter braid 400. The "pick count" PC of the braid is, as is well
known in the art, a function of the braid angle A (i.e., the
greater the braid angle the more picks per inch). Also, the torque
transmission and stiffness of the braided distal section 25 is a
function of the braid angle (i.e., a braid angle of 90 degrees
provides maximum torque transfer and a braid angle of 0 degrees
provides minimum torque transfer). Typically, cardiovascular
catheters used in procedures such as those described herein
utilizing a venous approach have braid angles A that result in a
pick count of 50-70 picks per inch. However, applicant has
determined that by decreasing the braid angle A of the braid 400
within the distal section 25 of the catheter 11 to result in a
lower pick count, it is possible to minimize or eliminate the
unwanted longitudinal expansion of the catheter 11 and/or its
components, while retaining sufficient torque transmission and
acceptable stiffness to accomplish the procedures for which the
catheter 11 is intended (examples of such procedures are
illustrated in FIGS. 7a-8d herebelow). This variation in braid
angle or picks per inch may vary depending on the material of
construction of the catheter and/or the braid fiber, and the
diameter of the catheter body.
[0044] In instances where the catheter 11 is intended for use in a
coronary artery, at least the distal section 25 of the catheter 11
is sized to be received within a coronary artery, and therefore can
be received within either a coronary artery or a coronary vein or
other lumens of equal diameter. The catheter body section 13 has a
penetrator lumen 27 that terminates distally at an exit location or
exit port 29 (FIG. 3a) on a peripheral wall 31 of the catheter
body. The penetrator lumen 27 extends proximally from the exit port
29 to the proximal end 15 of the catheter body 13 and communicates
with the interior of the handle 19 through the hub 21. The
penetrator lumen 27 contains or is adapted to receive an
instrument, such as the tissue penetrator 85 shown in FIG. 3a, for
penetrating out of the blood vessel in which the catheter 11
resides (i.e., the "resident vessel") and to a target location. The
exit port 29 is preferably located a short distance proximally of
the distal end 17. A radiopaque marker 33 is mounted on the lumen
27 adjacent the exit port 29.
[0045] The catheter body 13 also has a guidewire lumen 35 (FIG. 3a)
which extends to the distal end 17 of the catheter body 15. In this
embodiment, the guidewire lumen 35 extends proximally to an inlet
port 37 at the peripheral wall 31 closely adjacent the proximal
section 23. The catheter body also has a lead lumen 39 (FIG. 3c)
for a purpose described below.
[0046] A major section 51 of the catheter body 13 terminates
distally in a distal opening 53, and the catheter body includes a
distal tip section 55 of soft, flexible, biocompatible material
(FIGS. 3a and 3b). A proximal portion 56 of the distal tip section
55 is received in the distal opening 53 and a distal portion of the
distal tip section extends distally to the distal end 17. The
distal portion of the distal tip section 55, i.e. the portion of
the distal tip section 55 which extends beyond the distal end of
the major section 51 is of smaller cross sectional area than the
adjacent region of the major section to thereby define an annular
shoulder 57 on the catheter body 13. The exit port 29 is spaced
slightly proximally of the shoulder 57.
[0047] Phased Array Transducer:
[0048] An imaging transducer 81 is fixedly mounted on the catheter
11, and in the embodiment illustrated in FIG. 3a, the imaging
transducer is mounted on the distal tip section 55 just distally of
the shoulder 57. In this embodiment, the imaging transducer 81 is a
phased array transducer of the type shown schematically in FIG. 4a
and is operative to image 360.degree. about the catheter 11. This
imaging transducer 81 comprises an annular array of individual
crystals or elements 121 is coupled to a multiplex circuit 83 which
is within the major section 51 of the catheter body 13 adjacent the
shoulder 57, and the multiplex circuit 83 is in turn coupled to
leads 85 which extend through the lead lumen 39 and a port 87 (FIG.
2) of the hub 21 to an imaging console 89. When activated, the
imaging transducer emits ultrasound signals and receives back
echoes or reflections which are representative of the nature of the
surrounding environment. The imaging transducer provides an imaging
signal from which an image of the surrounding structure can be
created by signal processing apparatus located in the imaging
console 89 and viewed on a standard display screen located near the
operating table on which the patient is positioned. In a preferred
practice of this invention, the phased array transducer and the
accompanying circuitry and the imaging console 89 may be obtained
from Endosonics of Rancho Cordova, Calif. or Intravascular Research
Limited (United Kingdom).
[0049] Alternative Rotatable Transducer
[0050] In an alternate embodiment of this invention, a rotatable
imaging transducer 81r of the type illustrated schematically in
FIG. 4b may be used. This alternative transducer 81r comprises one
(or more than one) imaging element 121r that is mounted on a
rotating shaft 82 that extends through a portion of the catheter
body (e.g., and out of port 39) such that it can be rotated
relative to the catheter body. Alternatively, it will be
appreciated that this transducer 81r may be fixedly mounted within
or upon the catheter body and the entire catheter body may be
rotated in order to effect rotational movement of the transducer
element 121r.
[0051] Marker Structure:
[0052] In this first embodiment (FIGS. 3a-3e), an imageable marker
structure 101 is fixedly mounted on the catheter body 13 in a known
circumferential orientation relative to the exit port 29. In the
embodiment of FIG. 3a, the marker structure 101 is in the form cage
(FIG. 3f) and the transducer 81 is within the cage. This marker
structure 101 comprises a plurality of longitudinal members 103 and
103pp disposed at circumferentially spaced apart locations about a
hollow interior space 105. The hollow space 105 receives the distal
tip section 55 and the transducer 81, and the transducer 81 is an
onboard transducer in that it is inseparable from and not removable
from the catheter body 13. In this embodiment the transducer 81 is
attached to or wrapped around the catheter body 13 and permanently
retained by a suitable potting composition or adhesive. As shown in
FIG. 3g, one of the longitudinal members 103pp is designated as the
penetrator path indicating member and is positioned at a
circumferential position that is axially aligned with the exit port
29 or otherwise positioned to be indicative of the path that will
be followed by the tissue penetrator 85 as it is advanced from the
catheter body 13 through the exit port 29. Thus, the imageable
marker structure 101 forms on the image obtainable from the imaging
signal from the imaging transducer a penetrator path indication
that indicates the path that will be followed by the tissue
penetrator when the tissue penetrator 85 exits from the
catheter.
[0053] With the construction described above, the imaging
transducer 81 and the marker 101 are both mounted on the distal tip
section 55 which has a smaller cross sectional area than does the
adjacent region of the major section 51 of the catheter body 13.
Accordingly, the cross sectional area of the catheter body 13 at
the region containing the imaging transducer 81 and the marker 101
can still be relatively small. Also, the exit location 29 is
closely adjacent to the imaging transducer 81 and may be, for
example, about 3 mm from the imaging transducer. This minimizes the
likelihood of any significant torsional displacement of the exit
location 29 relative to the marker 101 and imaging transducer 89.
It may also be appreciated that the imaging transducer may be
mounted such that the exit port is located directly at the point at
which the transducer is affixed to the catheter, eliminating any
displacement.
[0054] FIGS. 6a and 6b show an image of what the operator sees on
the display screen of the imaging console 89 when the catheter 11
is advanced into the resident blood vessel. Specifically, FIG. 6a
shows an image of the catheter 11, an image 143 of the resident
blood vessel into which the catheter 11 has been inserted (i.e.,
the blood vessel in which the catheter 11 resides) and an image of
a target blood vessel 145 adjacent to the blood vessel 143. In this
particular illustration, the blood vessels represented by images
143 and 145 are a coronary artery and coronary vein, respectively.
In FIG. 6a, the image created by the penetrator-path-indicating
member 103pp of the marker structure 101, as represented by line or
artifact 147, does not extend into the lumen of the target blood
vessel 145. Thus, if the tissue penetrator 85 were to be advanced
from the catheter 11 while the catheter 11 is in the rotational
orientation shown in FIG. 6a, the tissue penetrator would not
advance into the lumen of the target blood vessel 145, as desired.
However, by rotating the catheter 11 within the resident blood
vessel 143, the operator may cause the image created by the
penetrator-path-indicating member 103pp of the marker structure
101, as represented by line or artifact 147, to extend into the
lumen of the target blood vessel 145 as illustrated in FIG. 6b.
Thus, if the tissue penetrator 85 were to be advanced form the
catheter 11 while the catheter 11 is in the rotational orientation
shown in FIG. 6b, the tissue penetrator 85 would advance into the
lumen of the target blood vessel 145, as desired.
B. Second Embodiment
Catheter with Fixedly Mounted Imaging Transducer Useable without
Marker Structure
[0055] FIG. 4 shows a second embodiment of the catheter 11a which
is identical to the catheter 11 in all respects not shown or
specified as being different herebelow. Portions of the catheter
11a corresponding to portions of the catheter 11 are designated by
corresponding reference numerals followed by the letter a.
[0056] The primary difference between the catheters 11 and 11a is
that the catheter 11a has no imageable marker structure 101.
Instead, its imaging transducer 81a is mounted in a fixed position
such that one particular element 121pp (or a group of particular
elements) is/are designated as the penetrator path but rather is
mounted in a fixed orientation within or upon the catheter such
that a selected one (or selected ones) of the individual imaging
elements 121 (e.g., crystals) of the phased array is positioned in
known spatial relation to the path or plane of the path that will
be followed by the tissue penetrator as exits from the catheter.
This selected one (or ones) of the imaging elements 121 shall be
referred to herein as the "penetrator-path-indicating element
121pp." The imaging elements 121, which may be adhered to the
catheter body 13a, are mounted on the catheter 11 at known
circumferential locations relative to the path that will be
followed by a tissue penetrator as the tissue penetrator advances
from the catheter 11 through the exit port 29a. The image obtained
from the imaging signal from the imaging transducer 81a is thereby
useable by the operator to rotationally orient the catheter 11 such
that when the tissue penetrator subsequently exits from the
catheter, the tissue penetrator will extend into the target as
desired. Thus, because the imaging elements 121a are mounted on the
catheter body 13 in fixed relationship to the catheter body and in
a known circumferential orientation relative to the exit location
29a, the imaging transducer 81a can be used to provide an imaging
signal for use in locating an adjacent blood vessel or other
structure and identifying the angular orientation of the exit
location. If desired, the imaging elements of the imaging
transducer 81 of the catheter 11 can be oriented in the same
fashion as described above for the catheter 11a. In this event, the
only difference between the catheters 11 and 11a would be that the
catheter 11 has an imaging marker 101 and the catheter 11a does
not.
[0057] FIG. 5a shows an image 151 of the catheter 11a (FIG. 4) in
the resident blood vessel 143 in which that catheter is positioned,
as well as an image of the target location 145, shown here as
another blood vessel. Standard serial hash marks 300a, 300b, 300c
and 300d are formed on the imaging screen as shown, generally
dividing the screen into four quadrants. In this instance, the
transducer 81b is fixedly mounted within the catheter 11a such that
its penetrator path indicating transducer element 121pp is in the
12 o'clock position and aligned with the top array of hash marks
300a on the imaging screen. Thus, the top array of hash marks 300a
serve as a visual indicator of the path that will be followed by
the tissue penetrator 85 as it is advanced from the catheter 11a.
In the showing of FIG. 5a, one can see that the top hash marks 300a
do not enter the target location 145 and thus, it can be concluded
from this image that the tissue penetrator 85 is not properly aimed
at the target location. However, by rotating the catheter 11a in
the resident blood vessel 143, to the position shown in FIG. 5b,
the top array of hash marks 300a is caused to pass directly through
the target location 145, thus indicating to the operator that the
tissue penetrator 85 can now be advanced from the exit port 29a to
properly penetrate from the resident vessel 143 into the target
location 145, as desired.
[0058] FIGS. 5c and 5d show an image 151a of the catheter 11a (FIG.
4) in the resident blood vessel 143 in which that catheter is
positioned, as well as an image of the target location 145, shown
here as another blood vessel. A vertical line 146 has been created
on the screen 146 in alignment with the position of a penetrator
path indicating transducer element 121pp of the phased array
transducer 81b. Thus, the line 146 serves as a visual indicator of
the path that will be followed by the tissue penetrator 85 as it is
advanced from the catheter 11a. It will be appreciated by those of
skill in the art that this line 146 may be created on the imaging
screen 89 electronically (e.g., as an illuminated or colored line
on the image) or it may be physically marked on the screen 89
(e.g., by felt tipped marker or other suitable marking material or
apparatus such as a template). In the showing of FIG. 5c, one can
see that the line 146 does not enter the target location 145 and,
thus, it can be concluded form this image that the tissue
penetrator 85 is not properly aimed at the target location 145.
However, by rotating the catheter 11a in the resident blood vessel
143, to the position shown in FIG. 5d, the line 146 is caused to
pass directly through the target location 145, thus indicating to
the operator that the tissue penetrator 85 can now be advanced from
the exit port 29a to properly penetrate from the resident vessel
143 into the target location 145, as desired.
[0059] FIGS. 5e and 5f show an image 151b of the catheter 11a (FIG.
4) in the resident blood vessel 143 in which that catheter is
positioned, as well as an image of the target location 145, shown
here as another blood vessel. The penetrator path indicating
element 121pp of the phased array transducer 81b has, in this case,
been modified to provide an image that is enhanced or otherwise
visually discernible from the images produced by the other
transducer elements 121b of the array. In this manner, a penetrator
path region 148 is visible on the screen 89 in the region that is
imaged by the penetrator path indicating element 121pp. Thus, the
penetrator path region 148 serves as a visual indicator of the path
that will be followed by the tissue penetrator 85 as it is advanced
from the catheter 11a. It will be appreciated by those of skill in
the art that this penetrator path region 148 may be created by
causing the penetrator path transducer element 121pp to receive
more power than the other transducer elements 121b or by otherwise
modifying or processing the signal received from that penetrator
path indicating transducer element 121pp. In the showing of FIG.
5e, one can see that the target 145 is not encompassed by the
penetrator path region 148 and, thus, it can be concluded from this
image that the tissue penetrator 85 is not within acceptable range
of the target location 145. However, by rotating the catheter 11a
in the resident blood vessel 143, to the position shown in FIG. 5f,
the target 145 is brought within an appropriate range of the
penetrator path region 148, thus indicating to the operator that
the tissue penetrator 85 can now be advanced from the exit port 29a
to properly penetrate from the resident vessel 143 into the target
location 145, as desired. Additionally, it is to be understood that
the penetrator path indicating transducer element 121pp or the
output on the imaging console may be additionally modified to allow
imaging or project images of only that region within a
predetermined distance (e.g., up to 3 mm) of the resident vessel
143 thereby signalling to the operator the possible target
locations that are out of the intended range of the tissue
penetrator 85 or subsequent systems or devices that may be employed
to complete the intended procedure.
[0060] As an alternative to creating a penetrator path region by
increasing the power transmitted to the penetrator path element
transducer(s), it will be appreciated that this region 148 may be
created on the imaging screen 89 electronically (e.g., as an
illuminated or colored sector on the image) or it may be physically
marked on the screen 89 (e.g., by felt tipped marker or other
suitable marking material or apparatus such as a template). In
addition, the penetrator path region may be defined by the
enhancement (e.g. electronic illumination, marker or template) of
two lines such as that depicted by line 146, modified to define
boundaries to the region 148 within which is defined an acceptable
range of penetration zone.
[0061] It will be appreciated that the electronically enhanced
penetrator path indicating transducer 121pp may be used in
conjunction with the hash marks 300a, 300b, 300c, and 300d shown in
FIGS. 5a-5b and/or the line 146 shown in FIGS. 5c and 5d, thereby
enabling the operator to utilize multiple indicia to determine the
appropriateness of the size and distance range of the target
location 145 before advancing the tissue penetrator 85. In this
way, the operator is provided with a range of acceptable accuracy
depending on the desired result and taking into account what
procedures may be performed subsequently (i.e. placement of a
connection device or other catheter devices).
C. Examples of Methods and Procedures
[0062] The catheters 11 and 11a may be used in the performance of
various revascularization procedures including, as described in
detail herebelow, a Percutaneous In Situ Coronary Artery Bypass
(PICAB) procedure as well as a Percutaneous In Situ Coronary Venous
Arterialization (PICVA) procedure. It will be appreciated that, in
addition to the particular PICAB and PICVA examples described in
detail herebelow, the catheter system of the present invention may
also be useable to perform various other procedures such as
directed drug delivery procedures of the type described in
co-pending U.S. patent application Ser. No. 09/048,147 and other
revascularization procedures.
[0063] i. A Preferred Method for Performing the PICVA
Procedure:
[0064] The PICVA procedure is useable to effectively provide
arterial perfusion of an ischemic region of myocardium, even in
cases where a coronary artery is so extensively obstructed that no
patent distal portion of the artery remains available to carry
bypassed arterial; flow.
[0065] FIG. 7a is a diagram of a portion of the coronary
vasculature known as known as the Triangle of Brouck-Moscheau. The
Triangle of Brock-Moscheau is defined by the left anterior
descending coronary artery LAD, the circumflex coronary artery CX,
the anterior inter ventricular vein AIV. The arteries CX and LAD
are both joined to and receive blood from the left main artery. The
great coronary vein GCV forms a downwardly opening U-shaped
configuration with the legs of the U being adjacent to arteries CX
and LAD. Obstructions resulting from a build up of plaque may be
found in either or both of the arteries CX and LAD. For example and
for purposes of illustrating a preferred embodiment of the method
of this invention, FIG. 7a shows an obstruction 171 in the left
anterior descending artery LAD.
[0066] In the first step of the procedure, shown in FIG. 7b, a
coronary guide catheter 173 is advanced into the left coronary
ostium and a guidewire 175 such as a 0.014 inch guidewire is
advanced through the guide catheter 173 into the lumen 176 of the
left anterior descending artery (LAD) to a location just proximal
of the obstruction 171 as shown in FIG. 7b.
[0067] Next, as shown in FIG. 7c, the tissue penetrating catheter
11 is percutaneously inserted and transluminally advanced through
the guide catheter 173 and over the guidewire 175 into the left
anterior descending artery LAD to a location just proximal of the
obstruction 171 (FIG. 7c). The axial position of the guidewire 175
and of the catheter 11 within the artery LAD is known by
conventional techniques which may include, for example, fluoroscopy
and the radiopaque marker 33. Although this procedure is described
with reference to the catheter 11, it should be understood that an
identical procedure would be followed for the catheter 11a. As
shown in FIG. 7d, with the catheter 11 in position within the LAD,
the leads 85 are coupled to the imaging console 89 and the imaging
transducer 81 is actuated to obtain images as shown, by way of
example, in FIG. 6a. The catheter 11 is moved, and more
specifically rotated within the artery LAD until the exit port 29
and hence a penetrator path indication or path region 148 is aimed
at the lumen of the vein AIV. At this point, the tissue penetrator
85 is advanced through the exit opening 29 from the catheter 11
through the walls of the artery LAD and the vein AIV and into the
lumen 177 of the vein AIV upstream of the obstruction 171 as shown
in FIG. 7d.
[0068] As shown in FIG. 7e, with the catheter 11 and the tissue
penetrator 85 in the position shown in FIG. 7d, a first crossing
guidewire 179 is advanced through the lumen 851 of the tissue
penetrator 85 and into the lumen 177 of the vein AIV. The tissue
penetrator 85 is then retracted into the catheter 11 leaving the
crossing guidewire 179 in place such that it extends from the lumen
176 of the artery LAD into the lumen 177 of the vein AIV.
[0069] As shown in FIG. 7f, the catheter 11 is then removed by
retracting it back over the guidewire 175 and out through the guide
catheter 173 leaving the guidewires 175 and 179 in place.
[0070] Thereafter, as shown in FIG. 7g, if it is necessary to
enlarge or modify the penetration tract created by the penetrator
85, a tract modification or enlargement apparatus 190 may be
advanced over the first crossing guidewire 179 to enlarge or
otherwise modify the penetration tract. This tract modifying
apparatus 190 may comprise a balloon catheter or radiofrequency
tissue severing device as described in U.S. patent application Ser.
No. 09/056,589, the entirety of which is expressly incorporated
herein by reference.
[0071] As shown in FIG. 7h, after any necessary enlargement or
modification of the penetration tract has been complete, the tract
modifying apparatus 190 and first crossing guidewire 179 are
removed, leaving open the passageway PW between the artery LAD and
vein GCV/AIV. Also, a catheter 191 is introduced into the coronary
venous sinus CS and a guidewire 198 is advanced through the
catheter 191 and into the vein GCV.
[0072] As shown in FIG. 7i, the catheter 191 is then removed and a
coronary sinus guide catheter 196 is introduced over the guidewire
198 into the coronary venous sinus. A subselective sheath 192 and
introducer 194 are then advanced through the coronary sinus guide
catheter 191, over the guidewire 179 and into the vein GCV proximal
to the passageway PW. This coronary sinus guide catheter 196,
subselective sheath 192 and introducer 194 may be of the type
described in detail in concurrently filed U.S. patent application
Ser. No. 09/282,276 entitled CATHETERS, SYSTEMS AND METHODS FOR
PERCUTANEOUS IN SITU ARTERIO-VENOUS BYPASS, the entirety of which
is expressly incorporated herein by reference.
[0073] Thereafter, as shown in FIG. 7j, the introducer 194 is
removed leaving the subselective sheath 192 and guidewire 194 in
place.
[0074] Thereafter, as shown in FIG. 7k, an embolic blocker 200 is
advanced through the subselective sheath 192 and implanted in the
vein GCV proximal to the passageway. This completes the PICVA
procedure, allowing arterial blood to flow from the artery LAD,
through the passageway PW and into the vein GCV/AIV where it flows
in the direction opposite normal venous return so as to
retro-perfuse the ischemic myocardium through the coronary
vein(s).
[0075] ii. A Preferred Method for Performing the PICAB
Procedure:
[0076] FIGS. 8a-8d show, in step-by-step fashion, an example of the
manner in which a two channel PICAB procedure may be performed, or
in the alternative, how the above-described PICVA procedure (FIGS.
7a-7k) may be converted into a two-channel PICAB procedure. This
PICAB procedure will typically be used in cases where the
obstruction 171a does not extend into the distal LAD and thus, a
patent distal LAD is available to carry blood flow to the ischemic
myocardium.
[0077] As shown in FIG. 8a, if the two channel PICAB technique is
to be employed then in lieu of the placement of the embolic blocker
200 being placed (starting from the step referenced in FIG. 7g) the
guidewire 175 is withdrawn and the catheter 11 is advanced over the
crossing guidewire 179 to the position shown in FIG. 8a. To
accomplish this, the tissue penetrator is retracted over the
crossing guidewire 189 to remove the first crossing guidewire from
the tissue penetrator 85 and then the crossing guidewire 179 is
introduced into the main guidewire lumen 35 of the catheter 11.
Consequently, the catheter 11 can be advanced over the crossing
guidewire 179 to the position of FIG. 8a wherein the catheter
extends through the lumen 176 of the artery LAD, through the
openings created in the walls of the artery LAD and the vein AIV
and into the lumen 177 of the vein AIV. The longitudinal or axial
position of the catheter 11 in the vein AIV relative to the
obstruction 171 is known using conventional techniques. With the
catheter 11 in the position shown in FIG. 8a, the imaging
transducer 81 is again actuated and the catheter ills rotated
within the vein AIV as required and as explained above in
connection with FIGS. 6a and 6b to cause the penetrator path
indication to be aimed at the lumen of the artery LAD at a location
downstream of the obstruction 171. With the penetrator path
indication and the exit port 29 properly aimed at the artery 171,
the tissue penetrator 85 is advanced from the catheter 11 through
the walls of the vein AIV and the artery LAD and into the lumen of
the artery LAD as shown in FIG. 8a. Also, as shown, a second
crossing guidewire 181 is advanced through the lumen 85L of the
tissue penetrator 85 and into the lumen of the artery LAD.
[0078] As shown in FIG. 8b, the tissue penetrator 85 is then
retracted into the catheter 11 leaving the second crossing
guidewire 181 in the artery LAD. The catheter 11 and the first
crossing guidewire 179 are then removed leaving the second crossing
guidewire 181 in place such that it extends from the artery LAD
into the lumen 177 of the vein AIV and back into the artery LAD as
shown in FIG. 8b.
[0079] To create a blood flow channel around the obstruction 171,
an expandable connector 191 may be employed. As shown in FIGS. 8c
and 8d, the connector 191 is implanted such that the connector
extends from the artery LAD through the openings created in the
walls of the artery LAD and the vein AIV, through the lumen 177 of
the vein AIV, through the openings created in the walls of the vein
and artery LAD distally of the obstruction 171 and back into the
artery LAD. The expandable connector may be implanted, for example,
by utilizing a connector delivery catheter (not shown) and
advancing such connector delivery catheter over the second crossing
guidewire 181. After implantation of the connector 191, the second
crossing guidewire is withdrawn and so is the guide catheter 173.
It will be appreciated that instead of deploying one expandable
connector, it may be preferred to employ two shorter connectors
(not shown) at each of the first and second crossing sites. In this
approach, a proximal and distal embolic blocker may be required to
be placed in the vein proximal to the first crossing site (in the
GCV) and distal to the second crossing site (in the AIV) to
complete the bypass circuit.
[0080] Although exemplary embodiments of the invention have been
shown and described, many changes, modifications and substitutions
may be made by those having ordinary skill in the art without
necessarily departing from the spirit and scope of this invention.
For example, where this patent application has listed the steps of
a method or procedure in a specific order, it may be possible (or
even expedient in certain circumstances) to change the order in
which some steps are performed, and it is intended that the
particular steps of the method or procedure claims set forth
herebelow not be construed as being order-specific unless such
order specificity is expressly stated in the claim. Another example
is that, although the specific procedures described in detail in
this application may involve penetrating through an "acceptable
penetration zone," such acceptable penetration zone need not be
occupied by tissue but rather such acceptable penetration zone may
fully or partially comprise an open space such as a body cavity or
void. Accordingly, it is intended that all such additions,
deletions, modifications and variations be included within the
scope of the following claims.
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