Stent delivery system and method of use

Described herein are various methods and apparatuses for delivering stents and other devices into the myocardium of a patient. One preferred stent delivery system provides access to the insertion site in the myocardium by advancing a delivery catheter through a blockage in a coronary artery, or around the blockage through a coronary vein or through a channel or tunnel formed around the blockage. In one embodiment, once the distal end of the delivery catheter is adjacent the myocardium, an angled bend is created in the catheter by actuating expandable steering guides mounted to the catheter which cooperate with the walls of the blood vessel to cause the catheter to turn. Then, a guidewire is advanced through the delivery catheter and into the myocardium. In another embodiment, a tip-deflecting pull wire extends from the distal end of the delivery catheter which may be actuated to turn towards and then inserted into the myocardium. In another embodiment, an exit port facing the insertion site is provided within the catheter or a balloon mounted on the catheter so that a guidewire may be directed through a lumen and out the exit port into the myocardium. Once the guidewire punctures into the myocardium, the guidewire is anchored using barbs, balloons or other actuatable members to secure the guidewire to the myocardium. Subsequently, using a push-pull mechanism, stents and other medical devices can be advanced over the guidewire into the myocardium.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The present invention relates to the delivery of a stent and other devices
 into the myocardium of a patient, and more particularly, to a stent
 delivery system to provide a bypass through the myocardium from the left
 ventricle into a coronary artery.
 2. Description of the Related Art
 Coronary arteries as well as other vessels frequently become clogged with
 plaque that at the very least impairs the efficiency of the heart's
 pumping action and can lead to heart attack and death. One conventional
 treatment for clogged coronary or other arteries is a bypass operation
 wherein one or more venous segments are inserted between the aorta and the
 coronary artery. The inserted venous segments or transplants act as a
 bypass of the clogged portion of the coronary artery and thus provide for
 a free or unobstructed flow of blood to the heart.
 Such coronary artery bypass surgery, however, is expensive, time-consuming
 and traumatic to the patient. Hospital stays subsequent to the surgery and
 convalescence are prolonged.
 A new coronary artery bypass technique is disclosed in U.S. Pat. No.
 5,429,144. That technique utilizes a stent made of a biocompatible
 material and comprises steps of moving the stent in a collapsed
 configuration through a blood vessel of a patient's vascular system to the
 patient's heart, inserting the stent in the patient's myocardium, and upon
 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.
 One problem with the coronary artery bypass method providing a stent
 through the myocardium of the heart is how to get the stent into the
 myocardium. U.S. Pat. No. 5,429,144 describes a percutaneous approach
 wherein the stent is brought to the myocardium through the patient's
 vasculature on the distal end of a catheter, and advanced into the
 myocardium over a guidewire. One particular challenge is how to make an
 angled bend in the guidewire to puncture through the wall of the vessel
 and into the myocardium.
 Another problem with this approach is that catheters delivering the
 guidewire, stent or other devices to be provided into the myocardium are
 conventionally guided to the puncture point through the blockage in the
 coronary artery. However, when the blockage is too large, a delivery
 catheter cannot access the desired insertion site.
 In addition, it is often difficult to advance devices into the myocardium
 because of the traction and force necessary to push through the
 myocardium. This problem arises not only for delivery of the stent, but
 also for the delivery of dilation catheters used to expand the
 cross-section of the passageway through the myocardium, and other devices.
 Accordingly, what is needed is a method and apparatus for delivering
 guidewires, stents and other devices into the myocardium. In particular,
 what is needed is a delivery system that can deliver these devices at an
 angled bend for transverse insertion into the myocardium. Moreover, what
 is needed is a delivery method and apparatus for advancing a delivery
 catheter to a puncture site in a coronary vessel when the blockage in the
 vessel is too large to permit passage of a catheter therethrough. What is
 also needed is a method and apparatus for advancement of a stent, dilation
 catheter or other device into and through the myocardium.
 SUMMARY OF THE INVENTION
 Briefly stated, the present invention addresses the above needs by
 providing various methods and apparatuses for delivering stents and other
 devices into the myocardium of a patient. One preferred stent delivery
 system provides access to the insertion site in the myocardium by
 advancing a delivery catheter through a blockage in a coronary artery, or
 around the blockage through a coronary vein or through a channel or tunnel
 formed around the blockage. In one embodiment, once the distal end of the
 delivery catheter is adjacent the myocardium, an angled bend is created in
 the catheter by actuating expandable steering guides mounted to the
 catheter which cooperate with the walls of the blood vessel to cause the
 catheter to turn. Then, a guidewire is advanced through the delivery
 catheter and into the myocardium. In another embodiment, a tip-deflecting
 pull wire extends from the distal end of the delivery catheter which may
 be actuated to turn towards and then inserted into the myocardium. In
 another embodiment, an exit port facing the insertion site is provided
 within the catheter or a balloon mounted on the catheter so that a
 guidewire may be directed through a lumen and out the exit port into the
 myocardium. Once the guidewire punctures into the myocardium, the
 guidewire is anchored using barbs, balloons or other actuatable members to
 secure the guidewire to the myocardium. Subsequently, using a push-pull
 mechanism, stents and other medical devices can be advanced over the
 guidewire into the myocardium.
 In one aspect of the present invention, a guidewire is delivered into the
 patient such that the proximal end of the guidewire extends out of the
 patient, while the distal end of the guidewire is positioned adjacent the
 myocardium. The distal end of the guidewire is inserted into the
 myocardium, and the guidewire is then anchored to the myocardium. An
 introducer catheter carrying a medical device is advanced over the
 guidewire to deliver the device into the myocardium.
 In another aspect of the present invention, a method for delivering a stent
 into the myocardium to bypass a blockage formed in a coronary artery is
 provided. A channel is created from a position proximal to the blockage in
 the coronary artery to a position distal to the blockage in the coronary
 artery. A guidewire is advanced through the channel until a distal end of
 the guidewire is adjacent the myocardium. The guidewire is inserted into
 the myocardium, and a stent is advanced over the guidewire into the
 myocardium.
 In another aspect of the present invention, a method is provided for
 creating a bypass through the myocardium of a patient to bypass a blockage
 formed in a coronary artery. A first tunnel is created through the
 myocardium having a proximal end and a distal end. The proximal end of the
 tunnel opens into the coronary artery proximal to the blockage. The distal
 end of the tunnel is positioned within the myocardium. A second tunnel is
 created through the myocardium, the second tunnel having a first branch
 extending from the distal end of the first tunnel and opening into the
 coronary artery at a position distal to the blockage. A second branch of
 the second tunnel extends from the distal end of the first channel and
 opens into the left ventricle. A stent is disposed in the second tunnel to
 provide a myocardial passageway therethrough.
 In another aspect of the present invention, a delivery catheter is
 provided. This delivery catheter comprises an elongate tubular body having
 a proximal end and a distal end and a lumen extending therethrough. A
 first steering member is mounted on the distal end of the tubular body,
 and a second steering member is mounted on the distal end of the tubular
 body at a position distal to that of the anchoring member.
 In another aspect of the present invention, a method for turning a distal
 end of a catheter within a body lumen is provided. The catheter comprises
 an elongate tubular body having a proximal end and a distal end. An
 anchoring member mounted to the distal end is actuated to secure the
 catheter against the body lumen. A steering member is mounted to the
 distal end of the of the guidewire at a position distal to that of the
 anchoring member. When actuated, the steering member cooperates with the
 body lumen to turn the distal end of the catheter.
 In another aspect of the present invention, a method is provided for
 delivering a medical device to a delivery site within a patient. This
 method comprises providing a delivery catheter having a proximal end and a
 distal end and a lumen extending therethrough into a body lumen of the
 patient. The delivery catheter is secured within the body lumen. The
 distal end of the catheter is turned by actuating a steering member
 mounted on the distal end of the catheter which pushes off against a wall
 of the body lumen. The medical device is advanced through the lumen of the
 delivery catheter and out the distal end.
 In another aspect of the present invention, a method for delivering a stent
 into the myocardium of a patient is provided. A delivery catheter is
 advanced into the vasculature of the patient, the delivery catheter having
 a proximal end and a distal end and a lumen extending therethrough, until
 the distal end is adjacent the myocardium. A pull wire extending from the
 distal end of the delivery catheter is actuated to turn the pull wire
 toward the myocardium. The pull wire is advanced from the distal end of
 the delivery catheter into the myocardium. The stent is delivered over the
 pull wire into the myocardium.
 In another aspect of the present invention, a method for delivering a stent
 into the myocardium of a patient is provided. A delivery catheter is
 advanced into the vasculature of the patient, the catheter having a
 proximal end and a distal end and a lumen extending from the proximal end
 to a side port near the distal end, until the side port faces the
 myocardium. A guidewire having a proximal end and a distal end is inserted
 into the lumen. The distal end of the guidewire is advanced through the
 lumen and out the side port. The guidewire punctures into the myocardium,
 and the stent is delivered over the guidewire into the myocardium.
 In another aspect of the present invention, a method for delivering a stent
 into the myocardium of a patient is provided. A delivery catheter is
 advanced into the vasculature of a patient, the catheter having a proximal
 end and a distal end, until the distal end is adjacent the myocardium. An
 anchoring member mounted on the distal end of the catheter is expanded to
 secure the delivery catheter within the vasculature. A guidewire having a
 proximal end and a distal end is inserted through a lumen in the expanded
 anchoring member, the lumen extending from a proximal end of the anchoring
 member to a side port facing the myocardium, so that the distal end of the
 guidewire exits through the side port. The guidewire punctures into the
 myocardium, and the stent is advanced over the guidewire into the
 myocardium.
 In another aspect of the present invention, a delivery catheter is
 provided. The catheter comprises an elongate body having a proximal end
 and a distal end. An expandable member is mounted on the distal end of the
 tubular body, the expandable member having a proximal end and a distal end
 and an exterior surface. A guide lumen extends from the proximal end of
 the balloon to a side port on the exterior surface of the expandable
 member for directing a medical device therethrough.
 In another aspect of the present invention, a method for treating an
 aneurysm is provided. A catheter having a proximal end and a distal end is
 advanced to the site of the aneurysm. An expandable member mounted on the
 distal end of the catheter is actuated to substantially enclose the
 aneurysm. An embolic element is inserted through a lumen in the expandable
 member into the aneurysm.
 In another aspect of the present invention, a method for delivering a
 medical device into a body tissue of a patient is provided. The method
 comprises inserting a guidewire having a proximal end and a distal end
 into the myocardium from a coronary blood vessel. The guidewire is
 anchored to the body tissue, and the medical device is pushed over the
 guidewire into the body tissue. The proximal end of the guidewire is
 correspondingly pulled proximally while the medical device is pushed
 distally in order to assist advancing the medical device through the body
 tissue.
 In another aspect of the present invention, a delivery system for directing
 medical treatment at least partially into the myocardium is provided. The
 delivery system comprises a guidewire having a proximal end and a distal
 end, means for turning the distal end of the guidewire toward the
 myocardium, means for anchoring the guidewire to the myocardium, and a
 catheter carrying the medical treatment having a lumen extending
 therethrough for receiving the guidewire and advancing the catheter into
 the myocardium.
 In another aspect of the present invention, a method for delivering a stent
 into the myocardium of a patient to bypass a blockage formed in a coronary
 artery is provided. The method comprises advancing a catheter having a
 proximal end and a distal end and a lumen extending at least partially
 therethrough from the proximal end to a distal opening through the
 coronary artery of the patient until the distal opening is past the
 blockage. The catheter is turned so that the distal opening faces the
 myocardium. A wire having a proximal end and a distal end is extended
 through the distal opening such that the distal end punctures into the
 myocardium. The distal end of the wire is anchored to the myocardium. A
 dilation catheter is delivered over the wire, the catheter carrying a
 dilation balloon on a distal end thereof, until the balloon is within the
 myocardium. The dilation balloon is inflated to create an opening in the
 myocardium. The dilation balloon is then deflated and the dilation
 catheter removed from the wire. A stent introducer catheter is delivered
 over the wire, the stent introducer catheter carrying a stent on a distal
 end thereof, until the stent is located within the opening in the
 myocardium. The stent is deployed within the opening in the myocardium.
 In another aspect of the present invention, a method for delivering medical
 treatment into the myocardium of a patient is provided. A tubular wire is
 delivered into the patient, the wire having a lumen extending
 therethrough. The wire once delivered has a proximal end extending out of
 the patient and a distal end positioned adjacent the myocardium. Means for
 turning the distal end of the wire towards the myocardium are provided.
 Then, the distal end of the wire is inserted into the myocardium. Medical
 treatment is delivered through the lumen in the wire into the myocardium.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
 The preferred embodiments described hereinbelow depict methods and
 apparatuses for delivering a stent into the myocardium to create a
 passageway between the left ventricle and coronary artery. It should be
 appreciated, however, that these embodiments may also be applied to the
 delivery of stents and other medical devices into other body tissues and
 vessels, and are particularly applicable for delivering devices at an
 angled bend relative to the axis of blood flow. In addition, the delivery
 methods and apparatuses described herein pertain to the placement of
 stents and other devices partially through the myocardium, as well as for
 drug delivery and similar applications.
 As illustrated in FIGS. 1A and 1B, a coronary artery bypass is accomplished
 by disposing a stent 10 in a heart wall or myocardium MYO of a patient's
 heart PH. Stent 10 preferably extends from the left ventricle LV of heart
 PH to a clogged coronary artery CA at a point downstream of a blockage BL
 to create a shunt 12 therethrough. Stent 10 is preferably made of a
 biocompatible material such as stainless steel or nitinol, although other
 materials such as Ti, Ti alloys, Ni alloys, Co alloys and biocompatible
 polymers may also be used. Stent 10 preferably has a one way valve 14 to
 allow blood to flow from the left ventricle LV to the coronary artery CA.
 Although the stent 10 may elastically deform under the contractive
 pressure of the heart muscle during systole, the stent remains open 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 12 is blocked by one-way valve 14 from returning to left ventricle
 LV. Further details are disclosed in U.S. Pat. No. 5,429,144, the entirety
 of which is hereby incorporated by reference. Other types of stents may
 also be used in accordance with the preferred embodiments described
 herein.
 FIG. 2 illustrates another application for which it is desirable to dispose
 a stent into the myocardium of a patient. In this application, a stent 10
 is provided partially through the myocardium MYO from the left ventricle
 LV. The stent 10 guides blood directly into the myocardium MYO from the
 left ventricle to replenish oxygen-deprived heart muscle. Further details
 are disclosed in the above-referenced U.S. Pat. No. 5,429,144. Other
 applications providing a stent in the myocardium, extending either
 partially or entirely therethrough and accessed from either the coronary
 artery or the left ventricle, are also contemplated by the present
 invention.
 To achieve some or all of the objects of the present invention, in
 particular creating a myocardial passageway between the left ventricle LV
 and the coronary artery CA for disposition of a stent therein, requires a
 delivery system capable of directing the necessary devices to and into the
 myocardium. As described in further detail below, the suitable delivery
 system: (1) provides access to the insertion site adjacent the myocardium;
 (2) creates an angled bend for transverse insertion of devices into the
 myocardium; and (3) directs devices into the myocardium for creation of
 the myocardial passageway.
 I. Access To The Myocardium
 The delivery system described herein preferably comprises one or more
 catheters or guidewires inserted percutaneously into the body, such as
 through the femoral artery and advanced in the patient's vasculature
 through the aorta AO, shown in FIG. 1A. It should be appreciated that the
 percutaneous approach is not essential to achieve many of the objects of
 the invention, and therefore, an open-chest or other approach may also be
 used.
 As shown in FIG. 3A, an exemplary delivery catheter or guidewire 20 which
 has been advanced percutaneously through the femoral artery and through
 aorta AO is advanced through the blockage BL in the coronary artery CA.
 The distal tip 22 of the catheter is delivered past the blockage so that
 it is positioned adjacent to a desired insertion point into the myocardium
 MYO. FIG. 3B shows an alternative access method wherein the catheter 20 is
 delivered to a position adjacent the myocardium through the left ventricle
 LV.
 FIGS. 4A and 4B depict an alternative access route used when a blockage in
 the coronary artery is too large for the catheter to be passed
 therethrough. In this alternate embodiment, a delivery catheter 20 enters
 the body through an access point preferably in the femoral vein (not
 shown). The catheter is advanced up the vein to the vena cava VC and into
 the right atrium RA, as shown in FIG. 4A. Then, the catheter 20 is
 directed into the coronary sinus CS, and then to the coronary vein CV
 which runs adjacent to the coronary artery CA.
 As shown in FIG. 4B, after the distal tip 22 of catheter 20 is past the
 blockage BL in the adjacent coronary vein, the delivery catheter 20 is
 inserted through the vessel wall VW separating the coronary vein CV from
 the coronary artery CA. Steering of catheter 20 between coronary vein CV
 and coronary artery CA may be accomplished using the methods and apparatus
 for turning catheters discussed in further detail below, or other suitable
 methods. As described in further detail below, the delivery catheter is
 turned toward the myocardium MYO either for insertion into the myocardium
 or for directing a guidewire to puncture therethrough. Access to the
 insertion point may also be accomplished by steering the delivery catheter
 through the coronary artery CA to a point proximal to the blockage,
 directing the catheter into the coronary vein to bypass the blockage, and
 reinserting the catheter from the coronary vein into the coronary artery
 past the blockage, as shown in FIG. 4B.
 An alternative method of accessing the myocardium MYO when the blockage BL
 is too large to pass a catheter therethrough employs creating a channel
 around the blockage. As illustrated in FIG. 5, a tunnel 24 is created from
 the coronary artery CA into the myocardium MYO at a point proximal to the
 blockage BL. The tunnel may be created using radiation, lasers, or a
 surgical drill, or any other suitable methods for creating a tunnel. The
 tunnel 24 extends underneath the blockage BL and connects with the
 coronary artery CA at a point distal to the blockage BL. As shown in FIG.
 6, a delivery catheter 20 is advanced through the coronary artery CA, into
 the tunnel 24, and back into the coronary artery CA past the blockage BL.
 It will be appreciated that other methods for diverting a delivery
 catheter around a blockage may be used, such as directing the catheter
 through a shunt into the pericardial space outside the coronary artery.
 While the tunnel 24 shown in FIG. 6 is described as providing access to a
 myocardial insertion point for a coronary bypass, it should also be
 appreciated that this tunneling technique may be useful for obliteration
 of the blockage BL. In particular, conventional methods for ablating a
 blockage only permit access to the blockage from one side. By employing
 the tunneling method shown in FIG. 6, however, a blockage BL can be
 treated not only from its proximal end, but also from its distal end
 simultaneously.
 In an alternative embodiment, a tunnel is created through the myocardium
 MYO from a point proximal to a blockage in the coronary artery into the
 left ventricle. As shown in FIG. 7, where a blockage BL substantially
 occludes a coronary artery CA, a first tunnel 26 is formed proximally of
 the blockage BL extending into the myocardium MYO beneath the blockage BL.
 The tunnel 26 has a proximal end 28 which opens into the coronary artery
 CA proximal to the blockage BL, and a distal end 30 within the myocardium
 MYO beneath the blockage BL. A second tunnel 32 extends from the distal
 end 30 of the first tunnel, with a first branch 34 opening a channel to
 the coronary artery CA past the location of the blockage BL. A second
 branch 36 of the second tunnel 32 extends downward from the distal end 30
 and opens into the left ventricle LV. As illustrated in FIG. 7, a
 substantially Y-shaped passageway is thereby created through the
 myocardium MYO to bypass the blockage BL.
 As shown in FIG. 8, after formation of the Y-shaped passageway in the
 myocardium MYO, one or more stents 10 are provided in the second tunnel 32
 extending between the left ventricle LV and the coronary artery CA. This
 stent 10 opens the myocardial passageway which provides the bypass past
 blockage BL. Positioning of stent 10 in the tunnel 32 is preferably
 accomplished by advancing a guidewire through the first tunnel 26 and into
 each branch 34 and 36 of the second tunnel 32, and then advancing the
 stent over the guidewire in the manner described below. After placement of
 the stent, the tunnel 26 between the coronary artery CA and stent 14 is
 preferably closed at least at distal end 30, and more preferably, also at
 proximal end 28. Closure of the tunnel may be accomplished by inserting
 plugs or other blocking means 38, or by sealing the tunnel with sutures or
 similar methods. Other suitable closure means include occlusion coils and
 balloons, adhesives such as cyanoacrylate, and plugs such as sold under
 the trade name GELFOAM. Alternatively, the tunnel may be closed due to the
 natural contraction of the openings 28 and 30 over time.
 II. The Delivery Catheter
 Once access to the desired insertion site is achieved, an appropriate
 delivery system is brought to the site. The preferred embodiments
 described hereinbelow are directed to a delivery system for inserting
 stents and other medical devices into the myocardium at an angle relative
 to the axis of blood flow. It should be appreciated that the angle of
 insertion may be adjusted between 0 and 180 degrees depending on the
 desired application. Furthermore, while the delivery systems below
 describe insertion of devices into the myocardium, these systems also
 enable angled delivery of medical devices into and through other body
 lumens and tissues.
 A. Dual Balloon Delivery System
 In one embodiment, the stent delivery system comprises a catheter which
 creates an angled bend for insertion of devices into the myocardium MYO.
 FIG. 9 illustrates a delivery catheter 40 which has been advanced into the
 coronary artery CA past the blockage BL. Catheter 40 is an elongate
 tubular body 42 having a lumen 44 (not shown) extending from a proximal
 end 46 (not shown) to a distal end 48. The catheter 40 is preferably
 formed from a flexible biocompatible material such as polymers, stainless
 steel or nitinol.
 Mounted adjacent distal end 48 of catheter 40 are two steering guides,
 which are preferably expandable members such as inflatable balloon 50 and
 52. As illustrated, a steering member, such as balloon 52, is preferably
 located distally of an anchoring member, such as balloon 50, such that
 steering balloon 52 is disposed near or at the very distal tip 48 of the
 catheter 40. Balloons 50 and 52 are each preferably mounted on opposite
 sides of the catheter tubular body 42, such that anchoring balloon 50 is
 mounted facing lower wall LW adjacent the myocardium MYO, and steering
 balloon 52 is mounted facing upper wall UW opposite lower wall LW.
 Alternatively, the anchoring balloon 50 may be mounted concentrically
 around the tubular body 42 so that inflation of the balloon expands
 against both the upper and lower walls. It will be appreciated that other
 devices, such as filters, posts and other expandable members may be used
 for the anchoring and/or steering members.
 As shown in FIG. 9, as the catheter 40 is advanced into position adjacent
 the myocardium MYO, the balloons 50 and 52 remain uninflated. As
 illustrated in FIG. 10, once the distal tip 48 of the catheter 40 is
 positioned adjacent the desired insertion site into the myocardium MYO,
 the balloons 50 and 52 are inflated. Inflation causes the balloons 50 and
 52 to cooperate with the walls of the blood vessel to turn the distal end
 of the catheter. More particularly, in an intermediate state, anchoring
 balloon 50 inflates against the lower wall LW of the coronary artery CA,
 while steering balloon 40 presses against the upper wall UW.
 As illustrated in FIG. 11, anchoring balloon 50 acts to secure the tubular
 body 42 within the coronary artery CA. Inflation of balloon 50 also
 preferably causes the catheter 40 to displace in a direction opposite
 lower wall LW, thereby placing the catheter into a better position for
 transverse insertion of the distal end 48 into the myocardium MYO.
 Steering balloon 52 is further inflated, causing the distal tip 48 of the
 tubular body 32 to turn downward towards lower wall LW and myocardium MYO
 due to the resistance provided by upper wall UW against the balloon. FIG.
 11 also illustrates the effect that the dual balloon inflation may have on
 the upper and lower walls of the coronary artery CA. When balloons 50 and
 52 are fully inflated, forces created on the lower wall LW and upper wall
 UW, respectively, may cause the walls to shift at least slightly in the
 direction of balloon inflation. In particular, the lower wall LW may have
 a tendency to bend upwards distally of the balloon 50 toward the distal
 end 48 of delivery catheter 40 to assist in angling of the catheter.
 Due to the turning action of catheter 40 caused by inflation of balloons 50
 and 52, as well as the bending of lower wall LW toward distal end 48, once
 inflation of the balloons 50 and 52 is complete, the distal tip 48 of
 catheter 30 is positioned at a substantially transverse angle to the lower
 wall LW of the coronary artery CA and the myocardium MYO. From this
 position, the catheter 40 may serve as a guide for the delivery of devices
 used in creating a myocardial passageway. For example, as shown in FIG. 11
 and described in further detail below, a puncture wire or guidewire 100 is
 advanced through the lumen 44 of tubular body 42, and then ejected out the
 distal tip 48 of the catheter 40 to puncture the lower wall LW into the
 myocardium MYO.
 B. Pull Wire Actuator
 FIG. 12 illustrates another embodiment for delivering devices transversely
 into the myocardium MYO of a patient's heart. A catheter 54 is shown
 extending through the coronary artery CA past a blockage BL. Catheter 54
 comprises an elongate tubular body 56 with a lumen 58 (not shown)
 extending therethrough from a proximal end 60 (not shown) to a distal end
 62. A tip-deflecting puncture wire or pull wire 64 extends from the distal
 end 62 of the catheter 54. The wire 64 is actuated at the proximal end
 (not shown) so that it deflects to form a near 90 degree angle relative to
 the catheter 54. The distal tip 66 of wire 64 is turned so that it is
 provided adjacent the myocardium MYO. This shape can be locked and the
 wire 64 is pushed forward through the coronary artery CA and into the wall
 of the myocardium MYO. As described in further detail below, with the wire
 64 in place medical devices are delivered over the wire into the
 myocardium.
 C. Side Port
 In another embodiment, a delivery catheter is provided with a side port
 which allows a puncture wire to exit therethrough. As shown in FIGS. 13A
 and 14A, delivery catheter 70 comprises an elongate tubular body 72 having
 a proximal end 76 (not shown) and a distal end 78 and a lumen 74 (not
 shown) extending at least partially therethrough. Preferably, mounted on
 distal end 78 is an expandable or anchoring member such as inflatable
 balloon 80, which is inflated to maintain the position of the catheter 70
 within the artery. The balloon 80 is preferably a perfusion type balloon
 having a channel 86 to allow blood flow through the artery during the
 procedure. Alternatively, filters or other devices which allow blood flow
 through the artery while anchoring the catheter 70 may also be utilized.
 Perfusion may also be provided through a lumen in the tubular body 72. A
 distal opening or side port exit 82 is provided through the wall of
 tubular body 72 near the distal end of the catheter extending from lumen
 74. The side port 82 may be located either proximal to the balloon 80, as
 in FIG. 13A, or distal to the balloon 80, as in FIG. 14A. Catheter 70 is
 delivered through the vasculature until the side port exit 82 is past the
 location of the blockage BL. Prior to balloon inflation, the catheter 70
 is turned about its longitudinal axis so that the opening 82 faces the
 myocardium.
 FIGS. 13B and 14B illustrate the pathway for a guidewire 100 to pass
 through the lumen 74 of catheter 70. In FIG. 13B, guidewire 100 extends
 through the lumen 74 toward the distal end 78 of the catheter. Proximal to
 balloon 80, the lumen 74 turns downward toward side port exit 82. Thus,
 before guidewire 100 reaches the proximal end of balloon 80, the guidewire
 100 is directed out of the side port 82 toward the lower wall LW of the
 coronary artery CA. A second lumen 84 is also provided within catheter 70
 to direct inflation fluid to balloon 80.
 FIG. 14B shows substantially the same configuration except that the lumen
 74 extends through the balloon 80 such that the side port exit 82 is
 located distal to the balloon 80. Guidewire 100 therefore extends through
 lumen 74 and out side port exit 82 toward the lower wall LW. As with FIG.
 13B, a second lumen 84 is provided through tubular body 72 to direct
 inflation fluid into the balloon 80.
 In another embodiment, as shown in FIG. 15A, the side port 82 is located on
 an exterior surface of the balloon 80. After the catheter 70 is delivered
 to a location past the blockage BL, balloon 80 is inflated. As shown in
 the cross-sectional view of FIG. 15B, balloon 80 preferably comprises a
 perfusion channel 86 extending from the proximal end to the distal end of
 the balloon 80 to allow blood to flow through the vessel. A lumen 74 is
 provided through the catheter 70 which extends into balloon 80 and turns
 downward into side port exit 82. The catheter 70 also has a lumen 84 for
 inflation of balloon 80. Guidewire 100 is advanced through lumen 74 and
 out side port exit 82 into the myocardium MYO.
 FIGS. 15C and 15D illustrate yet another embodiment of a delivery catheter
 with a side port exit. The catheter 70 comprises an elongate tubular body
 72 having a lumen 74 extending from a proximal end 76 (not shown) to
 distal end 78. This lumen 74 is in fluid communication with balloon 80 to
 provide inflation of the balloon. When inflated, balloon 80 has a
 perfusion lumen 86 which allows blood to perfuse therethrough. The balloon
 80 also has a guide lumen 88 extending therethrough which, when inflated,
 extends from a proximal end of the balloon to the lower wall LW. A
 guidewire 100 may then be inserted through the guide lumen 88 and out side
 port exit 82 into the myocardium MYO.
 The delivery catheters described and shown in FIG. 15A-15D are useful not
 only for disposing a stent into the myocardium but also for the treatment
 of aneurysms. Aneurysms are typically treated by introducing embolic
 elements to fill the aneurysm. When the aneurysm opens substantially into
 the blood vessel, it becomes difficult to retain the embolic elements
 within the aneurysm while the aneurysm is being filled. FIG. 16
 illustrates a method for solving this problem using the delivery catheter
 70 described above with respect to FIGS. 15C and 15D. In a blood vessel 90
 with an aneurysm 92, a catheter 70 carrying inflatable balloon 80 is
 advanced such that the balloon 80 is adjacent the aneurysm 92. The balloon
 80 is inflated to substantially enclose the aneurysm 92. A wire 94 or
 other embolic element is advanced through the guide lumen 88 of balloon 80
 and out side port 82. The wire 94 fills up the aneurysm 92, and is
 maintained in the aneurysm due to the fact that the balloon 80 encloses
 the aneurysm to prevent wire 94 from extending into the vessel. It should
 be appreciated that the wire 94 or other embolic element may also be
 delivered through a lumen 74, as shown with respect to the embodiment in
 FIG. 15B. After the aneurysm 92 is filled with wire 94, the wire 94 is
 cut, the balloon 80 is deflated, and the catheter 70 is removed from the
 vessel.
 II. Anchoring Guidewire
 The embodiments described above are directed primarily to providing a
 guidewire 100 into the patient's myocardium. As described in further
 detail below, this guidewire is used for delivering medical devices into
 the myocardium. However, it should be appreciated that many of the
 embodiments described above may also be used in conjunction with other
 methods for creating a passageway through the myocardium. For instance, a
 delivery catheter, such as described above, may be used for delivering a
 surgical drill or other tissue penetrating device ejected from the distal
 end thereof. This approach would be useful, for instance, in creating a
 tunnel through the myocardium as described above. Alternatively, a
 Seldinger wire may be ejected from the distal end of the delivery
 catheter. Further details are described in the above-referenced U.S. Pat.
 No. 5,429,144.
 As shown in FIG. 17, a puncture device such as guidewire 100 is directed
 into the myocardium 100 using any of the preferred methods described
 above. Guidewire 100 preferably has a proximal end 102 (not shown) which
 remains outside the patient's body, and a distal end 104 which is inserted
 through a delivery catheter as described above. Where the delivery
 catheter is provided through the coronary artery, the guidewire is
 advanced in one embodiment until the distal end 104 of the guidewire
 enters the left ventricle. Alternatively, where it is desired that a stent
 or other device extend only partially into the myocardium, the guidewire
 100 need not extend all the way through to the left ventricle. The distal
 tip 104 of the guidewire 100 is preferably made of a radiopaque material
 that can be visualized by the physician by an available method, such as
 fluoroscopy.
 The distal end of the guidewire 100 is preferably formed such that it is
 easily advanced but is difficult to pull back through the tissue. As shown
 in FIG. 17, one embodiment of the distal tip 104 comprises one or more
 barbs 106 extending from the tip in a type of "multi-winged arrowhead"
 configuration. These barbs allow the guidewire to be advanced distally
 into the myocardium but require more force to pull the guidewire 100
 proximally out of the myocardium, thus creating an effective anchor.
 FIG. 18A shows another embodiment wherein a guidewire 100 carries an
 expandable member such as balloon 110 on its distal end. Use of an
 expandable member reduces damage to the myocardium during subsequent
 retraction of the wire 100. As illustrated in FIG. 18B, once the balloon
 110 reaches the left ventricle LV, the balloon 110 is inflated. The
 balloon is then preferably pulled proximally back to the ventricle wall to
 anchor and secure the guidewire 100 in place.
 Alternatively, FIGS. 19A-19C show an expandable guidewire 100 extending
 through and actuated to anchor the guidewire within the myocardium MYO. In
 FIG. 19A, a guidewire 100 is shown advanced through the myocardium MYO.
 Guidewire 100 is provided with an expandable device 112 on distal end 104
 which may be actuated by an operator at the proximal end of the guidewire
 outside of the patient. Actuating of the device may be accomplished by
 using a shape memory material such as nitinol and heating the material
 above its transformation temperature. Alternatively, the guidewire may be
 mechanically actuated to assume the desired shape. FIG. 19B shows the
 guidewire 100 partially actuated at its distal end 104 to expand the
 device 112 into an anchorable shape. FIG. 19C shows the expandable device
 112 fully actuated to anchor the guidewire 100 against the ventricle wall.
 Other types of anchoring and expandable members may also be used to secure
 the guidewire 100.
 Once the guidewire 100 is anchored in place, the delivery catheter may be
 removed without displacing the guidewire inserted through the myocardium.
 Then, with the guidewire 100 anchored in place, catheters used in creating
 and stenting the passageway or other medical devices may be provided into
 the myocardium. Alternatively, the delivery catheter may remain within the
 blood vessel and other catheters or medical devices may be advanced over
 the guidewire and through the delivery catheter. Furthermore, an
 expandable member such as a balloon may be provided on the delivery
 catheter or on the guidewire 100 to anchor the catheter or guidewire to
 the wall of the blood vessel to provide for more secure deployment of
 medical devices into the myocardium.
 IV. Delivery Over the Guidewire
 The anchoring of the guidewire 100 within the myocardium MYO allows for the
 delivery of devices into the myocardium for creation of a myocardial
 passageway. In particular, the anchoring of the guidewire 100 facilitates
 advancement of over-the-wire catheters such as introducer catheters into
 the myocardium by employing a push-pull mechanism. When it is desired to
 push a catheter over the guidewire 100, the guidewire 100 may be pulled
 proximally by an operator from outside of the body. The anchoring member
 at the distal end of the guidewire, whether a balloon, barb, or other
 member, prevents the guidewire 100 from exiting the myocardium MYO.
 Meanwhile, a delivery catheter or other over-the-wire device may be pushed
 into the myocardium MYO, assisted by the pulling force of the anchoring
 member toward the catheter. The anchoring member also assists in placement
 of an over-the-wire catheter in the myocardium by preventing the catheter
 from extending beyond the location of the anchoring member.
 As illustrated in FIG. 20, to create a myocardial passageway, a catheter
 120 having a dilation balloon 122 is advanced over guidewire 100, into the
 myocardium MYO, as shown in FIG. 21. The anchored balloon 110 acts as a
 barrier to advancement of balloon 122, which is subsequently inflated
 within myocardium MYO to expand a myocardial passageway. The balloon 122
 is then deflated and the catheter 120 removed. The process may be repeated
 with successively larger dilation balloons to form a passageway of desired
 size.
 After inflation of the largest desired dilation balloon, the catheter 120
 is withdrawn and a stent introducer catheter 130 is advanced over wire
 100, as shown in FIG. 22. The catheter 130 has an inflatable balloon 132
 mounted on its distal end for deploying a stent 134 carried by balloon
 132. Upon the positioning of balloon 132 inside the myocardium MYO,
 balloon 132 is inflated, as shown in FIG. 23, to assist in an initial
 expansion of stent 134 in opposition to the compressive forces of the
 heart muscle. Upon the desired disposition of stent 134, balloon 132 is
 deflated and catheter 130 and wire 100 are withdrawn, leaving stent 134 in
 place to provide a coronary bypass between ventricle LV and artery CA.
 V. Drug Delivery
 The guidewire such as described above delivered into the myocardium MYO may
 also be used for delivering drugs into the myocardium. As shown in FIG.
 24, a guidewire 140 is advanced partially into the myocardium using any of
 the methods described above. The guidewire 140 comprises a tubular body
 142 having a lumen 148 (not shown) extending from a proximal end 144 (not
 shown) to a distal end 146. The guidewire may be angled using the turning
 methods described above to provide the distal end of the guidewire at a
 desired position within the myocardium for drug delivery. Drug delivery
 fluids 150 are ejected from the distal and 146 into the myocardium.
 Although the guidewire 140 shown in FIG. 24 is not anchored to the
 myocardium MYO, anchoring means as described above may be provided.
 Furthermore, the guidewire 140 may contain a plurality of ports 152 along
 the tubular body 142 near the distal end 146.
 The embodiments illustrated and described above are provided merely as
 examples of certain preferred embodiments of the present invention. Other
 changes and modifications can be made from the embodiments presented
 herein by those skilled in the art without departure from the spirit and
 scope of the invention, as defined by the appended claims.