Patent Description:
Surgical repair of bodily tissues often involves tissue approximation and fastening of such tissues in the approximated arrangement. When repairing valves, tissue approximation often includes coapting the leaflets of the valves in a therapeutic arrangement which may then be maintained by fastening or fixing the leaflets. Such fixation of the leaflets can be used to treat regurgitation which most commonly occurs in the mitral valve.

Mitral valve regurgitation is characterized by retrograde flow from the left ventricle of a heart through an incompetent mitral valve into the left atrium. During a normal cycle of heart contraction (systole), the mitral valve acts as a check valve to prevent flow of oxygenated blood back into the left atrium. In this way, the oxygenated blood is pumped into the aorta through the aortic valve. Regurgitation of the valve can significantly decrease the pumping efficiency of the heart, placing the patient at risk of severe, progressive heart failure.

Mitral valve regurgitation can result from a number of different mechanical defects in the mitral valve or the left ventricular wall. The valve leaflets, the valve chordae which connect the leaflets to the papillary muscles, the papillary muscles themselves, or the left ventricular wall may be damaged or otherwise dysfunctional. Commonly, the valve annulus may be damaged, dilated, or weakened, limiting the ability of the mitral valve to close adequately against the high pressures of the left ventricle during systole.

The most common treatments for mitral valve regurgitation rely on valve replacement or repair including leaflet and annulus remodeling, the latter generally referred to as valve annuloplasty. One technique for mitral valve repair which relies on suturing adjacent segments of the opposed valve leaflets together is referred to as the "bow-tie" or "edge-to-edge" technique. While all these techniques can be effective, they usually rely on open heart surgery where the patient's chest is opened, typically via a sternotomy, and the patient placed on cardiopulmonary bypass. The need to both open the chest and place the patient on bypass is traumatic and has associated high mortality and morbidity.

In some patients, a fixation device can be installed into the heart using minimally invasive techniques. The fixation device can hold the adjacent segments of the opposed valve leaflets together to reduce mitral valve regurgitation. One such device used to clip the anterior and posterior leaflets of the mitral valve together is the MitraClip® fixation device, sold by Abbott Vascular, Santa Clara, California, USA.

These fixation devices often include clips designed to grip and hold against tissue as the clip arms are moved and positioned against the tissue at the treatment site and then closed against the tissue. Such clips are designed to continue gripping the tissue as the fixation device is closed into a final position. In order to achieve this effect, these clips are sometimes equipped with barbs or hooks to grip the tissue as the clip is flexed into position against the tissue.

However, some tissue fixation treatments require a fixation device to move through a wide range of grasping angles in order to be properly positioned relative to the target tissue and then to grasp the tissue and bring it to a closed position. This moving and plastically deforming of components of the fixation device during pre-deployment, positioning, and closure of the device can lead to the weakening and pre-mature degradation of the fixation device. Additionally, some tissue fixation treatments require that the fixation device maintain a degree of flexibility and mobility to allow a range of physiological movement even after the device has been properly placed and the target tissue has been properly fixed into the desired position, This can increase the risk of pre-mature failure of the device as continued plastic deformation of the flexing components (e.g., from the continuous opening and closing of valve leaflets) leads to unfavorable degradation of the device.

In <CIT> there is described a holding device on a combined holding and lithotripsy instrument which consists of a highly elastic NiTi alloy and has at least three holding arms which in their unflexed state are curved in a tulip-like manner. The end of each holding arm is toothed and bent towards the instrument axis. When the holding arms are drawn into the instrument tube or working channel they position themselves on the calculus and grasp it when they are drawn in even further. The holding device is configured around the instrument axis in such a way that the angle between directly adjacent holding arms is never equal to or greater than <NUM> degrees. This ensures secure holding and grasping and thus prevents the grasped calculus from escaping sideways. The securely held calculus can then be fully fragmented to fragments of a predetermined size using the lithotriptor, irrespective of its technical construction, i.e. mechano-ballistically, by ultrasound, cryotechnically or thermally with laser light.

In <CIT> there is described a sealing plug for an opening in a wall of a vessel or hollow organ of an animal or human body, in particular a blood vessel. There is also described a device for placing such a sealing plug in such an opening, a surgery kit for percutaneously sealing an opening in a wall of a vessel or hollow organ of an animal or human body, in particular a blood vessel, and a method for percutaneously sealing an opening in a wall of a vessel or hollow organ of an animal or human body.

In <CIT> there is described a retrieval apparatus for entrapping and retaining an object located in a body for its extraction therefrom. The retrieval apparatus includes a snare and a snare control assembly. The snare has a proximal section and a distal section, and comprises a plurality of filaments extending from a proximal end of the proximal section towards the distal section, and then returning to the proximal end to form a plurality of loops. In the deployed state, the loops are interlaced to each other within the proximal section and are free and not interleaved within the distal section. Segments of the filaments of the distal section are bent with respect to segments of the filaments of the proximal section such that the retrieval snare in the contracted state forms a hollow cavity extending from the distal section towards the proximal section.

In <CIT> there is described a series of medical instruments that can be made with the use of a shape memory tube with a transformation temperature that is above or below the ambient temperature. In the first case, the material behaves with the shape memory effect and in the second case the behavior is superelastic. The wall of the tube is provided with a plurality of slots in specific places, often near or at the distal end of the instrument, and in specific arrangements which allow local variations in diameter, shape, and/or length. These variations can either be caused by the memory effect during temperature change or by superelastic behavior during change of the mechanical influences on the memory metal by the surrounding material.

In <CIT> there are described methods, devices, and systems for performing endovascular repair of atrioventricular and other cardiac valves in the heart. Regurgitation of an atrioventricular valve, particularly a mitral valve, can be repaired by modifying a tissue structure selected from the valve leaflets, the valve annulus, the valve chordae, and the papillary muscles. These structures may be modified by suturing, stapling, snaring, or shortening, using interventional tools which are introduced to a heart chamber. Preferably, the tissue structures are temporarily modified prior to permanent modification. For example, opposed valve leaflets may be temporarily grasped and held into position prior to permanent attachment.

In <CIT> and <CIT> there are described devices, systems and methods for tissue approximation and repair at treatment sites. The devices, systems and methods find use in a variety of therapeutic procedures, including endovascular, minimally-invasive, and open surgical procedures, and can be used in various anatomical regions, including the abdomen, thorax, cardiovascular system, heart, intestinal tract, stomach, urinary tract, bladder, lung, and other organs, vessels, and tissues. The devices, systems and methods are said to be particularly useful in those procedures requiring minimally-invasive or endovascular access to remote tissue locations, where the instruments utilized must negotiate long, narrow, and tortuous pathways to the treatment site. In addition, many of the devices and systems are adapted to be reversible and removable from the patient at any point without interference with or trauma to internal tissues.

In <CIT> there are described methods and apparatus for use in supporting tissue in a patient's body. In some examples, the patient's breast is supported. In some examples, the methods provide ways of supporting and adjusting tissue, and the apparatus includes components and examples for supporting and adjusting the tissue. Some examples include a supporting device, having a first portion, a second portion, and a support member positioned between the first portion and second portion. Some examples include advancing the first portion of the supporting device into the body to a first location in the body; advancing the second portion of the supporting device into the body to a second location in the body; securing the first portion of the supporting device at the first location; and shifting soft tissue in the body with the support member.

Nevertheless, there is an ongoing need to provide alternative and/or additional devices, and systems for tissue fixation that may provide beneficial elasticity and durability of the flexing components without unduly increasing the associated manufacturing costs of the flexing components. There is also a need to provide such devices, and systems in a manner that does not limit the tissue gripping ability of the tissue fixation device. At least some of the embodiments disclosed below are directed toward these objectives.

According to the present invention there is provided a tissue gripping device having the features of claim <NUM>.

There is also described a tissue fixation system configured for intravascular delivery and for use in joining mitral valve tissue during treatment of the mitral valve. The system includes a body; a first and second distal element, each including a first end pivotally coupled to the body and extending to a free second end and a tissue engagement surface between the first and second end, the tissue engagement surface being configured to approximate and engage a portion of leaflets of the mitral valve; and a tissue gripping device having the features of claim <NUM>. The tissue gripping device includes a first arm and a second arm, each arm having a first end coupled to the base section and a free end extending from the base section, the first and second arms being disposed opposite one another and each arm being configured to cooperate with one of the first or second distal elements to form a space for receiving and holding a portion of mitral valve tissue therebetween.

There is also described a method of gripping tissue, the method not being part of the claimed device, system, or kit. The method includes positioning a tissue gripping device near a target tissue, the tissue gripping device being formed from a shape-memory material and including a base section and a first arm and a second arm, each arm having a first end coupled to the base section and a free end extending from the base section, the first and second arms being disposed opposite one another. The method further includes moving the tissue gripping device from a pre-deployed configuration toward a deployed configuration, the first and second arms being configured to resiliently flex toward a relaxed configuration in a distal direction as the tissue gripping device is moved from a pre-deployed configuration toward a deployed configuration.

There is also described a method of manufacturing a tissue gripping device, the method not being part of the claimed device, system, or kit, and including: cutting one or more structural features into a strip or sheet stock material of a shape-memory alloy, the one or more structural features including a plurality of slotted recesses disposed at one or more side edges of the stock material; and heat shape setting one or more bend features into the stock material.

There is also described a tissue fixation kit, the kit including: a tissue gripping system that includes an actuator rod, an actuator line, and a first and second distal element, each including a first end pivotally coupled to the actuator rod and extending to a free second end and a tissue engagement surface between the first and second end, the first and second distal elements being positionable by the actuator rod. The tissue gripping system also includes a tissue gripping device having the features of claim <NUM>, the tissue gripping device being positionable by the actuator line. The tissue gripping system also includes a handle; and a delivery catheter having a proximal end and a distal end, the tissue gripping system being couplable to the distal end of the delivery catheter and the handle being couplable to the proximal end of the delivery catheter.

To further clarify the above and other advantages and features of the present disclosure, a more particular description of the disclosure will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. It is appreciated that these drawings depict only illustrated embodiments of the disclosure and are therefore not to be considered limiting of its scope. Embodiments of the disclosure will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:.

As shown in <FIG>, the mitral valve (MV) consists of a pair of leaflets (LF) having free edges (FE) which, in patients with normal heart structure and function, meet evenly to close along a line of coaption (C). The leaflets (LF) attach to the surrounding heart structure along an annular region called the annulus (AN). The free edges (FE) of the leaflets (LF) are secured to the lower portions of the left ventricle LV through chordae tendinae (or "chordae"). As the left ventricle of a heart contracts (which is called "systole"), blood flow from the left ventricle to the left atrium through the mitral valve (MV) (called "mitral regurgitation") is usually prevented by the mitral valve. Regurgitation occurs when the valve leaflets do not close properly and allow leakage from the left ventricle into the left atrium. A number of heart structural defects can cause mitral regurgitation. <FIG> shows a mitral valve with a defect causing regurgitation through a gap (G).

Several methods for repairing or replacing a defective mitral valve exist. Some defects in the mitral valve can be treated through intravascular procedures, where interventional tools and devices are introduced and removed from the heart through the blood vessels. One method of repairing certain mitral valve defects includes the intravascular delivery of a fixation device to hold portions of the mitral valve tissues in a certain position. One or more interventional catheters may be used to deliver a fixation device to the mitral valve and install it there as an implant to treat mitral regurgitation.

<FIG> illustrates a schematic of an interventional tool <NUM> or a tissue fixation system with a delivery shaft <NUM> and a fixation device <NUM>. The tool <NUM> has approached the mitral valve MV from the atrial side and grasped the leaflets LF. The fixation device <NUM> is releasably attached to the shaft <NUM> of the interventional tool <NUM> at the distal end of the shaft <NUM>. In this application, when describing devices, "proximal" means the direction toward the end of the device to be manipulated by the user outside the patient's body, and "distal" means the direction toward the working end of the device that is positioned at the treatment site and away from the user. When describing the mitral valve, proximal means the atrial side of the leaflets and distal means the ventricular side of the leaflets. The fixation device <NUM> includes grippers <NUM> and distal elements <NUM> which protrude radially outward and are positionable on opposite sides of the leaflets LF as shown so as to capture or retain the leaflets therebetween. The fixation device <NUM> is coupleable to the shaft <NUM> by a coupling mechanism <NUM>.

<FIG> illustrates that the distal elements <NUM> may be moved in the direction of arrows <NUM> to an inverted position. The grippers <NUM> may be raised as shown in <FIG>. In the inverted position, the device <NUM> may be repositioned and then be reverted to a grasping position against the leaflets as in <FIG>. Or, the fixation device <NUM> may be withdrawn (indicated by arrow <NUM>) from the leaflets as shown in <FIG>. Such inversion reduces trauma to the leaflets and minimizes any entanglement of the device with surrounding tissues.

<FIG> illustrates the fixation device <NUM> in a desired orientation in relation to the leaflets LF. The mitral valve MV is viewed from the atrial side, so the grippers <NUM> are shown in solid line and the distal elements <NUM> are shown in dashed line. The grippers <NUM> and distal elements <NUM> are positioned to be substantially perpendicular to the line of coaptation C. During diastole (when blood is flowing from the left atrium to the left ventricle), fixation device <NUM> holds the leaflets LF in position between the grippers <NUM> and distal elements <NUM> surrounded by openings or orifices O which result from the diastolic pressure gradient, as shown in <FIG>. Once the leaflets are coapted in the desired arrangement, the fixation device <NUM> is detached from the shaft <NUM> and left behind as an implant.

<FIG> illustrates an exemplary fixation device <NUM>. The fixation device <NUM> is shown coupled to a shaft <NUM> to form an interventional tool <NUM>. The fixation device <NUM> includes a coupling member <NUM>, a gripper <NUM> having a pair of opposed arms, and a pair of opposed distal elements <NUM>. The distal elements <NUM> include elongate arms <NUM>, each arm having a proximal end <NUM> rotatably connected to the coupling member <NUM> and a free end <NUM>. Preferably, each free end <NUM> defines a curvature about two axes, axis <NUM> parallel to a longitudinal axis of elongate arms <NUM>, and axis <NUM> perpendicular to axis <NUM> or the longitudinal axis of elongate arms <NUM>. Elongate arms <NUM> have tissue engagement surfaces <NUM>. Elongate arms <NUM> and tissue engagement surfaces <NUM> are configured to engage <NUM>-<NUM> of tissue, and preferably <NUM>-<NUM>, along the longitudinal axis of elongate arms <NUM>. Elongate arms <NUM> further include a plurality of openings.

The arms of the gripper <NUM> are preferably resiliently biased toward the distal elements <NUM>. When the fixation device <NUM> is in the open position, each arm of the gripper <NUM> is separated from the engagement surface <NUM> near the proximal end <NUM> of elongate arm <NUM> and slopes toward the engagement surface <NUM> near the free end <NUM> with the free end of the gripper <NUM> contacting engagement surface <NUM>, as illustrated in <FIG>. Arms of gripper <NUM> can include a plurality of openings <NUM> and scalloped side edges <NUM> to increase their grip on tissue. The arms of gripper <NUM> optionally include a frictional element or multiple frictional elements to assist in grasping the leaflets. The frictional elements may include barbs <NUM> having tapering pointed tips extending toward tissue engagement surfaces <NUM>. Any suitable frictional elements may be used, such as prongs, windings, bands, barbs, grooves, channels, bumps, surface roughening, sintering, high-friction pads, coverings, coatings or a combination of these. The gripper <NUM> may be covered with a fabric or other flexible material. Preferably, when fabrics or coverings are used in combination with barbs or other frictional features, such features will protrude through such fabric or other covering so as to contact any tissue engaged by gripper <NUM>.

The fixation device <NUM> also includes an actuator or actuation mechanism <NUM>. The actuation mechanism <NUM> includes two link members or legs <NUM>, each leg <NUM> having a first end <NUM> which is rotatably joined with one of the distal elements <NUM> at a riveted joint <NUM> and a second end <NUM> which is rotatably joined with a stud <NUM>. The actuation mechanism <NUM> includes two legs <NUM> which are each movably coupled to a base <NUM>. Or, each leg <NUM> may be individually attached to the stud <NUM> by a separate rivet or pin. The stud <NUM> is joinable with an actuator rod which extends through the shaft <NUM> and is axially extendable and retractable to move the stud <NUM> and therefore the legs <NUM> which rotate the distal elements <NUM> between closed, open, and inverted positions. Immobilization of the stud <NUM> holds the legs <NUM> in place and therefore holds the distal elements <NUM> in a desired position. The stud <NUM> may also be locked in place by a locking feature. This actuator rod and stud assembly may be considered a first means for selectively moving the distal elements between a first position in which the distal elements are in a collapsed, low profile configuration for delivery of the device, a second position in which the distal elements are in an expanded configuration for positioning the device relative to the mitral valve, and a third position in which the distal elements are secured in position against a portion of the leaflets adjacent the mitral valve on the ventricular side.

<FIG>, <FIG>, and <FIG> illustrate various possible positions of the fixation device <NUM> of <FIG>. <FIG> illustrates an interventional tool <NUM> delivered through a catheter <NUM>. The catheter <NUM> may take the form of a guide catheter or sheath. The interventional tool <NUM> comprises a fixation device <NUM> coupled to a shaft <NUM> and the fixation device <NUM> is shown in the closed position.

<FIG> illustrates a device similar to the device of <FIG> in a larger view. In the closed position, the opposed pair of distal elements <NUM> are positioned so that the tissue engagement surfaces <NUM> face each other. Each distal element <NUM> comprises an elongate arm <NUM> having a cupped or concave shape so that together the elongate arms <NUM> surround the shaft <NUM>. This provides a low profile for the fixation device <NUM>.

<FIG> illustrate the fixation device <NUM> in the open position. In the open position, the distal elements <NUM> are rotated so that the tissue engagement surfaces <NUM> face a first direction. Distal advancement of the actuator rod relative to shaft <NUM>, and thus distal advancement of the stud <NUM> relative to coupling member <NUM>, applies force to the distal elements <NUM> which begin to rotate around joints <NUM>. Such rotation and movement of the distal elements <NUM> radially outward causes rotation of the legs <NUM> about joints <NUM> so that the legs <NUM> are directed slightly outwards. The stud <NUM> may be advanced to any desired distance correlating to a desired separation of the distal elements <NUM>. In the open position, tissue engagement surfaces <NUM> are disposed at an acute angle relative to shaft <NUM>, and can be at an angle of between <NUM> and <NUM> degrees relative to each other, preferably at an angle of between <NUM> and <NUM> degrees or between <NUM> and <NUM> degrees relative to each other (e.g., between <NUM> and <NUM> degrees, between <NUM> and <NUM> degrees, between <NUM> and <NUM> degrees, between <NUM> and <NUM> degrees, between <NUM> and <NUM> degrees, or <NUM> degrees). In the open position, the free ends <NUM> of elongate arms <NUM> may have a span therebetween of <NUM>-<NUM>, or <NUM>-<NUM>, usually <NUM>-<NUM> or <NUM>-<NUM>, and preferably <NUM>-<NUM>.

The arms of gripper <NUM> are typically biased outwardly toward elongate arms <NUM> when in a relaxed configuration. The arms of gripper <NUM> may be moved inwardly toward the shaft <NUM> and held against the shaft <NUM> with the aid of gripper lines <NUM> which can be in the form of sutures, wires, nitinol wire, rods, cables, polymeric lines, or other suitable structures. The gripper lines <NUM> can extend through a shaft of a delivery catheter (not shown) and connect with the gripper <NUM>. The arms of the gripper <NUM> can be raised and/or lowered by manipulation of the gripper lines <NUM>. For example, <FIG> illustrates gripper <NUM> in a lowered position as a result of releasing tension and/or providing slack to gripper lines <NUM>. Once the device is properly positioned and deployed, the gripper lines can be removed by withdrawing them through the catheter and out the proximal end of the tool <NUM>. The gripper lines <NUM> may be considered a second means for selectively moving the gripper <NUM> between a first position in which the gripper arms are in a collapsed, low profile configuration for delivery of the device and a second position in which the gripper arms are in an expanded configuration for engaging a portion of the leaflets adjacent the mitral valve on the atrial side.

In the open position, the fixation device <NUM> can engage the tissue which is to be approximated or treated. The interventional tool <NUM> is advanced through the mitral valve from the left atrium to the left ventricle. The distal elements <NUM> are then deployed by advancing actuator rod relative to shaft <NUM> to thereby reorient distal elements <NUM> to be perpendicular to the line of coaptation. The entire assembly is then withdrawn proximally and positioned so that the tissue engagement surfaces <NUM> contact the ventricular surface of the valve leaflets, thereby engaging the left ventricle side surfaces of the leaflets. The arms of the gripper <NUM> remain on the atrial side of the valve leaflets so that the leaflets lie between the proximal and distal elements. The interventional tool <NUM> may be repeatedly manipulated to reposition the fixation device <NUM> so that the leaflets are properly contacted or grasped at a desired location. Repositioning is achieved with the fixation device in the open position. In some instances, regurgitation may also be checked while the device <NUM> is in the open position. If regurgitation is not satisfactorily reduced, the device may be repositioned and regurgitation checked again until the desired results are achieved.

It may also be desired to invert distal elements <NUM> of the fixation device <NUM> to aid in repositioning or removal of the fixation device <NUM>. <FIG> illustrates the fixation device <NUM> in the inverted position. By further advancement of actuator rod relative to shaft <NUM>, and thus stud <NUM> relative to coupling member <NUM>, the distal elements <NUM> are further rotated so that the tissue engagement surfaces <NUM> face outwardly and free ends <NUM> point distally, with each elongate arm <NUM> forming an obtuse angle relative to shaft <NUM>.

The angle between elongate arms <NUM> when the device is inverted is preferably in the range of <NUM> to <NUM> degrees (e.g., <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, or <NUM> to <NUM> degrees). Further advancement of the stud <NUM> further rotates the distal elements <NUM> around joints <NUM>. This rotation and movement of the distal elements <NUM> radially outward causes rotation of the legs <NUM> about joints <NUM> so that the legs <NUM> are returned toward their initial position, generally parallel to each other. The stud <NUM> may be advanced to any desired distance correlating to a desired inversion of the distal elements <NUM>. Preferably, in the fully inverted position, the span between free ends <NUM> is no more than <NUM>, or no more than <NUM> or <NUM>, usually less than <NUM>, preferably <NUM>-<NUM>, <NUM>-<NUM>, or <NUM>-<NUM>, more preferably <NUM>-<NUM>. Barbs <NUM> are preferably angled in the distal direction (away from the free ends of the grippers <NUM>), reducing the risk that the barbs will catch on or lacerate tissue as the fixation device is withdrawn.

Once the distal elements <NUM> of the fixation device <NUM> have been positioned in a desired location against the ventricle side surfaces of the valve leaflets, the leaflets may then be captured between the gripper <NUM> and the distal elements <NUM>. The arms of the gripper <NUM> are lowered toward the tissue engagement surfaces <NUM> by releasing tension from gripper lines <NUM>, thereby releasing the arms of the gripper <NUM> so that they are then free to move, in response to the internal spring bias force formed into gripper <NUM>, from a constrained, collapsed position to an expanded, deployed position with the purpose of holding the leaflets between the gripper <NUM> and the distal elements <NUM>. If regurgitation is not sufficiently reduced and/or if one or more of the leaflets are not properly engaged, the arms of the gripper <NUM> may be raised and the distal elements <NUM> adjusted or inverted to reposition the fixation device <NUM>.

After the leaflets have been captured between the gripper <NUM> and distal elements <NUM> in a desired arrangement, the distal elements <NUM> may be locked to hold the leaflets in this position or the fixation device <NUM> may be returned to or toward a closed position. This is achieved by retraction of the stud <NUM> proximally relative to coupling member <NUM> so that the legs <NUM> of the actuation mechanism <NUM> apply an upwards force to the distal elements <NUM>, which, in turn, rotate the distal elements <NUM> so that the tissue engagement surfaces <NUM> again face one another. The released grippers <NUM> which are biased outwardly toward distal elements <NUM> are concurrently urged inwardly by the distal elements <NUM>. The fixation device <NUM> may then be locked to hold the leaflets in this closed position. The fixation device <NUM> may then be released from the shaft <NUM>.

The fixation device <NUM> optionally includes a locking mechanism for locking the device <NUM> in a particular position, such as an open, closed, or inverted position, or any position therebetween. The locking mechanism may include a release harness. Applying tension to the release harness may unlock the locking mechanism. Lock lines can engage a release harnesses of the locking mechanism to lock and unlock the locking mechanism. The lock lines can extend through a shaft of the delivery catheter. A handle attached to the proximal end of the shaft can be used to manipulate and decouple the fixation device <NUM>.

Additional disclosure regarding such fixation devices <NUM> may be found in <CIT> and <CIT>.

The tissue fixation devices of the present disclosure include a gripper formed from a shape-memory material. The shape-memory material is configured to exhibit superelasticity when positioned in a physiological environment. Such shape-memory materials can include shape-memory alloys and/or shape-memory polymers. Shape-memory alloys included in embodiments of the grippers of the present disclosure include copper-zinc-aluminum; copper-aluminum-nickel; nickel-titanium (NiTi) alloys known as nitinol; nickel-titanium platinum; and nickel-titanium palladium alloys, for example. Shape-memory polymers included in embodiments of the grippers of the present disclosure include biodegradable polymers, such as oligo(ε-caprolactone)diol, oligo(ρ-dioxanone)diol, and non-biodegradable polymers such as, polynorborene, polyisoprene, styrene butadiene, polyurethane-based materials, vinyl acetate-polyester-based compounds, for example. In preferred embodiments, the gripper is formed from nitinol. Such nitinol grippers can be configured with linear elastic properties, non-linear elastic properties, pseudo linear-elastic properties, or other elastic properties.

<FIG> illustrate various views of an embodiment of a tissue gripper <NUM> formed from a shape-memory material. In preferred embodiments, the tissue gripper <NUM> is formed from a nickel titanium alloy with transformation temperature (e.g., an austenite finish temperature (Af)) of -<NUM> to <NUM> degrees C, or from -<NUM> to <NUM> degrees C, or from -<NUM> to <NUM> degrees C, or from -<NUM> to <NUM> degrees C, or from -<NUM> to <NUM> degrees C, or from -<NUM> to <NUM> degrees C, or from -<NUM> to <NUM> degrees C, or from <NUM> to <NUM> degrees C. In such embodiments, the gripper <NUM> can exhibit superelasticity at physiological temperatures, and can exhibit superelasticity during flexing, bending, and/or other maneuvering of the gripper <NUM>. For instance, the gripper <NUM> can exhibit superelasticity during positioning and deployment of the device at a treatment site and/or during continued movement after being deployed.

During a mitral valve repair procedure or other tissue fixing procedure, for example, portions of the tissue gripping device may need to repeatedly pass through wide angles as multiple tissue grasping attempts are made and/or as the gripper <NUM> is moved into an acceptable position against the leaflets of the mitral valve or against other targeted tissue. Furthermore, even after deployment, the tissue gripper <NUM> may need to provide some amount of flexibility and movement as the repaired and/or fixated tissue continues to flex and/or move. For example, one situation where additional flexibility and movement may be necessary is where mitral valve tissue continues to flex against the gripper <NUM> during cardiac cycles. In other situations, additional flexibility and movement may be necessary as the repaired and/or fixated tissue flexes, shifts, stretches, or otherwise moves relative to an original fixed position, such as with various musculoskeletal tissues during various forms of physiological movement (e.g., in response to muscle contraction and/or relaxation, movement at a joint, and movement between adjacent or nearby connective tissues).

Forming the tissue gripper <NUM> from a shape-memory material such as nitinol may avoid plastic deformation of the tissue gripper <NUM> during these movements. By configuring the shape-memory material to exhibit superelasticity at physiological temperatures, the tissue gripper <NUM> is able to stay entirely within the elastic deformation range throughout its life within the body. Preferably, the shape-memory material is configured to exhibit superelasticity throughout the range of temperatures expected to be encountered during pre-deployment, deployment, and implanted use within the body (e.g., <NUM> to <NUM> degrees C, <NUM> to <NUM> degrees C, <NUM> to <NUM> degrees C, <NUM> to <NUM> degrees C, <NUM> to <NUM> degrees C, and <NUM> to <NUM> degrees C).

For instance, in some embodiments, the shape-memory material can be nitinol, and the nitinol can be configured to have a hysteresis curve that leaves the tissue gripper <NUM> within the elastic deformation range throughout its life and throughout the range of temperatures that are expected to be encountered during pre-deployment, deployment, and implanted use within the body, or during any other time where the tissue gripper <NUM> is flexed and/or deformed, such as during post manufacturing testing and/or positioning within a delivery system prior to delivery to target tissue. Such embodiments can advantageously reduce and/or eliminate mechanical fatigue and degradation of the tissue gripper <NUM> from repeated and/or high levels of plastic deformation. In addition, as will be explained in more detail below, embodiments of the present disclosure can promote easier tissue grasping during deployment and/or positioning of the tissue gripper <NUM>.

In the illustrated embodiment, the tissue gripper <NUM> includes a proximal side <NUM>, a distal side <NUM>, a base section <NUM>, and a pair of arms <NUM>. Each arm <NUM> extends from the base section <NUM> to a free end <NUM>. In other arrangements there may be more than two arms extending from a base section. For example, some arrangements may have multiple arms arrayed about a base section (e.g., in a radial fashion), and/or may include a first plurality of arms disposed opposite a second plurality of arms.

The gripper <NUM> of the illustrated embodiment includes a pair of base bend features <NUM> disposed at the base section <NUM>, and a pair of arm bend features <NUM> partitioning the arms <NUM> from the base section <NUM>. The base bend features <NUM> form angles of <NUM> degrees or just under <NUM> degrees as measured from the proximal side <NUM>, and the arm bend features <NUM> form angles of <NUM> degrees or just under <NUM> degrees as measured from the distal side <NUM>.

The base bend features <NUM> and arm bend features <NUM> are configured to give the tissue gripper <NUM> a bent configuration when the tissue gripper <NUM> is in a relaxed state, such that when the tissue gripper <NUM> is forced into a stressed state (e.g., by bending the tissue gripper <NUM> at one or more of the base and/or arm bend features <NUM> and <NUM>), the tissue gripper <NUM> is resiliently biased toward the relaxed state.

For example, an arm <NUM> may be positioned at the arm bend feature <NUM> in a manner that flexes the arm <NUM> in a proximal direction and an inward direction, thereby flexing the arm <NUM> toward a straighter configuration (e.g., increasing the angle of the arm bend feature <NUM> as measured from the distal side <NUM>). In such a position, the tissue gripper <NUM> is in a stressed state such that the arm <NUM> of the tissue gripper <NUM> is resiliently biased toward a distal direction and an outward direction. Other arrangements may include additional bend features. These and other arrangements may include bend features with differing bend angles when in a relaxed state. For example, some arrangements may include bend features that measure greater than <NUM> degrees or less than <NUM> degrees when in a relaxed state.

In another example, prior to moving the tissue gripper <NUM> into position in the mitral valve or into position near other targeted tissue, the tissue gripper may be positioned in a pre-deployed configuration (see, e.g., <FIG> and related discussion) by positioning the arm bend features <NUM> toward a straighter configuration. The tissue grippers of the present disclosure, such as the illustrated tissue gripper <NUM>, beneficially and advantageously can be moved into such a pre-deployed configuration without being plastically deformed at the arm bend features <NUM> and/or at other areas. Accordingly, the tissue gripper <NUM> may move from such a pre-deployed configuration back toward a relaxed configuration by allowing the arms <NUM> to move distally and outwardly. In preferred embodiments, the relaxed configuration, after the tissue gripper <NUM> has been moved into a pre-deployed configuration and back, is the same or substantially the same as prior to the tissue gripper <NUM> being moved into the pre-deployed configuration and back (e.g., the angles at the arm bend features <NUM> in the relaxed configuration are unchanged, as opposed to being altered as a result of plastic deformation).

The tissue gripper <NUM> of the illustrated embodiment may include a plurality of holes <NUM> distributed along the length of each arm <NUM>. The holes <NUM> may be configured to provide a passage or tie point for one or more sutures, wires, nitinol wires, rods, cables, polymeric lines, other such structures, or combinations thereof. As discussed above, these materials may be coupled to one or more arms <NUM> to operate as gripper lines (e.g., gripper lines <NUM> illustrated in <FIG>) for raising, lowering, and otherwise manipulating, positioning and/or deploying the tissue gripper <NUM>. In some embodiments, for example, suture loops or other structures may be positioned at one or more of the holes <NUM>, and one or more gripper lines may be threaded, laced, or otherwise passed through the suture loops. Such suture loops or other suture fastening structures may be wrapped and/or threaded a single time or multiple times before being tied, tightened, or otherwise set in place. For example, some suture lines may be wrapped repeatedly and/or may double back on themselves in order to strengthen or further secure the coupling of the suture loop to an arm <NUM>.

Other embodiments may include a tissue gripper with more or fewer holes and/or with holes in other positions of the tissue gripper. For example, some embodiments may include only one hole and/or only one hole per arm. Other embodiments may include holes of different shapes and/or sizes, such as holes formed as slots, slits, or other shapes. In embodiments where more than one hole is included, the holes may be uniform in size, shape, and distribution or may be non-uniform in one or more of size, shape, and distribution.

Each arm <NUM> of the illustrated embodiment includes a furcated section <NUM>. The furcated section <NUM> may extend from the base section <NUM> to a position farther along the arm <NUM> toward the free end <NUM> of the arm <NUM>, as illustrated. In other arrangements, a furcated section may be positioned at other locations along an arm and/or base section. Other arrangements may include one or more furcated sections extending completely to the free end of an arm, thereby forming a bifurcated or forkshaped arm. The furcated sections <NUM> of the illustrated embodiment coincide with the arm bend features <NUM>. The furcated sections <NUM> may be configured (e.g., in size, shape, spacing, position, etc.) so as to provide desired resiliency, fatigue resistance, and/or flexibility at the coinciding arm bend features <NUM>.

As illustrated, the tissue gripper <NUM> includes a plurality of frictional elements <NUM> configured to engage with tissue at a treatment site and resist movement of tissue away from the tissue gripping member after the frictional elements <NUM> have engaged with the tissue. As shown in the illustrated embodiment, the frictional elements <NUM> are formed as angled barbs extending distally and inwardly from a side edge <NUM> of the arms <NUM> of the gripper <NUM>. In this manner, tissue that is engaged with the frictional elements <NUM> of a tissue gripper <NUM> is prevented from moving proximally and outwardly relative to the tissue gripper <NUM>.

The frictional elements <NUM> of the illustrated tissue gripper <NUM> protrude from a side edge <NUM> of each of the arms <NUM>, thereby forming a plurality of slotted recesses <NUM> disposed along side edges <NUM> of each arm <NUM> at sections adjacent to the frictional elements <NUM>. Other arrangements may include frictional elements of varying size, number, and/or shape. For example, in some arrangements the frictional elements may be formed as posts, tines, prongs, bands, grooves, channels, bumps, pads, or a combination of these or any other feature suitable for increasing friction and/or gripping of contacted tissue.

Embodiments of the devices and systems of the present disclosure can provide particular advantages and benefits in relation to a tissue gripping and/or tissue fixation procedure. For example, at least one use of the devices and systems of the present disclosure can include moving and/or flexing a tissue gripper from a pre-deployed configuration toward a deployed configuration at a wider angle (e.g., angle in which the arms of the gripping device are separated) than that disclosed by the prior art, providing advantages such as better grasping ability, less tissue trauma, better grasping of separate portions of tissue simultaneously (e.g., opposing leaflets of the mitral valve), reduced slip-out of tissue during additional device movements or procedural steps (e.g., during a closing step), reduced grasping force required in order to grip the targeted tissue, or combinations thereof. In addition, tissue grippers of the present disclosure may be moved into a pre-deployed configuration without resulting plastic deformation affecting the range of grasping angles of the device.

In addition, embodiments of the present disclosure can include increased resistance to mechanical fatigue than that disclosed by the prior art. For example, at least some of the tissue gripping devices of the present disclosure can be formed of a shape-memory material that provides resistance to progressive weakening of the device as a result of repeatedly applied and/or cyclic loads. For instance, as compared to a tissue gripping device not formed from a shape-memory material, at least some of the tissue gripping devices of the present disclosure have enhanced resistance to the formation of microscopic cracks and other stress concentrators (e.g., at grain boundaries or other discontinuity locations of the material).

<FIG> illustrate a prior art gripping system <NUM> in use in a tissue gripping application. <FIG> shows a tissue gripper <NUM> made from a plastically deformable material positioned in a pre-deployed configuration. A pair of distal elements <NUM> is illustrated in an open position at <NUM> degrees, as measured from a proximal side, the pair of distal elements being positioned near target tissue <NUM> on the distal side of target tissue. Upon movement or release of the tissue gripper <NUM> from the pre-deployment configuration, the arms of the tissue gripper <NUM> move slightly in a proximal and outward direction toward the target tissue <NUM>. However, the tissue gripper <NUM> is only able to reach a deployment angle, as measured by the separation of the opposing arms of the tissue gripper <NUM> on the proximal side, of <NUM> degrees. As illustrated in <FIG>, this may result in incomplete or missed grasping of the target tissue <NUM>, as the arms of the tissue gripper <NUM> are unable to flex or extend outwardly and proximally far enough to fully engage with the target tissue <NUM>.

As illustrated in <FIG>, gripping of the target tissue <NUM> requires at least an additional step of closing the distal elements <NUM> to <NUM> degrees in order to grip the target tissue <NUM> between the distal elements <NUM> and the arms of the tissue gripper <NUM> by moving the distal elements <NUM> proximally and inwardly toward the tissue gripper <NUM>. During this step and/or during the interim between the position illustrated in <FIG> and the position illustrated in <FIG>, the target tissue <NUM> may move or slip away from the gripping system <NUM>. In addition, the position of the target tissue <NUM> or portions of the target tissue <NUM> may shift relative to the tissue gripper <NUM> and/or the distal elements <NUM>, requiring repositioning of the gripping system <NUM> and/or its components. This can be particularly problematic in procedures, such as mitral valve repair procedures, where the target tissue is rapidly and continuously moving, where multiple portions of target tissue must be grasped simultaneously, and where precise gripping position is demanded. Such limitations limit the number of available tissue gripping and/or fixation procedures and their effectiveness.

In contrast, <FIG> illustrate an embodiment of a tissue gripping system <NUM> of the present disclosure in a tissue gripping application. As illustrated in <FIG>, a pair of distal elements <NUM> are coupled to a body <NUM> (e.g., an actuator rod) and are associated with a tissue gripper <NUM>. The tissue gripping system <NUM> may be positioned at or near target tissue <NUM>, where the tissue gripper <NUM> can be positioned in a pre-deployed configuration with the arms of the tissue gripper <NUM> extending proximally from the base of the tissue gripper <NUM>. In addition, the distal elements <NUM> may be moved to a distal side of the target tissue before, during, or after being positioned in an open configuration with an opening angle <NUM> of <NUM> degrees (e.g., <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, or <NUM> to <NUM> degrees). In other embodiments, the opening angle <NUM> may be more or less than <NUM> degrees (e.g., <NUM> to <NUM> degrees, or <NUM> to <NUM> degrees, or <NUM> to <NUM> degrees, or <NUM> to <NUM> degrees), though in preferred embodiments, the opening angle <NUM> is at least <NUM> degrees or more (e.g., <NUM> to <NUM> degrees). In some embodiments, the opening angle <NUM> can be more than <NUM> degrees (e.g., <NUM> degrees or <NUM> degrees or more).

As illustrated in <FIG>, after positioning the distal elements <NUM>, the tissue gripper <NUM> can be moved and/or dropped from the pre-deployed configuration, where the arms of the tissue gripper <NUM> are positioned in a stressed state, toward a deployed configuration, where the arms flex and/or move toward a relaxed state. The tissue gripper <NUM> may be moved, dropped, or otherwise actuated using, for example, one or more gripper lines (such as those illustrated in <FIG>).

As illustrated in <FIG>, upon actuation, the tissue gripper <NUM> moves outwardly and distally to fully engage with the target tissue <NUM>, and to fully engage the target tissue <NUM> against the proximal surface of the distal elements <NUM> by closing to an actuation angle <NUM> (as measured from the proximal side) that is substantially similar to the opening angle <NUM> of the distal elements <NUM>. For example, the actuation angle <NUM> may equal the opening angle <NUM> or may be slightly smaller than the opening angle <NUM> (e.g., by <NUM> to <NUM> degrees, or <NUM> to <NUM> degrees, or <NUM> to <NUM> degrees, or <NUM> to <NUM> degrees or less) as a result of target tissue <NUM> being gripped between the distal elements <NUM> and the arms of the tissue gripper <NUM>.

As shown by <FIG>, the full length of the arms of the tissue gripper <NUM> may be engaged against the target tissue <NUM> upon actuation of the tissue gripper <NUM> towards the deployed configuration. For example, because the actuation angle <NUM> is the same as or is substantially similar to the opening angle <NUM>, any separation between the proximal surfaces of the distal elements <NUM> and the arms of the tissue gripper <NUM> is due to an amount of target tissue <NUM> caught and/or engaged between the arms of the tissue gripper <NUM> and a proximal surface of a distal element <NUM>.

The tissue gripper <NUM> can be configured to provide an actuation angle <NUM> that is <NUM> to <NUM> degrees. In preferred embodiments, the actuation angle is <NUM> degrees (e.g., <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, <NUM> to <NUM> degrees, or <NUM> to <NUM> degrees). In other embodiments, the actuation angle <NUM> may be more or less than <NUM> degrees (e.g., <NUM> to <NUM> degrees, or <NUM> to <NUM> degrees, or <NUM> to <NUM> degrees, or <NUM> to <NUM> degrees).

In preferred embodiments, the tissue gripper <NUM> is configured such that the arms of the tissue gripper <NUM> resiliently flex against target tissue <NUM> and/or distal elements <NUM> after moving from a pre-deployed configuration toward a deployed configuration. For example, the tissue gripper <NUM> can be configured such that, when positioned in a relaxed configuration, the arms of the tissue gripper <NUM> are open at an angle that is greater than a selected opening angle <NUM> of the distal elements <NUM>. In some embodiments, for example, the arms of the tissue gripper <NUM>, while positioned in a relaxed configuration, can be angled apart, as measured from a proximal side, at an angle of between <NUM> degrees and <NUM> degrees. (e.g., <NUM> to <NUM> degrees). In such embodiments, the opening angle <NUM> of the distal elements <NUM> can be less than the angle between the arms of the tissue gripper <NUM> (e.g., <NUM> to <NUM> degrees, or <NUM> to <NUM> degrees, or <NUM> degrees). For example, when the opening angle <NUM> is <NUM> degrees, the actuation angle <NUM> of the tissue gripper <NUM> will expand to reach <NUM> degrees or beyond <NUM> degrees after moving toward a deployed configuration, but the arms of the tissue gripper <NUM> will not have moved to the full extent of the relaxed configuration. Thus, the arms of the tissue gripper <NUM>, in such embodiments, will continue to resiliently flex against target tissue <NUM> and/or distal elements <NUM> even after expanding the full range of the actuation angle <NUM>.

Accordingly, in such embodiments, when the tissue gripper <NUM> is moved from the pre-deployed configuration toward the deployed configuration, the arms of the tissue gripper <NUM> abut against the target tissue <NUM> and/or the distal elements <NUM> before reaching the full distal and outward extension of the relaxed configuration. In this manner, the arms of the tissue gripper <NUM> can resiliently flex against the target tissue <NUM> and/or distal elements <NUM> even after the tissue gripper <NUM> has moved the full or substantially full extent of the actuation angle <NUM>.

In preferred embodiments, the tissue gripper <NUM>, opening angle <NUM>, and actuation angle <NUM> are configured such that when the tissue gripper <NUM> moves toward a deployed configuration and engages with target tissue <NUM>, the tissue gripper <NUM> exerts a force of from <NUM> to <NUM>. 44N (<NUM> to <NUM> pounds) against the target tissue <NUM>. In other embodiments, the tissue gripper can exert a force of from <NUM> to <NUM>. 53N (<NUM> to <NUM> pounds) or from <NUM> to <NUM>. 76N (<NUM> to <NUM> pounds), for example.

<FIG> illustrates that, in some embodiments, following movement of the tissue gripper <NUM> toward a deployed configuration, the distal elements <NUM> may be closed or partially closed in order to move or position the target tissue <NUM> and/or the components of the tissue gripping system <NUM> to a desired position and/or to assess the grasped tissue prior to further closing and release of the tissue gripping system <NUM>. For example, the distal elements <NUM> can be actuated toward a closing angle <NUM> in order to move the distal elements <NUM> and the arms of the tissue gripper <NUM>, as well as any target tissue <NUM> grasped therebetween, into a closed position. In some embodiments, the closing angle <NUM> will be <NUM> degrees, or will range from <NUM> to <NUM> degrees (e.g., <NUM> to <NUM> degrees or <NUM> to <NUM> degrees or <NUM> degrees to <NUM> degrees). In other embodiments, closing or partially closing the distal elements is omitted. For example, the tissue gripping system <NUM> or components thereof may be left in place or may be considered as properly positioned after moving the tissue gripper <NUM> through the actuation angle <NUM>, without additional closing of the tissue gripping system <NUM>.

Various tissue gripping and/or tissue fixation procedures may call for different closing angles <NUM> to be used. For example, a closing angle <NUM> of <NUM> degrees or less may be useful in assessing the sufficiency of a tissue grasping attempt in a mitral valve regurgitation procedure, and a closing angle <NUM> that is greater than <NUM> degrees (e.g., up to <NUM> degrees) may be useful in a functional mitral valve regurgitation procedure and/or in assessing the sufficiency of a tissue grasping attempt in a functional mitral valve regurgitation procedure.

The tissue gripping devices of the present disclosure may be manufactured by forming a tissue gripper from a shape-memory material (such as nitinol), as illustrated in <FIG>. Forming the tissue gripper may be accomplished by cutting a pattern shape from a shape-memory stock material <NUM>. The stock material <NUM> can be strip stock, sheet stock, band stock, or other forms of stock material.

The stock material <NUM> may be subjected to a subtractive manufacturing processes in order to prepare the stock material <NUM> with a suitable size and shape prior to further manufacturing. For example, grinding of one or more surfaces of the stock material <NUM> may be carried out in order to achieve a desired dimension and/or a desired uniformity along a given direction (e.g., grinding of a top and/or bottom surface to achieve a desired thickness).

As illustrated in <FIG>, various structural features (e.g., furcated sections <NUM>, holes <NUM>, slotted recesses <NUM>) may be formed in the stock material <NUM>. This may be accomplished using any suitable subtractive manufacturing process such as drilling, lathing, die stamping, cutting, or the like. In preferred methods of manufacture, features are formed using a laser cut or wire-EDM process. For example, in a preferred method, a plurality of slotted recesses <NUM> are formed in the stock material <NUM> using a laser cutting process. In some methods, other features may be added using an additive manufacturing process.

As illustrated in <FIG>, in some methods, the tissue gripper may be further processed through a shape setting process. For example, one or more bend features may be formed in the tissue gripper by subjecting the tissue gripper to a heated shape setting process in order to set the shape of the bend(s) in the shape-memory material of the tissue gripper. For example, in cases where the grippers are formed from nitinol, the austenite phase (i.e., parent phase or memory phase) can be set with the desired bend features. In some methods of manufacture, this requires positioning and/or forming the desired shape while heating the gripper to a temperature high enough to fix the shape as part of the austenite phase (e.g., <NUM> to <NUM> degrees C).

For example, one or more of the base bend features <NUM>, arm bend features <NUM>, and frictional elements <NUM> may be formed in a heat shape setting process. In some methods, these features may be set at the same time in one heat shape setting process. In other methods, multiple heat shape setting steps may be used, such as a first heat shape setting process to form the base bend features <NUM>, followed by a second heat shape setting process to form the arm bend features <NUM>, followed by a third heat shape setting process to form the frictional elements <NUM> (e.g., by bending portions of the side edge <NUM> adjacent to slotted recesses <NUM> in order to form distally and inwardly projecting barbs). In yet other methods, other combinations of features may be set in any suitable number of heat shape setting steps in order to form the tissue gripper <NUM>.

In preferred methods of manufacture, the arm bend features <NUM> are formed in a heat shape setting process such that the angle between the opposing arms <NUM>, as measured from a proximal side <NUM> while the tissue gripper <NUM> is in a relaxed configuration, is <NUM> degrees or is slightly more than <NUM> degrees (e.g., <NUM> to <NUM> degrees). In such methods, the tissue gripper <NUM> formed as a result of the manufacturing process can be moved into a pre-deployed configuration by bending the arm bend features <NUM> to move the arms <NUM> proximally and inwardly. In such a stressed state, the arms <NUM> will resiliently flex toward the relaxed configuration for the full range of angles up to the relaxed configuration of <NUM> degrees or slightly more than <NUM> degrees. In addition, because the tissue gripper <NUM> is formed of a shape-memory material such as nitinol, and is configured to exhibit superelasticity at operational and physiological temperatures, the arms <NUM> of the tissue gripper <NUM> are able to move from the relaxed configuration to the pre-deployed configuration without being plastically deformed, and are thus able to fully flex toward the original relaxed configuration and return to the original relaxed configuration.

In some methods, one or more additional manufacturing processes may be performed to prepare a tissue gripper <NUM>. For example, mechanical deburring (e.g., small particulate blasting) and/or electropolishing (e.g., to clean edges and passivate the tissue gripper <NUM>) may be performed on the tissue gripper <NUM>, or on parts thereof. Such additional processes may be done prior to, intermittent with, or after one or more heat shape setting processes. In addition, the tissue gripper <NUM> may be cleaned in an ultrasonic bath (e.g., with DI water and/or isopropyl alcohol, in combination or in succession).

Kits can include any of the components described herein, as well as additional components useful for carrying out a tissue gripping procedure. Kits may include, for example, a tissue gripping system as described herein, including a tissue gripper, distal elements, actuator rod, and actuator lines (such as lock lines and gripper lines), a delivery catheter, and a handle, the tissue gripping system being couplable to the delivery catheter at a distal end of the delivery catheter and the handle being couplable to the delivery catheter at a proximal end of the delivery catheter. In such arrangements, the actuator lines and/or actuator rod can pass from the tissue gripping system through lumens of the delivery catheter and to the handle, and the handle can include one or more controls for actuating or otherwise controlling the components of the tissue gripping system.

Some kits may include additional interventional tools, such as a guidewire, dilator, needle, and/or instructions for use. Instructions for use can set forth any of the methods described herein. The components of the kit can optionally be packaged together in a pouch or other packaging, and in preferred arrangements will be sterilized. Optionally, separate pouches, bags, trays, or other packaging may be provided within a larger package such that smaller packages can be opened separately to separately maintain the components in a sterile manner.

The terms "approximately," "about," and "substantially" as used herein represent an amount or condition close to the stated amount or condition that still performs a desired function or achieves a desired result. For example, the terms "approximately," "about," and "substantially" may refer to an amount that is within less than <NUM>% of, within less than <NUM>% of, within less than <NUM>% of, and within less than <NUM>% of a stated amount. In addition, unless expressly described otherwise, all amounts (e.g., temperature amounts, angle measurements, dimensions measurements, etc.) are to be interpreted as being "approximately," "about," and/or "substantially" the stated amount, regardless of whether the terms "approximately," "about," and/or "substantially.

Additionally, elements described in relation to any embodiment depicted and/or described herein may be combinable with elements described in relation to any other embodiment depicted and/or described herein. For example, any element described in relation to an embodiment depicted in <FIG> may be combinable an embodiment described in <FIG>.

Claim 1:
A tissue gripping device (<NUM>) comprising:
a U-shaped base section (<NUM>) having a pair of base bend features (<NUM>) at a distal end of the U-shaped base section;
a pair of arms (<NUM>) comprising a first arm (<NUM>) and a second arm (<NUM>) each having a flat proximal side and a flat distal side, the first and second arms (<NUM>) being disposed opposite one another, and each arm (<NUM>) extending radially outward from a respective side of a proximal end of the U-shaped base section (<NUM>) to a free end (<NUM>); and
a pair of arm bend features (<NUM>) partitioning the arms (<NUM>) from the base section (<NUM>) such that the first arm (<NUM>) and the second arm (<NUM>) are separated, in a relaxed state, by an angle measured between the proximal sides of the first and second arms, the base bend features (<NUM>) and the arm bend features (<NUM>) being configured to give the tissue gripping device (<NUM>) a bent configuration when the tissue gripping device (<NUM>) is in the relaxed state, such that when the tissue gripping device (<NUM>) is forced into a stressed state, the tissue gripping device (<NUM>) is resiliently biased toward the relaxed state,
each arm (<NUM>) including a furcated section (<NUM>), the furcated sections (<NUM>) coinciding with the arm bend features (<NUM>), and
the tissue gripping device (<NUM>) including a plurality of frictional elements (<NUM>) configured to engage with tissue at a treatment site and resist movement of tissue away from the tissue gripping device (<NUM>) after the frictional elements (<NUM>) have engaged with the tissue, the frictional elements (<NUM>) being formed as angled barbs extending distally and inwardly from a side edge (<NUM>) of the arms (<NUM>) of the tissue gripping device (<NUM>), the frictional elements (<NUM>) integrally formed with and protruding from a side edge (<NUM>) of each of the arms (<NUM>) thereby forming a plurality of slotted recesses (<NUM>) disposed along side edges (<NUM>) of each arm (<NUM>) at sections adjacent to the frictional elements (<NUM>),
wherein the U-shaped base section (<NUM>), the arm bend features (<NUM>), and the arms (<NUM>) are formed from a shape-memory stock material configured to exhibit superelasticity in a physiological environment,
characterized in that the angle is of between <NUM> degrees and <NUM> degrees as measured between the proximal sides of the first and second arms.