U.S. patent application number 12/632762 was filed with the patent office on 2010-07-15 for device and method for treating ischemic heart disease.
This patent application is currently assigned to NEOVASC MEDICAL LTD.. Invention is credited to Ilan Shalev.
Application Number | 20100179643 12/632762 |
Document ID | / |
Family ID | 24132263 |
Filed Date | 2010-07-15 |
United States Patent
Application |
20100179643 |
Kind Code |
A1 |
Shalev; Ilan |
July 15, 2010 |
DEVICE AND METHOD FOR TREATING ISCHEMIC HEART DISEASE
Abstract
A narrowing intraluminal stent is disclosed and comprises a
hollow body and a flow passage therethrough, the hollow body
designed for intraluminal placement and having "at least one
portion of an inner cross sectional dimension smaller than the
cross sectional dimension of the lumen, so as to artificially
narrow a passage through the body lumen. A method of artificially
narrowing a passage through a body lumen using the stent is also
disclosed.
Inventors: |
Shalev; Ilan; (Givatayim,
IL) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET, FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Assignee: |
NEOVASC MEDICAL LTD.
Or Yehuda
IL
|
Family ID: |
24132263 |
Appl. No.: |
12/632762 |
Filed: |
December 7, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11186745 |
Jul 21, 2005 |
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12632762 |
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09534968 |
Mar 27, 2000 |
6953476 |
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11186745 |
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Current U.S.
Class: |
623/1.31 ;
128/898; 623/1.3 |
Current CPC
Class: |
A61F 2230/005 20130101;
A61F 2002/068 20130101; A61F 2230/0078 20130101; A61F 2/2475
20130101; A61F 2/91 20130101; A61F 2230/0006 20130101; A61F
2250/0039 20130101; A61F 2230/0069 20130101; A61F 2230/008
20130101; A61F 2002/91558 20130101; A61F 2002/91533 20130101; A61F
2002/91525 20130101; A61F 2220/0075 20130101; A61F 2220/0016
20130101; A61F 2002/018 20130101; A61F 2/01 20130101; A61F 2/88
20130101; A61F 2002/9155 20130101; A61F 2/915 20130101 |
Class at
Publication: |
623/1.31 ;
623/1.3; 128/898 |
International
Class: |
A61F 2/06 20060101
A61F002/06; A61B 17/00 20060101 A61B017/00 |
Claims
1. A method of affecting blood flow in coronary vessels,
comprising: (a) transvascularly guiding a catheter to a coronary
sinus; and (b) narrowing a cross-sectional dimension of a flow
lumen of said coronary sinus by implanting a flow reducer in said
flow lumen using said catheter, said flow reducer having a
cross-sectional dimension that is smaller than a cross-sectional
dimension of said flow lumen; wherein said cross-sectional
dimension of said flow reducer is non-expandable.
2. A method according to claim 1, wherein said flow reducer is
implanted using a balloon.
3. A method according to claim 1, wherein said flow reducer is a
self-expanding reducer.
4. A method according to claim 1, wherein narrowing comprises
narrowing in a manner that increases back pressure.
5. A method according to claim 1, wherein narrowing comprises
narrowing in a manner that initiates angiogenesis.
6. A method according to claim 1, wherein narrowing comprises
narrowing in a manner that accelerates angiogenesis.
7. A method according to claim 1, wherein narrowing comprises
narrowing in a manner that prevents ischemic heart disease.
8. A method according to claim 1, wherein narrowing comprises
permanently narrowing.
9. A method according to claim 1, comprising: determining that a
patient has ischemic heart disease; and performing (a)-(b).
10. A method according to claim 1, comprising reducing said a
diameter of said cross-section of said flow lumen by a factor of at
least 2.6.
11. A method of improving perfusion of a tissue, comprising: (a)
identifying a tissue having a deficient degree of blood flow there
through; and (b) transvascularly narrowing a cross-sectional
diameter of a vessel carrying blood from said tissue, said
narrowing comprising deploying a flow reducer in the vessel, said
flow reducer having a cross-sectional dimension that is smaller
than a cross-sectional dimension of said flow lumen, said narrowing
being effective to cause improvement in blood flow through the
tissue.
12. A method according to claim 11, wherein said vessel comprises a
coronary sinus.
13. A method according to claim 11, wherein said tissue comprises
cardiac tissue.
14. A method according to claim 11, wherein said narrowing is
sufficient to cause angiogenesis in said tissue.
15. A method of affecting blood flow in a coronary vessel,
comprising: narrowing a cross-sectional dimension of said coronary
vessel, wherein said narrowing comprises deploying a flow reducer
in said coronary vessel, said flow reducer being formed of a single
element configured to include: at least one portion having an inner
cross-sectional dimension smaller than that of said coronary
vessel, said inner cross-sectional dimension being non-expandable;
and at least one expandable portion, each of said at least one
expandable portion being disposed at a specific position along the
length of said flow reducer; wherein said deploying comprises
expanding said at least one expandable portion such that said flow
reducer is fixed in said coronary vessel.
16. A method according to claim 15, wherein said at least one
portion having an inner cross-sectional dimension smaller than that
of said coronary vessel comprises: a central portion having an
inner cross-sectional dimension smaller than that of said coronary
vessel; and wherein said at least one expandable portion includes
an expandable portion at each of first and second ends of said flow
reducer.
17. A method of affecting blood flow in a coronary sinus,
comprising: (a) providing a flow reducer having a specific length;
(b) narrowing a cross-sectional dimension of a flow lumen of said
coronary sinus, wherein said narrowing comprises deploying said
flow reducer in the coronary sinus, said flow reducer having a
non-expandable cross-sectional diameter that is smaller than a
cross-sectional diameter of said flow lumen, whereby the length of
said flow reducer is substantially maintained.
Description
FIELD AND BACKGROUND OF THE INVENTION
[0001] The present invention relates to a device and method for
treating ischemic heart disease and, more particularly, to a
coronary sinus stent and to surgical methods for implanting same.
Specifically, the present invention involves implantation of the
stent in the coronary sinus as a means of treating patients
suffering from, for example, diffuse coronary artery disease,
especially in cases where conventional balloon catheterization,
bypass surgery and drugs are infeasible or ineffective treatment
methods.
[0002] Blood arrives at the heart muscle via coronary arteries
which begin as vessels with a diameter of several millimeters and
branch progressively to smaller and smaller vessels in order to
supply all the cells of the heart muscle. Blood arriving at the
heart carries oxygen and nutrients which are exchanged for carbon
dioxide and other wastes produced by cellular respiration. The
carbon dioxide carrying blood leaves the heart muscle via a system
of coronary veins which begin as small vessels and progressively
merge into larger vessels. As in other organs, the veins are
approximately parallel to the arteries, although the blood flow
therein is in the opposite direction. The coronary veins terminate
in a reservoir referred to as the coronary sinus, which, in turn,
drains into the right atrium where it mixes with venous blood from
peripheral organs. Venous blood is pumped from the right atrium
into the pulmonary arteries which perfuse the lung and facilitate
an exchange of gases, with carbon dioxide being replaced with
oxygen.
[0003] In cases where the supply of blood flowing to the heart
muscle via the coronary arteries is insufficient, oxygenation of
the muscle tissue of the heart is reduced, producing a condition
known as cardiac ischemia. Ischemia can result in atrophy and or
necrosis of tissue. In the case of cardiac ischemia, this atrophy
or necrosis reduces heart function and adversely affects the blood
supply to the remainder of the body. Patients suffering from
cardiac ischemia typically suffer from chest pains and difficulty
in breathing. Cardiac ischemia may precipitate a heart attack in
some cases.
[0004] Cardiac ischemia is most often caused by atherosclerosis or
other conditions which block one or more coronary arteries. Current
treatment options include balloon catheterization, bypass surgery
and treatment with drugs. Balloon catheterization and bypass
surgery are only feasible options if the coronary artery blockage
exists in a small number of discrete locations, usually in fairly
large blood vessels.
[0005] Balloon catheterization involves insertion of a catheter
with an inflatable tip via a peripheral blood vessel into the
affected coronary artery. The procedure is performed with the aid
of a visualization (imaging) device (e.g., ultrasound, X-ray,
fluoroscopy) which shows the catheter tip and the coronary artery
occlusion. When the tip is in proximity to the occlusion, it is
inflated, thereby widening the artery and releasing the occlusion.
In cases, the balloon catheter serves for placing a stent within
the artery and to extend or erect the stent to its service
dimensions in a process known as stent catheterization. These
procedures are often preferred by patients and doctors because it
is relatively non-invasive.
[0006] Bypass surgery is an invasive procedure which involves
opening the thoracic cavity and implanting a tube so as to replace
or bypass an occluded portion of the coronary artery. The tube may
be either artificial, or a peripheral blood vessel derived from the
patient. While this method has proven efficacy, it has all of the
disadvantages inherent in invasive surgery, e.g., post-surgical
infection, complications with anesthesia, relatively long recovery
time and high cost.
[0007] Patients with cardiac ischemia caused by blockage of many
small vessels are not candidates for balloon catheterization or
bypass surgery and are currently treatable only with drugs. These
drugs include, for example, nitrates, .beta.-blockers and calcium
channel blockers. Unfortunately, patients treated with drugs often
continue to have difficulty performing daily activities, suffer
from shortness of breath and chest pains.
[0008] It has long been known that reducing the flow of blood
exiting the coronary sinus can have beneficial effects on cardiac
ischemia (Gross L. Blum L., Silverman G. J Exper. Med. (1937)
85:91, 1937; Robertson H. H. (1935) Am Heart. J. 10:533; Beck C.
S., Leighninger D. S. (1954) Am. Heart J. 156:1226; Beck C. S.,
Leighninger D. S. (1955) Am. Heart J. 159:1264; Beck C. S.,
Leighninger D. S. (1961) Med. Tms. (NY) 89:17; Beck C. S.,
Leighninger D. S., Brofman B. L., Bond J. F. (1958) J. Amer. Med.
Ass. 168:2110; Sandler G., Slesser B. V., Lawson C. W. (1967)
Thorax 22:34). It is believed that reducing the flow of blood
exiting the coronary sinus increases the blood pressure in the
coronary arteries, thereby inducing the formation of new blood
vessels, a process known as angiogenesis. The prior art procedure
of reducing the flow of blood exiting the coronary sinus involves
placement of a narrowing ring external to the coronary sinus, so as
to narrow its inner diameter and thereby restrict blood flow
therethrough. This procedure, however, is an open chest (thoracic)
procedure, and therefore suffers all the limitations associated
with such procedures, including, but not limited to, post-surgical
infection, complications with anesthesia, relatively long recovery
time and high cost. However, the prior art fails to teach minimal
invasive means of reducing the flow of blood exiting the coronary
sinus without thoracic surgery.
[0009] There is thus a widely recognized need for, and it would be
highly advantageous to have, a device and method for reducing the
flow of blood exiting the coronary sinus without thoracic surgery
as a means of treating or preventing cardiac ischemia caused by,
for example, diffuse coronary artery disease.
SUMMARY OF THE INVENTION
[0010] According to one aspect of the present invention there is
provided a narrowing intraluminal stent for placement in a body
lumen having a cross sectional dimension, the narrowing
intraluminal stent comprising a hollow body having a first end, a
second end, and a flow passage being defined therethrough from the
first end to the second end, the hollow body being designed for
intraluminal placement in the body lumen and having at least one
portion of an inner cross sectional dimension smaller than the
cross sectional dimension of the body lumen, so as to artificially
narrow a passage through the body lumen.
[0011] According to another aspect of the present invention there
is provided a method of artificially narrowing a passage through a
body lumen having a cross sectional dimension, the method
comprising the step of implanting a narrowing intraluminal stent in
the body lumen, thereby artificially narrowing the passage through
a body lumen.
[0012] According to yet another aspect of the present invention
there is provided a method of initiating or accelerating
angiogenesis in order to treat or prevent ischemia, the method
comprising the step of artificially narrowing a passage through a
blood vessel having a cross sectional dimension by implanting a
narrowing intraluminal stent therein, thereby reducing a flow of
blood therethrough, creating back pressure and initiating or
accelerating angiogenesis upstream thereto.
[0013] According to further features in preferred embodiments of
the invention described below, the stent is constructed of a
biologically inert material.
[0014] According to still further features in the described
preferred embodiments, the stent is coated with a biologically
inert material.
[0015] According to further features in preferred embodiments of
the invention described below, the biologically inert material is
selected from the group consisting of stainless steel, nitinol and
biocompatible plastic material.
[0016] According to still further features in the described
preferred embodiments, the hollow body further includes at least
one expandable portion for affixing the narrowing intraluminal
stent in the body lumen.
[0017] According to still further features in the described
preferred embodiments, the lumen is a coronary sinus and the stent
is configured for placement therein so as to decrease a flow of
blood therethrough.
[0018] According to still further features in the described
preferred embodiments, the decrease in flow of blood through the
coronary sinus is sufficient so as to cause coronary
angiogenesis.
[0019] According to still further features in the described
preferred embodiments, the inner cross sectional dimension of the
hollow body is greater than 7 mm.sup.2 and less than 28
mm.sup.2.
[0020] According to still further features in the described
preferred embodiments, the length of the hollow body, from the
first end to the is second end, is greater than 20 mm and less than
50 mm.
[0021] According to still further features in the described
preferred embodiments, an aspect ratio defined by an inner cross
sectional diameter of the hollow body divided by a length of the
hollow body from the first end to the second end is greater than
0.1 and less than 0.2.
[0022] According to still further features in the described
preferred embodiments, a ratio defined by a narrowest inner cross
sectional diameter of the hollow body divided by a length of the
hollow body from the first end to the second end is greater than
0.1 and less than 0.2.
[0023] According to still further features in the described
preferred embodiments, the at least one expandable portion expands
as a result of an occurrence selected from the group consisting of
(i) application of a force which expands the at least one
expandable portion; and (ii) removal of a force which contracts the
at least one expandable portion.
[0024] According to still further features in the described
preferred embodiments, the force which expands the at least one
expandable portion is suppliable by an inflatable balloon of a
catheter receivable within the hollow body of the stent.
[0025] According to still further features in the described
preferred embodiments, the affixing of the narrowing intraluminal
stent in the body lumen occurs as a result of a cause selected from
the group consisting of (i) a physical contact between a portion of
the narrowing intraluminal stent and an inner surface of the body
lumen; and (ii) a biological process occurring in cells of an inner
surface of the body lumen as a result of a presence therein of the
narrowing intraluminal stent.
[0026] According to still further features in the described
preferred embodiments, the hollow body further includes at least
two expandable portions for affixing the narrowing intraluminal
stent in the body lumen.
[0027] According to still further features in the described
preferred embodiments, an integrity of the at least one expandable
portion is preserved during a transition from elasticity to
plasticity.
[0028] According to still further features in the described
preferred embodiments, the at least one expandable portion
comprises a collapsible grid.
[0029] According to still further features in the described
preferred embodiments, the step of implanting the narrowing
intraluminal stent in the body lumen is effected with a
catheter.
[0030] According to still further features in the described
preferred embodiments, guiding the catheter to the lumen is
effected under imaging.
[0031] According to still further features in the described
preferred embodiments, the step of implanting the narrowing
intraluminal stent in the body lumen and the step of expanding the
at least one expandable portion are effected with a balloon
catheter.
[0032] According to still further features in the described
preferred embodiments, guiding the balloon catheter to the lumen is
effected under imaging.
[0033] According to still further features in the described
preferred embodiments, the imaging is accomplished by a method
selected from the group consisting of computer assisted tomography
(CT), magnetic resonance imaging (MRI), proton emission tomography
(PET), ultrasonography, three dimensional ultrasonography,
fluoroscopy, electrophysiological imaging, X-ray imagery and
echocardiography.
[0034] The present invention successfully addresses the
shortcomings of the presently known configurations by providing a
device and method for treating or preventing cardiac ischemia
caused by, for example, diffuse coronary artery disease which does
not require thoracic surgery.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] The invention is herein described, by way of example only,
with reference to the accompanying drawings. With specific
reference now to the drawings in detail, it is stressed that the
particulars shown are by way of example and for purposes of
illustrative discussion of the preferred embodiments of the present
invention only, and are presented in the cause of providing what is
believed to be the most useful and readily understood description
of the principles and conceptual aspects of the invention. In this
regard, no attempt is made to show structural details of the
invention in more detail than is necessary for a fundamental
understanding of the invention, the description taken with the
drawings making apparent to those skilled in the art how the
several forms of the invention may be embodied in practice.
[0036] In the drawings:
[0037] FIG. 1 is a perspective view of one embodiment of a core
construction of the stent of the present invention shown in a
non-expanded position;
[0038] FIG. 2 is a perspective view of the same embodiment of the
core construction of the stent of the present invention in an
expanded position;
[0039] FIGS. 3a-b show the particulars of a construction of a
collapsible grid for use in constructing the stent depicted in
FIGS. 1 and 2;
[0040] FIG. 4 is a schematic diagram illustrating placement of a
stent, the core construction thereof is depicted in FIGS. 1 and 2,
in a body lumen by means of a balloon catheter;
[0041] FIGS. 5a-b schematically illustrate an alternate method for
placing a stent of the present invention within a body lumen;
and
[0042] FIG. 6 is a cross sectional view of a stent according to the
present invention situated within a body lumen.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0043] The present invention is of a device and method which can be
used in treating or preventing ischemic heart disease and, more
particularly, to a coronary sinus narrowing stent and to surgical
methods for implanting same. Specifically, the present invention
involves implantation of the stent in the coronary sinus as a means
of treating patients suffering from, for example, diffuse coronary
artery disease, especially in cases where conventional balloon
catheterization, bypass surgery and drugs are infeasible or
ineffective treatment methods.
[0044] The principles and operation of a device and methods which
can be used for treating or preventing ischemic heart disease
according to the present invention may be better understood with
reference to the drawings and accompanying descriptions.
[0045] Before explaining at least one embodiment of the invention
in detail, it is to be understood that the invention is not limited
in its application to the details of construction and the
arrangement of the components set forth in the following
description or illustrated in the drawings. The invention is
capable of other embodiments or of being practiced or carried out
in various ways. Also, it is to be understood that the phraseology
and terminology employed herein is for the purpose of description
and should not be regarded as limiting.
[0046] Referring now to the drawings, FIGS. 1-6 illustrate a
narrowing intraluminal stent for placement in a body lumen 28,
which stent is referred to hereinbelow as stent 20. Stent 20
includes a hollow body 22. Body 22 has a first end 24, a second end
26, and a flow passage 30 (see FIG. 6) defined therethrough, from
first end 24 to second end 26. Hollow body 22 is designed for
intraluminal placement in the body lumen 28 and has at least one
portion 32 of an inner cross sectional dimension smaller than a
cross sectional dimension 34 of body lumen 28, so as to
artificially narrow a passage through body lumen 28.
[0047] Accordingly, the present invention is also provides a method
of artificially narrowing a passage through body lumen 28 having a
cross sectional dimension 34. The method includes the step of
implanting stent 20 in body lumen 28, thereby artificially
narrowing the passage through body lumen 28. Such placement, when
in a blood vessel, is used to initiate or accelerate angiogenesis
in order, for example, to treat or prevent ischemia by reducing a
flow of blood through the blood vessel, creating back pressure and
initiating or accelerating angiogenesis upstream thereto.
[0048] In order to facilitate safe use of stent 20, and to allow
practice of the methods described hereinabove, stent 20 is
preferably constructed of, or it is coated with, a biologically
inert material. Biologically inert materials suited for use in
constructing or coating stent 20 include, but are not necessarily
limited to, stainless steel, nitinol and biocompatible plastic
material.
[0049] Because the function of stent 20 requires that it be affixed
within lumen 28, hollow body 22 may further include at least one
expandable portion 36 (two are pictured) so as to fix stent 20 in
lumen 28. In order to more firmly affix stent 20 within lumen 28,
it is often desirable for hollow body 22 to further include at
least two expandable portions 36 as pictured in FIGS. 1, 2, 4, 5
and 6. Stent 20 is often configured so that integrity of expandable
portion 36 is preserved during a transition from elasticity to
plasticity. Frequently, expandable portion 36 takes the form of a
collapsible grid 42 containing a plurality of holes 48. Grid 42 is
generally fully contained within a coating 46 (see, FIGS. 4 and 6),
for example, a biologically inert coating as described hereinabove.
FIGS. 3a-b show an example of details of the construction of a
collapsible grid for use as part of stent 20. Stent 20 is depicted
in FIG. 2 in an expanded position with expandable portions 36,
expanded so that flow passage 30 (indicated by bent arrow) is
clearly visible (see also FIG. 6; hollow arrow).
[0050] Because the invention was originally conceived to address
the problem of ischemic heart disease, lumen 28 is often a coronary
sinus and stent 20 is configured for placement therein, so as to
decrease a flow of blood therethrough. Decreasing the flow of blood
through the coronary sinus, if the decrease is of sufficient
magnitude, can cause coronary angiogenesis, thereby eventually
reliving cardiac ischemia.
[0051] In order to suit stent 20 for use in a coronary sinus as
described hereinabove, stent 20 is often constructed with an inner
cross sectional dimension 32 of hollow body 22 greater than 7
mm.sup.2 and less than 28 mm.sup.2. For the same reason, stent 20
is often constructed with a length of hollow body 22, from first
end 24 to second end 26, greater than 20 mm and less than 50 mm.
These dimensions produce an aspect ratio defined by an inner cross
sectional diameter of the hollow body divided by a length of hollow
body 22 from first end 24 to second end 26 which is greater than
0.1 and less than 0.2.
[0052] According to a preferred embodiment of the present invention
a ratio defined by a widest inner cross sectional diameter of said
hollow body divided by a narrowest inner cross sectional diameter
of said hollow body is greater than 2.6 and less than 4.3.
[0053] During use of stent 20, expansion of expandable portions 36
may be achieved, for example, by application of a force which
expands expandable portions 36 or by removal of a force which
contracts expandable portions 36 as is further explained
hereinbelow.
[0054] The force which expands the expandable portion 36 is
suppliable by, for example, an inflatable balloon 40 of a catheter
38 receivable within hollow body 22 of stent 20 (FIG. 4). Catheter
38 may used to implant stent 20 into the body of a patient, for
example via the femoral vein, through the superior vena cava and
the right atrium to the coronary sinus. Guidance of catheter 38,
whether a balloon catheter or any other type of catheter, may be
effected under imaging. Imaging may be accomplished, for example,
by computer assisted tomography (CT), magnetic resonance imaging
(MRI), proton emission tomography (PET), ultrasonography, three
dimensional ultrasonography, fluoroscopy, electrophysiological
imaging, X-ray imagery or echocardiography. After stent 20 has
reached the desired position in lumen 28, the coronary sinus in
this example, balloon 40 is inflated, thereby expanding expandable
portion 36 and affixing stent 20 within lumen 28. Stent 20 may be
fixed in place, for example, as a result of a physical contact 44
between a portion of stent 20 and an inner surface of lumen 28.
Alternately, stent 20 may be fixed in place, as a result of a
biological process occurring in cells of an inner surface of lumen
28 as a result of a presence therein of stent 20. Biological
processes which would tend to fix stent 20 in place include, but
are not limited to, secretion of a fluid, cell death, tissue
growth, scarring, clotting, swelling and localized inflammation.
After placement of stent 20, balloon 40 is deflated and withdrawn
along with catheter 38. The end result of this process is that the
effective cross sectional dimension of lumen 28 is reduced from its
original size 34 to the size of inner cross sectional dimension 32
of hollow body 22 of stent 20.
[0055] An alternate method of affixing stent 20 in lumen 28 is
illustrated in FIGS. 5a-b. This method relies upon removal of a
force which contracts expandable portion 36. In contrast to the
balloon catheter method described hereinabove, this method employs
a catheter 38 equipped with a piston 50. As shown in FIG. 5a, stent
20 is inserted in catheter 38 in a collapsed position. In this
case, stent 20 has at least one expandable portion 36 (two are
pictured) having an inherent spring-like memory. Insertion and
guidance are as described hereinabove for the balloon
catheterization method. After stent 20 has reached the desired
position in lumen 28, the coronary sinus in this example, piston 50
is translated as indicated by an arrow, while catheter 38 is
retracted as indicated by a pair of arrows. Stent 20 is thereby
ejected into lumen 28, where expandable portion 36, having an
inherent spring-like memory, expands to affix stent 20 within lumen
28 (FIG. 5b). As in the balloon catheterization method, the end
result of this process is that the effective cross sectional
dimension of lumen 28 is reduced from its original size 34 to the
size of inner cross sectional dimension 32 of hollow body 22 of
stent 20.
[0056] As can be seen in FIG. 6, regardless of the method chosen to
place stent 20 in lumen 28, a flow passage 30 through lumen 28 is
now limited by cross sectional dimension 32 of stent 20 and not by
cross sectional dimension 34 of lumen 28. This limitation occurs as
a result of contact 44 between stent 20 and lumen 28. Flow through
holes 48 of expandable portion 36 is prevented by coating 46 on
stent 20.
[0057] Although the invention has been described in conjunction
with specific embodiments thereof, it is evident that many
alternatives, modifications and variations will be apparent to
those skilled in the art. Accordingly, it is intended to embrace
all such alternatives, modifications and variations that fall
within the spirit and broad scope of the appended claims. All
publications cited herein are incorporated by reference in their
entirety. Citation or identification of any reference in this
section or in any other section of this application shall not be
construed as an admission that such reference is available as prior
art to the present invention.
* * * * *