Heart valve sealing devices and delivery devices therefor

Abstract

An implantable prosthetic device such as might be used to treat poor function of a diseased heart valve in a medical patient includes a body portion and an anchor portion including a plurality of paddles. Clasps attached to the paddles include fixed arms and moveable arms operable to secure the device to the patient's native valve leaflets.

Description

TECHNICAL FIELD

The present application relates generally to prosthetic devices and related methods for helping to seal native heart valves and prevent or reduce regurgitation therethrough, as well as devices and related methods for implanting such prosthetic devices.

BACKGROUND OF THE INVENTION

The native heart valves (i.e., the aortic, pulmonary, tricuspid, and mitral valves) serve critical functions in assuring the forward flow of an adequate supply of blood through the cardiovascular system. These heart valves can be damaged, and thus rendered less effective, by congenital malformations, inflammatory processes, infectious conditions, or disease. Such damage to the valves can result in serious cardiovascular compromise or death. For many years the definitive treatment for such damaged valves was surgical repair or replacement of the valve during open heart surgery. However, open heart surgeries are highly invasive and are prone to many complications. Therefore, elderly and frail patients with defective heart valves often went untreated. More recently, transvascular techniques have been developed for introducing and implanting prosthetic devices in a manner that is much less invasive than open heart surgery. One particular transvascular technique that is used for accessing the native mitral and aortic valves is the transseptal technique. The transseptal technique comprises inserting a catheter into the right femoral vein, up the inferior vena cava and into the right atrium. The septum is then punctured and the catheter passed into the left atrium. Such transvascular techniques have increased in popularity due to their high success rates.

A healthy heart has a generally conical shape that tapers to a lower apex. The heart is four-chambered and comprises the left atrium, right atrium, left ventricle, and right ventricle. The left and right sides of the heart are separated by a wall generally referred to as the septum. The native mitral valve of the human heart connects the left atrium to the left ventricle. The mitral valve has a very different anatomy than other native heart valves. The mitral valve includes an annulus portion, which is an annular portion of the native valve tissue surrounding the mitral valve orifice, and a pair of cusps, or leaflets, extending downward from the annulus into the left ventricle. The mitral valve annulus can form a “D”-shaped, oval, or otherwise out-of-round cross-sectional shape having major and minor axes. The anterior leaflet can be larger than the posterior leaflet, forming a generally “C”-shaped boundary between the abutting free edges of the leaflets when they are closed together.

When operating properly, the anterior leaflet and the posterior leaflet function together as a one-way valve to allow blood to flow only from the left atrium to the left ventricle. The left atrium receives oxygenated blood from the pulmonary veins. When the muscles of the left atrium contract and the left ventricle dilates (also referred to as “ventricular diastole” or “diastole”), the oxygenated blood that is collected in the left atrium flows into the left ventricle. When the muscles of the left atrium relax and the muscles of the left ventricle contract (also referred to as “ventricular systole” or “systole”), the increased blood pressure in the left ventricle urges the two leaflets together, thereby closing the one-way mitral valve so that blood cannot flow back to the left atrium and is instead expelled out of the left ventricle through the aortic valve. To prevent the two leaflets from prolapsing under pressure and folding back through the mitral annulus toward the left atrium, a plurality of fibrous cords called chordae tendineae tether the leaflets to papillary muscles in the left ventricle.

Mitral regurgitation occurs when the native mitral valve fails to close properly and blood flows into the left atrium from the left ventricle during the systolic phase of heart contraction. Mitral regurgitation is the most common form of valvular heart disease. Mitral regurgitation has different causes, such as leaflet prolapse, dysfunctional papillary muscles and/or stretching of the mitral valve annulus resulting from dilation of the left ventricle. Mitral regurgitation at a central portion of the leaflets can be referred to as central jet mitral regurgitation and mitral regurgitation nearer to one commissure (i.e., location where the leaflets meet) of the leaflets can be referred to as eccentric jet mitral regurgitation.

Some prior techniques for treating mitral regurgitation include stitching portions of the native mitral valve leaflets directly to one another. Other prior techniques include the use of a spacer implanted between the native mitral valve leaflets. Despite these prior techniques, there is a continuing need for improved devices and methods for treating mitral valve regurgitation.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present invention will become better understood with regard to the following description and accompanying drawings in which:

FIGS. 1-6 show an implantable prosthetic device according to a first embodiment, in various stages of deployment;

FIGS. 7-12 show the implantable prosthetic device of FIGS. 1-6 being delivered and implanted within the native mitral valve;

FIG. 13 shows another implantable prosthetic device according to a second embodiment;

FIGS. 14-25 show another implantable prosthetic device according to a third embodiment being delivered and implanted within the native mitral valve;

FIG. 26 shows a barbed clasp for an implantable prosthetic device according to one embodiment;

FIG. 27 shows a barbed clasp for an implantable prosthetic device according to a second embodiment;

FIG. 28 shows a barbed clasp for an implantable prosthetic device according to a third embodiment;

FIGS. 29-31 show a side view of barbed clasp for an implantable prosthetic device in various stages of bending;

FIG. 32 shows a barbed clasp for an implantable prosthetic device according to a fourth embodiment;

FIG. 33 shows a barbed clasp for an implantable prosthetic device according to a fifth embodiment;

FIG. 34 shows a barbed clasp for an implantable prosthetic device according to a sixth embodiment;

FIG. 35 shows a barbed clasp for an implantable prosthetic device according to a seventh embodiment; and

FIG. 36 shows a barbed clasp for an implantable prosthetic device according to an eighth embodiment.

DETAILED DESCRIPTION

As described herein, when one or more components are described as being connected, joined, affixed, coupled, attached, or otherwise interconnected, such interconnection may be direct as between the components or may be indirect such as through the use of one or more intermediary components. Also as described herein, reference to a “member,” “component,” or “portion” shall not be limited to a single structural member, component, or element but can include an assembly of components, members, or elements. Also as described herein, the terms “substantially” and “about” are defined as at least close to (and includes) a given value or state (preferably within 10% of, more preferably within 1% of, and most preferably within 0.1% of).

A prosthetic spacer device has spacer body and at least one anchor. The body is configured to be positioned within the native mitral valve orifice to help form a more effective seal between the native leaflets, thereby reducing or preventing mitral regurgitation. The body can have a structure that is impervious to blood and that allows the native leaflets to close around the sides of the body during ventricular systole to block blood from flowing from the left ventricle back into the left atrium. The body is sometimes referred to herein as a spacer because the body can fill a space between improperly functioning native mitral leaflets that do not close completely.

The body can have various shapes. In some embodiments, the body can have an elongated cylindrical shape having a round cross-sectional shape. In other embodiments, the body can have an oval cross-sectional shape, a crescent cross-sectional shape, or various other non-cylindrical shapes. The body can have an atrial or upper end positioned in or adjacent to the left atrium, a ventricular or lower end positioned in or adjacent to the left ventricle, and an annular side surface that extends between the native mitral leaflets.

The anchor can be configured to secure the device to one or both of the native mitral leaflets such that the body is positioned between the two native leaflets. In some embodiments, the anchor can attach to the body at a location adjacent the ventricular end of the body. In some embodiments, the anchor can attach to a shaft, to which the body is also attached. In some embodiments, the anchor and the body can be positioned independently with respect to each other by separately moving each of the anchor and the body along the longitudinal axis of the shaft. In some embodiments, the anchor and the body can be positioned simultaneously by moving the anchor and the body together along the longitudinal axis of the shaft. The anchor can be configured to be positioned behind a native leaflet when implanted such that the leaflet is captured by the anchor.

The prosthetic device can be configured to be implanted via a delivery sheath. The body and the anchor can be compressible to a radially compressed state and can be self-expandable to a radially expanded state when compressive pressure is released. The device can be configured to allow the anchor to self-expand radially away from the still-compressed body initially in order to create a gap between the body and the anchor. A native leaflet can then be positioned in the gap. The body can then be allowed to self-expand radially, closing the gap between the body and the anchor and capturing the leaflet between the body and the anchor. The implantation methods for various embodiments can be different, and are more fully discussed below with respect to each embodiment. Additional information regarding these and other delivery methods can be found in U.S. Pat. No. 8,449,599 and U.S. Patent Application Publication Nos. 2014/0222136, and 2014/0067052, 2016/0331523 each of which is incorporated herein by reference in its entirety.

The disclosed prosthetic devices are prevented from atrial embolization by having the anchor hooked to a leaflet, taking advantage of the tension from native chordae tendineae to resist high systolic pressure urging the device toward the left atrium. During diastole, the devices can rely on the compressive and retention forces exerted on the leaflet that is captured by the anchor to resist embolization into the left ventricle.

Referring now to FIGS. 1-6, an implantable prosthetic device 100 is shown in various stages of deployment. The device 100 is deployed from a delivery sheath 102 and includes a body portion 104 and an anchor portion 106. The body portion 104 of the device includes a spacer 110 for implantation between the leaflets of the native mitral valve that is slideably attached to an actuation wire or shaft 112. Actuation of the actuation wire 112 opens and closes the anchor portion 106 of the device 100 to capture the mitral valve leaflets during implantation. The actuation wire or shaft 112 may take a wide variety of different forms. For example, the actuation wire or shaft may be threaded such that rotation of the actuation wire or shaft moves the anchor portion 106 relative to the body portion 104. Or, the actuation wire or shaft may be unthreaded, such that pushing or pulling the actuation wire or shaft 112 moves the anchor portion 106 relative to the body portion 104.

The anchor portion 106 of the device 100 includes outer paddles 120 and inner paddles 122 that are connected between a cap 114 and the spacer 110 by hinged portions 124, 126, 128. The actuation wire 112 extends through the delivery sheath and the spacer 110 to the cap 114 at the distal end of the anchor portion 106. Extending and retracting the actuation wire 112 increases and decreases the spacing between the spacer 110 and the cap 114, respectfully. A collar (not shown) removably attaches the spacer 100 to the delivery sheath 102 so that the spacer 100 slides along the actuation wire 112 during actuation to open and close the paddles 120, 122 of the anchor portion 106.

Referring to FIG. 3, the barbed clasps 130 include a base or fixed arm 132, a moveable arm 134, barbs 136, and a hinge portion 138. The fixed arms 132 are attached to the inner paddles 122, with the hinge portion 138 disposed proximate the spacer 110. The hinge portion 138 provides a spring force between the fixed and moveable arms 132, 134 of the barbed clasp 130. The hinge portion 138 can be any suitable hinge, such as a flexible hinge, a spring hinge, a pivot hinge, or the like. In certain embodiments, the hinge portion 138 is a flexible piece of material integrally formed with the fixed and moveable arms 132, 134. The fixed arms 132 are attached to the inner paddles 122 and remain stationary relative to the inner paddles 122 when the moveable arms 134 are opened to open the barbed clasps 130 and expose the barbs 136. The barbed clasps 130 are opened by applying tension to actuation lines 116 attached to the ends of the moveable arms 134, thereby causing the moveable arms 134 to pivot on the hinge portions 138.

During implantation, the paddles 120, 122 are opened and closed to capture the native mitral valve leaflets between the paddles 120, 122 and the spacer 110. The barbed clasps 130 further secure the native leaflets by engaging the leaflets with barbs 136 and pinching the leaflets between the moveable and fixed arms 134, 132. The barbs 136 of the barbed clasps 130 increase friction with the leaflets, or may partially or completely puncture the leaflets. The actuation lines 116 can be actuated independently so that each barbed clasp 130 can be opened and closed independently. Independent operation allows one leaflet to be captured at a time, or for the repositioning of a clasp 130 on a leaflet that was insufficiently captured, without altering a successful grasp on the other leaflet. The barbed clasps 130 not only open and close independent from each other, but can fully be opened and closed independent from the position of the inner paddle 122, thereby allowing leaflets to be captured in a variety of positions as the particular situation requires.

The barbed clasps 130 can be opened independently by pulling on an attached actuation line or suture 116 that extends through the delivery sheath 102 to the end of the barbed clasp 130. The barbed clasps 130 can be spring loaded so that in the closed position the barbed clasps 130 continue to provide a pinching force on the captured native leaflet. This pinching force remains constant regardless of the position of the inner paddles 122. Barbs 136 of the barbed clasps 130 pierce the native leaflets to further secure the native leaflets.

Referring now to FIG. 1, the device 100 is shown in an elongated or fully open condition for deployment from the delivery sheath. In the elongated condition the cap 114 is spaced apart from the spacer 110 such that the paddles 120, 122 of the anchor portion 106 are inverted or fully open. In some embodiments, an angle formed between the interior of the outer and inner paddles 120, 122 is approximately 180 degrees. The barbed clasps 130 are kept in a closed condition during deployment through the delivery sheath 102 so that the barbs 136 (FIG. 3) do not catch or damage the sheath or tissue in the patient's heart.

Referring now to FIG. 1A, the device 100 is shown in an elongated detangling condition, similar to FIG. 1, but with the barbed clasps 130 in a fully open position, up to about 180 degrees. Fully opening the device 100 and the clasps 130 has been found to improve ease of detanglement from anatomy of the patient during implantation of the device 100.

Referring now to FIG. 2, the device 100 is shown in a shortened or fully closed condition. The compact size of the device 100 in the shortened condition allows for easier maneuvering and placement within the heart. To move the device 100 from the elongated condition to the shortened condition, the actuation wire 112 is retracted to pull the cap 114 towards the spacer 110. The hinges 126 between the outer paddle 120 and inner paddle 122 are limited in movement such that compression forces acting on the outer paddle 120 from the cap 114 being retracted towards the spacer 110 cause the paddles 120, 122 to move radially outward. During movement from the open to closed position, the outer paddles 120 maintain an acute angle with the actuation wire 112. In certain embodiments, the hinge portion 124 is a spring loaded hinge that biases the outer paddles 120 in a closing direction. The acute angle maintained between the actuation wire 112 and the outer paddles 120 reduces strain on the spring loaded hinge 124. The inner paddles 122 during the same motion move through a considerably larger angle as they are oriented away from the spacer 110 in the open condition and collapse along the sides of the spacer 110 in the closed condition. In certain embodiments, the inner paddles 122 are thinner than the outer paddles, and the hinge portions 126, 128 connected to the inner paddles 122 are thinner to allow more movement than the hinge portion 124 connecting the outer paddle 124 to the cap 114.

Referring now to FIGS. 3-5, the device 100 is shown in a partially open, capture-ready condition. To transition from the fully closed to the partially open condition, the actuation wire 112 is extended to push the cap 114 away from the spacer 110, thereby pulling on the outer paddles 120, which in turn pulls on the inner paddles 122, causing the anchor portion 106 to partially unfold. The actuation lines 116 are also retracted to open the clasps 130 so that the leaflets can be captured.

Referring now to FIG. 4, one of the actuation lines 116 is extended to allow one of the clasps 130 to close. Referring now to FIG. 5, the other actuation line 116 is extended to allow the other clasp 130 to close. Either or both of the actuation lines 116 may be repeatedly actuated to repeatedly open and close the barbed clasps 130.

Referring now to FIG. 6, the device 100 is shown in a fully closed and deployed condition. The delivery sheath 102 and actuation wire 112 are retracted and the paddles 120, 122 and clasps 130 remain in a fully closed position. Once deployed, the device 100 may be maintained in the fully closed position with a mechanical latch, or may be biased to remain closed through the use of spring materials, such as steel, other metals, plastics, composites, etc. or shape-memory alloys such as Nitinol. For example, the hinged portions 124, 126, 128, 138 may be formed of metals such as steel or shape-memory alloy, such as Nitinol—produced in a wire, sheet, tubing, or laser sintered powder—and are biased to hold the outer paddles 120 closed around the spacer 110 and the barbed clasps 130 pinched around native leaflets. Similarly, the fixed and moveable arms 132, 134 of the barbed clasps 130 are biased to pinch the leaflets. In certain embodiments, the hinge portions 124, 126, 128, 138 may be formed of any other suitably elastic material, such as a metal or polymer material, to maintain the device in the closed condition after implantation.

Referring now to FIGS. 7-12, the implantable device 100 of FIGS. 1-6 is shown being delivered and implanted within a native mitral valve 40 of a heart 10. Referring now to FIG. 7, the delivery sheath is inserted into the left atrium 20 through the septum and the device 100 is deployed from the delivery sheath in the fully open condition. The actuation wire 112 is then retracted to move the device 100 into the fully closed condition shown in FIG. 8. As can be seen in FIG. 9, the device 100 is moved into position within the mitral valve 40 into the ventricle 30 and partially opened so that the leaflets 42, 44 can be captured. Referring now to FIG. 10, an actuation line 116 is extended to close one of the clasps 130, capturing a leaflet 42. FIG. 11 shows the other actuation line 116 being then extended to close the other clasp 130, capturing the remaining leaflet 44. Lastly, as can be seen in FIG. 12, the delivery sheath 102 and actuation wire 112 are then retracted and the device 100 is fully closed and deployed in the native mitral valve 400.

Referring now to FIG. 13, an implantable prosthetic device 200 is shown. The device 200 is deployed from a delivery sheath (not shown) and includes a body portion 204 and an anchor portion 206. The body portion 204 of the device includes a spacer 210 for implantation between the leaflets of the native mitral valve that is slideably attached to an actuation wire or shaft 212. Actuation of the actuation wire 212 opens and closes the anchor portion 206 of the device 200 to capture the mitral valve leaflets during implantation.

The anchor portion 206 of the device 200 includes outer paddles 220 and inner paddles 222 that are hingeably connected to the cap 214 and the spacer 210. The actuation wire 212 extends through a collar (not shown), delivery sheath, and the spacer 210 to the cap 214 at the distal end of the anchor portion 206. Extending and retracting the actuation wire 212 increases and decreases the spacing between the spacer 210 and the cap 214, respectively. The collar removably engages and attaches to an upper end 211 of the spacer 200 to the delivery sheath so that the spacer 210 slides along the actuation wire 212 during actuation to open and close the paddles 220, 222 of the anchor portion 206. In some embodiments, the collar is held closed around the upper end 211 by the actuation wire 212, such that removal of the actuation wire 212 allows fingers (not shown) of the collar to open, releasing the spacer 210.

The spacer 210 and paddles 220, 222 are formed from a covering that may be a mesh, woven, braided, or formed in any other suitable way. The covering may be cloth, shape-memory alloy wire—such as Nitinol—to provide shape setting capability, or any other flexible material suitable for implantation in the human body. Paddle frames 224 provide additional pinching force between the outer paddles 222 and the spacer 210, and assist in wrapping the leaflets around the sides of the spacer 210 for a better seal between the spacer 210 and the leaflets. In some embodiments, the covering extends around the paddle frames 224.

The barbed clasps 230 include a base or fixed arm 232, a moveable arm 234, barbs 236, and a hinge portion 238. The fixed arms 232 are attached to the inner paddles 222, with the hinge portion 238 disposed proximate the spacer 210. Sutures (not shown) attach the fixed arms 232 to the inner paddles 222 through holes or slots 233. The fixed arms 232 remain stationary relative to the inner paddles 222 when the moveable arms 234 are opened to open the barbed clasps 230 and expose the barbs 236. The barbed clasps 230 are opened by applying tension to actuation lines (not shown) attached to holes 235 disposed at ends of the moveable arms 234, thereby causing the moveable arms 234 to pivot on the hinge portions 238.

During implantation, the paddles 220, 222 are opened and closed to capture the native mitral valve leaflets between the paddles 220, 222 and the spacer 210. The barbed clasps 230 further secure the native leaflets by engaging the leaflets with barbs 236 and pinching the leaflets between the moveable and fixed arms 234, 232. The barbs 236 of the barbed clasps 230 increase friction with the leaflets, or may partially or completely puncture the leaflets. The actuation lines can be actuated independently so that each barbed clasp 230 can be opened and closed independently. Independent operation allows one leaflet to be captured at a time, or for the repositioning of a clasp 230 on a leaflet that was insufficiently captured, without altering a successful grasp on the other leaflet. The barbed clasps 230 not only open and close independent from each other, but can be fully opened and closed independent from the position of the inner paddle 222, thereby allowing leaflets to be captured in a variety of positions as the particular situation requires.

Referring now to FIGS. 14-25, an implantable device 300 is shown being delivered and implanted within the native mitral valve 40 of the heart 10. The device 300 is similar to implantable device 200 of FIG. 13, though device 300 has a covering that extends around the outer paddles 320. The device 300 is deployed from a delivery sheath 302 and includes a body portion 304 and an anchor portion 306. The body portion 304 of the device includes a spacer 310 for implantation between the leaflets of the native mitral valve that is slideably attached to an actuation wire or shaft 312. Actuation of the actuation wire 312 opens and closes the anchor portion 306 of the device 300 to capture the mitral valve leaflets during implantation.

The anchor portion 306 of the device 300 includes outer paddles 320 and inner paddles 322 that are hingeably connected to the cap 314 and the spacer 310. The actuation wire 312 extends through a collar 303 (see FIG. 20), delivery sheath 302, and the spacer 310 to the cap 314 at the distal end of the anchor portion 306. Extending and retracting the actuation wire 312 increases and decreases the spacing between the spacer 310 and the cap 314, respectfully. Fingers of the collar 303 removably attach the spacer 300 to the delivery sheath 302 so that the spacer 310 slides along the actuation wire 312 during actuation to open and close the paddles 320, 322 of the anchor portion 306. In some embodiments, the collar 303 is held closed around the spacer 310 by the actuation wire 312, such that removal of the actuation wire 312 allows the fingers of the collar 303 to open, releasing the spacer 310.

The spacer 310 and paddles 320, 322 are formed from a covering that may be a mesh, woven, braided, or formed in any other suitable way. The covering may be cloth, shape-memory alloy wire—such as Nitinol—to provide shape setting capability, or any other flexible material suitable for implantation in the human body.

The barbed clasps 330 include a base or fixed arm 332, a moveable arm 334, barbs 336 (see FIG. 20), and a hinge portion 338. The fixed arms 332 are attached to the inner paddles 322, with the hinge portion 338 disposed proximate the spacer 310. Sutures (not shown) attach the fixed arms 332 to the inner paddles 322. The fixed arms 332 remain stationary when the moveable arms 334 are opened to open the barbed clasps 330 and expose the barbs 336. The barbed clasps 330 are opened by applying tension to actuation lines 316 attached to the ends of the moveable arms 334, thereby causing the moveable arms 334 to pivot on the hinge portions 338.

During implantation, the paddles 320, 322 are opened and closed to capture the native mitral valve leaflets between the paddles 320, 322 and the spacer 310. The outer paddles 320 have a wide curved shape that fits around the curved shape of the spacer 310 to more securely grip the leaflets. The curved shape and rounded edges of the outer paddle 320 also prohibits tearing of the leaflet tissue. The barbed clasps 330 further secure the native leaflets by engaging the leaflets with barbs 336 and pinching the leaflets between the moveable and fixed arms 334, 332. The barbs 336 of the barbed clasps 330 increase friction with the leaflets, or may partially or completely puncture the leaflets. The actuation lines can be actuated independently so that each barbed clasp 330 can be opened and closed independently. Independent operation allows one leaflet to be captured at a time, or for the repositioning of a clasp 330 on a leaflet that was insufficiently captured, without altering a successful grasp on the other leaflet. The barbed clasps 330 not only open and close independent from each other, but can be fully opened and closed independent from the position of the inner paddle 322, thereby allowing leaflets to be captured in a variety of positions as the particular situation requires.

Referring now to FIG. 14, the delivery sheath is inserted into the left atrium 20 through the septum and the device 300 is deployed from the delivery sheath 302 in the fully open condition. The actuation wire 312 is then retracted to move the device 300 into the fully closed condition shown in FIGS. 15-16 and then maneuvered towards the mitral valve 40 as shown in FIG. 17. Referring now to FIG. 18, when the device 300 is aligned with the mitral valve 40, the actuation wire 312 is extended to open the paddles 320, 322 into the partially opened position and the actuation lines 316 are retracted to open the barbed clasps 330 to prepare for leaflet capture. Next, as shown in FIGS. 19-20, the partially open device 300 is inserted through the mitral valve 40 until leaflets are properly positioned in between the inner paddles 322 and the spacer 310 and inside the open barbed clasps 330. FIG. 21 shows the device 300 with both clasps 330 closed, though the barbs 336 of one clasp 330 missed one of the leaflets 44. As can be seen in FIGS. 22-23, the out of position clasp 330 is opened and closed again to properly capture the missed leaflet 44. When both leaflets 42, 44 are captured properly, the actuation wire 312 is retracted to move the device 300 into the fully closed position shown in FIG. 24. With the device 300 fully implanted in the native mitral valve 40, the actuation wire 312 is withdrawn to release the collar 303 from an upper end or plate 311 of the spacer 310. Once deployed, the device 300 may be maintained in the fully closed position with a mechanical means such as a latch, or may be biased to remain closed through the use of spring material, such as steel, and/or shape-memory alloys such as Nitinol. For example, the paddles 320, 322 may be formed of steel or Nitinol shape-memory alloy—produced in a wire, sheet, tubing, or laser sintered powder—and are biased to hold the outer paddles 320 closed around the spacer 310 and the barbed clasps 330 pinched around native leaflets.

Referring now to FIG. 26, an exemplary barbed clasp 400 for use in implantable prosthetic devices, such as devices 100, 200, 300 described above, is shown. The barbed clasp 400 is formed from a top layer 402 and a bottom layer 404. The two-layer design of the clasp 400 allows thinner sheets of material to be used, thereby improving the flexibility of the clasp 400 over a clasp formed from a single thicker sheet, while maintaining the strength of the clasp 400 needed to successfully retain a native valve leaflet.

The barbed clasp 400 includes a fixed arm 410, a hinged portion 420, and a movable arm 430 having a barbed portion 440. The top and bottom layers 402, 404 have a similar shape and in certain embodiments are attached to each other at the barbed end 440. The hinged portion 420 is spring-loaded so that the fixed and moveable arms 410, 430 are biased toward each other when the barbed clasp 400 is in a closed condition. When assembled to an implantable prosthetic device, the fixed arm 410 is attached to a portion of the prosthetic device. The clasp 400 is opened by pulling on an actuation line attached to the moveable arm 430 until the spring force of the hinge portion 420 is overcome.

The fixed arm 410 is formed from a tongue 411 of material extending from the hinged portion 420 between two side beams 431 of the moveable arm 430. The tongue 411 is biased between the side beams 431 by the hinge portion 420 such that force must be applied to move the tongue 411 from a neutral position located beyond the side beams 431 to a preloaded position substantially parallel with the side beams 431. The tongue 411 is held in the preloaded position by a T-shaped cross-bar 414 that is attached to the tongue 411 and extends outward to engage the side beams 431. In certain embodiments, the angle between the fixed and moveable arms 410, 430 when the tongue is in the neutral position is about 30 to about 100 degrees, 30 to about 90 degrees, or about 30 to about 60 degrees, or about 40 to about 50 degrees, or about 45 degrees.

The tongue 411 includes holes 412 for receiving sutures (not shown) that attach the fixed arm 410 to an implantable device. In certain embodiments, the holes 412 are elongated slots or oval-shaped holes to accommodate sliding of the layers 402, 404 without damaging the sutures attaching the clasp 400 to an implantable device.

The hinge portion 420 is formed by two beam loops 422 that extend from the tongue 411 of the fixed arm 410 to the side beams 431 of the moveable arm 430. In certain embodiments, the beam loops 422 are narrower than the tongue 411 and side beam 431 to provide additional flexibility. The beam loops 422 each include a center portion 424 extending from the tongue 411 and an outer portion 426 extending to the side beams 431. The beam loops 422 are bent into a somewhat spiral or helical shape by bending the center and outer portions 424, 426 in opposite directions, thereby forming an offset or step distance 428 between the tongue 411 and side beams 431. The step distance 428 provides space between the arms 410, 430 to accommodate the native leaflet of the mitral valve after it is captured. In certain embodiments, the step distance 428 is about 0.5 millimeter to about 1 millimeters, or about 0.75 millimeters.

When viewed in a top plan view, the beam loops have an “omega-like” shape. This shape of the beam loops 422 allows the fixed and moveable arms 410, 430 to move considerably relative to each other without plastically deforming the clasp material. For example, in certain embodiments, the tongue 411 can be pivoted from a neutral position that is approximately 45 degrees beyond the moveable arm 430 to a fully open position that is approximately 180 degrees from the moveable arm 430 without plastically deforming the clasp material. In certain embodiments, the clasp material plastically deforms during opening without reducing or without substantially reducing the pinch force exerted between the fixed and moveable arms in the closed position.

Preloading the tongue 411 enables the clasp 400 to maintain a pinching or clipping force on the native leaflet when closed while also being able to be opened wide to more easily capture the native leaflet. The preloading of the tongue 411 provides a significant advantage over prior art clips that provide little or no pinching force when closed. Additionally, closing the clasp 400 with spring force is a significant improvement over clips that use a one-time locking closure mechanism, as the clasp 400 can be repeatedly opened and closed for repositioning on the leaflet while still maintaining sufficient pinching force when closed.

The barbed portion 440 of the moveable arm 430 includes an eyelet 442, barbs 444, and barb supports 446. Positioning the barbed portion of the clasp 400 at an end of the moveable arm 430 increases the space between the barbs 444 and the fixed arm 410 when the clasp 400 is opened, thereby improving the ability of the clasp 400 to successfully capture a leaflet during implantation. This distance also allows the barbs 444 to more reliably disengage from the leaflet for repositioning. In certain embodiments, the barbs of the clasps may be staggered longitudinally to further distribute pinch forces and local leaflet stress.

The barbs 444 are laterally spaced apart at the same distance from the hinge portion 420, providing a superior distribution of pinching forces on the leaflet tissue while also making the clasp more robust to leaflet capture than barbs arranged in a longitudinal row. In some embodiments, the barbs 444 can be staggered to further distribute pinch forces and local leaflet stress.

The barbs 442 are formed from the bottom layer 404 and the barb supports 446 are formed from the top layer. In certain embodiments, the barbs are formed from the top layer 402 and the barb supports are formed from the bottom layer 404. Forming the barbs 444 only in one of the two layers 402, 404 allows the barbs to be thinner and therefore effectively sharper than a barb formed from the same material that is twice as thick. The barb supports 446 extend along a lower portion of the barbs 444 to stiffen the barbs 444, further improving penetration and retention of the leaflet tissue. In certain embodiments, the ends of the barbs 444 are further sharpened using any suitable sharpening means.

The barbs 444 are angled away from the moveable arm 430 such that they easily penetrate tissue of the native leaflets with minimal pinching or clipping force. The barbs 444 extend from the moveable arm at an angle of about 45 degrees to about 75 degrees, or about 45 degrees to about 60 degrees, or about 48 to about 56 degrees, or about 52 degrees. The angle of the barbs 444 provides further benefits, in that force pulling the implant off of the native leaflet will encourage the barbs 444 to further engage the tissue, thereby ensuring better retention. Retention of the leaflet in the clasp 400 is further improved by the position of the T-shaped cross bar 414 near the barbs 444 when the clasp 400 is closed. In this arrangement, the tissue pierced by the barbs 444 is pinched against the moveable arm 430 at the cross bar 414 location, thereby forming the tissue into an S-shaped torturous path as it passes over the barbs 444. Thus, forces pulling the leaflet away from the clasp 400 will encourage the tissue to further engage the barbs 444 before the leaflets can escape.

Each layer 402, 404 of the clasp 400 is laser cut from a sheet of shape-memory alloy, such as Nitinol. The top layer 402 is aligned and attached to the bottom layer 404. In certain embodiments, the layers 402, 404 are attached at the barbed end 440 of the moveable arm 430. For example, the layers 402, 404 may be attached only at the barbed end 440, to allow the remainder of the layers to slide relative to one another. Portions of the combined layers 402, 404, such as a fixed arm 410, barbs 444 and barb supports 446, and beam loops 422 are bent into a desired position. The clasp 400 is then subjected to a shape-setting process so that internal forces of the material will tend to return to the set shape after being subjected to deformation by external forces. After shape setting, the tongue 411 is moved to its preloaded position so that the cross-bar 414 can be attached. Consequently, the clasp 400 can be completely flattened for delivery through a delivery sheath and allowed to expand once deployed within the heart.

The clasp 400 is opened and closed by applying and releasing tension on a suture (not shown) attached to the moveable arm 430. The suture is inserted through an eyelet 442 near the barbed portion 440 of the moveable arm 430 and wraps around the end of the moveable arm 430 before returning to the delivery sheath. In certain embodiments, an intermediate suture loop is made through the eyelet and the suture is inserted through the intermediate loop. An intermediate loop of suture material reduces friction experienced by the actuation suture relative to the friction between the actuation suture and the clasp material. When the suture is looped through the eyelet 442 or intermediate loop, both ends of the actuation suture extend back into and through the delivery sheath 102 (see FIG. 1). The suture can be removed by pulling one end of the suture proximally until the other end of the suture pulls through the eyelet or intermediate loop and back into the delivery sheath.

Referring now to FIG. 27, an exemplary barbed clasp 500 for use in implantable prosthetic devices, such as devices 100, 200, 300 described above, is shown. The barbed clasp 500 is substantially the same as the barbed clasp 400, except the barbed clasp 500 includes a suture pin 543 disposed across an opening 542, instead of the hole 442. The barbed clasp 500 is formed from a top layer 502 and a bottom layer 504. The two-layer design of the clasp 500 allows thinner sheets of material to be used, thereby improving the flexibility of the clasp 500 over a clasp formed from a single thicker sheet, while maintaining the strength of the clasp 500 needed to successfully retain a native valve leaflet.

The barbed clasp 500 includes a fixed arm 510, a hinged portion 520, and a movable arm 530 having a barbed portion 540. The top and bottom layers 502, 504 have a similar shape and in certain embodiments are attached to each other at the barbed end 540. The hinged portion 520 is spring-loaded so that the fixed and moveable arms 510, 530 are biased toward each other when in the barbed clasp 500 is in a closed condition. When assembled to an implantable prosthetic device, the fixed arm 510 is attached to a portion of the prosthetic device. The clasp 500 is opened by pulling on an actuation line attached to the moveable arm 530 until the spring force of the hinge portion 520 is overcome.

The fixed arm 510 is formed from a tongue 511 of material extending from the hinged portion 520 between two side beams 531 of the moveable arm 530. The tongue 511 is biased between the side beams 531 by the hinge portion 520 such that force must be applied to move the tongue 511 from a neutral position located beyond the side beams 531 to a preloaded position substantially parallel with the side beams 531. The tongue 511 is held in the preloaded position by a T-shaped cross-bar 514 that is attached to the tongue 511 and extends outward to engage the side beams 531. In certain embodiments, the angle between the fixed and moveable arms 510, 530 when the tongue is in the neutral position is about 30 to about 100 degrees, or about 30 to about 90 degrees, or about 30 to about 60 degrees, or about 40 to about 50 degrees, or about 45 degrees.

The tongue 511 includes holes 512 for receiving sutures (not shown) that attach the fixed arm 510 to an implantable device. In certain embodiments, the holes 512 are elongated slots or oval-shaped holes to accommodate sliding of the layers 502, 504 without damaging the sutures attaching the clasp 500 to an implantable device.

The hinge portion 520 is formed by two beam loops 522 that extend from the tongue 511 of the fixed arm 510 to the side beams 531 of the moveable arm 530. In certain embodiments, the beam loops 522 are narrower than the tongue 511 and side beam 531 to provide additional flexibility. The beam loops 522 each include a center portion 524 extending from the tongue 511 and an outer portion 526 extending to the side beams 531. The beam loops 522 are bent into a somewhat spiral or helical shape by bending the center and outer portions 524, 526 in opposite directions, thereby forming a step distance 528 between the tongue 511 and side beams 531. The step distance 528 provides space between the arms 510, 530 to accommodate the native leaflet of the mitral valve after it is captured. In certain embodiments, the step distance 528 is about 0.5 millimeter to about 1 millimeters, or about 0.75 millimeters.

When viewed in a top plan view, the beam loops have an “omega-like” shape. This shape of the beam loops 522 allows the fixed and moveable arms 510, 530 to move considerably relative to each other without plastically deforming the clasp material. For example, in certain embodiments, the tongue 511 can be pivoted from a neutral position that is approximately 45 degrees beyond the moveable arm 530 to a fully open position that is approximately 180 degrees from the moveable arm 530 without plastically deforming the clasp material. In certain embodiments, the clasp material plastically deforms during opening without reducing the pinch force exerted between the fixed and moveable arms in the closed position.

Preloading the tongue 511 enables the clasp 500 to maintain a pinching or clipping force on the native leaflet when closed while also being able to be opened wide to more easily capture the native leaflet. The preloading of the tongue 511 provides a significant advantage over prior art clips that provide little or no pinching force when closed. Additionally, closing the clasp 500 with spring force is a significant improvement over clips that use a one-time locking closure mechanism, as the clasp 500 can be repeatedly opened and closed for repositioning on the leaflet while still maintaining sufficient pinching force when closed.

The barbed portion 540 of the moveable arm 530 includes an eyelet 542, barbs 544, and barb supports 546. Positioning the barbed portion of the clasp 500 at an end of the moveable arm 530 increases the space between the barbs 544 and the fixed arm 510 when the clasp 500 is opened, thereby improving the ability of the clasp 500 to successfully capture a leaflet during implantation. This distance also allows the barbs 544 to more reliably disengage from the leaflet for repositioning. In certain embodiments, the barbs of the clasps may be staggered longitudinally to further distribute pinch forces and local leaflet stress.

The barbs 544 are laterally spaced apart at the same distance from the hinge portion 520, providing a superior distribution of pinching forces on the leaflet tissue while also making the clasp more robust to leaflet capture than barbs arranged in a longitudinal row.

The barbs 544 are formed from the bottom layer 504 and the barb supports 546 are formed from the top layer. Forming the barbs 544 only in one of the two layers 502, 504 allows the barbs to be thinner and therefore effectively sharper than a barb formed from the same material that is twice as thick. The barb supports 546 extend along a lower portion of the barbs 544 to stiffen the barbs 544, further improving penetration and retention of the leaflet tissue. In certain embodiments, the ends of the barbs 544 are further sharpened using any suitable sharpening means.

The barbs 544 are angled away from the moveable arm 530 such that they easily penetrate tissue of the native leaflets with minimal pinching or clipping force. The barbs 544 extend from the moveable arm at an angle of about 45 to about 75 degrees, or about 45 to about 60 degrees, or about 48 to about 56 degrees, or about 52 degrees. The angle of the barbs 544 provides further benefits, in that force pulling the implant off of the native leaflet will encourage the barbs 544 to further engage the tissue, thereby ensuring better retention. Retention of the leaflet in the clasp 500 is further improved by the position of the T-shaped cross bar 514 near the barbs 544 when the clasp 500 is closed. In this arrangement, the tissue pierced by the barbs 544 is pinched against the moveable arm 530 at the cross bar 514 location, thereby forming the tissue into an S-shaped torturous path as it passes over the barbs 544. Thus, forces pulling the leaflet away from the clasp 500 will encourage the tissue to further engage the barbs 544 before the leaflets can escape.

Each layer 502, 504 of the clasp 500 is laser cut from a sheet of shape-memory alloy, such as Nitinol. The top layer 502 is aligned and attached to the bottom layer 504. In certain embodiments, the layers 502, 504 are attached at the barbed end 540 of the moveable arm 530. For example, the layers 402, 404 may be attached only at the barbed end 440, to allow the remainder of the layers to slide relative to one another. Portions of the combined layers 502, 504, such as a fixed arm 510, barbs 544 and barb supports 546, and beam loops 522 are bent into a desired position. The clasp 500 is then subjected to a shape-setting process so that internal forces of the material will tend to return to the set shape after being subjected to deformation by external forces. After shape setting, the tongue 511 is moved to its preloaded position so that the cross-bar 514 can be attached. Consequently, the clasp 500 can be completely flattened for delivery through a delivery sheath and allowed to expand once deployed within the heart.

The clasp 500 is opened and closed by applying and releasing tension on a suture (not shown) attached to the moveable arm 530. The suture is inserted through an opening 542 in the moveable arm 530 and looped around a pin 543 disposed in the opening 542. The smooth round shape of the pin 543 allows tension to be applied to the moveable arm 530 from many directions without causing the suture to wear. In certain embodiments, an intermediate suture loop is made through the opening and around the pin and the suture is inserted through the intermediate loop. An intermediate loop of suture material reduces friction experienced by the actuation suture relative to the friction between the actuation suture and the clasp material. When the actuation suture is looped around the pin 543, both ends of the suture extend back into and through the delivery sheath 102 (see FIG. 1). The suture can be removed by pulling one end of the suture proximally, until the other end of the suture pulls around the pin 543 and back into the delivery sheath.

Referring now to FIGS. 28-31, an exemplary barbed clasp 600 similar to barbed clasps 400 and 500 is shown in a variety of bent positions to illustrate the independent movement of the layers forming the barb clasps 400, 500, and 600. The barbed clasp 600 is formed from a top layer 602 and a bottom layer 604. The barbed clasp 600 includes a moveable arm 620, a fixed arm 622, a hinge portion 624. The moveable arm 620 includes a barbed portion 626 with barbs 628. The barbed clasp 600 does not include a cross-bar to prevent the moveable arm 620 from moving past the fixed arm 622. Instead of a cross-bar, the moveable arm 620 is held in a closed position with the fixed arm 622 by the inner paddle (not shown). To better illustrate the preloading of the clasp 600, FIGS. 28-31 show the fixed arm 622 moving relative to a stationary moveable arm 620. When assembled to an implantable device, however, the moveable arm 620 would move relative to the fixed arm 622 that is attached to the device.

Referring now to FIGS. 28-29, the clasp 600 is shown in a preloading or shape setting condition. The fixed arm 622 is bent below the moveable arm 620 by an angle 610 before the shape setting operation is performed. Force must be applied then to return the fixed arm 622 to a parallel relationship with the moveable arm 620. Thus, increasing the preloading angle 610 increases the force required to move the fixed arm 622, thereby increasing the preloading spring force pinching the arms 620, 622 together when the clasp 600 is closed. In other words, the greater the angle 610, the greater the spring force applied to captured tissue by the arms 620, 622.

Referring now to FIGS. 30-31, the clasp 600 is shown being opened to an opening angle 612. As can be seen in FIGS. 30 and 31, the beam loops of the hinge portion 624 tend to separate as the clasp 600 is opened. Allowing the layers 602, 604 to separate during bending decreases strain on the material, thereby further increasing the maximum opening angle 612 that can be achieved before plastic deformation of the clasp material. As noted above, the hinge portion 624 is shaped to form somewhat spiral or helical beam loops, thereby forming a gap or step distance 614 between the arms 620, 622 (FIG. 29) that allows the leaflet tissue to be captured.

As the clasp 600 is opened, the layers 602, 604 in the fixed arm 622 slide relative to each other. In some embodiments, holes through the fixed 622 arm are elongated so that sutures securing the fixed arm 622 to the implantable device are not pinched by the sliding movement of the layers, nor are the layers 602, 604 constrained from sliding, which reduces strain experienced by the clasp material.

Referring now to FIGS. 32-35, exemplary barb clasps 700, 800, 900, and 1000 are shown. Barb clasps 700, 800, 900, and 1000, like clasps 400, 500, 600 can be used in the implantable devices 100, 200, and 300 described above. Unlike barbed clasps 400, 500, 600, however, barbed clasps 700, 800, 900, and 1000 are formed by laser cutting material from the side of the clasp rather than from the top. Laser cutting from the side reduces the operations required to manufacture the clasp and allows the thickness of the clasp to be varied to vary the bending properties of portions of the clasp based on the function of each portion. For example, hinge portions may be thinner to provide more flexibility while arms may be thickened to provide more stiffness.

Referring now to FIG. 32, a laminated barb clasp 700 is shown. The barb clasp 700 has thick and thin portions 702, 704 and is formed from alternating spacer layers 706 and barbed layers 708 to form a laminated structure. The clasp 700 includes a moveable arm 720, a fixed arm 722, and a hinge portion 724. The moveable arm 720 includes a barbed portion 726 having barbs 728 formed in the barbed layers 708. Forming the layers 706, 708 by laser cutting from a side profile allows the barbs 728 to be tapered, thereby providing a stiff barb with a sharp point. The fixed arm 722 includes holes to secure the clasp 700 to an implantable device. When assembled to an implantable device, the fixed arm 722 is extended by the attached inner paddle, thus the native tissue is pinched between the moveable arm 720 and the inner paddle of the device.

Referring now to FIGS. 33-35, exemplary barb clasps 800, 900, 1000 are shown. The clasps 800, 900, 1000 are similar in overall shape while illustrating the variety of thicknesses possible when laser cutting clasps from the side. The clasps 800, 900, 1000 have a thin portion 804, 904, 1004 and a thick portion 802, 902, 1002. The clasps 800, 900, 1000 include a moveable arm 820, 920, 1020, a fixed arm 822, 922, 1022, a hinge portion 824, 924, 1024. The moveable arm 820, 920, 1020 includes a barb portion 826, 926, 1026 having barbs (not shown) similar to the barbs 726 of clasp 700. As can be seen in FIGS. 33-35, holes can be provided in the fixed arm 822, 922, 1022 to secure the clasp 800, 900, 1000 to an implantable device. When assembled to an implantable device, the fixed arm 822, 922, 1022 is extended by the attached inner paddle, thus the native tissue is pinched between the moveable arm 820, 920, 1020 and the inner paddle of the device.

Referring now to FIG. 36, an exemplary barbed clasp 1100 similar to barbed clasps 400, 500, 600 is shown. Unlike barbed clasps 400, 500, 600, however, barbed clasp 1100 is formed from a single layer of material that varies in thickness between a thick portion 1102 and a thin portion 1104. The barbed clasp 1100 includes a fixed arm 1110, a hinge portion 1120, and a moveable arm 1130. The fixed arm 1110 includes attachment holes 1112 and an optional integrated crossbar 1114. The hinge portion 1120 includes an arcuate hinge 1122 formed from the thin portion 1104. The moveable arm 1130 includes a barbed portion 1140 with barbs 1144. A suture (not shown) can be attached to an eyelet 1142 near the barbed portion 1140 to open and close the clasp 1100.

To form the barbed clasp 1100, a sheet of material is thinned to form the thin portion 1104. The shape of the clasp 1100 is then laser cut from the sheet of material so that the hinge portion 1120 is aligned with the thin portion 1104. The barbs 1144 and fixed arm 1110 are then bent into the position shown in FIG. 36 before shape setting. The optional T-shaped crossbar 1114 of the fixed arm 1110 must be twisted to insert it through the slot in the moveable arm 1130 for shape setting and to move the arms 1110, 1130 from the preloading position to a closed position. In certain embodiments, the optional T-shaped crossbar 1114 is omitted, is smaller, or is alternatively replaced with a relief in the moveable arm 1130, to facilitate ease of manufacture and shape setting. After the shape setting, the crossbar is twisted, moved back through the slot, and positioned on top of the thick portion 1102. The crossbar 1114 is positioned in generally the same manner as the crossbar 414 (see FIG. 26).

Like the clasps 400, 500 described above, the clasp 1100 can be opened fully without plastically deforming the clasp material while still providing pinching force when closed. Fewer steps are required to manufacture the clasp 1100 as compared to the clasps above, as the clasp 1100 is cut from a single sheet of material and no welding step is needed to weld layers of material together.

While various inventive aspects, concepts and features of the disclosures may be described and illustrated herein as embodied in combination in the exemplary embodiments, these various aspects, concepts, and features may be used in many alternative embodiments, either individually or in various combinations and sub-combinations thereof. Unless expressly excluded herein all such combinations and sub-combinations are intended to be within the scope of the present application. Still further, while various alternative embodiments as to the various aspects, concepts, and features of the disclosures—such as alternative materials, structures, configurations, methods, devices, and components, alternatives as to form, fit, and function, and so on—may be described herein, such descriptions are not intended to be a complete or exhaustive list of available alternative embodiments, whether presently known or later developed. Those skilled in the art may readily adopt one or more of the inventive aspects, concepts, or features into additional embodiments and uses within the scope of the present application even if such embodiments are not expressly disclosed herein.

Additionally, even though some features, concepts, or aspects of the disclosures may be described herein as being a preferred arrangement or method, such description is not intended to suggest that such feature is required or necessary unless expressly so stated. Still further, exemplary or representative values and ranges may be included to assist in understanding the present application, however, such values and ranges are not to be construed in a limiting sense and are intended to be critical values or ranges only if so expressly stated.

Moreover, while various aspects, features and concepts may be expressly identified herein as being inventive or forming part of a disclosure, such identification is not intended to be exclusive, but rather there may be inventive aspects, concepts, and features that are fully described herein without being expressly identified as such or as part of a specific disclosure, the disclosures instead being set forth in the appended claims. Descriptions of exemplary methods or processes are not limited to inclusion of all steps as being required in all cases, nor is the order that the steps are presented to be construed as required or necessary unless expressly so stated. The words used in the claims have their full ordinary meanings and are not limited in any way by the description of the embodiments in the specification.

Claims

1. An implantable prosthetic device comprising: an anchor portion comprising a plurality of paddles, the paddles being movable from a closed position to an open position;a clasp attached to each of the plurality of paddles, the clasp comprising: a fixed arm fixedly attached to the paddle;a moveable arm having an end that is rounded;a hinge portion hingeably connecting the fixed arm to the moveable arm; andwherein the fixed arm remains stationary relative to the paddle when the moveable arm is opened to open the clasp.

2. The implantable prosthetic device according to claim 1, wherein edges of the moveable arm are rounded.

3. The implantable prosthetic device according to claim 1, wherein the end of the moveable arm has a convex curved shape formed from a single radius.

4. The implantable prosthetic device according to claim 1, wherein the end of the moveable arm has a semi-circle shape.

5. The implantable prosthetic device according to claim 1, wherein the end of the moveable arm has a semi-elliptical shape.

6. The implantable prosthetic device according to claim 1, wherein the end of the moveable arm has a rounded triangle shape.

7. The implantable prosthetic device according to claim 1, wherein the clasp is formed from a top layer and a bottom layer, the top and bottom layers formed of shape memory material.

8. The implantable prosthetic device according to claim 1, wherein the clasp is formed from shape memory material and the fixed arms and moveable arms are shape set in a preloading position so that a pinch force exists between the fixed arms and moveable arms when the fixed arm is approximately parallel with the moveable arm.

9. The implantable prosthetic device according to claim 1, wherein a plastic limit of the material of the clasp is not exceeded when the moveable arm is opened to a fully open position about 140 degrees from the fixed arm.

10. The implantable prosthetic device according to claim 1, further comprising a cover that covers the rounded end of the moveable arm of the clasp.

11. A system for delivering an implantable prosthetic device, the system comprising: a catheter;an implantable prosthetic device coupled to the catheter, the implantable prosthetic device comprising: an anchor portion comprising a plurality of paddles being movable from a closed position to an open position;a clasp attached to each of the plurality of paddles, the clasp comprising: a fixed arm fixedly attached to the paddle;a moveable arm having an end that is rounded;a hinge portion hingeably connecting the fixed arm to the moveable arm,wherein the fixed arm remains stationary relative to the inner portion of paddle when the moveable arm is opened to open the clasp.

12. The system according to claim 11, wherein edges of the moveable arm are rounded.

13. The system according to claim 11, wherein the end of the moveable arm has a convex curved shape formed from a single radius.

14. The system according to claim 11, wherein the end of the moveable arm has a semi-circle shape.

15. The system according to claim 11, wherein the end of the moveable arm has a semi-elliptical shape.

16. The system according to claim 11, wherein the end of the moveable arm has a rounded triangle shape.

17. The system according to claim 11, wherein the clasp is formed from a top layer and a bottom layer, the top and bottom layers formed of shape memory material.

18. The system according to claim 11, wherein the clasp is formed from shape memory material and the fixed arms and moveable arms are shape set in a preloading position so that a pinch force exists between the fixed arms and moveable arms when the fixed arm is approximately parallel with the moveable arm.

19. The system according to claim 11, wherein a plastic limit of the material of the clasp is not exceeded when the moveable arm is opened to a fully open position about 140 degrees from the fixed arm.

20. The system according to claim 11, further comprising a cover that covers the rounded end of the moveable arm of the clasp.

21. The system according to claim 11, wherein the clasp is formed from only a single layer of material.