BACKGROUND OF THE INVENTION1. Field of the Invention[0001]
The present invention relates to the delivery of a shunt and other devices into the myocardium of a patient, and more particularly, to the delivery of a generally L-shaped shunt to provide a bypass through the myocardium from the left ventricle into a coronary artery.[0002]
2. Description of the Related Art[0003]
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.[0004]
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.[0005]
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.[0006]
U.S. Pat. No. 5,755,682 to Knudson discloses an L-shaped shunt (see FIG. 1A of Knudson) having one end in the lumen of an artery facing downstream from an obstruction and the other end in fluid communication with blood within the heart chamber. One problem with using this L-shaped shunt is how to get the shunt into the myocardium without undue trauma to the patient.[0007]
SUMMARY OF THE INVENTIONThe problem of delivering an L-shaped shunt or conduit is solved herein by providing an improved catheter delivery system. A shunt preferably made of semirigid material is inserted into the lumen of a delivery catheter. The delivery catheter is advanced within the patient until its distal end is located adjacent to the desired insertion site, which is preferably the junction between a coronary artery and passageway formed in the myocardium between the left ventricle and coronary artery. A proximal section of the shunt is first advanced out of the delivery catheter into the myocardial passageway. A distal section of the shunt is advanced into the coronary artery, preferably by advancing the distal section of the shunt into the myocardial passageway and then pulling the distal section back into the coronary artery, or by pushing the distal section of the shunt in a folded configuration out of the delivery catheter into the coronary artery. In one embodiment, the shunt is made of a collapsible material for insertion into the delivery catheter, the shunt expanding upon removal from the delivery catheter.[0008]
In one aspect of the present invention, a method of delivering a conduit into a portion of the body having a first passageway and a second passageway joined generally at an angle is provided. A delivery catheter is advanced into the patient, the delivery catheter having a proximal end and a distal end and a lumen extending therethrough. The delivery catheter once advanced has a proximal end that extends outside of the patient and a distal end located substantially adjacent the location where the first passageway and the second passageway are joined. A conduit is inserted into the lumen of the delivery catheter, the conduit having a proximal section and a distal section. The proximal section of the conduit is advanced out of the lumen at the distal end of the delivery catheter into the first passageway. The distal section of the conduit is advanced into the second passageway.[0009]
In another aspect of the present invention, a method for creating a bypass between a chamber of the heart and a blood vessel adjacent to that chamber is provided. A passageway is formed in a heart wall that extends between the chamber of the heart and the blood vessel. The passageway has a proximal end opening into the chamber of the heart and a distal end opening into the blood vessel. A conduit is advanced having a proximal end and a distal end through the distal end of the passageway toward its proximal end. The proximal end of the conduit once advanced extends past the heart wall into the chamber of the heart, and the distal end of the conduit once advanced is located in the heart wall. The distal end of the conduit is advanced out of the distal end of the passageway and into the blood vessel downstream of the passageway.[0010]
In another aspect of the present invention, a method for creating a bypass between a chamber of the heart and a blood vessel adjacent to that chamber is provided. A passageway is formed in the heart wall that extends between the chamber of the heart and the blood vessel. The passageway has a proximal end opening into the chamber of the heart and a distal end opening into the blood vessel. A conduit having a proximal end and a distal end is folded to define a proximal section and a distal section between the fold. The folded conduit is inserted into a delivery catheter having a proximal end and a distal end and a lumen extending therethrough. The conduit is inserted such that the proximal end of the conduit is nearer to the distal end of the delivery catheter than the distal end of the conduit is to the distal end of the delivery catheter. Both the proximal end and the distal end of the conduit face toward the distal end of the delivery catheter. The delivery catheter is advanced into a patient into the blood vessel until its distal end is adjacent to the distal end of the passageway in the heart wall. The proximal section of the conduit is advanced out of the lumen at the distal end of the delivery catheter into the passageway. The distal section of the conduit is advanced out of the lumen at the distal end into the blood vessel.[0011]
BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1A is a schematic, cross-sectional view of a human heart, showing an L-shaped shunt device in the myocardium of the heart for forming a bypass between the left ventricle and a coronary artery.[0012]
FIG. 1B is an enlarged view of the bypass shunt of FIG. 1A.[0013]
FIG. 2 is a perspective view of an L-shaped shunt according to one embodiment of the present invention.[0014]
FIG. 3 is a schematic partial cross-sectional view of a coronary artery adjacent the left ventricle, showing a guidewire being advanced through an obstruction in the coronary artery.[0015]
FIG. 4 is a schematic partial cross-sectional view of a coronary artery adjacent the left ventricle, showing a dilation catheter being advanced over the guidewire of FIG. 3 to create a myocardial passageway.[0016]
FIG. 5 is a schematic partial cross-sectional view of a coronary artery adjacent the left ventricle, showing the dilation catheter of FIG. 4 being retracted from the myocardium leaving a passageway through the myocardium.[0017]
FIG. 6 is a schematic partial cross-sectional view of a coronary artery adjacent the left ventricle, showing a delivery catheter having a distal end positioned at least partially in the myocardial passageway of FIG. 5.[0018]
FIG. 7 is a partial cross-sectional view of the delivery catheter of FIG. 6 having a shunt inserted therein.[0019]
FIG. 8 is a schematic partial cross-sectional view of a coronary artery adjacent the left ventricle, showing a delivery catheter delivering a shunt into the myocardial passageway of FIG. 5.[0020]
FIG. 9 is a schematic partial cross-sectional view of a coronary artery adjacent the left ventricle, showing the formation of an L-shaped shunt between the left ventricle and coronary artery.[0021]
FIG. 10 is a schematic partial cross-sectional view of a coronary artery adjacent the left ventricle, showing a delivery catheter facing partially into the myocardial passageway of FIG. 5 and partially downstream into the coronary artery.[0022]
FIG. 11 is a partial cross-sectional view of the delivery catheter of FIG. 10 having a folded shunt inserted therein.[0023]
FIG. 12 is a schematic partial cross-sectional view of a coronary artery adjacent the left ventricle, showing a delivery catheter delivering the proximal section of an L-shaped shunt into the myocardial passageway of FIG. 5.[0024]
FIG. 13 is a schematic partial cross-sectional view of a coronary artery adjacent the left ventricle, showing a delivery catheter delivering the distal section of an L-shaped shunt into the coronary artery.[0025]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTSThe preferred embodiments described hereinbelow depict methods and apparatus for delivering a shunt into the myocardium to create a conduit between the left ventricle and coronary artery. Although the embodiments below describe delivery of an L-shaped shunt, it will be appreciated that these embodiments may also be applied to the delivery of similar types devices such as stents and other devices. Moreover, the methods and apparatus described herein may be used for delivery of these devices into other body tissues and vessels. For example, an L-shaped shunt may be delivered between other heart chambers to other coronary vessels. Although the term “L-shaped” is used herein for convenience, it will be understand that the shunt is merely generally L-shaped. Thus, the “L-shaped” shunt includes shunts that are angled, cornered, or simply change the direction of flow within the shunt from its proximal end to its distal end.[0026]
The principles of the present invention are not limited to left ventricular conduits, and include conduits for communicating bodily fluids from any space within a patient to another space within a patient, including any mammal. Furthermore, such fluid communication through the conduits is not limited to any particular direction of flow and can be antegrade or retrograde with respect to the normal flow of fluid. Moreover, the conduits may communicate between a bodily space and a vessel or from one vessel to another vessel (such as an artery to a vein or vice versa). Moreover, the conduits can reside in a single bodily space so as to communicate fluids from one portion of the space to another. For example, the conduits can be used to achieve a bypass within a single vessel, such as communicating blood from a proximal portion of an occluded coronary artery to a more distal portion of that same coronary artery.[0027]
In addition, the conduits and related methods can preferably traverse various intermediate destinations and are not limited to any particular flow sequence. Preferred embodiments are disclosed, including direct transmyocardial communication from a left ventricle, through the myocardium and into the coronary artery. The term “transmyocardial” should not be narrowly construed in connection with the preferred fluid communication conduits, and other non-myocardial and even non-cardiac fluid communication are preferred as well. With respect to the walls of the heart (and more specifically the term “heart wall”), the preferred conduits and related methods are capable of fluid communication through all such walls including, without limitation, the pericardium, epicardium, myocardium, endocardium, septum, etc.[0028]
The bypass which is achieved with certain preferred embodiments and related methods is not limited to a complete bypass of bodily fluid flow, but can also include a partial bypass which advantageously supplements the normal bodily blood flow. Moreover, the occlusions which are bypassed may be of a partial or complete nature, and therefore the terminology “bypass” or “occlusion” should not be construed to be limited to a complete bypass or a complete occlusion but can include partial bypass and partial occlusion as described.[0029]
The preferred conduits and related methods disclosed herein can also provide complete passages or partial passages through bodily tissues. In this regard, the conduits can comprise stents, shunts, or the like, and therefore provide a passageway or opening for bodily fluid such as blood. Moreover, the conduits are not necessarily stented or lined with a device but can comprise mere tunnels or openings formed in the tissues of the patient.[0030]
The conduits of the present invention preferably comprise both integral or one-piece conduits as well as plural sections joined together to form a continuous conduit. The preferred conduit device and method for installation is preferably determined by appropriate patient indications in accordance with sound medical practices.[0031]
As illustrated in FIGS. 1A and 1B, a coronary artery bypass is accomplished by disposing a conduit or shunt[0032]100 in a heart wall or myocardium MYO of a patient's heart PH. As shown in FIG. 2, shunt100 preferably has afirst section102 that extends from the left ventricle LV of heart PH to a clogged coronary artery CA at a point downstream of a blockage BL. Once inside the coronary artery CA, theshunt100 bends to asecond section104 that extends downstream from the blockage BL. Although not shown in FIGS. 1A and 1B,shunt100 may also have a one-way valve disposed therein for preventing back flow of blood through shunt, such as described in U.S. Pat. No. 5,429,144, the entirety of which is hereby incorporated by reference.
The[0033]shunt100 illustrated in FIGS. 1A and 1B, and shown more particularly in FIG. 2, is preferably an elongate body having aproximal end106 and adistal end108 and alumen110 extending therethrough.Shunt100 is preferably made of a semi-rigid biocompatible material such as a biocompatible polymers, although other materials may also be used. The use of a semi-rigid material allows theshunt100 to be easily folded into an L-shaped configuration, as shown in FIGS. 1A and 1B and described below. Further details regarding conduits or shunts such as described herein, as well as other medical devices and methods for use with the preferred embodiments of the present invention, are disclosed in copending applications entitled DESIGNS FOR LEFT VENTRICULAR CONDUIT [Attorney Docket No. PERCAR.013A], Application Ser. No. ______, filed the same date herewith, LEFT VENTRICULAR CONDUIT WITH BLOOD VESSEL GRAFT [Attorney Docket No. PERCAR.005A], Application Ser. No. ______, filed the same date herewith, VALVE DESIGNS FOR LEFT VENTRICULAR CONDUITS [Attorney Docket No. PERCAR.006A], Application Ser. No. ______, filed the same date herewith, and LEFT VENTRICULAR CONDUITS TO CORONARY ARTERIES AND METHODS FOR CORONARY BYPASS [Attorney Docket No. PERCAR.033CP1], application Ser. No. ______, filed the same date herewith, as well as U.S. Pat. Nos. 5,662,124, 5,429,144 and 5,755,682, all of which are hereby incorporated by reference in their entirety.
Passageway Formation[0034]
In one preferred embodiment of the present invention, before delivery of the[0035]shunt100, a passageway is formed at a desired location within the patient for placement of theshunt100 within the patient. Although the formation of this passageway is described in a percutaneous approach, it will also be appreciated that surgical and other methods may be used as well.
FIGS.[0036]3-5 illustrate the formation of apassageway126 within the myocardium MYO of a patient extending between the left ventricle LV and the coronary artery CA. As shown in FIG. 3, aguidewire120 is inserted into the coronary artery CA through the myocardium and into the left ventricle. This guidewire is preferably inserted into the patient through the femoral artery (not shown) and advanced percutaneously through aorta AO (shown in FIG. 1A) and through the blockage BL in the coronary artery, as is well known by those in the art. The guidewire then turns into the myocardium and extends therethrough, where it may be anchored at the left ventricle to the myocardium. Further details regarding these and other delivery methods are described in copending application entitled DELIVERY METHODS FOR LEFT VENTRICULAR CONDUIT [Attorney Docket No. PERCAR.003CP1], application Ser. No. ______, filed on the same date as the present application, which is hereby incorporated by reference in its entirety.
After delivery of the[0037]guidewire120, adilation device122, as shown in FIG. 4, is delivered over theguidewire120 to open a passageway through the myocardium MYO. Thisdilation device122 may employ radiation, lasers, balloons, successfully larger catheters, a surgical drill or other methods to penetrate through the myocardium. FIG. 4 illustrates the use of acatheter122 having adilation balloon124 mounted on the catheter for forming the passageway. Thedilation catheter122 is advanced over theguidewire120, and theballoon124 is inflated within myocardium MYO to expand themyocardial passageway126, shown in FIG. 5. Theballoon124 is then deflated and thecatheter122 removed, as shown in FIG. 5, to leave thepassageway126 extending through the myocardium MYO. The process may be repeated with successively larger dilation balloons to form a passageway of desired size. Further details are described in the above-referenced application entitled DELIVERY METHODS FOR LEFT VENTRICULAR CONDUIT [Attorney Docket No. PERCAR.003CP1], application Ser. No. ______, filed on the same date as the present application, the entirety of which is hereby incorporated by reference. It will be appreciated that other methods may also be used to form thepassageway126.
After formation of the[0038]passageway126, theguidewire120 may be removed for subsequent delivery of theshunt100, or may remain in place to assist in the delivery as described below. It will be appreciated that other treatments known to one skilled in the art, such as angioplasty, may be used to reduce the size of the blockage BL before delivering the shunt.
Pullback Technique[0039]
In one embodiment of the present invention, the L-shaped shunt is delivered using a pullback technique. The term “pullback” is used for convenience only, and is not limited to pulling back only, but includes pushing and pulling of the shunt. According to this embodiment, a[0040]delivery catheter100 is used to deliver theshunt100 into a myocardial passageway such as formed in FIG. 5, or by any other method.
As shown in FIG. 6, a[0041]delivery catheter130 is advanced over aguidewire120, such as described above, toward the myocardium MYO. Thedelivery catheter130 preferably has a proximal end132 (not shown) extending outside of the patient and adistal end134 extending at least partially within thepassageway126 formed in the myocardium MYO. More preferably, thedistal end134 of thedelivery catheter130, once delivered as shown in FIG. 6, turns into thepassageway126 so that the lumen136 (not shown) of the delivery catheter faces into thepassageway126. After the delivery catheter has been placed in this position, theguidewire120 may be removed to prevent interference with subsequent delivery of the shunt.
The[0042]shunt100 is prepared for delivery into thepassageway126 by inserting the shunt into thedelivery catheter130. As shown in FIG. 7, theshunt100 is inserted into thelumen136 in a substantially linear configuration, and is positioned near thedistal end134 of thedelivery catheter130. In one embodiment, theshunt100 is preferably collapsible within thelumen136 so that it has a collapsed dimension for insertion smaller than its expanded dimension when implanted in the patient. Theshunt100 is positioned in thelumen136 preferably so that theproximal end106 of the shunt is nearest to thedistal end134 of the delivery catheter, and thedistal end108 of the shunt is nearest to theproximal end132 of the delivery catheter.
As shown in FIG. 7, a[0043]positioning rod140 assists insertion and positioning of theshunt100 within thelumen136 of the delivery catheter. Thisrod140 is preferably an elongate body having aproximal end142 and adistal end144, and is made of a material with sufficient stiffness to be pushable through the lumen of thedelivery catheter100 without bending back on itself. Moreover, therod140 also has sufficient flexibility so that it can bend and navigate through the pathways of the human vasculature. Suitable materials for therod140 include biocompatible materials such as nitinol, stainless steel and polymers.
The distal end of the[0044]rod140 is provided with a grasper or clasp146 for holding thedistal end108 of theshunt100. More particularly, theclasp146 is attached to theshunt100 prior to insertion of the shunt into the delivery catheter. Theshunt100 is preferably delivered by inserting the shunt into theproximal end132 of the delivery catheter, and pushing distally on therod140 outside of the patient until the shunt is at the distal end of the delivery catheter. It will also be appreciated that theshunt100 may be inserted into the delivery catheter before the delivery catheter is advanced into the patient, either by pushing the shunt through the proximal end of the delivery catheter or by pulling the shunt through the distal end of the delivery catheter.
As shown in FIG. 8, once the[0045]shunt100 is at thedistal end134 of thedelivery catheter130, with thedistal end134 turned at least partially into thepassageway126, therod140 is pushed distally to advance theshunt100 out of thelumen136 and into thepassageway126. Theshunt100 is preferably constructed from a material having sufficient pushability not only to enable pushing of the shunt through the lumen of the delivery catheter, but also through thepassageway126 formed in the myocardium MYO. It will be appreciated that when theshunt100 is collapsible withinlumen136, removal of theshunt100 from thedelivery catheter130, causes the shunt to expand to a size that substantially fills themyocardial passageway126, as shown in FIG. 8. Therod140 preferably pushes theshunt100 completely out of thedistal end134 of the delivery catheter, with theproximal end106 of theshunt100 extending past the myocardial wall and into the left ventricle LV. More preferably, theproximal end106 extends into the left ventricle LV by approximately the distance desired for thesection104 to extend into the coronary artery, as shown in FIG. 1B.
As shown in FIG. 9, the[0046]delivery catheter130 is then preferably pulled back proximally of thepassageway126 so that thelumen136 at thedistal end134 faces downstream in the coronary artery CA rather than into thepassageway126. Therod140 is then pulled back proximally to move thedistal end108 of theshunt100 out of thepassageway126 and into the coronary artery CA. Because thelumen136 of the delivery catheter faces into the coronary artery CA, pushing distally on therod140 as shown in FIG. 9, causes theshunt100 to bend around the corner between thepassageway126 and the coronary artery CA. Therod140 is pushed distally until theproximal end106 of theshunt100 is substantially flush with the myocardial wall at the left ventricle LV, and thedistal end108 of theshunt100 lies in the coronary artery CA downstream from thepassageway126. Because in the preferred embodiment theshunt100 is collapsible, theshunt100 does not interfere with pushing of therod140 downstream into the coronary artery CA.
After the[0047]shunt100 is positioned as described above, theclasp146 on therod140 is actuated at the proximal end of therod140 by an operator, outside of the patient, to release the shunt. Therod140 anddelivery catheter130 are then retracted from the body, leaving the L-shaped shunt in place for a bypass between the left ventricle LV and the coronary artery CA. As implanted, theshunt100 has aproximal section102 within themyocardial passageway126 and adistal section104 within the coronary artery CA, such as shown in FIG. 1B.
Folded Shunt Technique[0048]
FIG. 10 illustrates another embodiment for delivering an L-shaped shunt into the[0049]passageway126 formed in the myocardium MYO. As with the embodiment shown in FIG. 6, adelivery catheter130 having aproximal end132 and adistal end134 and a lumen136 (not shown) extending therethrough is advanced over aguidewire120 toward thepassageway126. Preferably, thedelivery catheter130 is advanced until thedistal end134 extends partially into thepassageway126, such that thelumen136 at the distal end faces at least partially into thepassageway126. Once the delivery catheter is placed in this position, theguidewire120 is preferably removed.
A[0050]shunt100 is positioned at thedistal end134 of thedelivery catheter130 in thelumen136. As shown in FIG. 11, this shunt is inserted into the catheter and preferably collapsed, such that itsproximal end106 is closest to thedistal end134 of thedelivery catheter130, and itsdistal end108 is folded over within thelumen136. Thefold112 causes thedistal end108 and theproximal end106 to face in the same distal direction while inserted into thelumen136 of the delivery catheter. More particularly, thefold112 in the shunt preferably divides the shunt into aproximal section102, which is to extend into thepassageway126, and adistal section104, which is to extend into the coronary artery CA. The location offold112 is preferably determined by the length of thepassageway126, and more particularly, is placed such that theproximal section102 has a length substantially corresponding with the length of thepassageway126.
As described with respect to the pullback technique above, the[0051]shunt100 is preferably collapsible withinlumen136. More preferably, theshunt100 may be made of a shape memory material such as nitinol to give the shunt100 a remembered expanded shape such as shown in FIG. 2. In this embodiment, theshunt100 is collapsed within thelumen136 from the expanded shape for insertion into the patient.
The folded[0052]shunt100 is preferably loaded into the delivery catheter through use ofrod140, as illustrated in FIG. 11. Thisrod140 is similar to the rod described with respect to FIG. 7 above, more particularly having aproximal end142 and adistal end144. Aclasp146 is provided at the distal end of therod140, which grasps theshunt100 at about thefold112. Theshunt100 is preferably loaded into thedelivery catheter130 through theproximal end132 after the delivery catheter has reached its position shown in FIG. 11 by pushing distally on therod140 which is attached to theshunt100. It will be appreciated, however, that the shunt may be loaded prior to inserting thedelivery catheter130 into the patient, either by pushing through theproximal end132 or pulling through thedistal end134.
Once the[0053]shunt100 has reached thedistal end134 of thedelivery catheter130, the delivery catheter is turned, if necessary, to ensure that theproximal section102 of theshunt100 is in the part of thelumen136 closest to thepassageway126. With the distal end of the delivery catheter facing at least partially into thepassageway126, when therod140 is pushed distally to advance theshunt100 out of thedelivery catheter130, this positioning causes theproximal section102 of the shunt to exit the delivery catheter first into thepassageway126, as shown in FIG. 12. As theproximal section102 exits thelumen136, theshunt100 begins to expand toward its expanded shape.
As the[0054]rod140 pushes theshunt100 further distally out of thedelivery catheter130, thedistal section104 of the shunt exits into the coronary artery CA because of the placement of thedistal section104 within thelumen136 away from the myocardium. In one embodiment, when thedelivery catheter130 is delivered, thelumen136 of thedistal end134 faces partially into thepassageway126, and partially into the coronary artery CA, as shown in FIG. 10. Then, because thecatheter130 is turned, as necessary, to position theproximal section102 of theshunt100 in the part of thelumen136 facing thepassageway126, correspondingly, thedistal section104 is positioned in the part of thelumen136 that faces into the coronary artery CA. This allows thedistal section104 to exit thedelivery catheter130 into the coronary artery CA. To further assist in delivering thedistal section104 into the coronary artery CA, thedelivery catheter130 may be pulled proximally back once theproximal section102 enters thepassageway126 so that thelumen136 at thedistal end134 faces only downstream into the coronary artery CA. As shown in FIG. 13, when the distal end of therod140 is pushed out of thedelivery catheter130, theproximal section102 has extended completely through thepassageway126 such thatproximal end106 of theshunt100 is approximately flush with the myocardial wall at the left ventricle LV. Thedistal section104 extends into the coronary artery CA downstream from thepassageway126. Once in this position, theclasp146 is removed from theshunt100 and thedelivery catheter130 androd140 are removed.
It will be appreciated that the position of the[0055]delivery catheter130 may be moved during delivery of theshunt100 to ensure that theproximal section102 is delivered into thepassageway126 and the distal section is delivered into the coronary artery CA. For example, thedelivery catheter130 may be pushed further into thepassageway126 prior to delivering the proximal section of theshunt100 therein. Then, prior to delivery of thedistal section104, thedelivery catheter130 may be pulled proximally back so that thelumen136 at thedistal end134 faces downstream into the coronary artery CA.
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.[0056]