Heart valve tissue dissection device

Abstract

The cardiac valve tissue dissection device includes a housing having an elongated opening formed therein, a cutting guide arm pivotally connected to the housing by a hinge assembly, the cutting guide arm having a slot formed therein, and an actuator wire coupled to the cutting guide arm. Movement of the actuator wire causes the cutting guide arm to pivot outward from the housing. A cutting element including a blade with a sharp tip is coupled to a track link configured to move along a track within the housing. An actuation slider is coupled to the elongated element and movable through a passage within the housing. Movement of the actuation slider causes the track link and cutting element to move along the track. When the track link is at one end of the track, the blade does not protrude from the housing, and when the track link is not at that end of the track, the blade protrudes from the housing.

Description

[Technical Field]

[0001] The present invention relates generally to devices and methods for transcatheter modification of bodily tissue, such as heart valve cusp tissue, for example, aortic valve cusps. [Background technology]

[0002] International Patent Application PCT / IB2020 / 054729 describes a transcatheter valve dehiscence device and method. This invention describes a method and device that can be used to perform BASILICA (Bioprosthetic or native Aortic Scallop Intentional Laceration to Prevent Iatrogenic Coronary Artery Obstruction) or LAMPOON (mitral valve) procedures. The device is a resection or division device designed to prevent damage to adjacent tissue. This device can be used in other cardiac procedures, such as tricuspid conversion of a bicuspid valve (transforming a bicuspid valve into a tricuspid valve by dehiscence or division of one of the valve leaflets), tricuspid conversion of a quadricuspid valve (transforming a tricuspid valve by dehiscence of one of the valve leaflets), or division of the anterior mitral valve leaflet (AML) to prevent left ventricular outflow tract obstruction (LVOTO), thereby preparing patients for safe transcatheter aortic or mitral valve replacement (TAVR / TMVR) or other procedures involving cardiac / vascular tissue modification. Summary of the Invention

[0003] The present invention, as described in more detail below, aims to provide devices and methods for dissecting cardiac valve tissue, such as, but not limited to, aortic valve tissue. For example, the present invention can be used in place of an electrical guidewire (the cutter used in the prior art BASILICA) to dissect across the aortic valve along the midline.

[0004] Although the device of the present invention is particularly useful for dissecting the aortic valve cusps via delivery through the aorta, the present invention can be used for dissecting any cardiac tissue from a variety of approaches, as well as dissecting cardiac tissue in other valves or portions of the heart.

[0005] The term "cutting" refers to any type of reduction in size or change in shape or form, including, but not limited to, cutting, dividing, dehiscing, slicing, crushing, chopping, etc., and the terms are used interchangeably throughout.

[0006] Thus, in accordance with a non-limiting embodiment of the present invention, there is provided a heart valve tissue dissection device comprising: a housing defining an elongated opening; a cutting guide arm pivotally attached to the housing by a hinge assembly, the cutting guide arm defining a slot; an actuator wire coupled to the cutting guide arm, wherein movement of the actuator wire causes the cutting guide arm to pivot outwardly away from the housing; a cutting element including a blade having a sharp tip, the cutting element coupled to a track link configured to move along a track within the housing; and an actuation slider coupled to an elongated element and movable within a passage within the housing, wherein movement of the actuation slider moves the track link and cutting element along the track, wherein the blade does not protrude from the housing when the track link is at one end of the track and the blade protrudes from the housing when the track link is not at one end of the track.

[0007] According to a non-limiting embodiment of the present invention, the hinge assembly comprises a four-hinge mechanism.

[0008] According to a non-limiting embodiment of the present invention, a blade protection rib is pivotally attached to the cutting guide arm, and the four-hinge mechanism includes a first hinge link pivotally attached to a first portion of the housing at a first hinge and to the blade protection rib at a second hinge, and a second hinge link pivotally attached to a second portion of the housing at a third hinge and to the cutting guide arm at a fourth hinge.

[0009] According to a non-limiting embodiment of the present invention, as the cutting guide arm pivots outward, a portion of the four-hinge mechanism passes through an elongated rib opening and through the slot.

[0010] According to a non-limiting embodiment of the present invention, the housing includes end caps that limit the movement of the four-hinge mechanism and define limits for the outward pivotal movement of the cutting guide arm. [Brief explanation of the drawings]

[0011] The present invention will be more fully understood from the following detailed description when read in conjunction with the drawings. [Figure 1] 1A, 1B, and 1C are schematic side, top, and bottom views of a heart valve tissue dissector in accordance with a non-limiting embodiment of the present invention. [Figure 2] Figure 2A is a simplified side view of a heart valve tissue dissector with the cutting guide arm pivoted outward and slotted to guide the cutting action of the cutting element. Figure 2B is a simplified side view similar to Figure 2A showing the internal components of the heart valve tissue dissector, particularly the pivoting cutting element in a stowed position within the dissector and the actuation slider coupled to the pivoting cutting assembly. [Figure 3]FIG. 3 is a simplified side view showing deployment of a cutting assembly of a heart valve tissue dissection device, in which an actuation slider is moved (e.g., moved proximally) from a first end (e.g., distal end) of the device toward a second end of the device, causing a pivoting cutting element to be deployed outward toward the cutting guide arm, with the cutting element blade about to enter a slot in the cutting guide arm. [Figure 4] 4A and 4B are simplified side and bottom perspective views, respectively, showing the actuation slider further moved toward the second end of the device with the blade of the cutting element entering the slot in the cutting guide arm. [Figure 5] 5A and 5B are simplified side and top perspective views, respectively, of the actuation slider moving further toward the second end of the device, allowing axial movement of the cutting element blade to slice tissue. [Figure 6] FIG. 6 is a simplified side view showing the cutting element blade at the limit of its axial travel. [Figure 7] 7A and 7B are simplified side views of a heart valve tissue dissector according to another non-limiting embodiment of the present invention, including a gripping member for gripping a valve leaflet or other tissue before and during cutting, with the gripping member shown in a retracted position and a deployed position, respectively. FIG. 7C is a simplified side view of the heart valve tissue dissector, with the cutting element blade deployed while the gripping member is in the deployed position. FIG. 7D is a simplified perspective view of the heart valve tissue dissector, with the gripping member in the deployed position. DETAILED DESCRIPTION OF THE INVENTION

[0012] Reference is now made to Figures 1A-1C, which illustrate a heart valve tissue dissection device 10 according to a non-limiting embodiment of the present invention.

[0013] The cardiac valve tissue dissection device is particularly useful for dissecting aortic valve tissue (such as the aortic valve cusps) by delivering it through the aorta and first stabbing or puncturing the tissue with the sharp, pointed tip of a blade located at the distal end of the device, and then moving the blade toward the proximal end (back toward the aorta) to slice the tissue axially. For this approach, the distal end is the left end in the drawings, and the proximal end is the right end in the drawings. It should be understood that distal and proximal are relative, non-limiting terms, and the invention can be used in other orientations. The invention is not limited to the aortic valve cusps. The device of the present invention can be performed in other cardiac procedures such as cutting or slicing mitral valve leaflets, tricuspidizing a bicuspid valve (dissecting or dividing one of the bicuspid valves into two leaflets to convert the bicuspid valve into a tricuspid valve), tricuspidizing a quadricuspid valve (dehiscence of one of the leaflets to convert the valve into a tricuspid valve), or dividing the anterior mitral valve (AML) to prevent LVOTO (left ventricular outflow tract obstruction), thereby preparing the patient for safe transcatheter aortic or mitral valve replacement (TAVR / TMVR) or other procedures involving cardiac / vascular tissue modification.

[0014] The heart valve tissue dissection device 10 includes a housing 12 (e.g., elongated, cylindrical), which may have rounded ends, that defines an elongated opening 14. The housing 12 may be made of medical grade stainless steel or other suitable material.

[0015] As best shown in FIG. 1C, housing 12 may include a guidewire lumen 16 along the lower axial length of housing 12 ("lower" refers to the drawing and not necessarily the lower side when the device is in use). Thus, device 10 may be delivered over a guidewire 18 passing through guidewire lumen 16. Housing 12 may include first and second end caps 13 and 15 (FIG. 1A).

[0016] The heart valve tissue dissection device 10 may include a cutting guide arm 20 (FIGS. 1A and 1B) pivotally attached to a housing 12 by a hinge assembly (described below with reference to FIGS. 2A and 2B). A blade protection rib 22 may be pivotally attached to the cutting guide arm 20 at a pivot or hinge 24 (FIG. 1B). In the retracted configuration of FIGS. 1A, 1B, and 1C, the blade protection rib 22 is located in an elongated rib opening 23 (best seen in FIGS. 1B and 5B) formed in the cutting guide arm 20. The cutting guide arm 20 may be formed with a slot 21 (see FIG. 4B) for guiding the cutting action of a cutting element, described below.

[0017] 2A and 2B, the cutting guide arm 20 may be pivotally attached to the housing 12 by a four-hinge mechanism. A first hinge link 26 may be pivotally attached to a first portion of the housing 12 at a first hinge (pivot) 25 and to the blade guard rib 22 at a second hinge 27. The second hinge 27 may be a sliding hinge in which a pin slides within a channel attached to the blade guard rib 22. A second hinge link 28 may be pivotally attached to a second portion of the housing 12 (near the first portion) at a third hinge 29 proximate to the first hinge 25 and to the cutting guide arm 20 at a fourth hinge 30. 2A and 2B, with cutting guide arm 20 pivoted outward, first hinge link 26, part of a four-hinge mechanism, passes through elongated rib opening 23 (as seen in FIG. 5B) and through slot 21 (as seen in FIG. 4B). Slot 21 is formed in a portion of cutting guide arm 20 below elongated rib opening 23 (thus, elongated rib opening 23 is not visible in FIG. 4B; again, "below" is a relative term). Second end cap 15 serves as a (proximal) stop for second hinge link 28, defining the limit of the extended position of cutting guide arm 20.

[0018] As shown in Figure 2B, an actuator wire 17 can be provided to rotate a first hinge link 26 about a first hinge (pivot) 25, thereby outwardly deploying the cutting guide arm 20. Pulling the actuator wire 17 proximally causes the cutting guide arm 20 to pivot about the first hinge 25 and the third hinge 29. Alternatively, a biasing device (such as a coil spring or leaf spring) can be used to spring-load the cutting guide arm 20 and allow it to pivot about the hinge.

[0019] Reference is now made to FIG. 3 , which illustrates the deployment of the pivoting cutting assembly. The pivoting cutting assembly may include a cutting blade 32 with a sharply pointed tip 33. A portion of the cutting blade 32 may be pivotally attached to a blade support arm 34 at a first pivot (hinge) 35, and another portion of the cutting blade 32 may be pivotally attached to a track 36 at a second pivot 37. The track 36 extends axially along the length of the housing 12. The blade support arm 34 may be coupled to a track link 38, such as by a pin or rivet 39 (or they may be integral). The track link 38 is configured to move along the track 36 by one or more pins 31 slidably received in the track 36. In the position shown in FIG. 2B , the track link 38 rests on a distal curved portion 40 of the track 36, thereby retracting the cutting blade 32 and preventing it from protruding outward. The proximal curved portion 40 of the track 36 curves from the central portion of the housing 12 toward the outer contour of the housing 12.

[0020] An actuation slider 42 is positioned for axial movement along the guidewire 18 (the bottom of the actuation slider 42 is visible in FIG. 1C). The actuation slider 42 may be coupled to a wire or other elongated element 47 (shown in FIG. 3) to move the actuation slider 42 along the guidewire 18. The elongated element may be used for pulling or pushing, or may be used only for pulling and may include a biasing device, such as a coil spring, that is compressed by proximal movement of the actuation slider 42 to return the actuation slider to its initial position.

[0021] 2B, the actuation slider 42 is near the first end cap 13. The actuation slider 42 abuts the track link 38. The actuation slider 42 is rectangular and can slide within a passageway 44 (shown in FIG. 5B) of a complementary shape corresponding to the shape of the actuation slider 42 to guide the axial movement of the actuation slider 42. For example, the cross-sectional shape of the passageway 44 can be rectangular to match the rectangular shape of the actuation slider 42, with sufficient tolerance to allow the actuation slider 42 to move easily and smoothly.

[0022] In the orientation of Figure 3, the actuation slider 42 is moved from a first end (e.g., the distal end) of the device toward a second end of the device (e.g., moved proximally as shown by arrow 43) to deploy the pivoting cutting blade 32 outward toward the cutting guide arm 20, with the blade 32 about to enter the slot in the cutting guide arm 20. In the position of Figure 3, the actuation slider 42 urges the track link 38 proximally away from the distal curved portion 40 of the track 36, which causes the blade support arm 34 to move outward and deploy the cutting blade 32 outward. The track link 38 slides down the straight portion of the track 36.

[0023] In the orientation of FIG. 3, the sharp tip 33 of the blade 32 can puncture (pierce) the heart valve tissue located between the blade 32 and the cutting guide arm 20 .

[0024] Referring now to Figures 4A and 4B, the actuation slider 42 has been moved further toward the second end of the device, and the blade 32 is now in the slot 21 (Figure 4B) of the cutting guide arm 20. The slot 21 guides the axial slicing motion of the blade 32 as it moves proximally. As shown in Figure 4B, the slot 21 may be formed with a widened portion 45 (which may be diamond-shaped or have another shape) at its distal end. This widened portion 45 absorbs any wobble of the blade at the initial puncture point and allows the blade to smoothly enter the remainder of the slot 21.

[0025] 5A and 5B, the actuation slider 42 is moved further towards the second end of the device, and axial movement of the blade 32 can slice the tissue.

[0026] 6, blade 32 is shown reaching the limit of its axial travel at first hinge link 26. At this limit, first hinge link 26 acts as an anvil to ensure blade 32 properly cuts through the full thickness of the valve leaflet or other tissue (the cutting action against this "anvil" is like the final cut on a guillotine or paper cutter).

[0027] 7A-7D, which illustrate a cardiac valve tissue dissection device 10 according to another non-limiting embodiment of the present invention. This embodiment includes a grasping member 50 for grasping the valve leaflets and other tissue before and during cutting. The grasping member 50 may be spring- or wire-driven, similar to that described herein above for deploying the cutting guide arm 20.

[0028] 7D, the gripping member 50 may include a pair of arms having ends 52 and 54 connected to one another by a bridge member 56. The cutting guide arm 20 is positioned over the desired location of the leaflet or other tissue to be cut or sliced, and the gripping member 50 is raised to hold (clamp) the leaflet or other tissue in place while the blade 32 is actuated.

Claims

1. 1. A heart valve tissue dissection device, comprising: a housing having an elongated opening formed therein; a cutting guide arm pivotally connected to the housing by a hinge assembly, the cutting guide arm having a slot formed therein; an actuator wire coupled to the cutting guide arm, wherein movement of the actuator wire causes the cutting guide arm to pivot away from the housing; and a cutting element including a blade having a sharp tip, the cutting element coupled to a track link configured to move along a track within the housing; and an actuation slider coupled to an elongated element and movable through a passage within the housing, wherein movement of the actuation slider causes the track link and the cutting element to move along the track, wherein the blade does not protrude from the housing when the track link is at one end of the track, and the blade protrudes from the housing when the track link is not at that end of the track.

2. The heart valve tissue dissection device of claim 1 , wherein the hinge assembly comprises a four-hinge mechanism.

3. 3. The cardiac valve tissue dissection device of claim 2, wherein a blade protection rib is pivotally attached to the cutting guide arm, and the four-hinge mechanism includes a first hinge link pivotally attached to a first portion of the housing at a first hinge and to the blade protection rib at a second hinge, and a second hinge link pivotally attached to a second portion of the housing at a third hinge and to the cutting guide arm at a fourth hinge.

4. The heart valve tissue dissection device of claim 3 , wherein when the cutting guide arm is pivoted outward, a portion of the four-hinge mechanism passes through an elongated rib opening and through the slot.

5. 3. The heart valve tissue dissection device of claim 2, wherein the housing includes end caps that limit the movement of the four-hinge mechanism and define limits for the outward pivotal movement of the cutting guide arm.

6. 4. The heart valve tissue dissection device of claim 3, wherein the second hinge is a sliding hinge with a pin sliding within a channel attached to the blade protection rib.

7. 7. The heart valve tissue dissection device of claim 1, wherein an end of the track where the blade does not protrude from the housing comprises a curved portion of the track that curves from a central portion of the housing toward an outer contour of the housing.

8. 8. The cardiac valve tissue dissection device according to claim 1, wherein the blade is pivotally connected to a blade support arm at a first pivot, another portion of the blade is pivotally connected to the track at a second pivot, and the blade support arm is coupled to the track link.

9. The heart valve tissue dissection device of any one of claims 1 to 8, wherein the blade moves through the slot as the cutting element moves along the track.

10. The heart valve tissue dissection device of any one of claims 1 to 9, further comprising a gripping member for gripping the valve leaflet or other tissue before and during cutting.

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