US20070055344A1 - Devices and methods for use in performing transmyocardial coronary bypass - Google Patents

Abstract

Devices and methods utilized in performing transmyocardial coronary bypass include retractors used to engage and support myocardial tissue, and mechanisms for supporting coronary vessels so as to allow precise entry into a vessel lumen. In addition, various conduits are provided having a configuration that permits their positioning in a heart wall to place a coronary vessel in communication with a heart chamber.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a continuation-in-part of application Ser. No. 09/023,492, filed Feb. 13, 1998, and entitled “Methods and Devices Providing Transmyocardial Blood Flow to the Arterial Vascular System of the Heart,” the entire subject matter of which application is incorporated herein by reference.
BACKGROUND OF THE INVENTION
• 1. Field of the Invention
• The invention relates to treating heart disease, and more particularly systems, devices and methods for reestablishing or improving blood flow to the myocardium.
• 2. Description of Related Art
• Despite the considerable advances that have been realized in cardiology and cardiovascular surgery, heart disease remains the leading cause of death throughout much of the world. Coronary artery disease, or arteriosclerosis, is the single leading cause of death in the United States today. As a result, those in the cardiovascular field continue the search for new and improved treatments.
• Coronary artery disease is currently treated by interventional procedures such as percutaneous transluminal coronary angioplasty (PTCA), atherectomy and intracoronary stenting, as well as surgical procedures including coronary artery bypass grafting (CABG). The goal of these procedures is to reestablish or improve blood flow through occluded (or partially occluded) coronary arteries, which is accomplished, for example, by enlarging the blood flow lumen of the artery or by forming a bypass that allows blood to circumvent the occlusion. What procedure(s) is used typically depends on the severity and location of the blockages. When successful, these procedures restore blood flow to myocardial tissue that had not been sufficiently perfused due to the occlusion.
• Technological and procedural advances have improved the results obtained by the medical procedures now used to treat heart disease, and in particular coronary artery disease. There is, however, still much room for improvement. For that reason there remains a need in the art for new and improved systems, devices and methods for treating heart disease such as arteriosclerosis.
SUMMARY OF THE INVENTION
• In one embodiment, the invention provides a device and method for engaging tissue of a coronary vessel or heart wall during a cardiovascular procedure. A device constructed according to this embodiment includes first and second members coupled together so as to permit relative movement. A tissue engaging mechanism is coupled to the first and second members and moves between first and second positions. In the preferred embodiment, the first and second positions are collapsed and expanded orientations. The tissue engaging mechanism includes at least one tissue engaging member that contacts engage body tissue when in the expanded orientation.
• A method carried out according to this embodiment includes steps of providing a tissue support device having a tissue engaging mechanism configured to assume an expanded, tissue supporting orientation, positioning the tissue support device through the wall of a patient's heart and locating the tissue engaging mechanism adjacent tissue, and placing the tissue engaging mechanism in the expanded, tissue supporting orientation in engagement with the tissue.
• In another embodiment, the invention provides a device and method for supporting a wall of a vascular structure in order to access the lumen of the vascular structure. A device constructed according to this embodiment includes a support structure adapted to be positioned in the lumen of a vascular structure, the support structure comprising a plurality of support elements coupled together so as to be movable relative to each other. The support elements move relative to each other to move the support structure from a collapsed orientation to an expanded orientation in order to support a wall of a vascular structure, and are sized and configured so that when the support structure is in the expanded orientation the support elements engage the wall of the vascular structure to prevent the wall from collapsing.
• Another device constructed according to this embodiment includes an introducer having a hollow interior and an elongated support member configured to be generally coiled when in an unbiased orientation and generally straight when in a biased orientation. The interior of the introducer is sized and configured to receive the elongated support member and hold the support member in the generally straight, biased orientation. The elongated support member is moved from the straight, biased orientation within the interior of the introducer to the coiled, unbiased orientation upon entering the interior of the vascular structure to support the vascular structure.
• A method carried out according to this embodiment includes steps of positioning a support within an interior of a vascular structure such that the support contacts and supports a wall of the vascular structure, and introducing a medical device into the interior of the vascular structure by passing the device through the wall of the vascular structure and through the support.
• In another embodiment, the invention provides a device and method for stabilizing an area of a patient's heart adjacent a coronary vessel. A device constructed according to this embodiment includes a base configured to be positioned adjacent a coronary vessel of a patient's heart, the base having at least one opening for accessing the coronary vessel. At least one tissue engaging element is coupled to the base so as to be movable with respect to the base, the tissue engaging element having a portion configured to securely engage the wall of a patient's heart in order to stabilize the wall of the heart upon moving the tissue engaging element with respect to the base. An actuator is provided for imparting relative movement to the base and the tissue engaging element in order to stabilize the heart while accessing the coronary vessel through the opening in the base.
• In yet another embodiment, the invention provides a conduit for placing a coronary vessel of a patient's heart in communication with a heart chamber. The conduit is in the form of a tubular element including first and second portions having different cross-sectional sizes and a bore defining a blood flow path. The cross-section of the first portion of the tubular element is larger than the cross-section of the second portion such that the tubular element is generally funnel-shaped, and the first and second portions of the tubular element are generally aligned so that the bore defines a generally straight blood flow path.
• In still another embodiment, the invention provides a conduit for communicating a chamber of a patient's heart with a coronary vessel. The conduit is in the form of an expandable stent including first and second portions having different cross-sectional sizes when the stent is expanded. Each of the first and second portions of the stent includes strut members disposed along a first direction when the stent is unexpanded and along a second direction when the stent is expanded, the second direction being transverse to the first direction. The strut members of the first portion are longer than the strut members of the second portion so that the stent is generally funnel-shaped when expanded.
• In another embodiment, the invention provides a conduit is in the form of an expandable tubular element having first and second portions with different cross-sectional sizes. This tubular element is preferably a coronary stent constructed so that the first and second portions are disposed in an orientation that provides the stent with maximum radial strength when expanded.
• In a final embodiment, the invention provides a conduit for placing a coronary vessel in communication with a heart chamber, the conduit including a vessel support mechanism configured to contact and support the vessel wall when the conduit is positioned in the heart wall.
BRIEF DESCRIPTION OF THE DRAWINGS
• The invention will be better understood from the following detailed description of preferred embodiments thereof, taken in conjunction with the accompanying drawing figures, wherein:
• FIG. 1 is a schematic view of a patient prepared to undergo a cardiovascular surgical procedure, the patient's heart being exposed via a retractor positioned in a thoracotomy formed in the patient's chest;
• FIG. 2 is a perspective view of the heart shown inFIG. 1, wherein a portion of the heart wall is broken away for clarity;
• FIG. 2A is an enlarged view of a portion ofFIG. 2;
• FIGS. 3A-3B are perspective views showing a tissue engaging device constructed according to one embodiment of the invention, the device being shown in collapsed and expanded orientations, respectively;
• FIGS. 4A-4B are elevation views, in section, illustrating one preferred construction of a tissue engaging device according to the embodiment ofFIGS. 3A-3B, wherein the device is shown being used to engage the heart wall shown inFIGS. 2-2A;
• FIGS. 5A-5B are elevation views, in section, illustrating another preferred construction of a tissue engaging device according to the embodiment ofFIGS. 3A-3B, wherein the device is shown being used to engage the heart wall shown inFIGS. 2-2A;
• FIGS. 6A-6C are elevation views, in section, sequentially illustrating a vessel support device constructed according to another embodiment of the invention being used to support the wall of a vascular structure;
• FIG. 7 is a perspective view of a vessel support device constructed according to an alternative embodiment of the invention, the device being shown positioned in the interior of a vascular structure;
• FIGS. 8A-8B are elevation views, in section, sequentially illustrating the device shown inFIG. 7 being used to support a coronary artery of the heart shown inFIGS. 2-2A;
• FIG. 9 is a perspective view of a vessel support device constructed according to another alternative embodiment of the invention, the device being shown positioned in the interior of a vascular structure;
• FIGS. 10A-10B are elevation views, in section, sequentially illustrating the device shown inFIG. 9 being used to support a coronary artery of the heart shown inFIGS. 2-2A;
• FIGS. 11A-11B are plan views of a tissue engaging device constructed according to another embodiment of the invention, wherein the device is shown engaging the wall of the heart shown inFIGS. 2-2A in non-retracting and retracting orientations, respectively;
• FIGS. 12A-12B are elevation views, in section, taken along lines A-A inFIGS. 1A-1B;
• FIG. 13 is an elevation view, in section, of an alternative tissue engaging device constructed according to the embodiment shown inFIGS. 12A-12B;
• FIGS. 14A-14B are elevation views of a tapered balloon forming part of another embodiment of the invention, wherein the balloon is shown in its collapsed and expanded orientations, respectively;
• FIGS. 15A-15B are elevation views of an expandable conduit mounted on the tapered balloon shown inFIGS. 14A-14B, the conduit being shown in its collapsed and expanded orientations, respectively;
• FIG. 16 is an elevation view, in section, of a portion of a heart wall and coronary vessel in which the conduit shown inFIG. 15A-15B has been positioned;
• FIGS. 17A-17B are elevation views showing a conduit constructed according to still another embodiment of the invention, wherein the conduit has a cross-sectional size that varies over its length;
• FIG. 18 is a perspective view of another embodiment of the invention providing a conduit for placing a coronary vessel in communication with a heart chamber while internally supporting the interior of the vessel;
• FIGS. 19A-19C are schematic representations of a preferred application for the conduit shown inFIG. 18;
• FIG. 20 is a perspective view of an alternative embodiment of a conduit for placing a coronary vessel in communication with a heart chamber while internally supporting the interior of the vessel;
• FIG. 21 is a perspective view of another alternative embodiment of a conduit for placing a coronary vessel in communication with a heart chamber while internally supporting the interior of the vessel; and
• FIG. 22 is a perspective view of yet another alternative embodiment of a conduit for placing a coronary vessel in communication with a heart chamber while internally supporting the interior of the vessel.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
• FIG. 1 schematically depicts a patient who has been prepared to undergo a cardiovascular surgical procedure. A thoracotomy T formed in the patient's chest by making an incision between two ribs (not shown) provides access to the thoracic cavity. A retractor, such as the rib retractor R shown inFIG. 1, may be used to spread the ribs and increase access to the heart H and great vessels. The retractor is preferably of a type that in addition to spreading the sides of the incision along a first plane, also raises one side of the incision with respect to the other side to increase the working space around the heart. Any suitable retractor may be used, for example, one of the commercially available rib retractors currently used in minimally invasive cardiac surgery. As shown inFIG. 1, the retractor R provides considerable access to the surfaces of the heart H and great vessels including the aorta A. The left side of the heart as well as the left coronary artery LCA is easily accessible via the thoracotomy T (FIG. 1).
• FIG. 2 is an anterior view of aheart10 showing theleft ventricle12,right ventricle14,right atrium16,aorta18,pulmonary trunk20 andpulmonary veins22. InFIG. 2 theheart10 is in diastole, or the relaxed phase of the heart cycle, so theaortic valve24 is shown closed. The leftcoronary artery26, including thecircumflex branch28 and the left anterior descending branch (LAD)30, is visible in this view, as is the rightcoronary artery32. Thecoronary arteries26,28,30,32 run along theheart wall34 and deliver oxygenated blood to the tissue comprising the heart wall (epicardium, myocardium and endocardium) while the coronary veins run alongside the arteries and return blood to the coronary sinus (not shown).
• A blockage orocclusion36 is shown in theLAD30 and results in partial or complete obstruction of theartery lumen42, a condition often referred to as narrowing of the arteries. This results in inadequate or no blood flow to the heart wall tissue fed by the portion of theLAD30 that is downstream of theocclusion36.FIGS. 2-2A show a portion of theheart wall34 disposed between theleft ventricle12 and theLAD30, as well as the inner andouter walls38,40 of theLAD30. The devices and methods of the different embodiments of the invention are illustrated and described in connection with their use on the portion of theheart10 shown inFIG. 2A. It will be understood, however, that such description is for explanatory purposes and exemplifies only one application for the invention.
• FIGS. 3A-3B illustrate a first embodiment of the invention that provides a device and method for engaging tissue of a coronary vessel or heart wall during a cardiovascular procedure. A preferred device is indicated generally by thereference numeral100 and includes first and second relatively movable members and a tissue engaging mechanism coupled to the members. In the illustrated embodiment the members comprise first and secondcoaxial shafts102,104 coupled to atissue engaging mechanism106. Specifically, thetissue engaging mechanism106 is coupled to theshafts102,104 so that relative movement imparted to the shafts results in themechanism106 moving between a collapsed orientation (FIG. 3A) and an expanded, tissue engaging orientation (FIG. 3B).
• Thefirst shaft102 has adistal end108 which is secured to adistal end110 of theshaft104. Thetissue engaging mechanism106 is disposed adjacent the distal ends108,110 of theshafts102,104 and comprises one or moretissue engaging members112 which move radially outward when the mechanism is in the expanded orientation. Eachtissue engaging member112 has oneend114 fixed to thedistal end108 ofshaft102 at116, and anotherend118 fixed to theshaft104 at120.FIG. 3A shows thetissue engaging mechanism106 in its collapsed orientation with themembers112 generally straight.FIG. 3B shows thetissue engaging mechanism106 in its expanded orientation in which themembers112 extend outward in a radial direction. The components of thedevice100 may be formed of any suitable material.
• The orientation of thetissue engaging mechanism106 is controlled by imparting relative movement to theshafts102,104. Thedevice100 is preferably introduced into a coronary vessel or heart wall with thetissue engaging mechanism106 in the low profile orientation shown inFIG. 3A. Thedevice100 may have a sharpened tip as shown, or it may have a dilating portion that dilates a previously-formed incision. Once passed through the tissue to a desired position, thetissue engaging mechanism106 is moved to the expanded orientation shown inFIG. 3B in order to engage tissue. This may be achieved by moving theinner shaft102 in the direction of the arrows with respect to theouter shaft104, which moves theends114,118 of thetissue engaging members112 toward each other to expand themechanism106. In the orientation shown inFIG. 3B, thedevice100 may be used to perform any of various functions, for example, to support, retract or stabilize tissue during a cardiovascular procedure.
• FIGS. 4A-4B show one application of thedevice100, namely, to engage the tissue of the wall of a patient's heart. As shown inFIG. 4A, thedevice100 is inserted through a coronary vessel such asLAD30 and theheart wall34 with thetissue engaging mechanism106 in its collapsed orientation. Upon moving thetissue engaging mechanism106 out of theheart wall34 and into a heart chamber such asleft ventricle12, theshafts102,104 are moved with respect to each other to expand thetissue engaging mechanism106 to the position shown inFIG. 4A. The expandedtissue engaging mechanism106 may then be used to engage and support theheart wall34 to facilitate carrying out a cardiovascular procedure, for example, placing a conduit (not shown) in the heart wall to place the coronary vessel in communication with the heart chamber, or forming a channel in the heart wall to place the coronary vessel in communication with the heart chamber.
• FIGS. 5A-5B show another application of thedevice100, namely, to engage the tissue of the wall of a coronary vessel. As above, thedevice100 is introduced with thetissue engaging mechanism106 in its collapsed orientation, the device being passed through theheart wall34 and then theinner wall38 of theLAD30. Once thetissue engaging mechanism106 has moved into thelumen42 of theLAD30, theshafts102,104 are moved with respect to each other to expand thetissue engaging mechanism106 to the orientation shown inFIG. 5A. Thetissue engaging mechanism106 may then be used to engage and support thewall38 of the LAD and theheart wall34 to facilitate carrying out a cardiovascular procedure. Examples of such procedures include placing a conduit (not shown) in the heart wall to place the coronary vessel in communication with the heart chamber, and forming a channel in the heart wall to place the coronary vessel in communication with the heart chamber.
• As shown inFIGS. 3A-3B, thedevice100 may have a secondtissue engaging mechanism106A so that a body of tissue may be sandwiched between the twomechanisms106,106A for added stability.
• FIGS. 6A-6C depict another embodiment of the invention that provides a device and method for supporting a wall of a vascular structure in order to access the lumen of the vascular structure. One device constructed according to this embodiment is designated generally by thereference numeral130 and includes anelongated support member132 and anintroducer134. The introducer has abore136 that is configured to receive thesupport member132, as shown inFIG. 6A and preferably has a small diameter in order to minimize the size of the opening in the vascular structure, which in the illustrated embodiment is a coronary vessel and, in particular,LAD30.
• Theelongated support member132 is preferably constructed so as to expand when in an unbiased orientation, i.e., when it is not constrained by theintroducer134. In the preferred embodiment, thesupport member132 is constructed to assume a coiled shape when in the unbiased orientation, for example, the helical configuration shown inFIG. 6B. When disposed in theintroducer134, however, thesupport member132 is in a biased orientation and assumes a generally straight shape within thebore136 of the introducer.
• An exemplary application for thedevice130 will be explained with reference toFIGS. 6A-6C. Initially, as shown inFIG. 6A, anend138 of theintroducer134 is positioned against the exterior of thewall40 of the LAD with theelongated support member132 disposed within theintroducer134. Alternatively, as shown in phantom inFIG. 6A, theend138 of theintroducer134 may be passed through thewall40 into thelumen42 of theLAD30. If used in this manner, thesupport member132 does not need to pierce the tissue of the vascular structure; if used as shown in solid lines inFIG. 6A, anend140 of thesupport member132 is preferably sharpened to pierce through the wall of the vascular structure.
• Theelongated support member132 is fed through theintroducer134 into thelumen42 of theLAD30. Thesupport member132 forms acoil142 as it exits theintroducer134, as shown inFIG. 6B. The support member is constructed so that thecoil142 has a size that contacts and distends slightly theLAD30, thereby providing support to the LAD to allow precise entry into thelumen42 of the LAD. A medical device may then be inserted through the wall of the vascular structure and the support member. For example,FIG. 6C shows amedical device144 inserted through thewall40 of theLAD30 and through thecoil142. Thedevice144 is then removed upon completing the procedure; theelongated support member132 may then be removed from theLAD30 by retracting the member back into thebore136 of theintroducer134.
• Theelongated support member132 may be formed of any suitable material having sufficient memory to assume an expanded configuration when unbiased, such as spring wire or nitinol. As an example, thesupport member132 could be formed of a length of nitinol wire having an approximate diameter of 0.007 inch that has been wrapped on a suitable mandrel (not shown), such as a stainless steel rod having an approximate diameter of 0.060 inch. The mandrel and wire are then heated to set the shape in the wire which, per se, is known in the art. The mandrel may have two apertures that receive the ends of the nitinol wire and a relief section that causes theend140 of the support member to roll inward toward the interior of thecoil142, which minimizes the risk of theend140 damaging tissue.
• It will be recognized that thedevice130 may be used to support a vascular structure independently of carrying out a medical procedure. As an example, thedevice130 could be used to introduce thesupport member132 into a coronary artery in order to stent the artery, thecoil142 remaining in place in the same manner as a conventional coronary stent. In this embodiment, it may be desirable to form the other end146 of thesupport member132 so that it too moves toward the interior of thecoil142 upon exiting theintroducer134 to avoid tissue damage.
• FIGS. 7 and 8A-8B depict an alternative embodiment of a device and method for supporting a wall of a vascular structure in order to access the lumen of the vascular structure. The device is indicated generally by thereference numeral160 and is configured to be placed in a collapsed orientation for introduction into a vascular structure and then expanded to contact and support the wall of the structure. Thedevice160 comprises asupport structure162 removably retained in anintroducer164. The illustratedsupport structure162 comprises a plurality ofstruts166 that form a basket-like member when moved out of theintroducer164. For example, thestruts166 may be in the form of resilient wires that move away from each other as thesupport structure162 exits theintroducer164, the wires extending between proximal anddistal portions168,170 of the support structure. Theintroducer164 may be a sheath or sleeve sized and configured to at least partially surround thesupport structure162 and hold thestruts166 together. The respective components may be formed of suitable materials, such as spring wire and a polymer sleeve.
• FIG. 7 shows one preferred use of thedevice160 wherein the device is inserted through an opening in a vascular structure, such asincision44 inLAD30. It will be noted, though, that the device may be passed through a peripheral vessel to a desired location within a vascular structure, and then expanded within the vascular structure by moving the support structure out of the introducer. As shown inFIG. 8A, the device is passed through theincision44 and into thelumen42 of theLAD30. Theintroducer164 is then retracted over theproximal portion168 of the support structure which results in thestruts166 moving away from each other to contact and support the wall ofLAD30. As explained above with respect to the previous embodiment, various medical devices may then be introduced through the wall of the vascular structure and through thesupport structure162. Upon completion of the procedure, theintroducer164 is slid back over thestruts166 to collapse thesupport structure162, which allows thedevice160 to be removed through theincision44.
• FIGS. 9 and 10A-10B illustrate another alternative embodiment of a device and method for supporting a wall of a vascular structure in order to access the lumen of the vascular structure. The device has a construction somewhat similar to thedevice160 inFIGS. 7 and 8A-8B. The device is indicated generally by thereference numeral180 inFIG. 9 and is configured to be placed in a collapsed orientation for introduction into a vascular structure and then expanded to contact and support the wall of the structure. Thedevice180 comprises asupport structure182 removably retained in anintroducer184. The illustratedsupport structure182 includes a plurality ofstruts186 which may be in the form of resilient wires that move away from each other as the support structure exits theintroducer184. Thestruts186 may be joined at their proximal ends188 and preferably havedistal ends190 with a non-traumatic configuration to prevent tissue damage. As in the previous embodiment, theintroducer164 may be a sheath or sleeve sized and configured to at least partially surround thesupport structure162 to hold thestruts186 together. The materials used in the embodiment ofFIG. 7 may be used in this embodiment.
• As shown inFIG. 10A, thedevice180 is passed through theincision44 and into thelumen42 of theLAD30, and theintroducer184 is then retracted to allow thestruts186 to move away from each other. This results in thesupport structure182 assuming the expanded orientation shown inFig. 10B wherein thestruts186 contact and support the wall ofLAD30. As with the previous embodiments, various medical devices may then be introduced through the wall of the vascular structure and through thesupport structure162.
• It will be appreciated that the vascular support devices and methods illustrated in the drawings are only preferred embodiments of the invention. This aspect of the invention encompasses supporting the wall of a vascular structure in order to allow precise entry into the lumen, which may be relatively difficult if the wall of the vascular structure is collapsed. Accordingly, many variations of the disclosed devices and methods will be apparent to those skilled in the art. For example, an alternative design utilizes an expandable support that may be in the form of a stent having one or more openings to allow passage of medical devices into the lumen of the vascular structure. The stent could have any desired coverage area with openings provided between adjacent stent elements or formed by removing portions of the stent elements.
• Another alternative design comprises a device in the form of a member configured to rest on the exterior of the vascular structure to provide access into the lumen of the structure. The device may have a distal portion shaped somewhat complementarily to the vascular structure to closely engage same. For example, the distal portion could include a concave recess that receives the vascular structure when the device is rested on surrounding tissue. The device preferably has a bore that opens into the recess so that a medical device inserted into the bore passes through the wall of the vascular structure.
• Additionally, while the vessel support devices are shown introduced into the vessel through the wall close to or at the area of the vessel that is supported. The support devices could be positioned in an alternative manner, for example, by passing the device through the artery lumen from a location downstream of the area that is supported.
• FIGS. 11A-11B and12A-12B show another embodiment of the invention that provides devices and methods for stabilizing an area of a patient's heart adjacent a coronary vessel. The illustrated device is indicated generally by thereference numeral200 and comprises a base202 configured to be positioned adjacent a coronary vessel of a patient's heart. Thebase202 has at least oneopening204 which provides access to the coronary vessel, which, in the illustrated embodiment, is theLAD30. Thedevice200 also includes at least one, and preferably a plurality, oftissue engaging elements206 coupled to the base202 so as to be movable with respect thereto. Eachtissue engaging element206 has anend208 configured to securely engage the tissue of a patient's heart in order to stabilize the heart, and anend210 coupled to thebase202. Eachend210 is pivotally attached to thebase202 by apivot pin212.
• Thebase202 has a plurality ofrecesses214 each of which mounts anend210 of atissue engaging element206. Each of therecesses214 has acam surface216 that engages theend210 of atissue engaging element206 upon actuating the device in order to retract the cardiac tissue and stabilize the heart. To that end, thedevice200 has an actuator to drive thetissue engaging elements206 and retract tissue. The actuator may comprise rotating the base202 so as to drive the cam surfaces216 ofrecesses214 against theends210 of thetissue engaging elements206.FIG. 11A shows thedevice200 before actuation;FIG. 11B shows the device after thebase202 has been rotated. Eachtissue engaging element206 is preferably biased to the position ofFIGS. 11 A and 12A by suitable means, such as tension springs extending between the base202 and thetissue engaging elements206. The components of thedevice200 may be made from any suitable materials; for example, the base may comprise a polymer while theelements206 are metal.
• FIGS. 11A-11B and12A-12B show one possible application for thedevice200, retracting the wall of a heart adjacent a coronary vessel to stabilize vessel. Thedevice200 is positioned on theheart wall34 so that theopening204 overlies theLAD30. The ends208 of thetissue engaging elements206 are engaged with the tissue of theheart wall34 by any suitable means. As shown inFIGS. 12A-12B, theends208 may simply have sharp tips which are passed into the tissue to engage the elements with the heart wall.
• Alternatively, as shown inFIG. 13, theends208 of thetissue engaging elements206 may have a mechanism for more securely engaging the tissue, such asexpandable members218. Theexpandable members218 may be constructed as described above with respect to the embodiment ofFIGS. 3A-3B, thereby allowing theends208 to be collapsed, for passage through the heart wall and then expanded once through the wall in order to positively secure thedevice200 to the tissue. Themembers218 may be expanded by moving one shaft relative to another as described above.
• Once the ends of the tissue engaging elements have been secured to the tissue, as shown inFIGS. 11A and 12A, thebase202 is rotated as described above,. which drives the tissue engaging elements relative to the base and the tissue. This action tensions the tissue of theheart wall34 to retract the wall and stabilize the heart in the area of the coronary vessel, as shown inFIGS. 11B and 12B. As a result, the coronary vessel, which is theLAD30 in the Figures, is stabilized so that subsequent procedures may be carried out on a relatively stable site. As an example, thedevice200 may be used to stabilize the heart while passing a conduit delivery device through the vessel and the heart wall in order to place the vessel in communication with a heart chamber.
• According to another embodiment of the invention, a conduit is provided for placing a coronary vessel of a patient's heart in communication with a heart chamber. The conduit comprises a tubular element including first and second portions having different cross-sectional sizes, and a bore defining a blood flow path. The cross-section of the first portion of the tubular element is larger than the cross-section of the second portion of the tubular element. In one preferred embodiment the different cross-sectional configurations are selected to produce a tubular element that is generally funnel-shaped.
• According to one aspect of this embodiment, the first and second portions of the tubular element are generally aligned and the bore defines a generally straight blood flow path. According to another aspect of this embodiment, the tubular element is an expandable stent including a bore defining a blood flow path and first and second portions, the first and second portions having different cross-sectional sizes when the stent is expanded. The first and second portions of the stent are preferably constructed to provide the stent with maximum radial strength when expanded.
• FIGS. 14A-14B and15A-15B show one preferred system for placing a funnel-shaped conduit in a patient's heart wall to communicate a coronary vessel with a heart chamber. The system includes aballoon220 and aconduit222. Theballoon220 is generally straight over its length when unexpanded (FIG. 14A); however, when expanded theballoon220 assumes a tapered orientation with alarge end224 and a small end226 (FIG. 14B). Theconduit222 is also preferably straight over its length when supported by theballoon220 in a collapsed orientation (FIG. 15A) and funnel shaped when expanded by the balloon (FIG. 15B). It should be understood that a tapered balloon is not necessary to expand a tapered or funnel-shaped stent. For example, a straight balloon could be used to expand a stent constructed to assume a funnel-shaped configuration, with the inflated size of the balloon preferably being sufficient to fully expand the large end of the stent.
• FIG. 16 depicts an exemplary application of theconduit202 shown inFIGS. 15A-15B. Theconduit202 is shown positioned in aheart wall34 with alarge diameter end228 located in a heart chamber such as theleft ventricle12 and asmall diameter end230 located in a coronary vessel such asLAD30. It will be appreciated that the shape, size and orientation of theconduit202 in the heart wall and coronary vessel may be varied from that shown inFIG. 16. For example, the taper of the conduit wall may be non-continuous or more gradual or severe than that shown in the Figures, or either end of the conduit may be flush or within the heart wall. Also, the conduit may be a rigid or expandable tubular element.
• FIGS. 17A-17B show one preferred funnel-shapedstent240 that includes a plurality of stent elements in the form ofstruts242 that move relative to each other as the stent moves to its expanded orientation. Thestruts242 are joined atnodes244 which move along with the struts as thestent240 moves to its expanded orientation. A plurality of open areas are defined between thestruts242 through which blood may flow.
• FIG. 17A shows thestent240 in its collapsed orientation. As shown, thestent240 comprises afirst portion246, asecond portion248 and athird portion250. These threeportions246,248,250 are designed so that upon expansion they have different diameters or cross-sectional dimensions. This may be achieved by using different length struts242 for therespective portions246,248,250. The relative dimensions of the struts (and thus the relative size of the expanded portions formed by the struts) may be varied to achieve different sizes and shapes. Referring toFIG. 17B, the illustratedstent240 is constructed so that thefirst portion246 expands to the smallest diameter while thethird portion250 expands to the largest diameter. Thesecond portion248 expands to a middle diameter that tapers between theportions246,250. Thestruts242 of thestent240 preferably assume a maximum load supporting position when fully expanded.
• Thestent240 may be used in various applications, including forming a blood flow path between a coronary vessel and a heart chamber. The stent240 (or another conduit constructed according to this embodiment of the invention) may be used as a coronary stent to improve blood flow through a coronary artery. In this application, thestent240 would be introduced into a peripheral vessel and guided to the desired artery by conventional means.
• FIGS. 18 and 19A-19C show another embodiment of the invention providing a conduit for placing a coronary vessel in communication with a heart chamber, the conduit including a mechanism for internally supporting the interior of the vessel.FIG. 18 shows aconduit260 in the form of a rigid, tubular element having afirst end262 and asecond end264. Theconduit260 has abore266 passing therethrough that defines a blood flow path. Amechanism268 is provided to support the wall of a coronary vessel with which theconduit260 communicates. Themechanism268 includes a pair ofsupport arms270 preferably in the form of flexible members made from any suitable material, such as stainless steel, nitinol, polymers, etc. A pair ofsupport arms270 is shown; however, any desired number of arms may be used. Eachsupport arm270 is secured to theconduit260 at272, for example, by welding, brazing or adhesive. Alternatively, thesupport arms270 may be integrally formed as part of theconduit260. Thesupport arms270 are provided withvessel supporting portions274 which may be formed by rounded lengths ofwire276, as shown.
• Referring toFIG. 19A, which schematically illustrates one preferred application of theconduit260, thesupport arms270 may be folded against the wall of theconduit260 so that the conduit assumes a relatively low profile position. Theconduit260 is then passed through an opening in the wall of a coronary vessel such as the LAD30 (FIG. 19A). Thesupport arms270 may be constrained against theconduit260 manually, with an instrument, or with a removable sheath or cover. Theconduit260 is delivered into thelumen42 of the LAD and theheart wall34 an amount sufficient to place all (or substantially all) of thesupport arms270 inside theouter wall40 of LAD30 (FIG. 19B). At this point thesupport arms270 spring out to the position shown inFIG. 18, which results in thevessel supporting portions274 of the arms contacting the walls of the LAD30 (FIG. 19C). The conduit is preferably configured so that when the support arms are in this position the conduit end262 extends into theleft ventricle12 while the conduit end264 extends into theLAD30.
• FIG. 20 shows an another embodiment of a conduit with a vessel supporting mechanism. The conduit is designated280 and preferably is a rigid tubular element as in the previous embodiment. Theconduit280 has amechanism282 that supports the wall of a coronary vessel in which the conduit is placed. Thesupport mechanism282 includes threesupport arms284 in the form of hoops made from any suitable material, as discussed above. Thesupport arms284 are also preferably flexible and secured to theconduit280 by welding, brazing or adhesive. Thesupport arms284 havevessel supporting portions286 that contact and may slightly distend the vessel wall. While threearms284 are shown, any desired number may of course be used.
• FIG. 21 shows still another embodiment of a conduit with a vessel supporting mechanism. The conduit is designated290 and preferably is a rigid tubular element as in the previous embodiments. Theconduit290 is provided with amechanism292 for supporting the wall of a coronary vessel. Thevessel support mechanism292 includes a first pair ofsupport arms294 and a second pair ofsupport arms296 in the form of tabs made from any suitable material, as discussed above. Thesupport arms294 extend generally along the longitudinal axis of theconduit290 and are adapted to contact the outer wall of a coronary vessel, while thesupport arms296 extend radially from theconduit290 and are adapted to contact the inner wall of the vessel. Thesupport arms294,296 are preferably integrally formed with theconduit290 and are flexible to assume a low profile position. It will be noted that thesupport arms294,296 could be separate members secured to the conduit by suitable means such as welding, brazing or adhesive. Also, although threearms284 are shown, any desired number may be used.
• FIG. 22 shows yet another embodiment of a conduit with a vessel supporting mechanism. The conduit is designated300 and, instead of being a rigid tubular element as in the previous embodiments, is an expandable tubular element, for example, a coronary stent. Theconduit300 has stent elements in the form ofstruts302 joined atnodes304. Theconduit300 may be formed substantially in the same manner as thestent240 inFIGS. 17A-17B. Theconduit300, however, is provided with amechanism306 for supporting the wall of a coronary vessel. Thevessel support mechanism306 in this embodiment includes a pair ofextensions308 that are preferably formed as an integral part of the stent struts302. Theextensions308 extend generally along the longitudinal axis of theconduit290 so as to contact the outer wall of a coronary vessel, thereby supporting the wall in the manner discussed above. The ends310 of theextensions308 may be unattached, as shown, or attached.
• Theconduit300 may be mounted on a balloon or other expandable member (not shown) in a collapsed orientation for introduction into the coronary vessel and the heart wall. Theextensions308 can be loaded on the balloon with the remaining portion of theconduit300. Once properly positioned in the heart wall, the balloon is inflated to expand theconduit300 to the orientation shown inFIG. 22. It should be recognized that this embodiment of the invention may be carried out using any expandable conduit, the particular stent shown inFIG. 22 representing only one possible construction. Also, theextensions308 could be separate members secured to theconduit300 by suitable means such as welding, brazing or adhesive. Finally, although twoextensions308 are provided on the illustrated conduit, any number of extensions may be used.
• It should be noted that, as used herein, the term conduit refers to any structure that is capable of conveying fluid from one point to another, for example, a tubular element with two or more open ends. In view of the fact that various characteristics of the conduit, for example, size, shape and surface configuration, may vary depending on the application, it will be recognized that the conduits in the illustrated embodiments are merely exemplary. For instance, the conduit could be a rigid, flexible or expandable tubular element formed of metal, polymers or composite materials having solid or perforated walls. The conduit could be straight over its length with the ends aligned or the ends could be offset, the exterior surface of the conduit may be treated to enhance fixation of the conduit in the heart wall, and the conduit may or may not include a valve or other flow controlling mechanism. Further, a conduit constructed according to the invention may be used to deliver various pharmaceutical substances, such as angiogenic growth factors or other substances that aid in the perfusion of surrounding myocardial tissue.
• It will be understood that theLAD30 illustrated in the Figures is but one example of a possible vessel which may be placed in communication with a heart chamber.
• Similarly, in the preferred embodiments theLAD30 is placed in communication with a heart chamber that contains blood, which, in the illustrated embodiments, is theleft ventricle12. It will be understood, however, that the invention may be used to place a conduit in communication with any source of blood (arterial or venous), for example, another heart chamber such as the left atrium, or the aorta, pulmonary veins, etc.
• It also will be appreciated that the various devices of the invention incorporated in the illustrated embodiments may be used together or separately, and the methods may be modified, carried out by combining particular steps, or varying the sequence of steps. Further, it will be understood that the embodiments may be used in various types of procedures, for example, the surgical approach depicted inFIG. 1, an open surgical procedure including a median sternotomy, or a minimally invasive procedure utilizing one or more relatively small access openings or ports. Endoscopes or thoracoscopes may be used for visualization if the procedure is truly minimally invasive. Additionally, rather than forming one or more incisions in the patient's chest wall, an endovascular approach may be used to guide various inventive devices to the heart through the patient's vascular system to the heart, for example, by introducing the devices into a peripheral vessel such as the femoral artery. Similarly, the different embodiments may be used in beating heart procedures, stopped-heart procedures utilizing cardiopulmonary bypass (CPB), or procedures during which the heart is intermittently stopped and started.
• The preferred embodiments of the invention are described above in detail for the purpose of setting forth a complete disclosure and for sake of explanation and clarity. It will be readily understood that the scope of the invention defined by the appended claims will encompass numerous changes and modifications.

Claims (46)

1. A device for engaging tissue of a coronary vessel or heart wall during a cardiovascular procedure, the device comprising:

a first member;

a second member coupled to the first member so as to permit relative movement of the first and second members; and

a tissue engaging mechanism coupled to the first and second members so as to be movable between a first position and a second, actuated position, the tissue engaging mechanism including at least one tissue engaging member configured to engage body tissue when the tissue engaging mechanism is in the second actuated position;

wherein relative movement of the fist and second members moves the tissue engaging mechanism between the collapsed and expanded orientations to selectively place the tissue engaging member in engagement with body tissue.

2. The device ofclaim 1, wherein the first and second members are first and second coaxial shafts with the tissue engaging mechanism extending therebetween, and relative axial movement of the first and second shafts moves the tissue engaging mechanism between a collapsed orientation and an expanded orientation.

3. The device ofclaim 2, wherein each of the first and second shafts has a proximal end and a distal end, and the tissue engaging mechanism is disposed adjacent the distal ends of the shafts.

4. The device ofclaim 3, wherein at least one of the first and second shafts has a portion configured to be passed through and dilate an opening in tissue, wherein the tissue engaging mechanism may be positioned adjacent tissue and then expanded to engage the tissue.

5. The device ofclaim 1, further comprising an actuator coupled to the first and second members for imparting relative movement thereto in order to move the tissue engaging mechanism between the collapsed and expanded orientations.

6. The device ofclaim 5, wherein the actuator comprises a handle coupled to one of the first and second members for moving the one member relative to the other member.

7. The device ofclaim 1, wherein the tissue engaging mechanism includes a non-inflatable structure that is moved between the collapsed and expanded orientations.

8. The device ofclaim 1, wherein the tissue engaging mechanism includes a plurality of tissue engaging members each of which has opposite ends coupled, respectively, to the first and second members, wherein relative movement of the first and second members imparts relative movement to the ends of the tissue engaging members to move the tissue engaging mechanism between the collapsed and expanded orientations.

9. The device ofclaim 1, wherein the tissue engaging mechanism includes a balloon that is inflated by pressurized fluid to engage the tissue.

10. The device ofclaim 1, wherein the tissue engaging mechanism includes an expandable mesh that is moved between the collapsed and expanded orientations in response to relative movement of the first and second members.

11. The device ofclaim 1, wherein first and second tissue engaging mechanisms are coupled to the first and second members so that each mechanism is movable between a collapsed orientation and an expanded orientation, the first and second tissue engaging mechanisms being spaced from each other to permit body tissue to be captured therebetween with the first and second tissue engaging mechanisms engaging opposite surfaces of the body tissue.

12. A method for supporting heart tissue during a medical procedure, the method comprising steps of:

providing a tissue support device having a tissue engaging mechanism configured to assume an expanded, tissue supporting orientation;

positioning the tissue support device through the wall of a patient's heart and locating the tissue engaging mechanism adjacent heart tissue; and

placing the tissue engaging mechanism in the expanded, tissue supporting orientation in engagement with the heart tissue.

13. The method ofclaim 12, further comprising positioning a conduit in the wall of the heart to place a coronary vessel in communication with a heart chamber.

14. A device for supporting a wall of a vascular structure, the device comprising:

a support structure adapted to be removably positioned in the lumen of a vascular structure, the support structure comprising a plurality of support elements coupled together so as to be movable relative to each other, wherein moving the support elements relative to each other moves the support structure from a collapsed orientation to an expanded orientation in order to support a wall of a vascular structure; and

wherein the support elements are sized and configured for positioning in the interior of the vascular structure such that when the support structure is in the expanded orientation the support elements engage the wall of the vascular structure to prevent the wall from collapsing.

15. The device ofclaim 14, wherein the support elements comprise a plurality of flexible struts each of which has a free end, wherein the free ends of the struts are moved apart to place the support structure in the expanded orientation.

16. The device ofclaim 15, further comprising a sheath coupled to the flexible struts so that movement of the sheath relative to the struts moves the free ends of the struts apart to place the support structure in the expanded orientation.

17. The device ofclaim 14, wherein the support elements comprise a plurality of flexible struts each of which has first and second ends and a central portion between the ends, wherein the first ends of the struts are fixed to each other and the second ends of the struts are fixed to each other such that the central portions of the struts move away from each other as the support structure moves to the expanded orientation.

18. The device ofclaim 16, further comprising a sheath slidable over the flexible struts, wherein the sheath is placed over at least a portion of the struts to move the support structure to the collapsed orientation and is removed from the said portion of the struts to move the support structure in the expanded orientation.

19. A device for supporting a vascular structure, the device comprising:

an introducer having a hollow interior;

an elongated support member configured to be generally coiled when in an unbiased orientation and generally straight when in a biased orientation;

wherein the interior of the introducer is sized and configured to receive the elongated support member and hold the support member in the generally straight, biased orientation; and

wherein the elongated support member is moved from the straight, biased orientation within the interior of the introducer to the coiled, unbiased orientation upon entering the interior of the vascular structure to support the vascular structure.

20. The device ofclaim 19, wherein the elongated support member is a superelastic wire that is generally straight when in the biased orientation and generally helical when in the unbiased orientation.

21. The device ofclaim 20, wherein an end of the elongated support member is sharpened for forming an opening in the wall of the vascular structure to pass the support member into the interior of the vascular structure.

22. The device ofclaim 19, wherein the elongated support member is adapted to be removed from the vascular structure via the opening through which the support member is passed into the vascular structure.

23. A method for internally supporting a wall of a vascular structure, the method comprising steps of:

(a) positioning a support within an interior of a vascular structure such that the support contacts and supports a wall of the vascular structure; and

(b) introducing a medical device into the interior of the vascular structure by passing the device through the wall of the vascular structure and through the support.

24. The method ofclaim 23, wherein the support is an elongated member configured in a generally straight orientation prior to being positioned in the interior of the vascular structure and assumes a generally coiled orientation once positioned in the interior of the vascular structure, the medical device being introduced between coils of the support into the vascular structure.

25. The method ofclaim 23, wherein the support is movable between collapsed and expanded orientations, and step (a) is carried out by introducing the support into the vascular structure in said collapsed orientation and then moving the support to said expanded orientation.

26. The method ofclaim 23, wherein the support comprises a sleeve having at least one opening formed therein through which the medical device is introduced.

27. The method ofclaim 23, wherein the vascular structure is a coronary artery and the medical device is a conduit delivery device that is passed through the coronary artery to position a conduit in the wall of the heart to communicate the coronary artery with a heart chamber.

28. The method ofclaim 23, further comprising the step of removing the medical device and the support from the vascular structure.

29. A method for supporting a wall of a vascular structure at an area adjacent an incision in the wall of the vascular structure, the method comprising steps of:

inserting a support through the incision in the wall of the vascular structure while the support is in a low profile orientation;

positioning at least a portion of the support within the interior of the vascular structure; and

moving the support from the low profile orientation into an expanded orientation so as to contact and support the wall of the vascular structure.

30. The method ofclaim 29, further comprising introducing a medical device into the interior of the vascular structure by passing the device through the support.

31. The method ofclaim 30, wherein the vascular structure is a coronary artery and the medical device is a conduit delivery device that is passed through the coronary artery to position a conduit in the wall of the heart to communicate the coronary artery with a heart chamber.

32. A device for stabilizing an area of a patient's heart adjacent a coronary vessel, the device comprising:

a base configured to be positioned adjacent a coronary vessel of a patient's heart, the base having at least one opening for accessing the coronary vessel;

at least one tissue engaging element coupled to the base so as to be movable with respect to the base, the tissue engaging element having a portion configured to securely engage the wall of a patient's heart in order to stabilize the wall of the heart upon moving the tissue engaging element with respect to the base; and

an actuator for imparting relative movement to the base and the tissue engaging element in order to stabilize the heart while accessing the coronary vessel through the opening in the base.

33. The device ofclaim 32, wherein the base has a single opening for accessing the coronary vessel and a plurality of tissue engaging elements are coupled to the base.

34. The device ofclaim 33, wherein the tissue engaging elements comprise legs each of which has one end pivotally attached to the base and another end provided with a member configured to at least partially penetrate the wall of the heart.

35. The device ofclaim 34, wherein the base has a plurality of recesses each of which pivotally mounts the one end of one of the legs, each recess having a cam surface that moves the leg with respect to the base when the base is rotated.

36. The device ofclaim 32, wherein the tissue engaging elements include a sharpened end configured to partially penetrate the wall of the heart.

37. The device ofclaim 36, wherein each tissue engaging element has an end provided with an expandable member, the expandable member configured to be passed through the wall of the heart to a location adjacent a surface of the wall opposite the coronary vessel and then expanded to engage said surface of the wall.

38. A conduit for placing a coronary vessel of a patient's heart in communication with a heart chamber, the conduit comprising:

a tubular element including first and second portions having different cross-sectional sizes, the tubular element having a bore defining a blood flow path;

wherein the cross-section of the first portion of the tubular element is larger than the cross-section of the second portion of the tubular element such that the tubular element is generally funnel-shaped; and

wherein the first and second portions of the tubular element are generally aligned and the bore defines a generally straight blood flow path.

39. A conduit for communicating a chamber of a patient's heart with a coronary vessel, the conduit comprising:

an expandable stent including first and second ends and a length defined between the ends, the length of the stent including first and second portions having different cross-sectional sizes when the stent is expanded;

wherein each of the first and second portions of the stent includes strut members disposed along a first direction when the stent is unexpanded and along a second direction when the stent is expanded, the second direction being transverse to the first direction; and

wherein the strut members of the first portion are longer than the strut members of the second portion and the stent is generally funnel-shaped when expanded.

40. A device for use in a coronary vessel of a patient's heart, the device comprising:

an expandable stent including a bore defining a blood flow path and first and second portions, the first and second portions having different cross-sectional sizes when the stent is expanded;

wherein the first portion has a larger cross-sectional dimension than the second portion when the stent is expanded such that the stent is generally funnel-shaped when expanded; and

wherein the first and second portions of the stent are constructed to provide the stent with maximum radial strength when expanded.

41. The device ofclaim 40, wherein the stent is configured to be positioned and retained in a heart wall to place a coronary vessel in communication with a heart chamber.

42. The device ofclaim 40, wherein the stent has a plurality of openings along the length of the stent through which blood may flow.

43. (canceled)

44. A conduit for placing a coronary vessel of a patient's heart in communication with a heart chamber, the conduit comprising:

a tubular element configured to positioned in the wall of a patient's heart, the tubular element including first and second ends and a bore defining a blood flow path; and

a vessel supporting mechanism carried by the tubular element, the vessel supporting mechanism being positioned on the conduit so as to contact and support the wall of a coronary vessel when the conduit is positioned in the heart wall.

45. The conduit ofclaim 44, wherein the tubular element is a rigid, solid walled structure.

46. The conduit ofclaim 44, wherein the tubular element is an expandable stent including a plurality of struts, and the vessel supporting mechanism comprises some of the struts.

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