Transcatheter valve dehiscence devices and methods

Abstract

The transcatheter valve dehiscence device (10, 100) comprises a leaflet support frame (12, 112) and a leaflet dissector assembly (14, 114), both of which are movably attached to a guide structure (16, 116) and movable between a contracted orientation and an expanded orientation, in which a blade protector (24, 124) of the leaflet support frame (12, 112) is positioned over a dissector element (36, 136) of the leaflet dissector assembly (14, 114).

Description

[Technical field]

[0001] The present invention relates generally to a transcatheter device and method for dehiscence of heart valve cusps, such as aortic valve cusps. [Background technology]

[0002] Transcatheter aortic valve replacement (TAVR) is used to treat congenital aortic stenosis. TAVR is also an effective treatment for failing bioprosthetic surgical aortic valves, a procedure known as valve-in-valve TAVR.

[0003] A complication of TAVR is known as coronary occlusion, which occurs when the transcatheter heart valve displaces the underlying surgical or native aortic valve cusps outward, resulting in a lower coronary ostium and insufficient sinus width, obstructing the coronary ostium by blocking the sinuses of Valsalva at the coronary anastomosis or by the valve cusps covering the coronary ostium themselves. Coronary occlusion is much more common in valve-in-valve TAVR ("TAVR-in-TAVR") than in TAVR for congenital aortic stenosis. A possible reason is that most surgical prostheses are supra-annular in shape, resulting in a lower coronary height compared to the valve cusps, and the valve sutures may pull the coronary arteries back, narrowing the sinus width. Another possible reason is that valve-in-valve TAVR in patients with a large aortic root may allow blood to bypass the old valve to reach the coronary arteries. However, in some patients with a small aortic root and low coronary arteries, the cusps of a dysfunctional surgical bioprosthesis may obstruct blood flow to the coronary arteries.

[0004] Khan et al., "Transcatheter Laceration of Aortic Leaflets to Prevent Coronary Obstruction During Transcatheter Aortic Valve Replacement," Journal of the American College of Cardiology, Cardiovascular Interventions, Vol. 11, No. 7, 2018, April 9, 2018, pp. 677-689, presents a new procedure to address these issues.

[0005] The electrosurgery procedure is called BASILICA (Bioprosthetic or native Aortic Scallop Intentional Laceration to prevent Iatrogenic Coronary Artery obstruction). BASILICA uses a powered guidewire threaded through a catheter to cut open the leaflets of a patient's dysfunctional bioprosthetic valve. Cutting the leaflets before TAVR allows blood to flow through the split leaflets into the coronary arteries when the new valve is deployed. Summary of the Invention

[0006] The present invention aims to provide a transcatheter valve laceration device and method. The present invention is a method and device that can be used to perform BASILICA. The device is a laceration device that takes care to prevent damage to adjacent tissue. The device of the present invention can be performed in other cardiac procedures such as tricuspidization of a bicuspid valve (changing a bicuspid valve into a tricuspid valve by dissecting or splitting one of the leaflets into two) or tricuspidization of a quadricuspid valve (dehiscing one of the leaflets to change the valve into a tricuspid valve), thereby preparing the patient for a safe TAVR or other procedure involving dissection of cardiac tissue.

[0007] According to a non-limiting embodiment of the present invention, a transcatheter valve dehiscence device includes a dissection element attached to a guide structure. The dissection element is expandable and contractable relative to the guide structure. The guide structure can be delivered to a heart valve and the dissection element expanded and moved toward the valve leaflets (in a direction different from the direction of expansion) to dissect them. A support structure can be provided opposite the leaflets to act as an "anvil" for the cutting force of the dissection element and to protect tissue that should not be cut from the dissection element. [Brief description of the drawings]

[0008] The present invention will be more fully understood from the following detailed description taken in conjunction with the drawings in which: [Figure 1] FIG. 1 is a simplified diagram of a transcatheter valve splitting device, constructed and operative in accordance with a non-limiting embodiment of the present invention, in a stowed (contracted) orientation for deployment to a surgical site. [Diagram 2] FIG. 2 is a simplified diagram of the transcatheter valve dehiscence device in the deployed (expanded) orientation used to dehiscence valves in situ. [Diagram 3] FIG. 3 is another view of the unfolded orientation. [Figure 4] 4A and 4B are simplified diagrams of a leaflet tomography assembly in respective retracted (contracted) and deployed (expanded) orientations. [Diagram 5] 5A and 5B are simplified diagrams of the sheathed delivery system during and after introduction into the aortic valve, respectively. [Figure 6] 6A and 6B are simplified diagrams of the delivery system after removal of the sheath in different perspective views. [Figure 7] 7A and 7B are simplified diagrams of the leaflet support frame of the deployed device, with FIG. 7A showing in situ deployment at the valve site and FIG. 7B showing the deployed device itself. [Figure 8]Figure 8 is a simplified diagram of the leaflet support frame and leaflet dissection assembly positioned in situ at the valve site. [Figure 9] 9A-9E are simplified illustrations of a method of splitting an aortic valve leaflet using a transcatheter valve splitting device. FIG. 9A is a simplified illustration of a transcatheter valve splitting device introduced and positioned in an aortic valve in its contracted orientation. FIG. 9B is a simplified illustration of a leaflet support frame deployed (expanded) on one side of the aortic valve and a leaflet dissector assembly in a contracted orientation within the aortic valve. FIG. 9C is a simplified illustration of a leaflet support frame expanded and positioned against one side of the aortic valve and a leaflet dissector assembly still in a contracted orientation on the other side of the aortic valve. FIG. 9D is a simplified illustration of the leaflet dissector assembly deployed and expanded radially outward. FIG. 9E is a simplified illustration of the leaflet dissector assembly moved axially to cut the leaflets. [Figure 10] FIG. 10 is a simplified diagram of a transcatheter valve opening device, constructed and operative in accordance with another non-limiting embodiment of the present invention. [Figure 11] FIG. 11 is a simplified diagram of a flattened aortic valve illustrating the ability to control the splitting device and the location at which the cutting element begins to cut the leaflet tissue. [Figure 12] Figure 12A is a simplified diagram of the native tricuspid valve complex, where θ represents the angle defining the distance from the native commissure to the desired incision location, and Figure 12B is a simplified diagram of the native bicuspid valve complex. [Figure 13] 13A-13G are simplified diagrams of a method for dehiscencing native valve tissue as a precursor to TAVI, according to another non-limiting embodiment of the present invention. [Figure 14] FIG. 14 is a simplified diagram of a transcatheter valve opening device, constructed and operative in accordance with another non-limiting embodiment of the present invention. [Figure 14]

[0031] Figures 14A and 14B are simplified exploded and schematic views, respectively, of the leaflet dissector assembly of the device of Figure 14. Figure 14C is a simplified diagram of the leaflet dissector assembly pivotally coupled to opposite ends of a first biasing device at pivot joints. Figures 14D and 14E are simplified diagrams of the leaflet dissector assembly assembled with a distal spring and frame. Figure 14F is a simplified exploded view of the leaflet support frame of the device of Figure 14. Figure 14G is a simplified diagram of the leaflet support frame attached to the frame. Figure 14H is a simplified diagram of the completed device with blade protector. [Figure 15] FIG. 15 is a simplified diagram of the leaflet support frame being moved distally towards the leaflet tomography assembly causing the leaflet support frame to expand radially outward. [Figure 16] 1 is a simplified diagram of an initial radial outward expansion of the leaflet tomography assembly; [Figure 17] FIG. 17 is a simplified diagram of further expansion of the leaflet dissector assembly, ultimately resulting in the tip of the dissector element approaching the blade protector of the leaflet support frame. [Figure 18] FIG. 18 is a simplified diagram of further expansion of the leaflet dissector assembly, ultimately resulting in the tip of the dissector element approaching the blade protector of the leaflet support frame. [Figure 19] 19A and 19B are simplified diagrams of a transcatheter valve dehiscence device constructed and operative in accordance with another non-limiting embodiment of the invention, shown in a contracted and expanded orientation, respectively, in which the leaflet tomography assembly is constructed as a foldable hinged parallelogram. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Reference is now made to Figures 1-3, which illustrate a transcatheter valve splitting device 10, constructed and operative in accordance with a non-limiting embodiment of the present invention.

[0010] The device 10 comprises a leaflet support frame 12 and a leaflet tomography assembly 14, both of which are attached to a guide structure 16 (FIG. 1).

[0011] In the embodiment shown in Figures 2 and 3, the leaflet support frame 12 comprises a strut arm 18 pivotally coupled at one end to a first portion 19 of a support frame tube 20 (which is part of the guide structure 16) at a pivot joint 22 and coupled at its opposite end to a blade protector 24. The blade protector 24 may be formed as a hemispherical tube. The strut arm 18 and the blade protector 24 may be collinear or angled relative to each other. An actuator arm 26 has one end pivotally coupled to the second portion 21 of the support frame tube 20 at a pivot joint 28 and an opposite end pivotally coupled to the strut arm 18 at a pivot joint 30.

[0012] In the embodiment shown in Figures 2 and 3, there are two or more strut arms 18 (three are shown spaced 120° apart, but there may be one, two, or any other number, and not necessarily symmetrically spaced relative to the guide structure). Only one of the strut arms 18 is coupled to the blade protector 24 (because there is only one cutting element), and each of the other strut arms 18 is coupled to a positioning member 32 that does not need to protect tissue from the cutting element, but may be useful for properly positioning, self-centering, and aligning the leaflet support frame 12 relative to the valve structure. The strut arms 18 may have a double arm structure, employing two parallel arms. An actuator arm 26 is disposed between the parallel arms and pivotally coupled to both of them at a pivot joint 30.

[0013] In the embodiment shown in Figures 2 and 3, the leaflet dissector assembly 14 includes a dissector element 36 extending from a blade arm 38. The dissector element 36 and the blade arm 38 may be collinear or may be angled relative to one another. The dissector element 36 has a pointed, sharp tip 37. The blade arm 38 has one end pivotally coupled to a first portion 39 of a first biasing device 40 (which is part of the guide structure 16) at a pivot joint 42. A blade actuator arm 44 is pivotally coupled at one end to a separator tube 41 at a pivot joint 46 and at an opposite end to the blade arm 38 at a pivot joint 48. The separator tube 41 separates the first biasing device 40 from the second biasing device 50. The second biasing device 50 extends from the second portion 21 of the support frame tube 20 to the separator tube 41.

[0014] In the embodiment shown in Figures 2 and 3, there are two or more blade arms 38 (three are shown spaced 120° apart, but there may be one, two, or any other number, not necessarily symmetrically spaced with respect to the guide structure). Only one cutting element 36 is coupled to one blade arm 38, but in other embodiments, two or more cutting elements 26 may be used. The blade arm 38 may have a double arm structure, in which case two parallel arms are used, and instead of the cutting element 36, an auxiliary arm 47 (Figure 3) is disposed between the parallel arms and pivotally coupled to the blade actuator arm 44 at a pivot joint 48. The blade actuator arm 44 may also have a double arm structure (two parallel arms). Now, reference is made to Figures 4A and 4B. In Figure 4A, the leaflet dissector assembly 14 is in a retracted (contracted) orientation. In this orientation, the cutting element 36 is between the double arms of the blade actuator arm 44. Thus, the blade actuator arm 44 acts as a cutting element protector in the stowed position of the device, preventing delicate tissue from being accidentally cut by the cutting element 36. The first biasing device 40 may be comprised of a repeating series of arcuate (e.g., wavy or sinusoidal) elements 43 wrapped at least partially around the actuator tube 45.

[0015] In the illustrated embodiment, there are two or more rows of arcuate elements 43 that together wrap around the circumference of the tube 45. The arcuate elements 43 may be made of a resilient material, such as Nitinol, and have a constant spring force. In the retracted position, the arcuate elements 43 of the first biasing device 40 are in tension and exert a tensile force on the blade arm 38 and the actuator arm 44, causing them to be normally "closed" (i.e., in a contracted orientation).

[0016] The actuator tube 45 has a distal cap 49 against which the distal-most arcuate element 43 abuts. The actuator tube 45 is axially movable relative to the support frame tube 20 (FIG. 2), and the actuator tube 45 can slide within the support frame tube 20.

[0017] Similar to the first biasing device 40, the second biasing device 50 may be constructed from a repeating series of arcuate (e.g., wavy or sinusoidal) elements 53 (FIG. 3) wrapped at least partially around the tube 20. The spring force of the first biasing device 40 is greater than the spring force of the second biasing device 50 (such as a 4:1 ratio, although the invention is not limited to this ratio).

[0018] In Figure 4B, the leaflet dissector assembly 14 is in a deployed (extended) orientation. This can be achieved by moving the actuator tube 45 proximally (towards the leaflet support frame 12). This action compresses the arcuate element 43 of the biasing device 40. The blade actuator arm 44 is now angled relative to the tube 45 (arms 38, 44 and tube 45 form a triangular structure) to act as a guiding surface over which the leaflet tissue slides towards the sharp tip 37 (and edge) of the dissector element 36.

[0019] Thus, the guide structure 16 includes tubes 20 and 45 .

[0020] 5A and 5B, the transcatheter valve splitting device 10 is shown covered by a sheath 52 during and after introduction, respectively, into the aortic valve 51. In FIGS. 5A and 5B, the left side of the aortic valve 51 is the aortic side and the right side is the left ventricular side. FIGS. 6A and 6B show the delivery system after the sheath has been removed (the sheath 52 has been moved proximally). The device 10 may include a blunt portion 54 distal to the leaflet splitting assembly 14.

[0021] 7A and 7B, a deployed leaflet support frame 12 is shown. FIG. 7A shows the device deployed in situ at the valve site, and FIG. 7B shows the device deployed with the valve omitted. This deployment is accomplished by moving the actuator tube 45 (FIGS. 2 and 3) proximally towards the leaflet support frame 12. As noted above, due to the fact that the spring force of the first biasing device 40 is greater than the spring force of the second biasing device 50, as the actuator tube 45 moves proximally, the stronger first biasing device 40 will not compress and the weaker second biasing device 50 will compress first. As the actuator tube 45 moves proximally, the actuator arms 26 (FIGS. 2 and 3) move radially outward, thereby deploying the strut arms 18 and the blade protector 24 radially outward. Because the first biasing device 40 has not yet been compressed, the dissection element 36 remains in the closed, stowed position.

[0022] 8. Further proximal movement of the actuator tube 45 compresses the first biasing device 40. This further movement of the actuator tube 45 results in deployment of the blade actuator arms 44, which in turn deploys the blade actuator arms 38 and the cutting element 36, which expand radially outward against the leaf tissue of the aortic valve 51. The sharp distal tip 37 of the cutting element 36 pierces the leaflet tissue.

[0023] 9A-9E, a method of splitting the aortic valve cusps using a transcatheter valve splitting device 10 is shown.

[0024] In FIG. 9A, device 10 has been introduced and placed in its contracted orientation at aortic valve 51.

[0025] In FIG. 9B, the leaflet support frame 12 is deployed (expanded) to one side (the aortic side) of the aortic valve, and the leaflet dissection assembly 14 remains in a contracted orientation at the aortic valve 51.

[0026] In FIG. 9C, the leaflet support frame 12 is expanded and positioned against one side of the aortic valve 51 (the aortic side) while the leaflet dissection assembly 14 is still in a contracted orientation on the other side of the aortic valve 51 (the left ventricular side).

[0027] In FIG. 9D, the leaflet tomography assembly 14 is deployed and expanded radially outward.

[0028] 9E, the leaflet tome assembly 14 is moved axially (proximal direction 57) to dehiscence one or more leaflets. After the procedure is completed, the actuator tube 45 is moved distally to retract the leaflet tome assembly 14 and leaflet support frame 12. The biasing force of the first biasing device 40 assists in the retraction of the leaflet tome assembly 14. The biasing force of the second biasing device 50 assists in the retraction of the leaflet support frame 12.

[0029] In summary, the device 10 with three strut arms and three blade arms has a triangular tripod structure for actuating the cutting elements, where axial movement is converted into an expanding movement of the tripod. The symmetrical spacing of the strut arms allows the device to self-position at the tip of the valve. The support frame structure expands so that the sharp tips of the blades (cutting elements) spread under the blade protector, allowing the blades to penetrate and protect the adjacent tissue. The blade action punctures the leaflets of the aortic valve, and then the axial proximal movement (pulling) of the frame and blade structure splits the leaflets by the blade structure forcing the centerline of the leaflets to split by the sharp blades. This fully hinged mechanism allows the mechanism to be retracted and covered by the catheter tube of the delivery system. Other embodiments can be based on other radial and non-radial bending methods.

[0030] Single or multiple protector elements or blades may be used. A constant force biasing device biases the mechanism to normally close (retracted) in the mechanism.

[0031] The puncture of the leaflet is performed with a circular upward movement of the blade tip from inside the left ventricle towards the convex surface of the leaflet. In this way, the cutting element punctures the leaflet while the blade protector prevents the tip of the cutting element from extending into the aorta, thus preventing damage to the aortic complex. The deployment and positioning of the support frame can be performed within the sinoaortic junction (STJ) volume, with minimal contact with adjacent elements of the aortic complex.

[0032] One embodiment of the support framework can include features and struts to prevent the leaflets from completely closing during the dissection action, which is done to fully dissect the leaflets along the axial direction.

[0033] Reference is now made to Figure 10, which illustrates a transcatheter valve splitting device, constructed and operative in accordance with another non-limiting embodiment of the present invention. The device includes one or more tissue splitting elements configured to radially expand from a contracted position (during delivery to a target site) to an expanded position (during a splitting operation).

[0034] The splitting device comprises a support element deployable on the aortic (downstream) side of the aortic valve and a dissection blade positioned on the ventricular side of the valve, specifically the outflow tract. The support element can be radially controlled to land on the aortic sinuses in a manner that defines the length of the split and the radial extent of the cut. Additionally, the orientation of the cut relative to the centerline of the valve leaflets can be adjusted.

[0035] FIG. 11 is a diagram of a flattened aortic valve showing the controllability of the dehiscence device and its ability to control the location at which the cutting element begins to cut the leaflet tissue. By adjusting the radial expansion of the support element, the depth to which the cutting element penetrates the ventricular leaflet can be controlled. Additionally, the rotational position of the support arm can be adjusted to make "off-center" cuts if multiple cuts are required.

[0036] 12A is a schematic diagram of the native tricuspid aortic valve complex. θ represents the angle that defines the distance from the native commissure to the intended cut location. Manipulation of θ also defines the cut length (r).

[0037] Figure 12B is a schematic diagram of the native bicuspid aortic valve complex. The shaded area represents the raphe, a thickened area located approximately in the middle of the larger of the two valve leaflets. The shape and thickness of the raphe often influence the degree and progression of valve degeneration. Figure 12B shows two dotted lines representing longitudinal cuts designed to free the area around the raphe to facilitate implantation of a prosthetic valve.

[0038] 13A-13G show a method of dehiscencing native valve tissue as a prelude to TAVI. Fig. 13A shows a tissue dehiscence device introduced into the native valve complex with a support element positioned and set in a specific orientation on the aortic side of the leaflets, with the majority positioned in the sinuses of Valsalva. The dehiscence element is positioned in the ventricular outflow tract such that one or more dehiscence tacks (dissection elements) face the native leaflets.

[0039] 13B shows the tack being inserted through the leaflet tissue and into a corresponding tack holder in the support element arm. The support element is then retracted with the tack still in the leaflet tissue with its tip secured firmly in the tack holder.

[0040] FIG. 13C is a close-up of the tacks that have entered the leaflets, with their tips secured within the tack holder.

[0041] Figure 13D shows the dehiscence device in place within the native valve complex and tethered by a separate wire to an external handle (not shown). Figure 13E shows the implantation process of a self-expanding TAVI valve (a self-expanding valve is shown, but any TAVI device can be used). The valve is shown partially open, still partially captured in the delivery system. The surgeon can position the prosthetic valve in the desired position prior to dehiscence of the native leaflets before fully releasing the prosthetic valve.

[0042] FIG 13F shows the native leaflets with the dehiscence tack inserted before and after the dehiscence procedure. As shown, the native leaflets are cut longitudinally. This dehiscence step is performed by pulling the outer end of the wire connecting the tack. Pulling the wire causes the tack and its tack holder to move cranially and dehisc the calcified native leaflets.

[0043] FIG. 13G shows the final step of TAVI, where the prosthesis is completely released after the dehiscence step.

[0044] Reference is now made to Fig. 14, which illustrates a transcatheter valve opening device 100, constructed and operative in accordance with a non-limiting embodiment of the present invention. Device 100 is similar to device 10, with differences as described below.

[0045] The device 100 comprises a leaflet support frame 112 and a leaflet dissection assembly 114, both of which are attached to a guide structure 116 (FIG. 14). Subassemblies of the device 100 of FIG. 14 will now be described with reference to FIGS. 14A-14H.

[0046] As shown in Figures 14A and 14B, the leaflet dissector assembly 114 includes a dissector element 136 extending from a blade arm 138. The dissector element 136 and the blade arm 138 may be collinear or angled relative to one another. The dissector element 136 has a pointed, sharp tip 137. The blade arm 138 may be fixed to the first blade support arm 103 (in the illustrated embodiment, it is fixed to a pair of first blade support arms 103), such as by a pin 105 or in other manner. The blade arm 138 may be pivotally coupled to the second blade support arm 107 (in the illustrated embodiment, it is pivotally coupled to a pair of second blade support arms 107), such as by another pin 105 or in other manner.

[0047] The assembly of the first blade support arm 103 pivotally coupled to the second blade support arm 107, without the cutting element 136 or blade arm 138, is referred to as a multi-arm assembly. As will become apparent from the following description, the multi-arm assembly may be used multiple times in the device 100, reducing manufacturing and inventory costs by using identical parts. Alternatively, the positioning arm support struts 103 and 107 may be constructed in a similar manner as the cutting assembly, but with different sizes. As shown in FIG. 14C (similar to that described for the device 10 of FIG. 4A), the leaflet cutting assembly 114 (including the cutting element 136 and the blade arm 138) is pivotally coupled at one end to both ends of the first biasing device 140 (which is part of the guide structure 116) at pivot joints 142 and 146. The first biasing device 140 may be formed from or coupled to the distal slider tube 141. The first biasing device 140 provides, among other things, a safety feature. That is, after the device has been used to cut tissue, first biasing device 140 retracts so that the assembly of first blade support arm 103 and second blade support arm 107 returns to a contracted state and does not protrude outwardly to traumatize nearby tissue. Thus, in the contracted state, first biasing device 140 acts as a limiter that limits the amount that cutting element 136 can move radially outward.

[0048] 14D and 14E, the distal spring 121 may be mounted over the distal slider tube 141. The leaflet dissection assembly 114 may be mounted to a frame 157 having an opening face 159. A frame plug 155 may be attached to the distal slider tube 141 between the distal end of the frame 157 and the proximal end of the distal spring 121.

[0049] As shown in FIG. 14F, the leaflet support frame 112 includes a pair of multi-arm assemblies 119 pivotally coupled to first and second pivot joints 122 and 123 secured to the spacer frame tube 120 (which is part of the guide structure 116). The second biasing device 150 is disposed on or part of the spacer frame tube 120 and is disposed between the first and second pivot joints 122, 123. Like the first biasing device 140, the second biasing device 150 provides, among other things, a safety function. That is, after the device is used to cut tissue, the second biasing device 150 retracts so that the assembly of the first blade support arm 103 and the second blade support arm 107 returns to a contracted state and does not protrude outwardly and injure nearby tissue. Thus, in the contracted state, the second biasing device 150 acts as a limiter that limits the amount that the positioning arms 103 and 107 of the multi-arm assembly 119 can move radially outward.

[0050] 14G, the multi-arm assembly 119 of the leaflet support frame 112 and the spacer frame tube 120 are attached to the frame 157. A guide spring 160 may be attached to the proximal end of the spacer frame tube 120.

[0051] As shown in FIG. 14H, the strut arm 118 from which the blade protector 124 extends may be secured to the first blade support arm 103 of the multi-arm assembly 119 (the arm on the same side as the opening 159). As with the device 10, the blade protector 124 may be formed as a hemispherical tube, and the strut arm 118 and the blade protector 124 may be collinear or angled relative to one another. A cable assembly 170, which may be made from a shape memory alloy such as Nitinol, may be coupled to the guide structure 116 adjacent the distal end of the distal spring 121. The cable assembly 170 may assist the distal spring 121 in collapsing the dissection element 136 and the multi-arm assembly 119 if any difficulty occurs in contracting the assembly.

[0052] Referring again to Figure 14, the device 100 is delivered to the surgical site with a sheath (not shown) covering the leaflet support frame 112 and the leaflet dissection assembly 114, such that the device 100 is delivered as a thin tubular structure. Figure 14 shows the device 100 after the sheath has been removed. This initially causes the blade protector 124 to expand (move) radially outward, as shown in Figure 14. In this initial position, the leaflet support frame 112 is axially spaced proximally from the leaflet dissection assembly 114.

[0053] 15. The guide structure 116 (such as, but not limited to, a stainless steel or Nitinol wire or tube) is moved distally such that the leaflet support frame 112 moves distally towards the leaflet dissection assembly 114. The distal end (distal arm 103) of the leaflet support frame 112 may abut an abutment 99 formed at the distal end of the opening 159 of the frame 157. The abutment 99 may act as a safety stop to limit the outward movement of the blade protector 124. Note that a distal end portion of the blade protector 124 is disposed over the tip 137 of the dissection element 136.

[0054] The spring force of biasing devices 140 and 121 is greater than the spring force of biasing devices 150 and 160 (such as a 2:1 ratio, although the invention is not limited to this ratio), such that leaflet support frame 112 expands outward before leaflet tomography assembly 114 begins to expand outward.

[0055] Referring now to Figure 16, as the guide structure 116 moves further distally, it begins to compress the first biasing device 140 and distal spring 121 (not shown), causing the leaflet dissection assembly 114 to begin to expand radially outward.

[0056] 17 and 18 show the leaflet dissection assembly 114 further expanded until the tip 137 of the dissection element 136 approaches the blade protector 124. The device 100 can be used to dehisce tissue as described for device 10.

[0057] 19A and 19B, there is shown a transcatheter valve dehiscence device 200, constructed and operative in accordance with another non-limiting embodiment of the present invention. As with the other embodiments, the device 200 includes a leaflet support frame 212 and a leaflet dissector assembly 214. The leaflet dissector assembly 214 may be constructed as a foldable hinged parallelogram 218 in which axial motion is translated into radial motion to effect the dissection of the leaflets.

[0058] The leaflet support frame 212 can be a triangular frame support structure that supports the leaflets by self-locating on the leaflets due to the shape of the support members of the frame 212 (e.g., approximately 120° apart). This support frame structure allows for the blades to penetrate and align by ensuring that they pass through the dual-strut design of the frame. After penetrating the aortic leaflets, the blades press the leaflets against the support frame 212, creating an anvil-like action to incise the leaflets.

[0059] The fully hinged mechanism allows the mechanism to be folded and covered onto the catheter tube of the delivery system. Other embodiments can be based on other radial and non-radial bending methods.

[0060] The incision element is configured as a three-lobe mechanism that allows for 120° simultaneous positioning of all leaflet incisions.

[0061] Actuation of the leaflet support frame 212 and leaflet tomography assembly 214 can be accomplished by moving two coaxial tubes in opposite directions.

[0062] A constant force biasing device 216 (such as, but not limited to, a Nitinol tube-based spring) can preload one or more blades of the leaflet torsion assembly 214 mechanism in a normally closed or collapsed position. In the loaded position, the biasing device 216 acts as a centering and radial support for the LVOT (left ventricular outflow tract) wall.

[0063] As with other embodiments of the present invention, leaflet puncture can be performed from within the left ventricle while circularly moving the blade tip towards the aorta to prevent damage to the aortic complex. With the support of the frame, the dissector blade can dissect the leaflets at any desired location without exerting force on the annular ring of the leaflets. The deployment and positioning of the support frame can be performed within the STJ (sinoascending junction) volume. An indicator may be placed on the actuation handle to indicate when the dissection operation is complete.

Claims

1. A transcatheter valve dehiscence device (10, 100), comprising: The valve includes a leaflet support frame (12, 112) and a leaflet dissection assembly (14, 114), both of which are movably attached to a guide structure (16, 116), the leaflet support frame (12, 112) and the leaflet dissection assembly (14, 114) being movable between a contracted orientation and an expanded orientation, and the leaflet dissection assembly (14, 114) being movable between a contracted orientation and an expanded orientation when only the leaflet support frame (12, 112) is in the expanded orientation. a blade protector (24, 124) of the leaflet support frame (12, 112) configured to support the valve leaflet (12, 112) and a blade tip (37, 137) of the cutting element (36, 136) of the leaflet cutting assembly (14, 114) piercing the leaflet while the leaflet cutting assembly (14, 114) moves from the contracted orientation to the expanded orientation, and the sharp tip (37, 137) of the cutting element (36, 136) is covered by a blade protector (24, 124) of the leaflet support frame (12, 112).

2. 2. The transcatheter valve splitting device of claim 1, wherein in the expanded orientation, the blade protector is positioned more radially outwardly relative to the guide structure than in the expanded orientation of the dissection element relative to the guide structure.

3. 3. The transcatheter valve dehiscence device (10, 100) of claim 1 or 2, wherein a valve leaflet pierced by the pointed sharp tip (37, 137) is located between the dissection element (36, 136) and the blade protector (24, 124), such that the dissection element (36, 136) is configured to dehiscence a valve leaflet located between the dissection element (36, 136) and the blade protector (24, 124).

4. 4. The transcatheter valve splitting device of claim 1, wherein the leaflet tometrotomy assembly comprises a support arm coupled to a first biasing device, the leaflet support frame comprises a frame arm coupled to a second biasing device, wherein contraction of the first biasing device causes deployment of the support arm relative to the guide structure and expansion of the leaflet tometrotomy assembly, and contraction of the second biasing device causes deployment of the frame arm relative to the guide structure and expansion of the leaflet support frame.

5. 5. The transcatheter valve splitting device of claim 4, wherein the first biasing device has a stronger biasing force than the second biasing device.

6. 6. The transcatheter valve dehiscence device of claim 1, wherein support elements of the leaflet support frame are controllable to define the length of the cut made by the leaflet tome assembly and to adjust the orientation of the cut made by the leaflet tome assembly relative to a leaflet centerline.

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