U.S. patent application number 10/156969 was filed with the patent office on 2002-10-03 for cerebral embolic protection assembly and method of use.
Invention is credited to Macoviak, John A., Samson, Wilfred J..
Application Number | 20020143362 10/156969 |
Document ID | / |
Family ID | 46276566 |
Filed Date | 2002-10-03 |
United States Patent
Application |
20020143362 |
Kind Code |
A1 |
Macoviak, John A. ; et
al. |
October 3, 2002 |
Cerebral embolic protection assembly and method of use
Abstract
The present invention is related to cerebral embolic protection
assemblies (CEPA) to be used during a medical procedure to help
redirect or catch emboli before it is pumped into the cerebral
circulation. A variety of CEPA's are disclosed including a
perfusion filter catheters and fluid flow dividers for capturing
and redirecting potential emboli within the aorta during heart
surgery and cardiopulmonary bypass. The catheter devices may
further include one or more additional or auxiliary flow control
members. Furthermore, oxygenated blood is perfused through a
perfusion lumen in the catheter. The present invention describes
devices that are capable of capturing and/or redirected emboli away
from the cerebral circulation. The devices are configured for
percutaneous, intercostal, lateral or central insertion with
attendant administration of cardiopulmonary bypass and cardioplegic
arrest with protection from undesirable embolic events.
Inventors: |
Macoviak, John A.;
(Cupertino, CA) ; Samson, Wilfred J.; (Cupertino,
CA) |
Correspondence
Address: |
Gunther Hanke
Fulwider Patton Lee & Utecht
P.O. Box 22615
Long Beach
CA
90801-5615
US
|
Family ID: |
46276566 |
Appl. No.: |
10/156969 |
Filed: |
May 28, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10156969 |
May 28, 2002 |
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09447458 |
Nov 22, 1999 |
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6395014 |
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09447458 |
Nov 22, 1999 |
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09158405 |
Sep 22, 1998 |
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6361545 |
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09447458 |
Nov 22, 1999 |
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09378676 |
Aug 20, 1999 |
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6371935 |
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60060117 |
Sep 26, 1997 |
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60116836 |
Jan 22, 1999 |
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Current U.S.
Class: |
606/200 |
Current CPC
Class: |
A61F 2230/0006 20130101;
A61B 17/12036 20130101; A61F 2230/0095 20130101; A61F 2230/0067
20130101; A61B 17/12109 20130101; A61F 2250/0003 20130101; A61B
17/12136 20130101; A61F 2/014 20200501; A61F 2002/018 20130101 |
Class at
Publication: |
606/200 |
International
Class: |
A61M 029/00 |
Claims
What is claimed is:
1. An aortic catheter comprising: an elongated shaft; a cerebral
embolic protection assembly mounted to said elongate shaft and
positioned on said elongated shaft such that, when the aortic
catheter is in an operative position, said cerebral protection
assembly is positioned within a lumen of an aortic arch of a
patient, said cerebral embolic protection assembly having a
deployed position wherein said cerebral embolic protection assembly
is configured to partition the lumen of the aortic arch
longitudinally into a first fluid flow channel in fluid
communication with the aortic arch vessels and a second fluid flow
channel in fluid communication with the patient's corporeal
circulation and wherein said cerebral embolic protection assembly
is configured to allow blood flow to enter the cerebral circulation
while excluding emboli from the cerebral circulation.
2. The aortic catheter of claim 1, wherein at least a portion of
said cerebral embolic protection assembly is porous.
3. The aortic catheter of claim 2, wherein the porous portion of
said cerebral embolic protection assembly is constructed of filter
mesh that is permeable to blood and impermeable to emboli.
4. The aortic catheter of claim 2, wherein the porous portion of
said cerebral embolic protection assembly is configured to allow
blood flow to enter the first fluid flow channel from the second
fluid flow channel, while excluding emboli from entering the first
fluid flow channel from the second fluid flow channel.
5. The aortic catheter of claim 2, wherein the porous portion of
said cerebral embolic protection assembly is configured to exclude
macroemboli from the cerebral circulation.
6. The aortic catheter of claim 2, wherein the porous portion of
said cerebral embolic protection assembly is configured to exclude
macroemboli and microemboli from the cerebral circulation.
7. The aortic catheter of claim 2, wherein the porous portion of
said cerebral embolic protection assembly is configured to divert
micro emboli downstream to the patient's corporeal circulation and
to capture macroemboli.
8. The aortic catheter of claim 1, wherein said cerebral embolic
protection assembly is configured to exclude macroemboli from the
cerebral circulation.
9. The aortic catheter of claim 1, wherein said cerebral embolic
protection assembly is configured to exclude macroemboli and
microemboli from the cerebral circulation.
10. The aortic catheter of claim 1, wherein said cerebral embolic
protection assembly is configured to divert emboli downstream to
the patient's corporeal circulation.
11. The aortic catheter of claim 1, wherein said cerebral embolic
protection assembly is configured to divert microemboli downstream
to the patient's corporeal circulation and to capture
macroemboli.
12. The aortic catheter of claim 1, wherein said cerebral embolic
protection assembly is passively deployable from a compressed
condition wherein said cerebral embolic protection assembly is
folded or compressed toward said elongate shaft and an expanded
condition wherein said cerebral embolic protection assembly extends
from said elongate shaft.
13. The aortic catheter of claim 1, wherein said cerebral embolic
protection assembly is actively deployable from a compressed
condition wherein said cerebral embolic protection assembly is
folded or compressed toward said elongate shaft and an expanded
condition wherein said cerebral embolic protection assembly extends
from said elongate shaft.
14. The aortic catheter of claim 1, wherein said cerebral embolic
protection assembly comprises an upper portion comprised of
impermeable material and a lower portion comprised of impermeable
material.
15. The aortic catheter of claim 1, wherein said cerebral embolic
protection assembly comprises an upper portion comprised of porous
material and a lower portion comprised of porous material.
16. The aortic catheter of claim 1, wherein said cerebral embolic
protection assembly comprises an upper porous portion impermeable
to macroemboli and microemboli and a lower porous portion
impermeable to macroemboli.
17. The aortic catheter of claim 1, further comprising a fluid
lumen extending at least in part along the length of said elongated
shaft and having a fluid port configured to provide fluid to the
cerebral circulation.
18. The aortic catheter of claim 1, further comprising an auxiliary
flow control member.
19. The aortic catheter of claim 18, wherein said auxiliary flow
control member is in the form of an inflatable balloon.
20. The aortic catheter of claim 18, wherein said auxiliary flow
control member comprises a peripheral flow control valve.
21. The aortic catheter of claim 1, wherein said elongated shaft is
sized and configured to be inserted into a peripheral vein and
navigated proximate the aortic arch.
22. The aortic catheter of claim 1, wherein said elongated shaft is
sized and configured to be inserted directly into the aorta.
23. The aortic catheter of claim 1, wherein said elongated shaft is
sized and configured to be inserted through an intercostal
space.
24. A cerebral embolic protection assembly comprising: a body
having an upper surface and a lower surface, said body being
configured to be inserted in an operative position within a lumen
of an aortic arch of a patient with said upper surface facing
toward the aortic arch vessels and said lower surface facing away
from the aortic arch vessels, said body having a deployed position
wherein said body is configured to partition the lumen of the
aortic arch longitudinally into a first fluid flow channel in fluid
communication with the aortic arch vessels and a second fluid flow
channel in fluid communication with the patient's corporeal
circulation and wherein said body is configured to allow blood flow
to enter the cerebral circulation while excluding emboli from the
cerebral circulation.
25. The cerebral embolic protection assembly of claim 24, wherein
at least a portion of said body is porous.
26. The cerebral embolic protection assembly of claim 25, wherein
the porous portion of said body is constructed of filter mesh that
is permeable to blood and impermeable to emboli.
27. The cerebral embolic protection assembly of claim 25, wherein
the porous portion of said body is configured to exclude
macroemboli from the cerebral circulation.
28. The cerebral embolic protection assembly of claim 25, wherein
the porous portion of said body is configured to exclude
macroemboli and microemboli from the cerebral circulation.
29. The cerebral embolic protection assembly of claim 25, wherein
the porous portion of said body is configured to divert emboli
downstream to the patient's corporeal circulation.
30. The cerebral embolic protection assembly of claim 25, wherein
the porous portion of said body is configured to divert microemboli
downstream to the patient's corporeal circulation and to capture
macroemboli.
31. The cerebral embolic protection assembly of claim 25, wherein
the porous portion of said body is configured to allow blood flow
to enter the first fluid flow channel from the second fluid flow
channel, while excluding emboli from entering the first fluid flow
channel from the second fluid flow channel.
32. The cerebral embolic protection assembly of claim 24, wherein
said body is configured to exclude macroemboli from the cerebral
circulation.
33. The cerebral embolic protection assembly of claim 24, wherein
said body is configured to exclude macroemboli and microemboli from
the cerebral circulation.
34. The cerebral embolic protection assembly of claim 24, wherein
said body is configured to divert emboli downstream to the
patient's corporeal circulation.
35. The cerebral embolic protection assembly of claim 24, wherein
said body is configured to divert microemboli downstream to the
patient's corporeal circulation and to capture macroemboli.
36. The cerebral embolic protection assembly of claim 24, wherein
said body is foldable or compressible into compressed condition for
insertion into the patient's aorta.
37. A method of cerebral embolic protection comprising: inserting a
cerebral embolic protection assembly into an operative position
within a lumen of an aortic arch of a patient with an upper surface
of the cerebral embolic protection assembly facing toward the
aortic arch vessels and a lower surface of the cerebral embolic
protection assembly facing away from the aortic arch vessels; and
deploying the cerebral embolic protection assembly to partition the
lumen of the aortic arch longitudinally into a first fluid flow
channel in fluid communication with the aortic arch vessels and a
second fluid flow channel in fluid communication with the patient's
corporeal circulation, wherein the cerebral embolic protection
assembly allows blood flow to enter the cerebral circulation while
excluding emboli from the cerebral circulation.
38. The method of claim 37, wherein the cerebral embolic protection
assembly diverts emboli downstream to the patient's corporeal
circulation.
39. The method of claim 37, wherein the cerebral embolic protection
assembly comprises a filter material permeable to blood and
impermeable to emboli.
40. The method of claim 39, wherein the filter material of the
cerebral embolic protection assembly diverts emboli downstream to
the patient's corporeal circulation.
41. The method of claim 39, wherein the filter material of the
cerebral embolic protection assembly excludes macro emboli from the
patient's cerebral circulation.
42. The method of claim 39, wherein the filter material of the
cerebral embolic protection assembly excludes macroemboli and
microemboli from the patient's cerebral circulation.
43. The method of claim 39, wherein the filter material of the
cerebral embolic protection assembly diverts microemboli downstream
to the patient's corporeal circulation and captures macroemboli
within the filter material.
44. The method of claim 37, further comprising: perfusing the
patient's cerebral circulation through a lumen within the cerebral
embolic protection assembly.
45. The method of claim 37, wherein the cerebral embolic protection
assembly is inserted into the patient's aorta through a peripheral
arterial access point.
46. The method of claim 37, wherein the cerebral embolic protection
assembly is inserted directly into the patient's aorta through an
incision in the aortic wall.
Description
CROSS REFERENCE TO OTHER APPLICATIONS
[0001] This application is a continuation of application Ser. No.
09/447458, filed Nov. 22, 1999, now U.S. Pat. No. 6,395,014, which
is a continuation-in-part of application Ser. No. 09/158,405 filed
Sep. 22, 1998, now U.S. Pat. No. 6,361,545, which claims the
benefit of U.S. Provisional Application No. 60/060,117 filed Sep.
26, 1997, and a continuation-in-part of application Ser. No.
09/378,676, filed Aug. 20, 1999, now U.S. Pat. No. 6,371,935, which
claims the benefit of U.S. Provisional Application No. 60/116,836
filed Jan. 22, 1999. These and all other U.S. patents and patent
applications referred to herein are incorporated by reference in
their entirety for all purposes.
FIELD OF THE INVENTION
[0002] The present invention relates generally to a catheter or
cannula for infusion of oxygenated blood or other fluids into a
patient for cardiopulmonary support and cerebral protection. More
particularly, it relates to an arterial perfusion catheter with a
deployable cerebral embolic protection assembly (CEPA) for
protecting a patient from adverse effects due to emboli that are
dislodged during cardiopulmonary bypass.
BACKGROUND
[0003] Over the past decades tremendous advances have been made in
the area of heart surgery, including such life saving surgical
procedures as coronary artery bypass grafting (CABG) and cardiac
valve repair or replacement surgery. Typically, in order to gain
access to the heart a median sternotomy is performed, which creates
an open surgical field, conducive for the placement of cannulae and
direct visualization for performing the required procedure. Heart
activity generally ceases for some period of time, and
cardiopulmonary support is provided by diverting blood through an
extracorporeal circuit to maintain sufficient oxygenated blood flow
to the body and brain while the heart is arrested. Cardiopulmonary
bypass (CPB) is a technology that has made these advances
possible.
[0004] Recently, however, there has been a growing awareness within
the medical community as well as the patient population concerning
the adverse affects associated with heart surgery, the large amount
of trauma associated with median sternotomies, as well as well the
physiological reactions associated with cardiopulmonary bypass.
Chief among these concerns is the potential for stroke or
neurologic deficit.
[0005] Clinical research has indicated that one of the primary
causes of stroke or neurologic deficit is cerebral embolization.
Emboli vary in size as well as physical properties and their
sources vary. However, embolic materials include atherosclerotic
plaques or calcific plaques residing within the ascending aorta or
cardiac valves and thrombus or clots from within the chambers of
the heart. Emboli may also be dislodged during surgical
manipulation of the heart, the ascending aorta, cross-clamping,
aortic cannulation or due to high velocity jetting (sometimes
called the "sandblasting effect") from the aortic perfusion
cannula. In addition, air can enter the heart chambers or the blood
stream during surgery through open incisions or through the aortic
perfusion cannula. As blood is pumped to the brain, either through
the extracorporeal circuit or by the beating heart in an off-pump
minimally invasive procedure, transient or mobile emboli can become
lodged in the brain causing a stroke or other neurologic deficit.
Clinical studies have shown a correlation between the number and
size of emboli passing through the carotid arteries and the
frequency and severity of neurologic damage. At least one study has
found that frank strokes seem to be associated with macroemboli
larger than approximately 100 micrometers in size, whereas more
subtle neurologic deficits seem to be associated with multiple
microemboli smaller than approximately 100 micrometers in size. In
order to improve the outcome of cardiac surgery and to avoid
adverse neurological effects it would be very beneficial to
eliminate or reduce the potential of such cerebral embolic
events.
[0006] Therefore, what has been needed and heretofore unavailable,
is a catheter device for standard open chest surgery and for use in
minimally invasive medical procedures that is simple and relatively
inexpensive. One which is capable of isolating the circulation of
the arch vessels, while still allowing the heart to perform the
function of perfusing the body or alternatively one that can be
used in conjunction with an extracorporeal circuit. The present
invention solves these problems as well as others.
[0007] The terms downstream and upstream, when used herein in
relation to the patient's vasculature, refer to the direction of
blood flow and the direction opposite that of blood flow,
respectively. In the arterial system, downstream refers to the
direction further from the heart, while upstream refers to the
direction closer to the heart. The terms proximal and distal, when
used herein in relation to instruments used in the procedure, refer
to directions closer to and farther away from the operator
performing the procedure. Since the present invention is not
limited to peripheral or central approaches, the device should not
be narrowly construed when using the terms proximal or distal since
device features may be slightly altered relative to the anatomical
features and the device position relative thereto.
SUMMARY OF THE INVENTION
[0008] In keeping with the foregoing discussion, the present
invention takes the form of a catheter or cannula having a cerebral
embolic protection assembly (CEPA) mounted on an elongated tubular
catheter shaft. The elongated tubular catheter shaft is adapted for
introduction into a patient's ascending aorta either by a
peripheral arterial approach or by a direct aortic puncture. The
CEPA has an undeployed state where it is compressed or wrapped
tightly around the catheter shaft and a deployed state where it
expands to the size of the aortic lumen. The CEPA assembly can be
passively or actively deployed. Various mechanisms are disclosed
for both passive and active deployment.
[0009] Radiopaque markers and/or sonoreflective markers may be
located on the catheter and/or CEPA. Preferably, a perfusion lumen
extends through the elongated tubular catheter shaft to one or more
perfusion ports upstream and/or downstream of the CEPA. Oxygenated
blood is perfused through the perfusion lumen, through the beating
heat or a combination of both. Any embolic materials that might be
dislodged are captured or rerouted by the CEPA.
[0010] Embodiments are also described that combine the CEPA with an
aortic occlusion device, which may be a toroidal balloon, an
expandable balloon or a selectively deployable external catheter
flow control valve. The combined device allows percutaneous
transluminal administration of cardiopulmonary bypass and
cardioplegic arrest with protection from undesirable embolic
events, as well as differential perfusion.
[0011] In use, the CEPA is introduced into the patient's aorta,
either by a peripheral arterial approach or by direct aortic
puncture, with the CEPA in a collapsed state. The CEPA is advanced
across the aortic arch and into the arch and ascending aorta. When
a portion of the CEPA is positioned in the ascending aorta between
the aortic valve and the brachiocephalic artery, the CEPA is either
actively or passively deployed. The position of the catheter and
the deployment state of the CEPA may be monitored using
fluoroscopy, ultrasound, transesophageal echography (TEE) or aortic
transillumination using visible, infrared or near infrared light.
Once the CEPA is deployed, oxygenated blood may be infused into the
aorta through the perfusion lumen or alternatively the beating
heart may supply all the blood or a combination of both. Any
potential emboli are captured or rerouted by the CEPA and are
thereby prevented from entering the neurovasculature. After use,
the CEPA is returned to the collapsed position and the catheter is
withdrawn from the patient. Methods according to the present
invention are described using the aortic catheter for occluding and
compartmentalizing or partitioning the patient's aortic lumen and
for performing selective filtered aortic perfusion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIGS. 1-3 show a perfusion filter catheter configured for
retrograde deployment via a peripheral arterial access point.
[0013] FIG. 1 is a cutaway perspective view of the perfusion filter
catheter deployed within the aorta via femoral artery access.
[0014] FIG. 2 shows the distal end of the catheter with the embolic
filter assembly in a deployed state.
[0015] FIG. 3 shows the distal end of the catheter with the embolic
filter assembly in a collapsed state for insertion or withdrawal of
the device from the patient.
[0016] FIGS. 4-6 show a method of actively deploying an embolic
filter assembly with an inflatable filter support structure.
[0017] FIGS. 7-9 show a perfusion filter catheter adapted for
antegrade deployment via direct aortic puncture.
[0018] FIGS. 10-14 show the operation of an embodiment of a
perfusion filter catheter that combines an embolic filter assembly
with a toroidal balloon aortic occlusion device.
[0019] FIG. 15 shows an embodiment of a perfusion filter catheter
that combines an embolic filter assembly with an inflatable balloon
aortic occlusion device.
[0020] FIG. 16 shows an embodiment of a perfusion filter catheter
that combines an embolic filter assembly with a selectively
deployable external catheter flow control valve.
[0021] FIG. 17 shows an embodiment of a perfusion filter catheter
with an embolic filter assembly having areas of different filter
porosity.
[0022] FIG. 18 shows a bottom view of another CEPA of the present
invention configured for retrograde deployment via a peripheral
artery access point, such as the femoral artery.
[0023] FIG. 19 shows a side view of the catheter of FIG. 18,
showing the CEPA in the form of a divider in the collapsed
state.
[0024] FIG. 20 shows a cross section of the aortic catheter of FIG.
18 taken along line 20-20 in FIG. 18.
[0025] FIG. 21 shows a top view of the catheter of FIG. 18 with the
flow divider deployed.
[0026] FIG. 22 shows a perspective view of an embodiment of the
catheter of the invention including a deployed auxiliary flow
control member positioned between the flow divider and the distal
end of the catheter.
[0027] FIG. 23 shows a perspective view of the catheter of FIG. 22
with the auxiliary flow control member partially collapsed.
[0028] FIG. 24 shows an embodiment of the catheter of the invention
configured for antegrade deployment.
[0029] FIG. 25 shows a cut-away view of an embodiment of the flow
divider including a mesh or porous portion for perfusing from the
upper surface of the flow divider.
[0030] FIG. 26 shows a cut-away view of an alternate internal
structure of the flow divider of FIG. 25.
[0031] FIG. 27 shows an embodiment of the flow divider of the
invention comprising a peripheral tube and membrane structure.
[0032] FIG. 28 shows a cross section of the flow divider of FIG. 27
taken along line 28-28.
[0033] FIG. 29 shows an embodiment of the flow divider of the
invention with welds or joined areas between an upper and a lower
film of the flow divider to give additional structure and rigidity
to the flow divider.
[0034] FIG. 30 shows a cross section of the flow divider of FIG. 29
taken along line 30-30 of FIG. 29.
[0035] FIG. 31 shows an alternate embodiment of FIG. 29 with larger
joined areas between the upper and lower films of the flow
divider.
[0036] FIG. 32 shows another embodiment of the flow divider of the
invention deployed from a lumen within a catheter.
[0037] FIG. 33 shows a cross section of the flow divider and aorta
of FIG. 32 taken transversely through the aorta.
DETAILED DESCRIPTION
[0038] FIGS. 1-3 illustrate a first embodiment of the present
invention having a CEPA in the form of a perfusion filter catheter.
FIGS. 1-3 show a perfusion filter catheter 100 according to the
present invention configured for retrograde deployment via a
peripheral arterial access point. FIG. 1 is a cutaway perspective
view of the perfusion filter catheter 100 deployed within the aorta
of a patient via femoral artery access. FIG. 2 shows the distal end
of the catheter 100 with the embolic filter assembly 102 in a
deployed state. FIG. 3 shows the distal end of the catheter 100
with the embolic filter assembly 102' in a collapsed state for
insertion or withdrawal of the device from the patient.
[0039] Referring now to FIG. 1, the catheter 100 includes a cannula
shaft having a tubular body 104 and a CEPA in the form of a filter
assembly 102. The tubular body has a proximal end 108 and distal
end 110 and is preferably extruded from a flexible thermoplastic
material or a thermoplastic elastomer. Suitable materials for the
tubular body 104 include, but are not limited to,
polyvinylchloride, polyurethane, polyethylene, polypropylene,
polyamides (nylons), and alloys or copolymers thereof, as well as
braided, coiled or counterwound wire or filament reinforced
composites. The tubular body 104 may have a single lumen or
multilumen construction. In the exemplary embodiment shown, the
catheter 100 has a single perfusion lumen 106 extending from the
proximal end 108 to the distal end 110 of the catheter shaft 104.
The perfusion lumen 106 is open at the distal end 110 of the
catheter shaft 104. The distal end 110 of the catheter shaft 104
may have a simple beveled or rounded distal edge, as shown, or it
may include additional side ports or a flow diffuser to reduce
jetting when oxygenated blood is infused through the perfusion
lumen 106. The proximal end 108 of the elongated tubular catheter
shaft 104 is adapted for connecting the perfusion lumen 106 to a
cardiopulmonary bypass pump or other source of oxygenated blood
using standard barb connectors or other connectors, such as a
standard luer fitting (not shown) and suitable medical tubing.
Preferably, the catheter shaft 104 is made with thin walled
construction to maximize the internal diameter and therefore the
flow rate of the perfusion lumen 106 for a given outside diameter
and length of the catheter shaft 104. Thin walled construction also
allows the outside diameter of the catheter shaft 104 to be
minimized in order to reduce the invasiveness of the procedure and
to reduce trauma at the insertion site. The perfusion lumen 106
should be configured to allow sufficient blood flow to preserve
organ function without hemolysis or other damage to the blood. For
standard cardiopulmonary support techniques, a catheter shaft 104
of 18-24 French size (6-8 mm outside diameter) is sufficient to
deliver the requisite 3-4 liters of oxygenated blood to preserve
organ function. For low flow cardiopulmonary support techniques,
such as described in commonly owned, copending patent application
Ser. No. 60/084,835, filed May 8, 1998 and its corresponding
utility application Ser. No. 09/306,555 filed on May 6, 1999 which
are hereby incorporated by reference, the size of the catheter
shaft 104 can be reduced to 9-18 French size (3-6 mm outside
diameter) for delivering 0.5-3 liters of oxygenated blood to
preserve organ function. The catheter shaft 104 should have a
length sufficient to reach from the arterial access point where it
is inserted to the ascending aorta of the patient. For femoral
artery deployment, the catheter shaft 104 preferably has a length
from approximately 80-120 cm.
[0040] A deployable embolic filter assembly 102 is located just
proximal to the distal end 110 of the catheter shaft 104. The
embolic filter assembly 102 includes a filter screen 112 made of a
fine mesh material. In this exemplary embodiment and each of the
other embodiments described below, the fine mesh material of the
filter screen 112 may be a woven or knitted fabric, such as Dacron
polyester or nylon mesh, or other textile fabrics, or it may be a
nonwoven fabric, such as a spun bonded polyolefin or expanded
polytetrafluoroethylene or other nonwoven materials. The fine mesh
material of the filter screen 112 may be woven, knitted or
otherwise formed from monofilament or multifilament fibers. The
fine mesh material of the filter screen 112 may also be a fine wire
mesh or a combination of wire and textile fibers. Alternatively,
the fine mesh material of the filter screen 112 may be an open cell
foam material. The fine mesh material of the filter screen 112 must
be nontoxic and hemocompatible, that is, non-thrombogenic and
non-hemolytic. Preferably, the fine mesh material of the filter
screen 112 has a high percentage of open space, with a uniform pore
size. The pore size of the filter screen 112 can be chosen to
capture macroemboli only or to capture macroemboli and microemboli.
In most cases the pore size of the filter screen 112 will
preferably be in the range of 1-200 micrometers. For capturing
macroemboli only, the pore size of the filter screen 112 will
preferably be in the range of 50-200 micrometers, more preferably
in the range of 80-100 micrometers. For capturing macroemboli and
microemboli, the pore size of the filter screen 112 will preferably
be in the range of 1-100 micrometers, more preferably in the range
of 5-20 micrometers. In other applications, such as for treating
thromboembolic disease, a larger pore size, e.g. up to 1000
micrometers (1 mm) or larger, would also be useful. In some
embodiments, a combination of filter materials having different
pore sizes may be used.
[0041] Alternatively or additionally the material of the filter
screen in each embodiment of the filter catheter may be made of or
coated with an adherent material or substance to capture or hold
embolic debris which comes into contact with the filter screen
within the embolic filter assembly. Suitable adherent materials
include, but are not limited to, known biocompatible adhesives and
bioadhesive materials or substances, which are hemocompatible and
non-thrombogenic. Such materials are known to those having ordinary
skill in the art and are described in, among other references, U.S.
Pat. Nos. 4,768,523, 5,055,046, 5,066,709, 5,197,973, 5,225,196,
5,374,431, 5,578,310, 5,645,062, 5,648,167, 5,651,982, and
5,665,477. In one particularly preferred embodiment, only the
upstream side of the elements of the filter screen are coated with
the adherent material to positively capture the embolic debris
which comes in contact with the upstream side of the filter screen
after entering the filter assembly. Other bioactive substances, for
example, heparin or thrombolytic agents, may be impregnated into or
coated on the surface of the filter screen material or incorporated
into an adhesive coating.
[0042] The embolic filter assembly 102 is movable between a
collapsed state, as shown in FIG. 3, and an expanded or deployed
state, as shown in FIGS. 1 and 2. The filter screen 112 may be
attached directly to the catheter shaft 104 and it may constitute
the entire embolic filter assembly 102, particularly if the filter
screen 112 is made of a resilient or semirigid fabric that has
enough body to be self-supporting in the deployed state. Generally,
however, the embolic filter assembly 102 will also include a filter
support structure 114, particularly if a highly flexible or flaccid
material is used for the filter screen 112. The filter support
structure 114 attaches and supports the filter screen 112 on the
catheter shaft 104. In the illustrative embodiment of FIGS. 1-3,
the filter support structure 114 is constructed with an outer hoop
116 and a plurality of struts 118 which extend approximately
radially from a ring-shaped hub 126 that is mounted on the catheter
shaft 104. In this case four struts 118 are shown, however, two,
three or more struts 118 may be used. The open distal end 122 of
the filter screen 112 is attached to the outer hoop 116 and the
proximal end 120 of the filter screen 112 is sealingly attached to
the catheter shaft 104. When the embolic filter assembly 102 is
deployed, the outer hoop 116 of the filter support structure 114
holds the open distal end 122 of the filter screen 112 against the
inner wall of the aorta, as shown in FIG. 1. To accommodate most
normal adult aortas, the outer hoop 116 of the filter support
structure 114 and the distal end 122 of the filter screen 112 have
a diameter of approximately 2.5 to 4 cm, plus or minus 0.5 cm.
Larger and smaller diameter filter support structures 114 may be
made to accommodate patients with distended or Marfan syndrome
aortas or for pediatric patients.
[0043] The embolic filter assembly 102 may be deployed by a passive
means or by an active means. Passive means for deploying the
embolic filter assembly 102 could include using the elastic memory
of the filter screen 112 and/or the filter support structure 114 to
deploy the embolic filter assembly 102, and/or using pressure from
the blood flow in the aorta to deploy the embolic filter assembly
102. By contrast, active means for deploying the embolic filter
assembly 102 could include one or more actuation members within the
catheter shaft 104 for mechanically actuating the filter support
structure 114 to deploy the embolic filter assembly 102 from the
proximal end 108 of the catheter 100. Shape memory materials may
also be used as actuation members for deploying the embolic filter
assembly 102. Alternatively, active means for deploying the embolic
filter assembly 102 could include one or more lumens within the
catheter shaft 104 for hydraulically actuating the filter support
structure 114 to deploy the embolic filter assembly 102. Passive
means may be used to augment the action of the active deployment
means. As shown in FIG. 3, an outer tube 124 may be provided to
cover the embolic filter assembly 102 when it is in the collapsed
state in order to create a smooth outer surface for insertion and
withdrawal of the catheter 100 and to prevent premature deployment
of the embolic filter assembly 102, particularly if passive
deployment means are used.
[0044] The perfusion filter catheter 100 is prepared for use by
folding or compressing the embolic filter assembly 102' into a
collapsed state within the outer tube 124, as shown in FIG. 3. The
distal end 110 of the catheter 100 is inserted into the aorta in a
retrograde fashion. Preferably, this is done through a peripheral
arterial access, such as the femoral artery or subclavian artery,
using the Seldinger technique or an arterial cutdown.
Alternatively, the catheter 100 may be introduced directly through
an incision into the descending aorta after the aorta has been
surgically exposed. The embolic filter assembly 102 is advanced up
the descending aorta and across the aortic arch while in the
collapsed state. The position of the catheter 100 may be monitored
using fluoroscopy or ultrasound, such as transesophageal echography
(TEE). Appropriate markers, which may include radiopaque markers
and/or sonoreflective markers, may be located on the distal end 110
of the catheter 100 and/or the embolic filter assembly 102 to
enhance imaging and to show the position of the catheter 100 and
the deployment state of the embolic filter assembly 102. When the
distal end 110 of the catheter 100 is positioned in the ascending
aorta between the aortic valve and the brachiocephalic artery, the
outer tube 124 is withdrawn and the embolic filter assembly 102 is
deployed, as shown in FIG. 1. Optionally, a distal portion of the
catheter shaft 104 may be precurved to match the curvature of the
aortic arch to aid in placement and stabilization of the catheter
100 and the embolic filter assembly 102 within the aorta. Once the
embolic filter assembly 102 is deployed, oxygenated blood may be
infused through the perfusion lumen 106 to augment cardiac output
of the beating heart or to establish cardiopulmonary bypass so that
the heart can be arrested. Any potential emboli are captured by the
filter screen 112 and prevented from entering the neurovasculature
or other branches downstream. After use, the embolic filter
assembly 102 is returned to the collapsed position and the catheter
100 is withdrawn from the patient.
[0045] Preferably, the embolic filter assembly 102 is configured so
that, when it is in the deployed state, at least a majority of the
filter screen 112 is held away from the aortic walls so that flow
through the pores of the filter screen 112 is not occluded by
contact with the aortic wall. In addition, this also assures that
blood flow into the side branches of the aorta will not be
obstructed by the filter screen 112. In this way, each side branch
of the aorta will receive the benefit of flow through the full
surface area of the filter screen 112 so that blood flow is not
restricted by the area of the ostium of each side branch. In the
illustrative embodiment of FIGS. 1-3, the filter screen 112 has a
roughly conical shape with an open distal end 122. The conical
shape holds the fine mesh material of the filter screen 112 away
from the aortic walls and away from the ostia of the side branches
so that blood can flow freely through the pores of the filter
screen 112.
[0046] FIGS. 4-6 illustrate a second embodiment of the present
invention having an actively deployable CEPA in the form of an
embolic filter assembly 202 attached to a perfusion catheter 200.
In this embodiment, the filter support structure 204 includes an
outer hoop 206 and a plurality of struts 208, which are all
interconnected hollow tubular members. Preferably, the outer hoop
206 and the struts 208 are made of a flexible polymeric material.
The filter support structure 204 is connected to an inflation lumen
210, which parallels the perfusion lumen 218 within the catheter
shaft 212. At its proximal end, the inflation lumen 210 branches
off from the catheter shaft 212 to a side arm 214 with a luer
fitting 216 for connecting to a syringe or other inflation device.
By way of example, this embodiment of the embolic filter assembly
202 is shown with a trumpet-shaped filter screen 220. The filter
screen 220 includes a skirt portion 222 extending distally from a
proximal, filter pocket 224. The skirt portion 222 is in the shape
of a frustum of a cone with an open distal end, which is attached
to the outer hoop 206. The filter pocket 224 is roughly cylindrical
in shape with a closed proximal end, which is sealingly attached to
the catheter shaft 212. The skirt 222 and the filter pocket 224 may
be made of the same filter material or they may be made of
different filter materials having different porosities. The skirt
222 of the filter screen 220 may even be made of a nonporous
material.
[0047] The perfusion filter catheter 200 is shown in FIG. 6 with
the embolic filter assembly 202 folded into a collapsed position.
The outer hoop 206 and the struts 208 of the filter support
structure 204 are deflated and the material of the filter screen
220 is folded or collapsed around the catheter shaft 212. An outer
tube 226 covers the embolic filter assembly 202 in the collapsed
position to facilitate insertion of the catheter 200. Optionally,
the outer tube 226 may have a slit or a weakened longitudinal tear
line along its length to facilitate removal of the outer tube 226
over the side arm 214 at the proximal end of the catheter 200. Once
the perfusion filter catheter 200 is in position within the
patient's aorta, the outer tube 226 is pulled back to expose the
embolic filter assembly 202. Then, the embolic filter assembly 202
is deployed by inflating the outer hoop 206 and the struts 208 with
fluid injected through the inflation lumen 210 to actively expand
the filter support structure 204, as shown in FIG. 5. When the
embolic filter assembly 202 is deployed, the outer hoop 206 of the
filter support structure 204 seals against the inner wall of the
aorta, as shown in FIG. 4. Preferably, at least the outer wall of
the outer hoop 206 is somewhat compliant when inflated in order to
compensate for patient-to-patient variations in aortic luminal
diameter.
[0048] FIGS. 7-9 illustrate a third embodiment of the present
invention having a CEPA in the form of a perfusion filter catheter
300 adapted for antegrade deployment via direct aortic puncture. In
this exemplary embodiment, the perfusion filter catheter 300 is
depicted with a hybrid-style embolic filter assembly 302, which is
a compromise between a conical filter screen and a trumpet-style
filter. Because the catheter 300 is introduced directly into the
ascending aorta, the catheter shaft 304 can be reduced to a length
of approximately 20-60 cm and an outside diameter of approximately
12-18 French size (4-6 mm outside diameter) for delivering the 3-4
liters of oxygenated blood needed to preserve organ function during
cardiopulmonary bypass. One modification that may be made to the
catheter 300 for antegrade deployment is to configure it so that
the perfusion port or ports 306 which connect to the perfusion
lumen 308 exit the catheter shaft 304 proximal to the filter screen
310 so that fluid flow will come from the upstream side of the
embolic filter assembly 302. The catheter shaft 304 need not extend
all the way to the distal end of the filter screen 310. The filter
screen 310 may be entirely supported by the filter support
structure 312, particularly if the embolic filter assembly 302 is
to be passively deployed. Alternatively, a small diameter filter
support member 314 may extend from the catheter shaft 304 to the
distal end of the filter screen 310. If the embolic filter assembly
302 is intended to be actively deployed, the filter support member
314 may be slidably and/or rotatably received within the catheter
shaft 304. Either of these configurations allows the embolic filter
assembly 302 to be folded or compressed to a size as small as the
diameter of the catheter shaft 304 to facilitate insertion of the
catheter 300. Optionally, an outer tube 316 may be placed over the
folded embolic filter assembly 302 to hold it in the collapsed
position.
[0049] In use, the ascending aorta of the patient is surgically
exposed, using open-chest or minimally invasive surgical
techniques. A purse string suture 318 is placed in the ascending
aorta and an aortotomy incision is made through the aortic wall.
The catheter 300, with the embolic filter assembly 302 in the
collapsed position within the outer tube 316, is inserted through
the aortotomy and advanced antegrade into the aortic arch. When the
proximal end of the embolic filter assembly 302 is positioned in
the ascending aorta between the aortic valve and the
brachiocephalic artery, the outer tube 316 is withdrawn and the
embolic filter assembly 302 is either actively or passively
deployed, as shown in FIG. 7. Once the embolic filter assembly 302
is deployed, oxygenated blood may be infused into the aorta through
the tubular catheter shaft 304. Any potential emboli are captured
by the embolic filter assembly 302 and prevented from entering the
neurovasculature or other branches downstream. After use, the
embolic filter assembly 302 is returned to the collapsed position,
the catheter 300 is withdrawn from the patient, and the purse
string suture 318 is tightened to close the aortotomy.
[0050] In general, each of the passive and active deployment
methods described above may be used interchangeably or together in
combinations with each of the embodiments of the perfusion filter
catheter and each of catheter insertion methods which are described
above and below. Likewise, many of the features of the embodiments
described may be used in various combinations with one another to
create new embodiments, which are considered to be a part of this
disclosure, as it would be too cumbersome to describe all of the
numerous possible combinations and subcombinations of the disclosed
features. In general, each of the described embodiments may be
passively or actively deployed by the methods described above. Each
embodiment of the CEPA described can also be adapted for retrograde
deployment via peripheral arterial access, such as femoral or
subclavian artery access, or for antegrade or retrograde deployment
via direct aortic puncture.
[0051] FIGS. 10-12 illustrate a fourth embodiment of the present
invention having a CEPA in the form of a perfusion filter catheter
600. FIG. 10 illustrates the CEPA in a collapsed or undeployed
state having an embolic filter assembly 602 with a toroidal balloon
aortic occlusion device 604 collapsed or folded about the elongated
catheter shaft 606. The perfusion filter catheter 600 is inserted
in the collapsed state and advanced into the patient's ascending
aorta until the embolic filter assembly 602 is positioned between
the coronary ostia and the brachiocephalic artery. The toroidal
balloon aortic occlusion device 604 is then inflated to expand and
deploy the embolic filter assembly 602, as shown in FIG. 11. The
embolic filter assembly 602 may assume a simple conical shape or,
more preferably, one of the surface area increasing geometries
described above. In addition, the embolic filter assembly 602 may
include a structure or other means to hold the filter material
apart from the aortic wall to maximize the effective filter area.
With the embolic filter assembly 602 deployed, cardiopulmonary
bypass with embolic protection can be started through the perfusion
ports 610.
[0052] When it is desired to initiate cardioplegic arrest, the
toroidal balloon aortic occlusion device 604 is further inflated
until it expands inward to occlude the aortic lumen, as shown in
FIG. 12. A cardioplegic agent is infused through the cardioplegia
port 608 and into the coronary arteries to arrest the heart.
Oxygenated blood continues to be infused through the perfusion
ports 610. After completion of the surgical procedure, the toroidal
balloon aortic occlusion device 604 is partially deflated, leaving
the embolic filter assembly 602 deployed, as shown in FIG. 13.
Oxygenated blood enters the coronary arteries to restart the heart
beating. If any embolic materials 612 are dislodged during
manipulation of the heart or when the heart resumes beating, they
will be captured by the embolic filter assembly 602. Once the
patient is weaned off bypass, the toroidal balloon aortic occlusion
device 604 is deflated to collapse the embolic filter assembly 602,
as shown in FIG. 14. Any potential emboli are trapped within the
embolic filter assembly 602 and can be removed along with the
catheter 600.
[0053] FIG. 15 illustrates a fifth embodiment of the present
invention having a CEPA in the form of an embolic filter assembly
622 with an inflatable balloon aortic occlusion device 624. The
embolic filter assembly 622 may be any one of the actively or
passively deployed embolic filter assemblies described herein.
Preferably, the inflatable balloon aortic occlusion device 624 is
an elastomeric balloon of sufficient inflated diameter to occlude
the ascending aorta and is mounted on the elongated catheter shaft
626 upstream of the embolic filter assembly 622. Alternatively, the
inflatable balloon aortic occlusion device 624 may be positioned to
occlude the inlet end of the embolic filter assembly 622 to
minimize the area of contact between the perfusion filter catheter
620 and the aortic wall. The inflatable balloon aortic occlusion
device 624 is connected to an inflation lumen within the elongated
catheter shaft 626. A cardioplegia lumen, which may also serve as a
guidewire lumen, connects to a cardioplegia port 628 at the distal
end of the catheter shaft 626. A perfusion lumen connects to one or
more perfusion ports 630 located on the catheter shaft 626
downstream from the inflatable balloon aortic occlusion device 624,
but upstream of the embolic filter assembly 622. The operation of
the perfusion filter catheter 620 of FIG. 15 is quite similar to
that described for the embodiment of FIGS. 10-14.
[0054] FIG. 16 illustrates a sixth embodiment of the present
invention having a CEPA in the form of an embolic filter assembly
642 combined with a selectively deployable external catheter flow
control valve 644. The embolic filter assembly 642 may be any one
of the actively or passively deployed embolic filter assemblies
described herein. The selectively deployable external catheter flow
control valve 644 is mounted on the elongated catheter shaft 646
upstream of the embolic filter assembly 642. Alternatively, the
selectively deployable external catheter flow control valve 644 may
be positioned to occlude the inlet end of the embolic filter
assembly 642 to minimize the area of contact between the perfusion
filter catheter 640 and the aortic wall. Selectively deployable
external catheter flow control valves suitable for this application
are described in commonly owned, copending U.S. patent applications
Ser. Nos. 08/665,635, 08/664,361 and 08/664,360, filed Jun. 17,
1996, which are hereby incorporated by reference in their entirety.
The elongated catheter shaft 646 may include one or more deployment
lumens as needed for actuating the external catheter flow control
valve 644. A cardioplegia lumen, which may also serve as a
guidewire lumen, connects to a cardioplegia port 648 at the distal
end of the catheter shaft 646. A perfusion lumen connects to one or
more perfusion ports 650 located on the catheter shaft 646
downstream from the external catheter flow control valve 644, but
upstream of the embolic filter assembly 622. The operation of the
perfusion filter catheter 640 of FIG. 16 is quite similar to that
described for the embodiment of FIGS. 10-14.
[0055] FIG. 17 illustrates a seventh embodiment of the present
invention having a CEPA capable of being used in combination with
many of the features and embodiments previously described. FIG. 17
shows an embodiment of a perfusion filter catheter 660 with a CEPA
in the form of an embolic filter assembly 662 having areas of
different filter porosity. The embolic filter assembly 662 is
mounted on an elongated catheter shaft 666 that can be adapted for
peripheral introduction via the femoral artery or subclavian artery
or for central insertion directly into the ascending aorta either
through a median sternotomy, transternally, thoracotomy or an
intercostal space. The embolic filter assembly 662 may resemble any
one of the actively or passively deployed embolic filter assemblies
described herein. Preferably, the embolic filter assembly 662
assumes one of the surface area increasing geometries described
above, such as a trumpet-style embolic filter assembly 662 as
shown. The embolic filter assembly 662 is divided along a
longitudinal dividing line into areas of different filter porosity.
In a preferred embodiment, the embolic filter assembly 662 has an
upper portion 664 of finer porosity facing toward the aortic arch
vessels and a lower portion 668 of courser porosity facing away
from the aortic arch vessels. Preferably, the elongated catheter
shaft 666 will have a preformed curve to help orient the upper
portion 664 and the lower portion 668 of the embolic filter
assembly 662 in the proper position once deployed. The filter mesh
of the upper portion 664 may be selected to exclude both
macroemboli and microemboli, and the filter mesh of the lower
portion 668 may be selected to exclude macroemboli only.
Alternatively, the upper portion 664 may be impermeable so as to
act like a shunt to direct potential emboli downstream away from
the aortic arch vessels.
[0056] Another feature that may be combined with the features and
embodiments of the present invention is an aortic transillumination
system or infrared emitting means for locating and monitoring the
position of the catheter, the filter and the optional occlusion
devices without fluoroscopy by transillumination of the aortic
wall. Aortic transillumination systems using optical fibers and/or
light emitting diodes or lasers suitable for this application are
described in commonly owned, copending U.S. patent application Ser.
No. 60/088,652, filed Jun. 9, 1998 and its corresponding utility
application Ser. No. 09/326,816 filed Jun. 7, 1999, which are
hereby incorporated by reference in their entirety.
[0057] FIGS. 18-21 illustrate an eighth embodiment of the present
invention having a CEPA in the form of an aortic flow divider. The
flow divider 810 may be formed in a variety of configurations,
however the flow divider 810 in the undeployed state will be
contained in a relatively small volume around the circumference of
the distal end of the catheter and in the deployed state will have
a length and width sufficient to divide blood flow in the aorta in
the vicinity of the ostia of the arch vessels. In the undeployed
state, the flow divider 810 is collapsible around the catheter
shaft creating a low profile not significantly larger than the
outer diameter of the catheter body. The flow divider 810 may
comprise one or more inflatable chambers, the chambers all being in
fluid communication, or one or more selectively deployable shrouds.
The inflatable chambers may be relatively non-compliant or they may
be compliant, exhibiting elastic behavior after initial inflation,
for example, to closely fit the size, shape and curvature of the
aortic lumen.
[0058] The catheter may further include one or more additional or
auxiliary flow control members located on the catheter either
distal or proximal from the flow divider 810 to further segment the
patient's circulatory system for selective perfusion to different
organ systems within the body or to assist in anchoring the
catheter in a desired position. These auxiliary flow control
members may comprise inflatable balloons or selectively deployable
external catheter valves as described in connection with to FIGS.
15 and 16. Preferably, the flow divider 810, and any auxiliary flow
control members, or anchoring members, if present, are mounted
directly on an elongated catheter shaft. In a preferred embodiment,
the catheter shaft includes at least three lumens, one lumen for
inflating or otherwise deploying the flow divider 810, a second for
perfusion of the arch vessels, and a third guidewire lumen. In
alternate embodiments, additional lumens may be included for
deploying the auxiliary flow control members, for measuring the
pressure at desired locations within the aorta, or for perfusing
other isolated segments of the patient's circulatory system.
Suitable methods and apparatus for performing isolated segmental
perfusion for use in conjunction with the present invention are
described in commonly owned, copending U.S. patent application Ser.
No. 60/084,835 filed May 9, 1998 and its corresponding utility
application Ser. No. 09/306,555 filed May 6, 1999, which are hereby
incorporated by reference in their entirety.
[0059] The catheter may be configured for retrograde deployment via
a peripheral artery, such as the femoral artery, or it may be
configured for antegrade deployment via an aortotomy incision or
direct puncture in the ascending aorta. The catheter is
characterized by a flexible catheter shaft placed by surgical
cutdown or Seldinger technique into the vessels of the lower or
upper extremity or neck. Other large internal vessels may also be
used.
[0060] Anticoagulants, such as heparin and heparinoids, may be
applied to the surfaces of the catheter and/or flow control members
as desired. Anticoagulants may be painted or sprayed onto the
device. Anticoagulants other than heparinoids may also be used, for
example monoclonal antibodies such as REOPRO (Eli Lilly and Co.,
Indianapolis, Ind.). A chemical dip comprising the anticoagulant
may also be used. In addition an echogenic coating may also be
applied to the catheter to enhance visualization. Other methods
known in the art for applying chemicals to catheters may be
used.
[0061] FIG. 18 illustrates the aortic catheter 800 of the present
invention having an elongated catheter shaft 802 with a proximal
end and a distal end. The proximal end 804 preferably extends out
of the patient's body and the distal end 806 is closest to the
patient's heart. The elongated catheter shaft 802 preferably has an
overall length sufficient to reach from the arterial access point
to a selected location within a patient's aorta. For femoral artery
deployment in adult human patients, the elongated catheter shaft
802 preferably has an overall length from approximately 60 cm to
120 cm, and more preferably 70 cm to 90 cm.
[0062] In one illustrative embodiment, the elongated catheter shaft
802 has an outer diameter that is preferably approximately 9 to 22
French (3.0 to 7.3 mm), and more preferably 12 to 18 French (4.0 to
6.0 mm) for use in adult human patients. Catheters for pediatric
use, or use in non-human subjects, may require different dimensions
and would be scaled accordingly. The elongated catheter shaft 802
is preferably formed of a flexible thermoplastic material, a
thermoplastic elastomer, or a thermoset elastomer. Suitable
materials for use in the elongated catheter shaft 802 include, but
are not limited to, polyvinylchloride, polyurethane, polyethylene,
polyamides, polyesters, silicone, latex, and alloys or copolymers
thereof, as well as braided, coiled or counterwound wire or
filament reinforced composites. Additionally or alternatively, the
elongated catheter shaft 802 may be constructed using metallic
tubing or a solid wire, for example stainless steel hypodermic
tubing or wire or superelastic nickel-titanium alloy tubing or
wire. Preferably, the aortic catheter 800 includes one or more
location markers 816, such as radiopaque markers and/or
sonoreflective markers, to enhance imaging of the aortic catheter
800 during deployment using standard fluoroscopy, ultrasound, MRI,
MRA, transesophageal echocardiography, or other techniques. For
example, in the illustrative embodiment shown in FIG. 18, a
radiopaque location marker 816 is positioned near the distal end
806 of the catheter shaft 802, and another near the proximal end of
the flow divider 810, to assist in positioning the flow divider 810
within the aortic arch. The radiopaque location markers 816 may be
formed as a ring or disk of dense radiopaque metal such as gold,
platinum, tantalum, tungsten, or compounds or alloys thereof, or a
ring of a polymer or adhesive material heavily loaded with a
radiopaque filler material.
[0063] The flow divider 810, of FIG. 18, is mounted proximate the
distal end 806 of the elongated catheter shaft 802. The embodiment
shown in FIGS. 18 through 21, shows the flow divider 810 in the
form of a flat elongate expandable inflatable balloon or mattress
bonded to the catheter shaft 802 by heat welding or with an
adhesive. The inflatable flow divider 810 has a deflated state in
which the flow divider 810 adheres closely to the catheter shaft
802 so that the collapsed diameter of the flow divider 810 is,
preferably, not substantially larger than the diameter of the
catheter shaft 802, and an inflated state in which the flow divider
810 expands to dimensions sufficient to divide blood flow in the
aortic arch of the patient into two fluid flow channels. The distal
end of the flow divider may expand beyond the distal end of the
catheter as illustrated in FIG. 21 or alternatively may expand to a
distance equal to or less than the distal end. Preferably, the flow
divider 810 will be formed so that, when inflated, the flow divider
810 automatically assumes and maintains a desired shape, without
any additional stiffening structure. However, in some embodiments,
it may be desirable to include means for assisting the flow divider
810 in maintaining a desired shape, and any known means for
accomplishing this may be used. For example, the divider may
include ribs or other stiffening structures coupled to the flow
divider 810, or formed as an integral part of the flow divider 810.
Alternatively, the flow divider 810 may include mattress type
welds, or internal welds or columns. The outer surface of flow
divider 810 may include a friction increasing means such as a
friction increasing coating or texture to increase friction between
the flow divider 810 and the aortic wall, to assist in maintaining
the flow divider 810 in a desired position within the aorta, when
deployed.
[0064] FIG. 19 is a side view of the catheter 800, showing that the
flow divider 810 is preferably coupled only to a portion of the
diameter of the catheter shaft 802. Thus, perfusion ports 818 are
unobstructed. Alternatively, the flow divider may be mounted above
the perfusion ports 818 wherein the material covering the ports 818
is skived or cut away to allow for perfusion therethrough. In the
inflatable embodiments a heat seal can be created around the skived
out area or in the case of mattress type welds the skived area can
be in an area of an already existing weld. Furthermore, the
material covering the ports 818 may only be partially cut away
leaving part of the port covered in order to help facilitate the
direction and flow of fluid out the ports 818. In addition, FIG. 21
illustrates the catheter shaft 802 being substantially centered
relative to the divider 810, alternative embodiments can have the
catheter shaft off center, tangential or in any geometric position
that helps facilitate placement and optimal flow.
[0065] FIG. 20 is a cross section of the catheter shaft 802 taken
along line 20-20 of FIG. 18. The elongated catheter shaft 802
preferably has at least three lumens, an inflation lumen 808 that
is used to deploy the flow divider 810, a perfusion lumen 812 that
is used to perfuse one or both of the fluid flow channels, and a
guidewire lumen 814. The configuration of the lumens is shown for
illustrative purposes only, and any reasonable configuration of
lumens within the catheter may be used. Furthermore, additional
perfusion lumens may be added to perfuse both of the fluid flow
channels separately and independently. Additional fluid ports
similar to ports 818 only positioned in the other fluid flow
channel would also be necessary.
[0066] The flow divider 810 is shown in a deployed state in FIG.
21. Preferably, the flow divider 810 in its deployed configuration
includes a distal portion 820 that extends beyond the distal end of
the catheter 800 in order to seal or touch against the aortic lumen
wall. The proximal portion 822 of the divider 810 is shown shaped
similarly to the distal portion 820, however, in this embodiment
the shape of the proximal portion 822 of the divider 810 is not
critical to the invention and could be triangular, square, or any
other desired shape. In other embodiments, it may be preferable
that the shape be chosen to encourage low turbulence, or possibly
laminar, fluid flow where the fluid flow from the flow channel
above the divider 810 and the fluid flow from below the flow
divider 810 meet at the trailing edge of the proximal portion 822.
However in a preferred embodiment, the divider is constructed such
that any flow around the catheter is directed toward the corporeal
circulation and not to the arteries leading to the brain. One
preferred method for accomplishing such desirable flow
characteristics is to direct any excess flow to the arch around the
proximal portion 822 of the divider and down to the corporeal
circulation. Such a flow relationship protects the brain by
directing any extra flow into the second fluid path and away from
the brain. This is also beneficial in that no real seal is
necessary, but rather laminar flow is established and emboli are
directed away from the divider and the brain by the fluid flow.
Even if turbulence results near the trailing edge of the flow
divider 810, embolic material in the blood will have already passed
the arch vessels, thereby achieving the objective of preventing
embolic material from entering the cerebral circulatory system.
[0067] It may not be essential that the edges of the flow divider
810 create a perfect seal or any seal with the wall of the aorta.
Some leakage of blood around the flow divider 810 may be tolerated
because the fluid perfused through the perfusion lumen 812 creates
a pressure gradient from above the flow divider 810 to below the
flow divider 810 so that any potential embolic material will not
enter the flow channel above the flow divider 810.
[0068] Any embodiments of the catheter 800 of the invention
described above may further include auxiliary flow control members.
The auxiliary flow control members may be used to further
compartmentalize the patient's circulatory system, or may be used
for other functions such as assisting in securely anchoring the
catheter in a chosen position. An example of a catheter of the
invention further comprising an auxiliary flow control member is
seen in FIGS. 22 and 23, which illustrate an auxiliary flow control
member 830 coupled to the distal end of the catheter 800 proximate
the distal end 122 of the flow divider 810. The auxiliary flow
control member 830 is positioned within the aorta and can be fully
deployed to occlude or substantially occlude the aorta. The
auxiliary flow control member 830 shown in FIG. 22 is an inflatable
balloon bonded to the catheter shaft 802 by heat welding or with an
adhesive. Alternatively, the auxiliary flow control member 830
could be a deployable valve, or other structure. Deployable valves
suitable for use in this application are described in commonly
owned U.S. Pat. Nos. 5,827,237 and 5,833,671, which have been
previously incorporated by reference. Suitable materials for the
inflatable balloon include, but are not limited to, elastomers,
thermoplastic elastomers, polyvinylchloride, polyurethane,
polyethylene, polyamides, polyesters, silicone, latex, and alloys
or copolymers and reinforced composites thereof. In alternate
embodiments, the auxiliary flow control member 830 may be
positioned on the proximal side of the flow divider 810, if
desired. The auxiliary flow control member 830 may also be used to
anchor the catheter 800 so that it does not migrate out of its
optimal position during the medical procedure. The outer surface of
an auxiliary flow control member 830 used to anchor the catheter
800 may include a friction increasing means, such as a friction
increasing coating or texture, to increase friction between the
auxiliary flow control member 830 and the aortic wall, when
deployed. Alternatively, an auxiliary flow control member 830,
which may be an inflatable balloon or deployable valve, can be
mounted on a separate catheter and introduced through a lumen
within the catheter 800.
[0069] FIGS. 22 and 23 show the flow divider 810 fully deployed,
and the auxiliary flow control member 830 partially collapsed and
fully deployed. As blood flow resumes from the heart A, embolic
material C is diverted away from the arch vessels by the flow
divider 810.
[0070] The previous embodiments have been described using a
catheter configured for a retrograde approach to the aorta from a
peripheral vessel such as the femoral artery. The invention could
easily be modified for alternate deployment means. For example,
FIG. 24 shows a catheter 900 configured for central antegrade
deployment in the aortic arch through an aortotomy or direct
puncture in the ascending aorta. The catheter 900 and flow divider
910 are configured similarly to the catheters disclosed in previous
embodiments. Other embodiments of the invention may be configured
for peripheral insertion through the subclavian or axillary
arteries.
[0071] FIG. 25 discloses an alternate embodiment of the flow
divider 910, wherein the top surface of the flow divider 910
comprises a mesh or porous region 932. The perfusion ports 918
allow a selected fluid to enter the interior chamber 934 of the
flow divider 910 before the fluid passes through the mesh or porous
region 932 to perfuse the aorta. The material or materials used in
the flow divider 910 are preferably characterized by properties
that allow an internal pressure within the flow divider 910 to be
maintained at a sufficient level to maintain the deployed
configuration of the flow divider 910 to divide the aorta, while
also allowing a controlled volume of fluid to escape from the flow
divider 910 through the mesh or porous region 932 on the upper
surface of the flow divider 910 for perfusing the arch vessels.
Thus, the surface of the flow divider 910 may have porous regions
that allow a fluid to be perfused at a known rate when a specific
pressure is attained. The inflatable peripheral tube 936 surrounds
the periphery of the flow divider 910, however, in alternate
embodiments, this feature may be omitted. In embodiments including
an inflatable peripheral tube 936, it is preferable that the
peripheral tube 936 be inflated from a separate additional
lumen.
[0072] FIG. 26 discloses an embodiment of the flow divider 910 of
FIG. 25 wherein a single inflation and perfusion lumen may be used.
In this embodiment, perfused fluid passes through a lumen 1006 in
the shaft 1002 of the catheter 1000 into the peripheral tube 1036
to inflate the peripheral tube 1036. Apertures 1038 between the
inflatable peripheral tube 1036 and the interior chamber 1034 of
the flow divider 1010 allow fluid to flow from the peripheral tube
1036 into the chamber 1034 within the inflatable flow divider 1010.
The fluid then passes through the mesh or porous region 1032 of the
flow divider 1010 to perfuse the aorta. Preferably, the apertures
1038 of the peripheral tube 1036 are sized so that the pressure
within the peripheral tube 1036 is higher than the pressure within
the chamber 1034 of the flow divider 1010.
[0073] The porous and non-porous sections of the flow divider 1010
may be formed from the same or separate materials. Suitable
materials for the non-porous portions of the flow divider 1010
include, but are not limited to, elastomers, thermoplastic
elastomers, polyvinylchloride, polyurethane, polyethylene,
polyamides, polyesters, silicone, latex, and alloys or copolymers,
and reinforced composites thereof. Suitable materials for the
porous portions of the flow divider 1010 include meshes, woven and
nonwoven fabrics, and porous membranes, such as microperforated or
laser perforated polymer or elastomer films. For example, polyester
meshes may be used, such as meshes made by Saati Corporation and
Tetko, Inc. These are available in sheet form and can be easily cut
and formed into a desired shape. Other meshes and porous materials
known in the art, which have the desired characteristics, are also
suitable.
[0074] Referring to FIG. 27, an embodiment of the flow divider 1110
is disclosed having a nonporous film 1140 surrounded by a
peripheral tube 1136 acting as a support structure. Inflation of
the peripheral tube 1136 causes deployment of the film 1140 within
the aorta. Holes are positioned over the perfusion apertures 1118
to allow perfusion of the region above the flow divider 1110. FIG.
28 is a cross section view of the flow divider 1110 of FIG. 27
taken along line 28-28. It is possible to make the flow divider
1110 of FIG. 27 by fabricating an oval balloon and affixing the
central portion of the top and bottom layers together, leaving a
peripheral region where the upper and lower layers are not coupled
together, forming the inflatable peripheral tube 1136.
Alternatively, the peripheral tube 1136 and film 1140 of the flow
divider 1110 may be formed of separate components and affixed
together by a known means for joining such materials, such as by
heat welding or adhesives.
[0075] FIGS. 29-31 represent alternate embodiments of the flow
divider 1210 with welds or joined areas between an upper and a
lower film of the flow divider 1210 to give additional structure
and rigidity to the flow divider 1210. FIG. 29 discloses an
embodiment wherein the interior surface of the upper film has been
coupled 1242 to the interior surface of the lower film, preferably
by spot heat welding or adhesive. The resulting structure maintains
the geometry of the flow divider 1210 and provides it with
additional rigidity. FIG. 30 is a cross section view of the flow
divider 1210 of FIG. 29 taken along line 30-30 of FIG. 29. FIG. 31
shows an alternate embodiment of FIG. 29 with larger joined areas
1342 between the upper and lower films of the flow divider 1310,
creating a well defined peripheral tube 1336 and lateral or branch
support members 1344. In alternative embodiments, the film 1340 and
peripheral tube 1336 and lateral or branch support members 1344
maybe fabricated as separate components and joined using any known
means for doing so, including the use of adhesive or heat
welding.
[0076] All of the previously described flow divider embodiments
have been deployed from the external surface of the catheter shaft.
However, in other embodiments, the flow divider may be deployed
from within one or more lumens in the catheter shaft. For example,
FIG. 32 discloses a flow divider 1410 deployed within an aorta B,
and coupled to a deployment wire 1470 that is extended from a lumen
with an opening in the distal end 1406 of the catheter shaft 1402.
The flow divider 1410 is preferably comprised of a material or
materials with a shape memory, so that the flow divider 1410 will
assume the desired configuration on release from the catheter shaft
1402. Any known suitable materials may be used including, but not
limited to, elastomers, thermoplastic elastomers,
polyvinylchloride, polyurethane, polyethylene, polyamides,
polyesters, silicone, latex, and alloys or copolymers, and
reinforced composites thereof. In some embodiments, the flow
divider 1410 may include lateral or branch stiffeners to assist the
flow divider 1410 in maintaining a desired configuration or shape.
Perfusion of the arch vessels in this embodiment, may be provided
by another perfusion source, such as a second catheter. FIG. 33 is
a cross section view of the flow divider 1410 of FIG. 32 taken
transversely through the aorta B showing a preferred position of
the flow divider 1410 within the aorta B.
[0077] While the present invention has been described herein with
respect to the exemplary embodiments and the best mode for
practicing the invention, it will be apparent to one of ordinary
skill in the art that many modifications, improvements and
subcombinations of the various embodiments, adaptations and
variations can be made to the invention without departing from the
spirit and scope thereof.
* * * * *