Coronary artery by-pass method

A stent is disposed in the myocardium so that it extends only in the myocardium. The stent may extend only partially through the myocardium, from the left ventricle of the heart or from a coronary artery, upstream of a vascular obstruction. Alternatively, the stent may extend completely through the myocardium to establish a blood flow path from the left ventricle to a coronary artery, downstream of a vascular obstruction.

BACKGROUND OF THE INVENTION 
This invention relates to a method for effectuating a coronary artery 
bypass. 
Coronary arteries frequently become clogged with plaque which at the very 
least impairs the efficiency of the heart's pumping action and can lead to 
heart attack. The conventional treatment for a clogged coronary artery is 
a coronary by-pass operation wherein one or more venous segments are 
inserted between the aorta and the coronary artery. The inserted venous 
segments or transplants by-pass the clogged portion of the coronary artery 
and thus provide for a free or unobstructed flow of blood to the heart. 
Such conventional coronary artery by-pass surgery is expensive, 
time-consuming, and traumatic to the patient. Hospital stay subsequent to 
surgery and convalescence are prolonged. 
OBJECTION OF THE INVENTION 
An object of the present invention is to provide a new method for 
performing a coronary artery by-pass operation. 
Another object of the present invention is to provide such a method which 
is less invasive and less traumatic to the patient than conventional 
by-pass surgery. 
An additional object of the present invention is to provide such a method 
which is less expensive than conventional by-pass surgery. 
A more particular object of the present invention is to provide such a 
method which requires no incision through the chest wall. 
Yet another object of the present invention is to provide a catheter 
assembly for use in performing the method of the invention. 
These and other objects of the present invention will be apparent from the 
drawings and detailed descriptions herein. 
SUMMARY OF THE INVENTION 
A cardiovascular treatment method comprises, in accordance with the present 
invention, the steps of (a) providing a stent made of a biocompatible 
material, (b) moving the stent in a collapsed configuration through a 
blood vessel of a patient's vascular system to the patient's heart, (c) 
inserting the stent in the patient's myocardium so that the stent extends 
at least partially through the myocardium and only within the myocardium, 
and (d) upon the disposition of the stent in the myocardium, expanding the 
stent from the collapsed configuration to a substantially tubular expanded 
configuration so that a blood flow path is formed at least partially 
through the myocardium. 
The stent may be disposed in the myocardium so that it extends only 
partially through the myocardium, from a coronary artery, upstream of a 
vascular obstruction, or from the left ventricle of the heart. 
Alternatively, the stent may extend completely through the myocardium to 
establish a blood flow path from the left ventricle to a coronary artery, 
downstream of a vascular obstruction. In any case, the stent is deployed 
so that it extends only within the myocardium and does not protrude beyond 
the heart tissues, either into the left ventricle or into the coronary 
artery. 
Where the stent extends only partially through the myocardium and thus 
terminates within the cardiac tissues, the stent guides blood directly 
into the heart tissues and particularly into cardiac vesicles which 
naturally occur in the myocardium. The blood is naturally distributed from 
the vesicles into the cardiac tissues and is collected by the veins of the 
heart. This function of heart tissue is known from cases in which arteries 
from the chest were rerouted from the chest to the heart. 
Where the stent terminates within the myocardium and extends from a 
coronary artery, upstream of a vascular obstruction, the stent is 
necessarily designed to maintain its expanded form during diastole, so 
that blood pumped from the heart is forced into the stent and from thence 
into the cardiac tissues. 
Where the stent terminates within the myocardium and extends from the left 
ventricle, the stent may be designed to collapse during systole, under the 
compressive forces exerted by the contracting heart muscle. In that case, 
blood is delivered to the myocardium during diastole: blood flows into the 
stent from the left ventricle as the ventricle is filling with blood. 
Alternatively, where the stent terminates within the myocardium and 
extends from the left ventricle, the stent may be designed to maintain its 
expanded form during systole, despite the compressive forces exerted by 
the contracting heart muscle. In that case, blood is forced into the stent 
and from thence into the cardiac tissues during heart contraction. 
Where the stent traverses or extends through the myocardium, it may be 
designed to either collapse or remain expanded during systole. In any 
event, where the stent maintains its expanded configuration, it is 
provided with a one-way valve preventing reverse flow of blood during 
diastole. 
According to another feature of the present invention, the step of 
inserting the stent into the myocardium or heart wall includes the step of 
ejecting the stent from a distal end of a catheter into the myocardium. 
The catheter is inserted along a predetermined path through the vascular 
system of the patient. 
According to a further feature of the present invention, the step of 
inserting the stent into the myocardium further includes the step of 
forming a perforation or recess in the myocardium prior to the ejection of 
the stent from the catheter. 
In addition, the step of inserting the stent into the myocardium may 
includes the steps of ejecting a collapsed inflatable balloon with the 
stent into the myocardium from the distal end of the catheter, the stent 
surrounding the balloon, and inflating the balloon and opening the stent 
upon ejection of the balloon and the stent into the myocardium. Generally, 
it is contemplated that the steps of inflating the balloon and opening the 
stent are performed during diastole. 
The balloon and the stent may be inserted into the myocardium over a guide 
wire. In that case, the method further includes the step of inserting the 
guide wire into the perforation or recess prior to the ejection of the 
collapsed inflatable balloon and the stent from the distal end of the 
catheter. 
According to feature of the present invention, the coronary bypass method 
further comprises the steps of inserting a distal end portion of the 
catheter into the perforation or recess prior to the ejection of the 
stent, and sensing pressure on the catheter along the distal end portion, 
thereby determining a thickness of the myocardium at the perforation or 
recess. The stent is cut from a piece of stent material so that the stent 
has a length corresponding to the sensed or measured thickness of the 
myocardium at the perforation or recess. 
Other techniques for determining an optimal stent length may be used. For 
example, an MRI or CAT scan may be undertaken to determine myocardium 
thickness. In addition, such a scan may be used to determine an optimal 
location and angle for placing the stent. These variable can only be 
determined, of course, in a clinical setting, depending on the particular 
anatomy of the patient. 
According to further features of the present invention, the formation of 
the perforation or recess includes the step of ejecting a needle into the 
myocardium from the distal end of the catheter, pushing a drill head into 
the myocardium from the distal end of the catheter and rotating the drill 
head during the step of pushing. Preferably, these steps of forming and 
ejecting are performed during diastole. The synchronization or 
coordination of the drilling, stent ejecting, and balloon inflating steps 
with heart action is implementable by computer. 
Where the stent is disposed in the myocardium so that the stent extends 
only partially through the myocardium from the patient's left ventricle, 
the stent is inserted into the myocardium from the left ventricle. 
Accordingly, a distal end of the catheter is passed into the left 
ventricle prior to the deployment of the stent, while the stent is moved 
in its collapsed configuration through the catheter and into the left 
ventricle of the heart. 
Where the stent is disposed in the myocardium so that the stent extends 
only partially through the myocardium from a coronary artery of the 
patient, the stent is inserted into the cardiac tissues from the coronary 
artery, preferably upstream of all vascular obstructions in the artery. 
Where the stent extends from the left ventricle through the myocardium to 
the coronary artery, the stent is inserted from the coronary artery. The 
distal end of the catheter is inserted into the coronary artery prior to 
the deployment of the stent. 
According to another feature of the present invention, the stent has an 
inherent spring bias tending to form the stent into the opened 
configuration The method then further comprises the steps of opening the 
stent and thereby allowing blood to flow from the left ventricle into the 
stent during diastole and closing the stent by heart contraction during 
systole. 
Where the stent is provided with a one-way valve, the method further 
comprises the steps of maintaining the stent expanded in the opened 
configuration during both diastole and systole upon expansion of the stent 
(with the balloon or otherwise), permitting flow into the stent during 
systole, and blocking flow from the stent back through the valve during 
diastole. 
A method for supplying blood to the heart comprises, in accordance with the 
present invention, the step of directing blood directly into the 
myocardium via a stent extending only partially through the myocardium and 
only within the myocardium. The method may include the steps of, during 
systole, forcing blood directly into the myocardium through the stent and, 
during diastole, closing a valve in the stent to block a return of blood 
through the stent. Alternatively, particularly where the stent extends 
from the left ventrical partially into the myocardium, the step of 
directing includes the steps of, during diastole, guiding blood into the 
myocardium through the stent and, during systole, closing the stent. 
A cardiovascular treatment method comprises, in accordance with a 
particular embodiment of the present invention, the steps of (i) providing 
a stent made of a biocompatible material, (ii) moving the stent in a 
collapsed configuration through a blood vessel of a patient's vascular 
system to the patient's heart, (iii) upon reaching the patient's heart, 
disposing the stent in a wall of the patient's heart so that the stent 
extends only partially into the myocardium and extends only within the 
myocardium and does not extend into the left ventricle or the coronary 
artery, and (iv) upon the disposition of the stent in the myocardium, 
expanding the stent from the collapsed configuration to a substantially 
tubular permanently expanded configuration so that a flow path is formed 
directly into the myocardium through the stent. 
As discussed above, a perforation or recess is formed in the myocardium 
prior to the disposition of the stent in the myocardium. The stent is 
inserted into the perforation or recess. To dispose the stent, a collapsed 
inflatable balloon is inserted with the stent into the myocardium from a 
distal end of a catheter. The stent surrounds the balloon. Upon insertion 
into the myocardium, the balloon is inflated and the stent concomitantly 
opened. 
A method in accordance with the present invention greatly reduces the 
expense of coronary surgery, as well as the trauma to the patient and the 
convalescence required after the by-pass operation. A coronary artery 
by-pass operation in accordance with the present invention may be 
performed by a radiologist, through the vascular system of the patient. 
Accordingly, only one or two small incisions in the patient are necessary.

DETAILED DESCRIPTION 
As illustrated in FIG. 1, a coronary artery by-pass is accomplished by 
disposing an alternately collapsible and expandable stent 12 in a wall HW 
of a patient's heart PH. Stent 12 extends from the left ventricle LV of 
heart PH to a clogged coronary artery CA at a point downstream of a 
blockage BL. Stent 12 is made of a biocompatible material and has an 
inherent spring bias or memory tending to form the stent into a 
substantially tubular opened configuration (FIG. 2A) during the relaxation 
of the surrounding heart muscle during the diastolic phase of a cardiac 
cycle. Stent 12 thus opens a passageway between ventrical LV and artery CA 
during diastole to allow blood to flow from the ventricle into the artery, 
as indicated by arrows 14 and 16 in FIG. 2A. Upon contraction of the 
surrounding heart muscle in the systolic phase of a cardiac cycle, stent 
12 is forced closed, thus blocking or preventing blood flow between 
ventricle LV and coronary artery CA, as represented by an arrow 18 in FIG. 
2B. FIG. 2A shows coronary artery CA in a partially collapsed 
configuration characteristic of diastole. Other drawing figures herein 
show coronary artery CA expanded for purposes of illustration 
simplification and clarity. 
As illustrated in FIG. 3A, implantation or disposition of stent 12 in heart 
wall or myocardium HW begins with the insertion of a catheter 20 through 
the aorta AO (FIG. 1) and into coronary artery CA. In artery CA, catheter 
20 is forced past blockage BL so that the distal tip 22 of catheter 20 is 
disposed in a desired location opposite heart wall HW. Catheter 20 has a 
steerable tip, as discussed more fully hereinafter with reference to FIG. 
4, so that distal tip 22 may be controllably oriented to face wall HW, as 
indicated in FIG. 3A. 
Upon a bringing of distal tip 22 into contact with wall or myocardium HW, a 
rotary head 24 of a surgical drill is ejected from distal tip 22, as shown 
in FIG. 3B. Head 24 is rotated during a pushing of catheter 20 in the 
distal direction, thereby forming a perforation or passage in heart wall 
HW. A distal end portion 26 of catheter 20 including tip 22 is inserted 
into the perforation in the heart wall HW during the formation of the 
perforation by drill head 24, as depicted in FIG. 3C. 
Upon the disposition of distal end portion 26 of catheter 20 in heart wall 
HW, the surgical drill is withdrawn from the catheter. Stent 12 is then 
inserted in a collapsed configuration down catheter 20. A push rod (not 
shown) may be used to position stent 12 in distal end portion 26 of 
catheter 20 so that the stent is coextensive with heart wall HW. 
Upon the positioning of stent 12 in a collapsed configuration inside distal 
end portion 26 of catheter 20, catheter 20 is withdrawn from heart wall 
HW, while stent is maintained in position relative to heart wall. Upon the 
consequent ejection of stent 12 from distal tip 22 of catheter 20, as 
illustrated in FIG. 3D, stent 12 automatically expands from its collapsed 
configuration, provided that heart PH is in a diastolic phase of a cardiac 
cycle. Subsequently to the completed ejection of stent 12 from catheter 
20, catheter 20 is withdrawn, as illustrated in FIG. 3E. 
FIG. 4 shows an angioplastic surgical device for use in the method 
described above with reference to FIGS. 3A-3E. The device includes 
catheter 20 insertable into aorta AO and coronary artery CA. Steering 
componentry including a plurality of wires 28 and an orientation control 
actuator 30 is connected to catheter 20 for enabling an operator to 
control, from outside the patient, an orientation of distal tip 22 of 
catheter 20 upon insertion of the catheter into the patient. A pressure 
sensor assembly 32 is operatively connected to catheter 20 for measuring 
the length of distal end portion 26 which is coextensive with heart wall 
HW upon completion of the catheter insertion (FIG. 3C). Pressure sensor 
assembly 32 may include a multiplicity of strain gauges 34 embedded in 
distal end portion 26, the strain gauges being connected to a current 
sensor array 36 and a voltage source 38. Current sensor array 36 is in 
turn connected to a logic circuit 40 which determines the length of that 
portion of catheter 20 at a distal end thereof which is subjected to 
increased compressive pressure especially during the systolic phase of the 
cardiac cycle. Circuit 40 is connected to a display 42 by means of which 
the thickness of the heart wall HW is communicated to a surgeon or 
radiologist. Stent 12 may then be customized to the patient. The length of 
stent 12 is matched to the measured thickness of heart wall HW by cutting 
the stent from a provided stent segment. Alternatively, stent 12 may be 
selected from a kit of different stent sizes. Of course, the cutting of 
stent 12 or the selection thereof may be implemented automatically by a 
computer operated according to a numerical control program. 
As illustrated in FIGS. 5A-5C, in another procedure for disposing stent 12 
in heart wall HW, a catheter 44 with a steerable distal end 46 is 
maneuvered to position distal end 46 in coronary artery CA and to place 
the end of the catheter into contact with heart wall HW. A hollow needle 
48 (FIG. 5A) is then ejected from distal end 46 of catheter 44 into heart 
wall HW, whereupon a Seldinger wire 50 (FIG. 5B) is moved in the distal 
direction through catheter 44 and needle 48. Upon the projection of the 
distal end of wire 50 from needle 48, needle 48 is withdrawn and an 
auxiliary catheter 52 (FIG. 5B) is inserted through catheter 44 and over 
wire 50. Catheter 52 is provided with a pressure sensor assembly (not 
shown), as discussed hereinabove with reference to FIG. 4, for measuring 
the thickness of heart wall HW. 
Upon the measurement of the thickness of heart wall HW, catheter 52 is 
withdrawn and a balloon 54 surrounded by stent 12 (not separately shown in 
FIG. 5C) is inserted through catheter 44 and over wire 50. Upon a 
positioning of balloon 54 and stent 12 inside heart wall HW, balloon 54 is 
inflated (FIG. 5C) to assist in an initial expansion of stent 12 in 
opposition to the compressive forces of the heart muscle. Upon the desired 
disposition of stent 12, balloon 54 and wire 50 and subsequently catheter 
44 are withdrawn, leaving stent 12 in place as a coronary artery by-pass 
or shunt between ventricle LV and artery CA. 
As illustrated in FIGS. 6A-6C, in another procedure for disposing stent 12 
in heart wall HW, a catheter 56 with a steerable distal end 58 is 
maneuvered to position the distal end in coronary artery CA and to place 
the end of the catheter into contact with heart wall HW. A needle or wire 
60 (FIG. 6A) is then ejected from distal end 58 of catheter 56 into heart 
wall HW, whereupon a series of dilating catheters 62 (FIG. 6B) of 
progressively increasing diameter are inserted in the distal direction 
through catheter 56 and over needle 60 into heart wall HW. Upon the 
ejection of a largest dilating catheter 62 from catheter 56 so that it 
traverses heart wall HW, the dilating catheter is withdrawn and a balloon 
64 surrounded by stent 12 (FIG. 6C) is inserted through catheter 56 and 
over needle or wire 60. Upon a positioning of balloon 64 and stent 12 
inside heart wall HW, balloon 64 is inflated (FIG. 6C) to assist in an 
initial expansion of stent 12 in opposition to the compressive forces of 
the heart muscle. 
Upon the measurement of the thickness of heart wall HW, catheter 52 is 
withdrawn and a balloon 54 surrounded by stent 12 (not separately shown in 
FIG. 6C) is inserted through catheter 56 and over wire 50. Upon a 
positioning of balloon 54 and stent 12 inside heart wall HW, balloon 54 is 
inflated (FIG. 6C) to assist in an initial expansion of stent 12 in 
opposition to the compressive forces of the heart muscle. Upon the desired 
disposition of stent 12, balloon 54 and wire 50 and subsequently catheter 
56 are withdrawn, leaving stent 12 in place as a coronary artery by-pass 
or shunt between ventricle LV and artery CA. 
The disposition of a by-pass stent as described hereinabove may be 
implemented in part via a computer programmed to enable the timing of 
heart perforation, catheter or stent insertion, balloon inflation, and 
other operations so that those operations are performed only during the 
diastolic phase of a cardiac cycle. The programming and utilization of a 
computer in such a procedure will be clear to one skilled in the art from 
the teachings of U.S. Pat. No. 4,788,975 to Shturman et al., the 
disclosure of which is hereby incorporated by reference. 
As shown in FIGS. 7A and 7B, a coronary by-pass may be effectuated by 
disposing a stent 66 with a one-way valve 68 in a heart wall or myocardium 
HW' of a patient. In accordance with the embodiment of FIGS. 7A and 7B, 
once stent 66 is positioned in heart wall HW', the stent remains in a 
substantially expanded configuration. Although the stent may elastically 
deform under the contractive pressure of the heart muscle during systole, 
the stent remains opened to allow blood to pass from the patient's left 
ventricle LV' into the coronary artery CA'. During diastole, the blood 
pumped into coronary artery through shunt 66 is blocked by one-way valve 
68 from returning to left ventricle LV'. 
Stent 66 is installed in the patient's heart via essentially the same 
procedure or procedures described hereinabove for inserting stent 12. The 
difference between the use of stent 12 and the use of stent 66 arises from 
their structure. Stent 12 is designed to collapse and close during 
systole, while stent 66 is designed to resist the contractive pressure of 
the heart and to remain opened during systole to permit the flow of blood 
through the stent into coronary artery CA'. 
As illustrated in FIGS. 8A and 8B, a stent 70 designed to resist the 
contractive pressure of the heart and to remain opened during systole 
comprises a plurality of interlocking segments 72 which overlap one 
another in a collapsed insertion configuration of the s tent (FIG. 8A). 
Along their longitudinally or axially extending edges, stent segments 72 
are provided with mating or interdigitating fingers 74. In the insertion 
configuration, the projections are spaced from one another. Upon insertion 
of stent 70 into the myocardium and subsequent expansion of the stent by a 
balloon (not shown), fingers 74 slip into an interleaved configuration, 
thereby locking the stent in an opened tubular configuration which resists 
collapse during the systolic contractions of the heart. 
Stent 70 is provided with valve flaps 76. Stent 70, like stent 12 and stent 
66, is made of a biocompatible material. Valve flaps may be made of 
similar material in with a smaller thickness. It is to be noted that 
stents 66 and 70 may deform elastically during systole. Their lengths may 
increase during such deformation. However, they remain sufficiently open 
to allow the passage of blood from the left ventricle into the coronary 
artery. 
As illustrated in FIG. 9, a stent 78 for use in a by-pass procedure as 
described hereinabove includes an outer layer 80 of interwoven helical 
strands of biocompatible material. An inner layer 82 is a vascular graft 
taken from the patient prior to the by-pass operation. Vascular graft 
layer 82 may be connected to outer layer 80, for example, by adhesive or 
laser welding. FIGS. 8A and 8B also show a vascular graft layer 84 inside 
stent segments 72. Where a graft lining is inserted in a stent with a 
valve, it may be necessary to insert two vascular graft sections into the 
prosthetic device from opposite ends thereof. 
As illustrated in FIG. 10, blood is supplied directly to the myocardium MYO 
of a patient's heart HP from a left ventricle VL via one or more stents 
86, 88, and 90 extending from the left ventricle and terminating within 
myocardium MYO. Each stent 86, 88, and 90 thus extends only partially into 
myocardium MYO. Also, each stent 86, 88, and 90 is disposed entirely 
within myocardium MYO; none protrudes beyond myocardium MYO either into 
left ventricle VL or into a coronary artery AC (or, of course, into the 
pericardial fluid). 
Stents 86, 88, and 90 are disposed in myocardium MYO using essentially the 
same technique as described above. A distal end of a catheter (not shown 
in FIG. 10) is inserted along a predetermined path 92, 94, 96 through the 
vascular system of the patient and into left ventricle VL. Upon insertion 
of the catheter tip into left ventricle VL and upon the orientation of the 
catheter tip at a predetermined angle al (FIG. 11) with respect to the 
perpendicular 98 to the myocardium MYO, a surgical drill (not shown) is 
ejected from the catheter, as described hereinabove with reference to FIG. 
3B. The drill is operated to form a perforation or recess at angle al in 
myocardium MYO. A distal end portion of the catheter is inserted into the 
recess in myocardium MYO during the formation of the perforation by the 
drill head, as described above with reference to FIG. 3C. Upon the 
disposition of the distal end portion of the catheter in myocardium MYO, 
the surgical drill is withdrawn from the catheter. Stent 86, 88 or 90 is 
then inserted in a collapsed configuration down the catheter. Upon the 
positioning of stent 86, 88, or 90 in a collapsed configuration inside the 
distal end portion of the catheter (e.g. via use of a push rod), the 
catheter is withdrawn from myocardium MYO, while stent 86, 88, or 90 is 
maintained in position relative to the myocardium so that the stent 
extends partially into myocardium MYO and does not protrude therefrom. 
Upon the consequent ejection of stent 86, 88, or 90 from the distal end of 
the catheter, as described hereinabove with reference to FIG. 3D, stent 
86, 88, or 90 automatically expands from its collapsed configuration, 
provided that heart HP is in a diastolic phase of a cardiac cycle. 
Subsequently to the completed ejection of stent 86, 88, or 90 from the 
catheter, the catheter may be used to place another stent 86, 88, or 90, 
if required. 
Stents 86, 88, and 90 guide blood directly into myocardium MYO and 
particularly into cardiac vesicles CVS (schematically depicted in FIG. 11) 
which naturally occur in the myocardium. The blood is naturally 
distributed from vesicles VCS into cardiac tissues and is collected by the 
veins (not shown) of the heart. 
Stents 86, 88, and 90 may be designed to collapse during systole, under the 
compressive forces exerted by the contracting heart muscle. In that case, 
blood is delivered to myocardium MYO during diastole: blood flows into 
stents 86, 88, and 90 from left ventricle VL as the ventricle is filling 
with blood. In an alternative design, stents 86, 88, and 90 maintain their 
expanded form during systole, despite the compressive forces exerted by 
the contracting heart muscle, as described hereinabove with reference to 
FIGS. 7A, 7B, 8A, and 8B. In that case, blood is forced into stents 86, 
88, and 90 and from thence into myocardium MYO during heart contraction. 
Valves prevent blood from returning during diastole. 
Depending on the anatomy and problems of the individual patient, a 
combination of the techniques described herein may constitute an optimal 
treatment for the patient. For example, where a plurality of stents 86, 
88, and 90 are inserted from the left ventricle VL into myocardium MYO, 
one or two stents 86, 88, and 90 may be adapted for diastolic blood 
delivery, while the other(s) is designed for systolic delivery of blood. 
The stents have appropriate structures, as described above. 
Moreover, in addition to one or more stents 86, 88, and 0 inserted from the 
left ventricle VL partially into myocardium MYO, one or more stents 12 or 
66 may be deployed to connect left ventricle VL with coronary artery AC, 
as described above. 
FIG. 12 depicts another coronary by-pass technique which may be used alone 
or together with one or more of the other procedures described above. A 
stent 100 is inserted from a coronary artery COR into the myocardium MYC 
of a patient's heart so that the stent extends only part way through the 
myocardium MYC and does not protrude from the heart wall. Stent 100 is 
deployed in coronary artery COR upstream of a substantially complete 
vascular blockage VB. In this case, stent 100 is necessarily of the 
diastolic type: it expands to an opened configuration during diastole to 
deliver blood to myocardium MYC by virtue of backflow from the aorta. 
Stent 100 closes during systole to prevent blood outflow through stent 100 
during systole. 
Although the invention has been described in terms of particular 
embodiments and applications, one of ordinary skill in the art, in light 
of this teaching, can generate additional embodiments and modifications 
without departing from the spirit of or exceeding the scope of the claimed 
invention. For example, other equivalent techniques may be used for 
measuring the thickness of heart wall HW or determining an appropriate 
length of stent 12. A "measuring rod" of a predetermined length may be 
inserted through the angioplastic catheter. A computer connected to a 
CAT-scanner, an MRI machine or other imaging device then automatically 
determines myocardium thickness by comparing the dimensions thereof to the 
known length of the "measuring rod." The computer with scanner input may 
be additionally used to determine optimal locations and insertion angles 
of multiple stents, e.g., stents 86, 88, and 90. 
It is to be noted that several stents in accordance with the present 
invention may be disposed in the myocardium of a single heart, thereby 
connecting the left ventricle to one or more points along a coronary 
artery or to several arteries during the diastolic phase of a cardiac 
cycle. 
Accordingly, it is to be understood that the drawings and descriptions 
herein are profferred by way of example to facilitate comprehension of the 
invention and should not be construed to limit the scope thereof.