Bicuspid valve dissection device

Abstract

To provide methods and apparatuses for bisection of heart valve leaflets using a catheter having a cutting element.SOLUTION: The invention is a device, system, and method for repairing the heart valve function, which may include bisecting native valve leaflets for improved deployment of a prosthetic heart valve in the native valve annulus. The invention may include a catheter having a cutting element shaft with a cutting element configured to puncture a valve leaflet and / or make a controlled cut through the leaflet. The device may have an extendable foot configured to be positioned on an opposite side of the valve leaflet from the cutting element shaft. The device may include magnets to guide the cutting element and / or cutting element shaft in proper alignment with the extendable foot and to hold the elements in place during leaflet bisection.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to the repair and / or replacement of heart valves, and more particularly to methods and devices for bisecting heart valve leaflets using a catheter having a cutting element. [Background technology]

[0002] In vertebrates, the heart is a hollow muscular organ with four pumping chambers: the left and right atria and the left and right ventricles, each with its own one-way outflow valve. Natural heart valves are identified as the aortic, mitral (or bicuspid), tricuspid, and pulmonary valves. These valves separate the heart's chambers and reside in annulus sections between them. The annulus comprises a dense fibrous annulus attached either directly or indirectly to atrial and ventricular muscle fibers. The valve leaflets are flexible collagen structures that attach to and extend inward from the annulus, meeting at the coaptation margin. The aortic, tricuspid, and pulmonary valves typically have three leaflets, while the mitral valve typically has two.

[0003] The operation of the heart, and therefore the health of the patient, can be severely compromised if any of these heart valves do not function properly. Various problems with heart valves can develop due to multiple clinical causes. Stenosis in a heart valve is a condition in which the valve does not open properly. Regurgitation is a condition in which the valve does not close properly. Repair or replacement of the aortic or mitral valve is most common because these valves are located on the left side of the heart where pressure and stress are greatest. In valve replacement surgery, a replacement prosthetic valve is implanted into the native valve annulus, which may involve removal of the native valve leaflets.

[0004] Heart valves can lose their ability to close properly due to annular dilation around the valve or flaccid, prolapsed leaflets. Valve leaflets can also contract due to diseases such as rheumatoid arthritis, leaving gaps between the leaflets in the valve. The inability of a heart valve to close allows blood to leak in the reverse direction (opposite to normal blood flow), commonly referred to as regurgitation. Common examples of such regurgitation include mitral valve regurgitation (i.e., leakage of blood back through the mitral valve into the left atrium) and aortic valve regurgitation (i.e., leakage of blood back through the aortic valve into the left ventricle). Regurgitation can severely impair heart function because more blood must be pumped through the regurgitating valve to maintain adequate circulation. In the early stages, heart valve regurgitation causes fatigue and shortness of breath. If left unchecked, this problem can lead to congestive heart failure, arrhythmia, or death.

[0005] Heart valve regurgitation can be caused by a change in the shape of the heart valve annulus, damage to one or more heart valve leaflets, and / or damage to the chordae tendineae. In such regurgitation, the heart valve leaflets do not coapt properly together to seal the valve, so that the leaflets do not coapt completely to close the annulus during systole, and openings remain between the edges of the leaflets.

[0006] Dysfunctional heart valves, in which the leaflets do not coapt for proper sealing during systole, can be repaired or replaced with an artificial device, such as a prosthetic valve. In some cases, it may be desirable to remove natural structures, such as the leaflets, in order to properly implant a prosthetic valve within the native valve annulus. For example, in traditional open-heart surgical procedures, surgeons manually cut the natural heart valve leaflets using a scalpel. In some cases, a replacement valve may be placed directly on the native valve without the need to remove or cut natural structures, such as the leaflets. For example, in a transcatheter aortic valve replacement (TAVR) procedure, the prosthetic valve is delivered through a catheter and deployed within the native valve annulus by pushing the natural leaflets laterally. In some cases, it may be desirable to cut (e.g., bisect) the natural valve leaflets in order to properly deploy the prosthetic valve within the native valve annulus. Examples of situations in which bisecting the natural valve leaflets may be desirable include situations in which the natural valve leaflets are (or will be) deforming the prosthetic valve into an undesirable shape (e.g., deforming the prosthetic valve into an elliptical shape). For example, highly calcified native valve leaflets may have multiple portions that collectively distort a prosthetic valve deployed in the annulus.

[0007] Another situation in which bisection of the native valve leaflets may be desirable is in the case of a so-called bicuspid aortic valve (BAV). In a BAV, the aortic valve has only two leaflets (as opposed to the usual three leaflets), or the aortic valve has adjacent leaflets fused together (e.g., in edge-to-edge alignment along a raphe / fusion line between the adjacent leaflets) into a single leaflet structure, such that the valve has only two or even one active leaflet. Prior to deployment of a prosthetic valve within such a valve, it may be desirable to bisect the leaflets into two separate leaflet structures or separate the two fused leaflets (such as by bisecting the fused leaflets along the raphe).

[0008] Various devices and methods are known in the art for valve leaflet bisection and removal. For catheter-based leaflet bisection, cutting devices are known that can be delivered via a catheter.

[0009] When bisection of the valve leaflets is desired to facilitate valve repair and replacement, conventional cutting devices can have difficulty advancing a cutting element through the leaflets (due to the hard tissue / deposits that often accompany damaged leaflets, such as calcified leaflets).

[0010] There is currently a need for improved means for performing heart valve repair and replacement. The present invention meets this need. Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention provides multiple devices and methods for cutting (e.g., bisecting) valve leaflets. The devices and methods herein allow for precise cutting of valve leaflets during percutaneous or other procedures without damaging surrounding tissue. [Means for solving the problem]

[0012] It should be understood that each element disclosed herein can be used with any other element disclosed herein, even if that specific combination of elements is not explicitly shown in the drawings herein. In other words, based on the description of a particular device, one skilled in the art should have little difficulty combining some features of two such devices. It should therefore be understood that many of these elements are interchangeable, and the present invention encompasses any and all permutations thereof.

[0013] The devices of the present invention can be used in standard open surgical procedures, minimally invasive procedures, or subcutaneous procedures. In one embodiment, the devices can be delivered transapically through a small chest incision. In another embodiment, the devices can be introduced transatrially through an incision made in the upper wall of the left or right atrium. In yet another embodiment, the devices can be delivered transthoracically into the left or right ventricle via a thoracoscope, which can be performed transapically. The devices can also be delivered percutaneously, such as via a catheter into the patient's atrial system (e.g., via the femoral or brachial artery).

[0014] Advantages of this device include a low delivery profile, which contributes to a minimally invasive and percutaneous delivery method. The device is configured to properly interface with the native valve leaflets to ablate them with minimal interference with surrounding tissues such as the ventricle, atrium, and subvalvular complex.

[0015] Embodiments of the present disclosure provide devices and methods for cutting valve leaflets, such as the aortic valve or mitral valve. The devices and methods disclosed herein are delivered to a subject's heart in a desired manner using percutaneous or minimally invasive surgical methods. Thus, the desired methods described herein may not require extracorporeal circulation (e.g., blood from a subject's circulatory system is sent outside the body for application to the subject's circulatory system and then returned to the circulatory system). For example, in one embodiment, an ablation catheter (or similar device) is inserted through an incision in the chest wall and then inserted through cardiac tissue (e.g., through the apex of the heart) into a chamber of the patient's beating heart. Because such methods do not require extracorporeal circulation, complications may be significantly reduced compared to traditional open-heart surgery.

[0016] A device according to one embodiment of the present invention includes a steerable catheter shaft, a foot sheath slidably disposed within the steerable catheter shaft, and a foot element located at the distal end of the foot sheath, configured to engage the valve leaflets from below the leaflets. The foot element may have a foot opening. A cutting element sheath may be slidably disposed within the steerable catheter. The cutting element may be selectively extendable from the distal end of the cutting element sheath into the foot opening. An alignment magnet (such as a selectively activated electromagnet) may be provided within the foot element and / or the distal end of the cutting blade sheath. The foot may be configured to extend laterally from the foot sheath when extended distally from the catheter shaft and may have an overall length of between 0.5 and 2.0 centimeters and / or an overall width of between 0.3 and 0.8 centimeters, up to 1.0 cm, up to 1.5 cm, up to 2 cm, or 1.0 to 2.0 cm. The feet may be self-expanding when extended from the catheter shaft and may be formed from nitinol or similar memory material. A variety of cutting elements are within the scope of the present invention, such as simple cutting blades, motor-driven rotating rods with abrasive surfaces, electrocautery devices, curved blades, and / or scissors. The device may include an embolic filter configured to extend from the steerable catheter.

[0017] A system for treating a heart valve according to one embodiment of the present invention may include a device for bisecting a native heart valve, a delivery catheter for delivering the prosthetic heart valve, the delivery catheter comprising a flexible, elongated delivery shaft having a delivery shaft distal end and further comprising a prosthetic heart valve retaining portion on the delivery shaft distal end, and a radially expandable prosthetic heart valve. The radially expandable prosthetic heart valve may be retained by the prosthetic heart valve retaining portion of the delivery catheter. The prosthetic heart valve may be radially expandable, such as radially self-expanding or balloon-expandable. The delivery catheter may be a balloon catheter having an expandable balloon at the delivery shaft distal end.

[0018] A method for bisecting a heart valve leaflet according to the present invention may include the steps of advancing a steerable catheter shaft through a patient's anatomy to a position near a native heart valve having an annulus, advancing a foot from the steerable catheter shaft distally past the leaflets of the native heart valve, positioning the foot against a distal side of the leaflet, advancing a cutter sheath from the steerable catheter shaft, the cutter sheath comprising a cutter sheath distal end, positioning the cutter sheath distal end against a proximal side of the leaflet, holding the leaflet between the foot and the cutter sheath distal end, and advancing a cutting element from the cutter sheath into the leaflet at a selected entry position on the leaflet. The cutting element may be moved across the leaflet, thereby forming a cut extending across at least a portion of the leaflet. The selected entry location in the valve leaflet may be adjacent to the annulus, and moving the cutting element across the leaflet may include moving the cutting element from the selected entry location adjacent to the annulus to the free edge of the valve leaflet so that the cut extends from the desired entry location to the free edge. Alternatively, the entry point can be a location along the free edge, and the cut proceeds along a selected path into the leaflet. If the leaflet has calcified deposits, moving the cutting element across the leaflet may include avoiding contact between the cutting element and the calcified deposits so that the cut does not dislodge the calcified deposits. The cutter sheath distal end may have a first magnet, and the foot may have a second magnet, and positioning the cutter sheath distal end against the proximal side of the leaflet may include aligning the first magnet with the second magnet due to the magnetic attraction of the respective magnets. At least one of the first magnet or the second magnet may be a selectively activated electromagnet, and the step of positioning the distal end of the cutter sheath against the proximal side of the valve leaflet may include the step of activating the electromagnet.

[0019] Various valves, including the aortic, mitral, tricuspid, and pulmonary valves, can be treated using the devices and methods of the present invention. The specific approach for advancing the device through the patient's anatomy can depend on the particular valve being treated. For example, in the case of the aortic valve, the approach can involve advancing a steerable catheter shaft through the patient's anatomy to a location near the native heart valve, including advancing the steerable catheter shaft through the femoral artery into the aorta and around the patient's aortic arch.

[0020] The present invention may include one or more embolic filter elements. For example, prior to advancing a cutting element out of the cutter sheath and into the valve leaflet, an embolic filter may be deployed from the steerable catheter shaft to a position such that substantially all blood flowing past the valve leaflet passes through the embolic filter before passing through the patient's lungs or brain.

[0021] The device may be delivered using a variety of approaches, including percutaneously or transapically via the subject's blood vessels.

[0022] Other objects, features and advantages of the present invention will become apparent from a consideration of the following detailed description. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a cross-sectional view of a heart into which a device according to one embodiment of the present invention has been advanced. [Figure 2] 2A-2E are top views of a heart valve before treatment according to an embodiment of the present invention. [Figure 3] 3A-3E are top views of a heart valve after treatment according to an embodiment of the present invention. [Figure 4] 4A-4B are top views of a heart valve before treatment according to one embodiment of the present invention. [Figure 5] 5A-5D are side views of a device according to one embodiment of the present invention. [Figure 6]6A-6D are side views (cross-sections) of a heart valve being treated with a device according to one embodiment of the present invention. [Figure 7] 7A and 7B are perspective views of a device according to one embodiment of the present invention, and FIGS. 7C and 7D are perspective views (enlarged views) of the device. [Figure 8] 1 is a perspective view of a device according to one embodiment of the present invention. [Figure 9] 1 is a perspective view of a device according to one embodiment of the present invention. [Figure 10] 1 is a perspective view of a device according to one embodiment of the present invention. [Figure 11] 1 is a perspective view of a device according to one embodiment of the present invention. [Figure 12] 12A-12F are a side view, a side view, a top view (cutaway), a side view, a top view (cutaway), and a side view of a device according to one embodiment of the present invention. [Figure 13] 13A-13F are a side view, a side view, a top view (cutaway), a side view, a top view (cutaway), a side view, a top view (cutaway), and a side view of a device according to one embodiment of the present invention. [Figure 14] FIG. 1 is a side view of a heart with a device according to one embodiment of the present invention in operation therein. [Figure 15] FIG. 1 is a side view of a system according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] In FIG. 1, a cross-sectional view of a human heart 10 is shown. Heart 10 has a myocardial wall 11, an apex 19, and four chambers: right atrium 12, right ventricle 14, left atrium 16, and left ventricle 18. Blood flow is controlled by four major valves: tricuspid valve 20, pulmonary valve 22, mitral valve 24, and aortic valve 26. Blood flows through superior vena cava 28 and inferior vena cava 30 into the right atrium 12 of heart 10. The right atrium 12 pumps blood through tricuspid valve 20 (in its open configuration) into right ventricle 14. The right ventricle 14 then pumps blood through pulmonary valve 22 into pulmonary artery 32 (which branches into the arteries that lead to the lungs) with tricuspid valve 20 closed to prevent backflow of blood from the right ventricle 14 into the right atrium. The free edges of the leaflets of the tricuspid valve 20 are connected by right ventricular chordae tendineae 34 to right ventricular papillary muscles 36 in the right ventricle 14 to control movement of the tricuspid valve 20 .

[0025] After leaving the lungs, oxygenated blood flows through pulmonary veins 38 and enters the left atrium 16 of the heart 10. The mitral valve 24 controls blood flow between the left atrium 16 and the left ventricle 18. The mitral valve 24 closes during ventricular systole, when blood is ejected from the left ventricle 18 into the aorta 40. The mitral valve 24 then opens to refill the left ventricle 18 with blood from the left atrium 16. The free leaflet edges 42a, 42p of the mitral valve 24 are connected by left ventricular chordae tendineae 44 to left ventricular papillary muscles 46 in the left ventricle 18 to control the mitral valve 24. Blood from the left ventricle 18 passes through the aortic valve 26 and into the aorta 40, which branches into arteries that lead to all parts of the body except the lungs. The aortic valve 26 includes three cusps 48 (or two cusps if the aortic valve is bicuspid), which open and close to control blood flow from the left ventricle 18 of the heart into the aorta 40 as the heart beats. A device 50 according to the present invention is shown with an elongate shaft 52 advanced through the patient's vasculature to position a distal end 54 of the device adjacent the aortic valve 26 to bisect the cusps 48 of the aortic valve 26.

[0026] Figures 2A-2E show top views of aortic valves with various defects, along with proposed bifurcation lines. Figure 2A shows a Type 0 bicuspid aortic valve 26a, i.e., a "complete" bicuspid aortic valve, in which only two leaflets 48L (left) and 48R (right) are present, as opposed to the normal three leaflets of the aortic valve. The valve 26a may have calcific deposits 60, which may contribute to valve stenosis / insufficiency. Such aortic valves 26a may have a tendency to form an elliptical shape when radially expanded, such as when a prosthetic heart valve is radially expanded within the annulus 62a. Figure 2B shows a Type 1 bicuspid aortic valve 26b, in which the adjacent left and right leaflets 48L and 48R are fixed at their edges by a raphe 64, but the non-septal (posterior) leaflet 48N is not fused. Figure 2C shows another Type 1 bicuspid aortic valve 26c in which adjacent leaflets 48R, 48L are secured at their edges by raphe 64. Figure 2D shows another Type 1 bicuspid aortic valve 26d in which adjacent leaflets 48N, 48L are secured at their edges by raphe 64. Figure 2E shows a Type 2 bicuspid aortic valve 26e in which adjacent leaflets 48L, 48N, 48R are secured at their edges by multiple raphe 64.

[0027] In the case of such bicuspid aortic valves, proper deployment of an expandable transcatheter prosthetic heart valve within the native valve leaflets may be difficult because the bicuspid valve leaflets may resist the desired circular expansion of the prosthetic heart valve within the annulus more strongly on some sides or regions of the native valve annulus than on other sides / regions. For example, in the fully bicuspid valve 26a of FIG. 2A, the leaflets 48L, 48R resist prosthetic valve expansion more strongly than the commissures of the native valve 26a, so the prosthetic valve deployed therein may be forced into an elliptical shape by the native leaflets 48L, 48R, as opposed to the desired circular shape.

[0028] By cutting one or more bisection cuts through one or more of the native valve leaflets, the tendency of the native leaflets to deform the native valve annulus and / or resist proper circular expansion of the prosthetic heart valve within the native leaflet can be significantly reduced. Preferably, such bisection cuts can be made to prevent embolization of the leaflet tissue, such as by avoiding calcified regions and avoiding cuts that result in the leaflet tissue being detached from the native valve. Preferably, a specific cutting path can be selected by a user (e.g., a physician) based on the desired outcome and the particular native valve anatomy to avoid embolization of the native leaflet tissue. Figures 3A-3E show top views of a heart valve with bisection cuts 66 formed, according to an embodiment of the present invention. Preferably, the bisection cuts 66 originate from a portion of the leaflet adjacent the annulus and then are cut to exit the leaflet at a location toward the center of the annulus. Note that if the adjacent leaflets are fused at a raphe, the bisection cuts 66 can be formed along or parallel to the raphe 64. The bisecting section effectively increases the number of leaflets by cutting individual leaflets (Figure 3A) or two coapted leaflets (Figures 3B-3D) or three coapted leaflets (Figure 3E) into two or more separate leaflet structures.

[0029] 4A and 4B illustrate a cutting method according to one embodiment of the present invention. As shown in FIG. 4A, an initial perforation 68 may be formed adjacent the annulus 62, followed by a cutting path 70 running toward the leaflet free edge and center of the valve opening. As a result, the left leaflet 48L is bisected by the cut 66 into two separate leaflet structures 72, as shown in FIG. 4B.

[0030] 5A-5D, a device 50 according to the present invention is shown having an elongated steerable sheath 52, a distal end 54, and a proximal end 56. The device 50 includes a cutting blade sheath 78 having a cutting blade member 80 slidingly disposed therein. The cutting blade sheath 78 and a foot shaft 82 are slidingly disposed within the steerable outer sheath 52. The cutting blade sheath 78, cutting blade member 80, and foot shaft 82 are configured to be moved distally and proximally relative to one another. A control handle 84 located at the proximal end 56 includes various controls, including a steering control 86 for steering the steerable sheath, sliding controls 88, 90 configured to advance and retract the cutting blade sheath 78 and foot shaft 82, and a blade control 91 configured to advance and retract a blade 92 through the blade member 80.

[0031] The cutting blade member 80 has a cutting blade 92 at its distal end, and the foot shaft 82 has a foot 94 with a blade-receiving opening 96 at its distal end. As shown in FIGS. 5A-5C , prior to piercing the valve leaflet, the cutting blade 92 is positioned proximal to the foot opening 96. In the cutting configuration, as shown in FIG. 5D , the cutting blade 92 is advanced distally relative to the foot 94 until a portion of the cutting blade 92 is positioned within the foot opening 96. Note that in the delivery configuration, the cutting blade sheath 78, cutting blade member 80, cutting blade 92, and foot 94 are retracted within the steerable catheter 52 or positioned entirely outside the patient.

[0032] When deployed, the foot 94 extends laterally from the foot shaft 82 to extend beneath the valve leaflet and support at least a portion of the leaflet from the distal side when the device approaches the leaflet from the proximal side. When deployed, the foot 94 may have an overall width 95 (e.g., 0.3-0.8 cm, 1.0-2.0 cm, up to 1.0 cm, up to 1.5 cm, or up to 2 cm) and / or an overall length 97 (e.g., 0.5-2.0 centimeters). The foot 94 may have a distal lip 98 extending beyond the opening 96, which separates the blade 92 from the distal lip tip 102 by a distance 100 (e.g., 0.1-0.5 centimeters) sufficient to prevent the blade 92 from accidentally severing adjacent cardiac structures, such as the aortic and ventricular structures.

[0033] The cutting blade 92 has a sharp tip 104 for piercing tissue and a cutting edge 106 for slicing tissue, the cutting edge 106 being oriented toward the foot shaft 82. With the sharp tip 104 driven through a layer of material (such as valve tissue) and positioned within the foot opening 96, retracting the device 50 from the layer of material (e.g., by pulling the device proximally from the layer of material) causes the cutting edge 106 to engage and cut through the layer of material.

[0034] Magnets 110, 112 may be included to assist in guiding the cutting blade sheath 78 and / or cutting blade 92 into proper alignment with the foot 94 and foot opening 96 and / or to hold the distal end of the cutting blade sheath 78 against the foot 94 to hold the device against the valve leaflets. One or more magnets may be located on or adjacent to the blade or blade sheath, and the blade or blade sheath itself may be magnetic. One or more magnets may be located on or adjacent to the foot, and the foot itself may be magnetic. These magnets may be permanent magnets or electromagnets configured to be selectively activated by the user when it is desired to advance and hold the cutting blade sheath 78 in place between the foot 94.

[0035] The device may be formed from a variety of materials, for example, the foot 94 and / or the blade sheath 78 may be formed from Nitinol.

[0036] Device 50 may include radiopaque and / or other visualization-enhancing elements. For example, radiopaque markers may be included on blade sheath 78 and / or blade 92 and / or foot 94, such as at or adjacent to magnets 110, 112.

[0037] Various approaches for advancing the device into position to bisect the valve leaflets are within the scope of the present invention. When treating an aortic valve, one preferred approach is a transcatheter approach via the femoral artery. This method may include the deployment of a transcatheter aortic valve replacement (TAVR), which can be performed using the same transcatheter approach. For example, a bladed bifurcating catheter, such as that disclosed herein, may be used to bisect the leaflets of the native valve. An ablation procedure may be performed first, followed by the deployment of a transcatheter prosthetic valve. While the ablation procedure may reduce the competence of the native valve, this temporary reduction in the competence of the native valve is not detrimental to the outcome of the procedure because the transcatheter prosthetic valve will be deployed immediately after the bisection of the valve leaflets.

[0038] In one example of a procedure for bisecting native valve leaflets according to the present invention, femoral artery access is achieved through an access sheath of the type utilized for TAVR procedures. The access sheath is positioned at the access site. A guidewire is advanced from the femoral access site through the aortic arch and into the patient's left ventricle. A steerable shaft can be advanced over the guidewire, such as by standard over-the-wire techniques, to advance the distal end of the device to the target location. For example, the device can have a guidewire lumen. Echo and fluoroscopic visualization techniques can be utilized.

[0039] With the steerable shaft 52 positioned at the target location, the foot 94 is extended distally out of the steerable shaft 52 and into the left ventricle 18 to a location below the aortic valve cusp 48 to be bisected. The foot 94 is then retracted proximally to engage the cusp 48 from the ventricular side, as shown in FIG. 6A. The position of the foot 94 may be visualized, such as by echo and / or fluoroscopy techniques.

[0040] Once the proper position of the foot 94 has been confirmed, the blade sheath 78 may be advanced distally toward the leaflet 48 and foot 94, as shown in FIG. 6B. The magnets 110, 112 assist in aligning the blade sheath 78 with the foot 94. Visualization, such as by echo and / or fluoroscopy, may be utilized to confirm the alignment of the blade sheath 78 with the foot 94. Once aligned, the blade sheath 78 and foot 94 may be pressed toward each other to hold the target leaflet 48 between the blade sheath 78 and foot 94, with the sheath 78 engaging the leaflet 48 from the aortic side and the foot 94 engaging the leaflet 48 from the ventricular side, and the magnets 110, 112 holding the sheath 78 and foot 94 in their respective positions. Once alignment and positioning of the blade sheath 78 and foot 94 has been achieved, the blade 92 may be advanced distally from the blade sheath 78 to penetrate the leaflet 48 and enter the foot opening 96, as shown in FIG. 6C. Once the blade 92 is advanced through the leaflet 48 and secured within the foot opening 96, the foot 94 is pulled proximally, thereby pulling the blade 92 distally while pulling the blade edge 106 proximally, causing the blade edge 106 to slice through the leaflet 48. Preferably, the blade sheath 78, blade member 80, and foot 94 may be flexible (which may include being formed from Nitinol) so that the pulling direction of the blade cutting edge 106 as the foot 94 is pulled is away from the aortic wall and generally axial to the aortic valve axis, as shown in FIG. 6D . This procedure may be repeated for different leaflets and / or for the same leaflet if multiple cuts are desired in a single leaflet.

[0041] 7A-7D illustrate an alternative embodiment of a device 120 in accordance with the present invention. The device 120 includes a steerable catheter 122, a distally extendable foot 124, a braid sheath 126, and a braid 128. The steerable catheter 122 is configured to house the braid sheath 126, the foot 124, and the braid 128, all of which may extend distally from the steerable catheter 122 when the distal end of the steerable catheter is positioned at a desired treatment location. The foot 124 is configured to be extended distally to a position distal to the valve leaflet, with a proximal side 130 of the foot 124 pointing toward the distal side of the valve leaflet. The foot 124 may then be retracted until the valve leaflet is compressed, thereby being held between the proximal side 130 of the foot and the distal end 132 of the steerable catheter 122. The distal end 132 of the steerable catheter may have a gripping surface, as may the proximal side 130 of the foot 124, such that the distal end 132 and the proximal side 130 together form a traction clamp capable of physically restraining the valve leaflets therebetween. The foot proximal surface 132 and the proximal side 130 of the foot 124 may have interlocking surfaces. The foot 124 may have a pocket 134 or other opening configured to receive the blade 128 therein.

[0042] Once the leaflet is secured within the traction clamp, the blade 128 may be advanced distally from the blade sheath 126 into the leaflet tissue and into the pocket 134. The blade 128 may be contoured for optimal cutting or may allow for pullback as a cutting method, such as those described above with respect to other embodiments. The blade 128 may have a sharp cutting edge 136 that may be curved along the periphery of the blade 128 on the bottom and sides, allowing the device 120 to cut both toward and away from the leaflet edge. The blade 128 may be manually actuated by a user with a sliding control, such as those described above, or may be driven (e.g., via an electric motor) for repeated strokes in a sawing action.

[0043] FIG. 8 illustrates another embodiment of a device 140 according to the present invention. The device 140 includes a steerable catheter 142, a foot sheath 144, and a foot 146 having a foot opening 148. A cutter sheath 150 is slidably extendable from the steerable catheter 142 and includes a rotatable cutting element 152 that can be advanced and retracted distally from the cutter sheath 150. The rotatable cutting element 152 can be driven distally by a small electric motor (not shown) or similar power source that can rotate the cutting element 152 at high speeds. The cutting element 152 can have an abrasive surface (such as a diamond coating) to improve cutting ability when rotated at high speeds. With the foot 146 positioned distal to the leaflet, the cutting element 152 is driven into the leaflet and into the foot opening 148. Note that the motor can be activated to rotate the cutting element 152 either before or after a perforation is formed in the leaflet. With the motor running and the cutting element 152 pivoting, the cutting element 152 is drawn through (and cuts) the desired cutting path through the valve leaflet.

[0044] A further embodiment of the device 160, as shown in FIG. 9 , includes a steerable catheter 162, a distally extendable foot sheath 164, and a foot 166 having a foot opening 168. A cutter sheath 170 is extendable distally from the steerable catheter 162 and includes an electrocautery tip 172 that can be extended distally and retracted from the cutter sheath 170. The electrocautery tip 172 can be powered with DC or AC power sufficient to cut the leaflet tissue. In use, the foot 166 is positioned distally of the valve leaflet. The cutter sheath 170 is advanced to a position proximal to the leaflet, which may involve grasping the leaflet between the foot and the distal end of the cutter sheath. With power supplied to the electrocautery tip 172, the tip 172 is driven through the leaflet at the desired puncture site. With power applied, the tip 172 is pulled through the leaflet, cutting it along the desired cutting path.

[0045] 10 shows another embodiment of a device 180 according to the present invention with a steerable catheter 182. A distally extendable foot sheath 184 has a foot 186 with a foot opening 188. A cutter sheath 190 includes a laser cutting element 192, such as a waveguide laser fiber. Laser energy can be supplied from a variety of laser sources, such as a thulium YAG laser.

[0046] 11 , the device 200 can have a scissors-cutting element 212. In the illustrated example, a foot sheath 204 and a cutting sheath 210 are slidably extendable from the steerable catheter 202. A foot 206 having a foot opening 208 is advanced to the distal side of the valve leaflet, and the scissors-cutting element 212 can be advanced out of the cutter sheath 190 to cut the valve tissue, with the lower cutting blade 214b extending into the foot opening 208 and below the valve leaflet, and the upper cutting blade 214a extending above the valve leaflet. The scissors-cutting element 212 can be driven manually (e.g., by manipulation of elements on the proximal end of the device) or by an electric motor (which can have controls on the proximal end of the device).

[0047] Numerous variations on the foot element are within the scope of the present invention. The foot element may be configured to be advanced up to and through the native heart valve leaflets in a reduced diameter and / or longitudinal configuration to better navigate the patient's anatomy, including through the inter-leaflet space. Figures 12A-12E show a device 220 having a steerable catheter 222, a cutting element sheath 224, and a cutting element 226, and having a foot base element 230 that can be mechanically steered in that configuration. The foot base element 230 is secured to the distal end of a flexible, elongated foot control rod 228 via a hinged connection 234. The foot base element 230 has a foot hole 232 configured to receive the cutting element 226. As shown in Figure 12A, the steerable catheter 222 is advanced into the patient's anatomy to a position adjacent the heart valve leaflet 236 to be treated. The base foot element 230 is advanced distally from the steerable catheter 222 in a longitudinal configuration (i.e., aligned with the distal portion of the steerable catheter 222) to a position beyond the leaflet edge 238, as shown in FIGS. 12B-12C. The base foot element 230 is then moved, such as by rotation about the hinged joint 234, to a transverse configuration at a position beneath the leaflet 236, as shown in FIGS. 12D and 12E. Note that in this transverse configuration, the foot base element 230 can be positioned at an angle 235 between 45 and 135 degrees from the distal portion of the elongate foot control rod 228. The foot base element 230 is then moved proximally (e.g., by proximal retraction of the elongate foot rod 228) and into contact with the distal surface of the leaflet 236, and the cutting element sheath 224 can be advanced distally into engagement with the proximal surface of the leaflet 236, as shown in FIG. 12F. Thus, the leaflets 236 can be held between the foot base element 230 and the cutting sheath 224. The cutting element 226 can then be moved through the leaflets 236 to make the desired cut.

[0048] It should be noted that in other embodiments similar to those of Figures 12A-12F, the foot hole 232 does not have to be completely constrained by the foot base element 230, such as when the foot base element 230 is formed from two strip-like shapes on each side of the foot hole 232 whose distal ends are not connected to each other, so that the foot base element 230 is open at its distal end.

[0049] The foot element may be formed from a memory material, such as Nitinol, and preset to assume a desired foot shape (e.g., upon exposure to human temperature, such as upon exposure to blood flow within the heart). One such embodiment is shown in FIGS. 13A-13H , in which a device 240 includes a steerable catheter 242, a cutting element sheath 244, and a cutting element 246, as well as a foot base element 252 having a preset memory foam shape. The foot base element 252 includes a memory shape loop 253 that surrounds and defines a foot hole 254 configured to receive the cutting element 246 when expanded. The foot base element 252 is positioned at the distal end of a flexible, elongated foot control rod 250, which may be formed as a single piece of Nitinol or other material. During the delivery configuration shown in FIG. 13A , the foot base element 252 is mechanically held in a radially compressed configuration by a hollow sheath 248. The steerable catheter 242 is advanced to a position adjacent the cardiac valve leaflet 256 to be treated, and the hollow sheath 248 is advanced from the steerable catheter 242 to a desired position, such as a position adjacent the leaflet edge 258 as shown in FIGS. 13B-13C. As the foot base element 252 is advanced distally from the hollow sheath 248, the base foot element 252 begins to expand to assume a preset memory shape, as shown in FIGS. 13D-13E. Once the foot base element 252 is fully advanced from the hollow sheath 248, the loop 253 assumes its preset memory shape to define the foot hole 254 and form a shape that can mate with the desired valve leaflet 256, as shown in FIGS. 13F-13G. Note that the preset expanded shape of the base foot element 252 is perpendicular to the elongated foot rod 250 and extends below the distal side of the valve leaflet 256. 13H, the foot base element 252 may then be moved proximally (e.g., by proximal retraction of the elongate foot rod 250) and into contact with the distal surface of the valve leaflet 256, and the cutting element sheath 244 may be advanced distally into engagement with the proximal surface of the valve leaflet 256. Thus, the valve leaflet 256 may be held between the foot base element 252 and the cutting sheath 244.The cutting element 246 can then be moved through the leaflets 236 to make the desired cut.

[0050] It should be noted that embodiments similar to those of Figures 13A-13H may be made from a non-memory material such as stainless steel and / or may be open shaped (e.g., formed by a pair of strip-like elements extending to each side of the foot hole but not completely surrounding the foot hole) as opposed to the closed loop 253 of Figures 13A-13H.

[0051] The desired dimensions (e.g., length and / or width and / or shape) of the foot base element of the device of the present invention depend on the particular application, including factors such as the dimensions of the native valve annulus and the dimensions of the native valve leaflets to be bisected, as well as the particular cut to be made in the native valve leaflets. For example, if the foot length is too short, the length of the cut that the device can make will be relatively short. If the foot is too long, the mobility of the device within the operating space (e.g., the native valve annulus) may be reduced.

[0052] Systems according to the present invention may include an embolic protection element. For example, as shown in FIG. 14 , a device 260 includes a steerable catheter 262 advanced into the aorta 40 along a guidewire 263 to a position adjacent the aortic valve 26, with a cutting element 266 extendable from a cutting element sheath 264 and a foot 270 on a foot sheath 268 extending out from the catheter 262. The device 260 includes an embolic protection filter 272 that may be slidably advanced and retracted from the catheter 262. When extended from the catheter 262, the embolic protection filter 272 may expand outward against the vessel wall and / or organ wall (e.g., an arterial wall) to capture loose material that may be dislodged during cutting of the valve leaflets.

[0053] The embolic protection filter 272 may be deployed prior to cutting of the native valve leaflets. Once cutting of the native valve leaflets is complete, the filter 272 may be retracted, such as by being retracted within the catheter 262, with the emboli retained within the filter 272. Note that the embolic protection filter, such as that shown in FIG. 14, may be incorporated into the same device / catheter as the cutting element and foot and / or may be a separate catheter.

[0054] 15 illustrates a system 280 for deploying a prosthetic heart valve 286 in a patient according to one embodiment of the present invention, in which a leaflet ablation catheter 282 (such as that shown in FIGS. 5-14) is used in conjunction with a heart valve deployment catheter 284 having a prosthetic heart valve 286 positioned in a valve-retaining portion 288 of the catheter 284. The prosthetic heart valve 286 may be radially expandable, such as being radially self-expanding (e.g., having a nitinol support frame) or radially balloon-expandable (e.g., a stainless steel or cobalt-chromium support frame). The catheter 284 may be a balloon catheter, such as having a balloon in the valve-retaining portion 288 to radially expand the prosthetic heart valve 286.

[0055] It should be noted that each element of each embodiment disclosed herein can be used with any other embodiment disclosed herein. For example, alignment magnets, such as the magnets (110, 112) discussed in connection with the embodiment of Figures 5A-5D, may be incorporated into each of the other embodiments of the present invention. Radiopaque markers or other enhanced visualization markers may be included on the device to more clearly visualize the device and its key elements when the device is deployed or inspected using fluoroscopy or other visualization techniques. For example, enhanced visualization markers, such as radiopaque markers, may be secured to portions such as sealing elements and / or anchor elements.

[0056] It should be noted that the dimensions and shape of the device and its elements depend on the particular application. For example, the dimensions and shape of the foot depend on the particular foot design and cutting element involved. Relatively narrow and long feet (e.g., 0.3-0.8 cm / less than 1 cm overall width and 0.5-2.0 cm overall length) may be used when the foot is a mechanically expandable foot, such as those shown in Figures 12A-12F, while wider feet (e.g., 1.0-2.0 cm, up to 1.5 cm, up to 2.0 cm overall width) may be used for Nitinol or similar expandable wire feet (such as those shown in Figures 13A-13H). Also, for mechanical cutting elements such as blades and rotating rods, smaller foot widths (e.g., 0.3-0.8 cm / up to 1.0 cm overall width) may provide better stability and avoid tissue stretching. However, for laser and electrocautery cutting, a wider foot (e.g., 1.0-2.0 cm, up to 1.5 cm, or up to 2 cm overall width) may be desirable to engage a larger surface area of ​​the leaflet for improved leaflet retention during cutting.

[0057] Any dimensions listed are exemplary, and devices according to the present invention may have dimensions outside of these specific values ​​and ranges. Although specific embodiments are discussed above with respect to use for bisecting the cusps of an aortic valve, embodiments of the present invention may also be applicable for use in bisecting the cusps of other heart valves, including the mitral, tricuspid, and pulmonary valves.

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. In order to facilitate review of the various embodiments of the present disclosure, the following terminology is provided.

[0059] The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. The term "or" refers to a single element or a combination of two or more elements from a stated alternative element, unless the context clearly dictates otherwise.

[0060] The term "comprises" means "has." For example, a device that includes or comprises A and B encompasses A and B, but may optionally include C or other components other than A and B. Furthermore, a device that includes or comprises A or B may encompass A or B or A and B, and may optionally include one or more other components, such as C.

[0061] The term "subject" refers to both human and other animal subjects. In certain embodiments, the subject is a human or other mammal, such as a primate, cat, dog, cow, horse, rodent, sheep, goat, or pig. In certain embodiments, the subject is a human patient.

[0062] Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of this disclosure, suitable methods and materials are described below. In case of conflict, the present specification, including the terminology, will control. Furthermore, the materials, methods, and examples are illustrative only and not intended to be limiting.

[0063] In view of the many possible embodiments to which the principles of the disclosed invention may be applied, it is to be understood that the illustrated embodiments are merely examples of the invention and should not be construed as limiting the scope of the invention. Rather, the scope of the invention is defined by the appended claims. Accordingly, everything that comes within the scope and spirit of those claims is claimed as the invention. [Explanation of symbols]

[0064] 10 Human heart 11 Myocardial wall 12 Right atrium 14 Right ventricle 16 Left atrium 18 Left ventricle 19 Apex 20 Tricuspid valve 22 Pulmonary valve 24 Mitral valve 26 Aortic valve 28 Superior vena cava 30 Inferior vena cava 32 Pulmonary artery 34 Right ventricular chordae tendineae 36 Right ventricular papillary muscle 38 Pulmonary vein 40 Aorta 42a Free edge of valve leaflet 42p Free edge of valve leaflet 44 Left ventricular chordae tendineae 46 Left ventricular papillary muscle 48 Aortic valve cusp 48L left leaflet 48R Right leaflet 48N No septum posterior leaflet 50 devices 52 Thin shaft 78 Cutting Blade Sheath 80 cutting blade member 82 Foot shaft 84 Control Handle 86 Steering control unit 88 Sliding control section 90 Sliding control section 91 Blade control unit 92 Cutting Blade 94 feet 96 Blade receiving opening 98 Distal Lip 102 distal lip tip 104 Sharp tip 106 Blade Edge 110 Magnet 120 devices 122 Steerable Catheter 124 distally extendable foot 126 Blade Sheath 128 Blades 130 Proximal Lateral Foot 132 Distal end of steering catheter, proximal surface of foot 134 pockets 136 Sharp cutting edge

Claims

[Claim 1] 10. A device for bisecting heart valve leaflets substantially as herein described with reference to the specification and accompanying drawings.

Images