Impedance sensing for tissue capture assessment

Abstract

A fixation device includes a first distal element and a first proximal element. The first distal element and first proximal element each have a first end and a second end and are moveable relative to each other. First and second electrodes are coupled to either the first distal element or the first proximal element between the first and second ends thereof. The electrodes at least partially form a circuit. The circuit is an open circuit generating a first impedance response when tissue contacts the first electrode and not the second electrode. The circuit is a closed circuit generating a second impedance response when tissue contacts the first and second electrode. The first impedance response has a first impedance value greater than a second impedance value of the second impedance response.

Description

Atty Docket No. ABTEVA-0064PCTIMPEDANCE SENSING FOR TISSUE CAPTURE ASSESSMENTCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 729,555, filed December 9, 2024, the disclosure of which is hereby incorporated by reference herein in its entirety.BACKGROUND

[0002] The cardiac cycle is divided into two phases — diastole and systole. Diastole is generally characterized by the muscular relaxation of the heart and the filling of its chambers with blood. On the other hand, systole is generally characterized by the muscular contraction of the ventricles which pumps blood from the ventricles to the arteries. During ventricular systole, ventricular pressure increases relative to atrial pressure resulting in the closure of the mitral valve and the tricuspid valve. The mitral valve separates the left atrium from the left ventricle, and the tricuspid valve separates the right atrium from the right ventricle. These valves operate as check valves preventing blood from flowing back into the atria during ventricular contraction. However, valvular insufficiency may appear in one or both of these valves which may result in a regurgitative flow back into the atrium across the effected valve. Such regurgitative flow can be in the form of mitral valve regurgitation (“MVR”) and / or tricuspid valve regurgitation (“TVR”). Left untreated, MVR and TVR can lead to severe health consequences, such as progressive heart failure, cardiac arrythmias, pulmonary hypertension, stroke, and endocarditis, to name a few.

[0003] MVR and TVR can have a variety of etiologies which typically fall into the categories of degenerative (primary) and functional (secondary) regurgitation. Degenerative valve regurgitation principally occurs due to abnormalities or degeneration of the valve apparatus, such as the valve leaflets, valve annulus, chordae tendineae, and / or papillary muscles. One example of a degenerative valve condition is mitral valve prolapse. Functional valve regurgitation is often a secondary condition that arises from underlying heart conditions or diseases that affect the structure or function of the heart. Examples of conditions that can result in functional regurgitation include dilated cardiomyopathy, ischemic heart disease, pulmonary hypertension, and heart failure. Regardless of the underlying condition precipitating the regurgitative flow, the primary mechanism by which regurgitation occurs is the failure ofAtty Docket No. ABTEVA-0064PCT the valve leaflets to properly and completely seal or coapt during systole which allows a jet of blood to flow back into the atrium between the effected leaflets.

[0004] Treatment options for MVR and TVR generally include Guideline-Directed Medical Therapy (“GDMT”), valve replacement, and valve repair. GDMT usually involves the administration of a combination of drugs that treat an underlying heart condition. Valve replacement and repair may include open-heart surgical options and catheter-based options. Catheter-based repair procedures are sometimes referred to as transcatheter edge-to-edge repair (“TEER”).BRIEF SUMMARY OF THE DISCLOSURE

[0005] In one aspect of the present disclosure, a fixation device includes a center portion, a first distal element, and a first proximal element. The first distal element is coupled to the center portion and extends therefrom. The first distal element is moveable between an open position and a closed position, and has first end, a second end, and a length extending therebetween. The first proximal element is disposed opposite the first distal element and is moveable relative to the first distal element between a first position and a second position. The first proximal element has a first end, a second end, and a length extending therebetween. The fixation device may also include a second distal element extending from the center portion, and a second proximal element disposed opposite the second distal element.

[0006] The fixation device may also have a first electrode and a second electrode disposed on one of the first distal element, the first proximal element, and the center portion. When coupled the first distal element or the first proximal element, the first and second electrodes are disposed between the first and second ends of the respective proximal element and distal element. The first and second electrodes at least partially form a circuit. The circuit is an open circuit generating a first impedance response when tissue contacts the first electrode and not the second electrode, and the circuit is a closed circuit generating a second impedance response when tissue contacts the first and second electrode. The first impedance response has a first impedance value greater than a second impedance value of the second impedance response. In some examples, the first electrode is a cathode or an anode, and the second electrode is the other of an anode or cathode.

[0007] In some implementation of the proximal element, the first end of the proximal element may be a fixed end, the second end of the proximal element may be a free end, and the first proximal element may have a midline equidistant between the free end and the fixed end.Atty Docket No. ABTEVA-0064PCTIn one example, the first electrode is positioned between the free end and the midline of the proximal element, and the second electrode is positioned between the midline and the fixed end of the proximal element. In another example, the first electrode is positioned between the free end and the midline of the proximal element, and the second electrode is positioned at the midline of the proximal element. In a further example, the first electrode is positioned at the midline of the proximal element, and the second electrode is positioned between the midline and the fixed end of the proximal element. In yet another example, the first electrode and the second electrode are each disposed at the midline of the proximal element.

[0008] In some implementations of the first proximal element, the first proximal element may include an elongate body and a plurality of frictional elements extending from the elongate body. In one example, the first electrode is coupled to a first frictional element, and the second electrode is coupled to a second frictional element. In another example, the first electrode is coupled to the elongate body, and the second electrode is coupled to one of the frictional elements.

[0009] In some implementations of the fixation device, the fixation device further includes a third electrode. In one example, the first electrode is positioned between the free end and the midline of the first proximal element, the second electrode is positioned at the midline of the first proximal element, and the third electrode is positioned between the midline and the fixed end of the first proximal element. The first electrode and the second electrode may form a first series circuit, and the first electrode and the third electrode may form a second series circuit. The first series circuit may be configured as an open circuit when tissue only contacts the first electrode, and a closed circuit when tissue contacts the first and second electrodes. The second series circuit may be configured as an open circuit when tissue only contacts the first electrode or only the first and second electrodes and not the third electrode, and as a closed circuit when tissue contacts the first electrode and the third electrode. In other examples, the second and third electrodes are in parallel.

[0010] In some implementations of the fixation device, the fixation device further includes a third electrode and a fourth electrode. In one example, the first and second electrodes are positioned between the free end and the midline of the first proximal element, the third electrode is positioned at the midline of the first proximal element, and the fourth electrode is positioned between the midline and the fixed end of the first proximal element, The first andAtty Docket No. ABTEVA-0064PCT third electrodes may form a first series circuit, and the second and fourth electrodes may form a second series circuit.

[0011] In some implementations of the first distal element, the first end of the first distal element is a fixed end, the second end of the first distal element is a free end, and the first distal element has a midline equidistant between the free end and the fixed end. In one example, the first electrode is positioned between the free end and the midline of the first distal element, and the second electrode is positioned between the midline and the fixed end of the distal element. In another example, the first electrode is positioned between the free end and the midline of the first distal element, and the second electrode is positioned at the midline of the first distal element. In a further example, the first electrode is positioned at the midline of the first distal element, and the second electrode is positioned between the midline and the fixed end of the first distal element. In yet another example, the first electrode and the second electrode are each disposed midline of the first distal element.

[0012] In some implementations of the first distal element, the first distal element includes an elongate body and first and second wing portions extending outwardly therefrom. In one example, the first electrode is coupled to the first wing portion, and the second electrode is coupled to the second wing portion. In another example, the first electrode is coupled to the elongate body of the first distal element, and the second electrode is coupled to the first wing portion of the first distal element.

[0013] In some implementations of the fixation device, the fixation device further includes a third electrode. In one example, the first electrode is positioned between the free end and the midline of the first distal element, the second electrode is positioned at the midline of the first distal element, and the third electrode is positioned between the midline and the fixed end of the first distal element. The first electrode and the second electrode may form a first series circuit, and the first electrode and the third electrode may form a second series circuit. The first series circuit may be configured as an open circuit when tissue only contacts the first electrode, and a closed circuit when tissue contacts the first and second electrodes. The second series circuit may be configured as an open circuit when tissue only contacts the first electrode or only the first and second electrodes and not the third electrode, and as a closed circuit when tissue contacts the first electrode and the third electrode. In other examples, the second and third electrodes are in parallel.Atty Docket No. ABTEVA-0064PCT

[0014] In some implementations of fixation device, the fixation device further comprises a third electrode and a fourth electrode. In one example, the first and second electrodes are positioned between the free end and the midline of the first distal element. In another example, the third electrode is positioned at the midline of the first distal element, and the fourth electrode is positioned between the midline and the fixed end of the first distal element. The first and third electrodes may form a first series circuit, and the second and fourth electrodes form a second series circuit.

[0015] In another aspect of the present disclosure, an interventional system includes a delivery system and a fixation device. The delivery system includes a delivery device handle and a delivery catheter extending from the delivery device handle. The fixation device includes a first distal element and a first proximal element. The fixation device may also include a center portion from which the first distal element extends. The first proximal element is disposed opposite the first distal element and is moveable relative thereto to capture tissue therebetween.

[0016] The interventional system may also include an impedance system. The impedance system includes a control unit and first and second electrodes in communication with the control unit. The first and second electrodes are coupled to one of the first proximal element, the first distal element, the center portion, and the delivery catheter. The first and second electrodes at least partially form a circuit. The circuit is an open circuit generating a first impedance response when tissue contacts the first electrode and not the second electrode, and the circuit is a closed circuit generating a second impedance response when tissue contacts the first and second electrodes. The first impedance response has a first impedance value greater than a second impedance value of the second impedance response.

[0017] In some implementations of the impedance system, the impedance system includes an interface between the first and second electrodes and the control unit. In one example, the interface is a hardwired interface extending from the fixation device and through the delivery catheter to the delivery device handle. The delivery catheter and the fixation device may comprise a coupler configured to disconnect the fixation device from the delivery catheter and to disconnect the interface. As an example, the shaft may have a plurality of spring arms each including a first electrical terminal. An actuator rod may be extendable through the shaft. Additionally, the coupling member may have second electrical terminals corresponding with the first electrical terminals. Moving the actuator rod in a first direction may urge the spring arms into engagement with the coupling member and the first electrical terminals intoAtty Docket No. ABTEVA-0064PCT engagement with the second electrical terminals. Moving the actuator rod in a second direction may disengage the spring anus from the coupling member and the first electrical terminals from the second electrical terminals.

[0018] In another example of the interface, the interface is a wireless interface configured with a wireless protocol of one of Bluetooth Low Energy, Near Field Communication, and Zigbee.

[0019] In some implementations of the control unit, the control unit includes a power source and a measurement module. In one example, the power source is configured to deliver an AC signal to the first and second electrodes within a range of frequencies, and the measurement module is configured to determine a type of tissue in contact with the first and second electrodes based on an impedance response detectable by the measurement module. In one example, the range of frequencies is 10 Hz to 10 kHz. In another example, the range of frequencies is 10 kHz to 10 MHz. In some examples, the control unit is disposed within the delivery device handle.

[0020] In some implementations of the impedance system, the impedance system includes a display. In one example, the display is disposed within the delivery device handle. The measurement module may be coupled to the display and may be configured to transmit output signals indicative of the first and second impedance response to the display.

[0021] In a further aspect of the present disclosure, a method of securing tissue with a fixation device includes delivering a fixation device to a target tissue. In one example, the target tissue is a mitral valve. In another example, the target tissue is a tricuspid valve. The method also includes directing a first tissue (e.g., a first valve leaflet) into a space between a first proximal element and a first distal element of the fixation device. The method further includes measuring at least one of a first impedance response and a second impedance response from first and second electrodes coupled to one of a first proximal element and a first distal element where contact with only the first electrode generates the first impedance response having a first impedance value and contact with the first and second electrode generates the second impedance response having a second impedance value less than the first impedance value.

[0022] The method may also include determining a depth of insertion of a first leaflet between the first proximal element and the first distal element based on the measured impedance response.Atty Docket No. ABTEVA-0064PCT

[0023] The method may also include transmitting an AC signal from a power source to the first and second electrodes. In one example, the transmitting step includes transmitting the AC signal from a delivery device handle through a delivery catheter to the fixation device.

[0024] The method may also include modulating a frequency of the AC signal within a range of frequencies. In one example, the range of frequencies is 10 Hz to 10 kHz. In another example, the range of frequencies is 10 kHz to 10 MHz.

[0025] The method may also include determining the type of tissue in contact with the first and second electrodes based on the measured impedance response across the range of frequencies. In on example, the step of determining the type of tissue in contact with the first and second electrodes includes analyzing resistive and reactive components of the measured impedance response.BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 A is a cross-sectional representation of a heart illustrating its four valves.

[0027] FIG. IB is a cross-sectional representation of a heart illustrating the left ventricle and left atrium during systole.

[0028] FIG. 2A is a schematic view of a mitral valve during normal coaptation.

[0029] FIG. 2B is a schematic view of a mitral valve during regurgitate coaptation.

[0030] FIGS. 3 A and 3B are schematic views of a fixation device according to an embodiment of the present disclosure grasping leaflets of a mitral valve.

[0031] FIG. 4A is a perspective view of a fixation device according to another embodiment of the present disclosure.

[0032] FIG. 4B is a perspective view of the fixation device of FIG. 4A including a covering.

[0033] FIG. 5A is a perspective view of a gripping device of the of the fixation device of FIG. 4A according to an embodiment of the present disclosure.

[0034] FIG. 5B is an elevational view of the gripping device of FIG. 5 A.

[0035] FIG. 6A is a perspective view of a gripping device according to another embodiment of the present disclosure.

[0036] FIG. 6B is a partial schematic view of the gripping device of FIG. 6A coupled to a distal element of the fixation device of FIG. 4A.Atty Docket No. ABTEVA-0064PCT

[0037] FIG. 6C is a partial schematic view of a gripping device according to an alternative embodiment of the present disclosure coupled to a distal element according to an alternative embodiment of the present disclosure.

[0038] FIG. 7 A is an elevational view of a coupling system according to an embodiment of the present disclosure for coupling the fixation device of FIG. 4A and a delivery system.

[0039] FIGS. 7B and 7C are schematic views of the coupling system of FIG. 7A in respective first and second configurations.

[0040] FIGS. 8A and 8B are schematic cross-sectional views of a coupling system according to another embodiment of the present disclosure for coupling a fixation device, such as the fixation device of FIG. 4A, and a delivery system.

[0041] FIGS. 9A-9B, 10A-10B, 11A-11B, 12A-12B and 13A-13C illustrate the fixation device of FIG. 4A in various possible positions during introduction and placement of the device within a mammalian body to perform a therapeutic procedure.

[0042] FIG. 14 is a perspective view of the fixation device of FIG. 4A including a locking mechanism according to an embodiment of the present disclosure and illustrating a plurality of proximal element lines and a lock line coupled to the fixation device.

[0043] FIG. 15 is an elevational view of the locking mechanism and proximal elements of the fixation device of FIG. 14 and illustrating a lock line and single proximal element line respectively coupled thereto.

[0044] FIG. 16 is a schematic view of the fixation device of FIG. 4 A coupled to a delivery system and illustrating a plurality of proximal element lines coupled to a shaft of the delivery system.

[0045] FIGS. 17A and 17B are partial enlarged views of a distal end portion of the delivery system shaft of FIG. 16 according to an embodiment of the present disclosure.

[0046] FIG. 17C is a cross-sectional view of the delivery system shaft taken along line C-C of FIG. 17B.

[0047] FIG. 17D is a partial perspective view of a distal end portion of one of the proximal element lines of FIG. 16 including a catch according to an embodiment of the present disclosure.

[0048] FIG. 17E is a partial elevational view of the delivery system shaft of FIG. 17A having holes configured to receive the catch of FIG. 17D.Atty Docket No. ABTEVA-0064PCT

[0049] FIG. 17F is a partial elevational view of the delivery system shaft of FIG. 17A and an actuator rod disposed therein intersecting the holes of the delivery system shaft.

[0050] FIG. 17G is a partial elevational view of a distal end portion of one of the proximal element lines of FIG. 16 including a catch according to another embodiment of the present disclosure.

[0051] FIG. 18A is an enlarged cross-sectional view of the locking mechanism of FIG. 14 taken along a midline thereof and in an unlocked configuration.

[0052] FIG. 18B is an enlarged elevational view of the locking mechanism of FIG. 14 and in a locked configuration.

[0053] FIG. 18C is a perspective view of a release harness of the locking mechanism of FIG. 14.

[0054] FIG. 19 A is an elevational view of a locking mechanism of the fixation device of FIG. 4A according to another embodiment of the present disclosure.

[0055] FIG. 19B is a transparent perspective view of a binding plate of the locking mechanism of FIG. 19A.

[0056] FIG. 19C is an enlarged elevational view of the locking mechanism of FIG. 19A.

[0057] FIGS. 20A and 20B are schematic pinch force diagrams along proximal and distal elements of different lengths.

[0058] FIG. 21 A is a schematic view of an impedance system according to an embodiment of the present disclosure.

[0059] FIG. 21B is a schematic view of an exemplary measurement module of the impedance system of FIG. 21.

[0060] FIG. 21 C is a schematic view of electrodes of the impedance system of FIG. 21 A according to one example.

[0061] FIG. 2 ID is a schematic view of electrodes of the impedance system of FIG. 21 A according to another example.

[0062] FIGS. 22 A and 22B are perspective views of an interventional system according to an embodiment of the present disclosure.

[0063] FIGS. 23 A and 23B are partial cross-sectional views of a coupler of the interventional system of FIGS. 22A and 22B according to one example.Atty Docket No. ABTEVA-0064PCT

[0064] FIG. 24A is a botom view of a proximal element according to an embodiment of the present disclosure.

[0065] FIGS. 24B and 24C are schematic electrical circuit diagrams of the proximal element of FIG. 24A.

[0066] FIG. 24D is an exemplary impedance response graph of the proximal element of FIG. 24A.

[0067] FIG. 25 is a bottom view of a proximal element according to another embodiment of the present disclosure.

[0068] FIG. 26 is a bottom view of a proximal element according to a further embodiment of the present disclosure.

[0069] FIG. 27 is a partial bottom view of a proximal element according to another embodiment of the present disclosure.

[0070] FIG. 28 is a partial bottom view of a proximal element according to a further embodiment of the present disclosure.

[0071] FIG. 29A is a botom view of a proximal element according to another embodiment of the present disclosure.

[0072] FIGS. 29B-29D are schematic electrical circuit diagrams of the proximal element of FIG. 29 A.

[0073] FIG. 30 a bottom view of a proximal element according to a further embodiment of the present disclosure.

[0074] FIG. 31 is a perspective view of a distal element according to an embodiment of the present disclosure.

[0075] FIG. 32 is a perspective view of a distal element according to another embodiment of the present disclosure.

[0076] FIG. 33 is a schematic view of a distal end of an interventional system according to another embodiment of the present disclosure.

[0077] FIG. 34 is a schematic view of a fixation device according to another embodiment of the present disclosure.

[0078] FIG. 35 is a schematic view of a fixation device according to a further embodiment of the present disclosure.

[0079] FIG. 36 is a block diagram of a method according to an embodiment of the present disclosure.Atty Docket No. ABTEVA-0064PCT

[0080] FIG. 37 A is a schematic block diagram of a fixation device according to an embodiment of the present disclosure.

[0081] FIG. 37B is a schematic block diagram of the fixation device of FIG. 37A showing details of the first proximal element including a fixed end, a free end, a midline, and a positional indicator.

[0082] FIG. 37C is a schematic block diagram of the fixation device of FIG. 37A showing the first proximal element with an elongate body and frictional elements.

[0083] FIG. 37D is a schematic block diagram of the fixation device of FIG. 37A showing the first proximal element with an elongate body and frictional elements, with the first electrode coupled to the elongate body and the second electrode coupled to one of the frictional elements.

[0084] FIG. 37E is a schematic block diagram of the fixation device of FIG. 37A including a third electrode on the first proximal element.

[0085] FIG. 37F is a schematic block diagram of the fixation device of FIG. 37E showing first and second series circuits formed by the first, second, and third electrodes.

[0086] FIG. 37G is a schematic block diagram of the fixation device of FIG. 37F showing the first series circuit in open and closed circuit configurations.

[0087] FIG. 37H is a schematic block diagram of the fixation device of FIG. 37F showing the second series circuit in open and closed circuit configurations.

[0088] FIG. 371 is a schematic block diagram of the fixation device of FIG. 37E showing the second and third electrodes arranged in parallel.

[0089] FIG. 37J is a schematic block diagram of the fixation device of FIG. 37A including first, second, third, and fourth electrodes on the first proximal element and showing first and second series circuits.

[0090] FIG. 37K is a schematic block diagram of the fixation device of FIG. 37A with electrodes disposed on the first distal element, showing details of the first distal element including a fixed end, a free end, midline, and a positional indicator.

[0091] FIG. 37L is a schematic block diagram of the fixation device of FIG. 37A showing the first distal element with an elongate body and first and second wing portions.

[0092] FIG. 37M is a schematic block diagram of the fixation device of FIG. 37L showing the first electrode coupled to the elongate body and the second electrode coupled to the first wing portion.Atty Docket No. ABTEVA-0064PCT

[0093] FIG. 37N is a schematic block diagram of the fixation device of FIG. 37K including a third electrode on the first distal element.

[0094] FIG. 370 is a schematic block diagram of the fixation device of FIG. 37N showing first and second series circuits formed by the three electrodes.

[0095] FIG. 37P is a schematic block diagram of the fixation device of FIG. 370 showing the first series circuit in open and closed circuit configurations.

[0096] FIG. 37Q is a schematic block diagram of the fixation device of FIG. 370 showing the second series circuit in open and closed circuit configurations.

[0097] FIG. 37R is a schematic block diagram of the fixation device of FIG. 37N showing the second and third electrodes arranged in parallel.

[0098] FIG. 37S is a schematic block diagram of the fixation device of FIG. 37K including first, second, third, and fourth electrodes on the first distal element and showing first and second series circuits.

[0099] FIG. 37T is a schematic block diagram of the fixation device of FIG. 37A further including a second distal element and a second proximal element.

[0100] FIG. 37U is a schematic block diagram of an interventional system according to an embodiment of the present disclosure, the system including the fixation device of FIG. 37 A, a delivery system, and a control unit.

[0101] FIG. 37 V is a schematic block diagram of the interventional system of FIG. 37U showing a coupler including a shaft with spring arms, electrical terminals, and an actuator rod.

[0102] FIG. 37W is a schematic block diagram of the interventional system of FIG. 37U showing the control unit including a power source and a measurement module.

[0103] FIG. 37X is a schematic block diagram of the interventional system of FIG. 37W showing a display coupled to the measurement module.

[0104] FIG. 37Y is a schematic block diagram of an interventional system according to another embodiment of the present disclosure, the system including electrodes coupled to a delivery catheter.

[0105] FIG. 37Z is a schematic block diagram of the interventional system of FIG. 37Y showing the control unit with a power source configured to deliver an AC signal or a DC signal.

[0106] FIG. 37AA is a schematic block diagram of the interventional system of FIG. 37Y showing a display configured to provide visual indicators, audio alerts, haptic feedback, and real-time visual feedback indicative of tissue insertion depth.Atty Docket No. ABTEVA-0064PCTDETAILED DESCRIPTION

[0107] The valves of a normal heart H are illustrated in FIGS. 1A and IB. These valves include the mitral valve MV, the tricuspid valve TV, the aortic valve AV, and the pulmonary valve PV. The mitral valve MV separates the left atrium LA and the left ventricle LV, and the tricuspid valve TV separates the right atrium RA and the right ventricle RV. The mitral valve MV and the tricuspid valve TV are sometimes referred to as the atrioventricular valves. The mitral valve MV is a bicuspid valve in that it has two leaflets referred to as the posterior leaflet PL and the anterior leaflet AL. The tricuspid valve TV typically has three leaflets referred to as the anterior leaflet AL, the posterior leaflet PL, and the septal leaflet SL. However, studies have shown that, although the TV is typically composed of three leaflets of unequal size, in many cases, two or more than three leaflets may be present as anatomic variants in healthy subjects. Thus, reference herein to the tricuspid valve TV should be understood to refer to the atrioventricular valve located between the right atrium RA and right ventricle RV regardless of the number of leaflets be it two, three, or more than three leaflets. However, exemplary embodiments discussed herein refer to the usual anatomic structure of the tricuspid valve TV that includes three leaflets.

[0108] As illustrated in FIG. IB, the anterior leaflet AL and posterior leaflet PL of the mitral valve MV extend from a valve annulus AN to respective free edges FE. The free edges FE are secured to the lower portions of the left ventricle LV through chordae tendineae CT (referred to hereinafter as the chordae). The chordae CT include a plurality of branching tendons that are attached to papillary muscles PM at the lower portions of the left ventricle LV and extend upwardly to the lower surfaces of each of the valve leaflets where they are attached. The three leaflets of the tricuspid valve TV similarly extend from a valve annulus AN to respective free edges FE which are secured via chordae to the papillary muscles of the right ventricle RV.

[0109] The mitral valve MV depicted in FIGS. IB and 2A illustrate the proper functioning of an atrioventricular valve during ventricular systole. As the ventricles contract, the free edges FE of adjacent leaflets LF meet along a line of coaptation LOC. The joinder of the leaflets LF at this line of coaptation LOC seals off the ventricle from the atrium and prevents the back flow of blood or “regurgitation” from entering into the atrium. Thus, with the right atrium RA and left atrium LA respectively sealed off by the mitral valve MV and tricuspidAtty Docket No. ABTEVA-0064PCT valve TV, blood in the left ventricle LV can only flow through the aortic valve AV to the body, and blood in the right ventricle RV can only flow through the pulmonary valve PV to the lungs.

[0110] A number of structural defects in the heart H can cause mitral valve regurgitation (“MVR”) and / or tricuspid valve regurgitation (“TVR”). MVR and TVR occur when their respective leaflets LF do not close properly allowing leakage from the ventricle into the atrium. The mitral valve MV depicted in FIG. 2B illustrates valvular insufficiency of an atrioventricular valve resulting in regurgitation. In the depicted example, an enlargement of the heart H may cause the valve annulus AN to become enlarged, making it impossible for the free edges FE of the valve leaflets LF to meet during systole. This may result in a gap G between the leaflets LF which allows blood to leak through the valve. In another example, ruptured or elongated chordae CT can cause a valve leaflet LF to prolapse at least due to inadequate tension transmitted to the leaflet via the chordae CT. While an adjacent leaflet LF may maintain a normal profile, the prolapsing leaflets LF may flail about preventing the proper joinder between the leaflets LF resulting in leakage into the atrium. In a further example, regurgitation can occur in patients who have suffered ischemic heart disease which may result in weak ventricular contractions insufficient to effect proper closure.

[0111] The present disclosure describes exemplary systems, devices, and methods for percutaneously repairing a valve to treat cardiac valve regurgitation, particularly MVR and TVR. When referring to such disclosed systems, devices, and methods, the term "proximal" (P) shall mean closer to the user or in a direction toward a device to be manipulated by the user outside the patient’s body, and the term "distal" (D) shall mean more distant from the user or in a direction toward a device that is positioned at the treatment site within the patient’ s body (e.g., fixation device 112). With respect to the mitral valve and tricuspid valve, “proximal” shall refer to the atrial or upstream side of the valve leaflets, and “distal” shall refer to the ventricular or downstream side of the valve leaflets.

[0112] FIGS. 3 A and 3B depict a fixation device 12, according to an embodiment of the present disclosure, grasping leaflets LF of an atrioventricular valve, which is illustrated as a mitral valve MV. Fixation device 12 may be releasably coupled to a distal end of a shaft 11 of a delivery system to form an interventional tool 10. Fixation device 12 may include distal elements 20 (also referred to herein as fixation elements) and proximal elements 40 (also referred to herein as gripping elements). Distal and proximal elements 20, 40 may be moveable relative to each other and may protrude radially outward relative to a longitudinal axis Al ofAtty Docket No. ABTEVA-0064PCT fixation device 12. As shown in FIG. 3 A, fixation device 12 may be positionable on opposite sides of adjacent leaflets LF of the valve so as to capture or retain the leaflets LF therebetween. In this regard, proximal elements 40 may be positioned at a proximal side of the valve leaflets LF, and distal elements 20 may be positioned on a distal side of the valve leaflets LF. Proximal elements 40 may be made from cobalt chromium, nitinol, or stainless steel, for example, and distal elements 20 may be made from cobalt chromium or stainless steel, for example.

[0113] Fixation device 12 may be releasably coupled to shaft 11 such that it can be detached and left behind as an implant to hold the leaflets LF together in the coapted position. In this regard, fixation device 12 may be delivered to a target valve percutaneously using any one of a number of different approaches, such as via a transfemoral, a transapical, or a transjugular approach, for example. Thus, in one example of treating MVR, fixation device 12 may be delivered to the deficient mitral valve MV using a transfemoral approach in which fixation device 12 is guided through the inferior vena cava IVC (see FIG. 1A), across the interatrial septum S, and into left atrium LA where fixation device 12 is advanced into the mitral valve MV. Also, in one example of treating TVR, fixation device 12 may be guided transfemorally through the inferior vena cava IVC to the right atrium RA where fixation device 12 is advanced to a desired position within the tricuspid valve TV.

[0114] FIG. 3B is an atrial-side view of fixation device 12 in one example of a desired orientation in relation to adjacent leaflets LF of an atrioventricular valve, such as the depicted mitral valve MV. The distal and proximal elements 20, 40 are positioned to be substantially perpendicular to the line of coaptation LOC. Thus, in the case of a mitral valve MV, fixation device 12 may be oriented perpendicular (+ / - 5 degrees) to a line of coaptation LOC between the posterior leaflet PL and anterior leaflet AL, and in the case of a tricuspid valve TV, fixation device 12 may be positioned perpendicular (+ / - 5 degrees) to a line of coaptation between the septal leaflet SL and the anterior leaflet AL, the septal leaflet SL and the posterior leaflet PL, or the anterior leaflet AL and the posterior leaflet PL, for example. Device 12 may be moved roughly along the line of coaptation LOC to the location of regurgitation. The leaflets LF may be held in place so that, during diastole, the leaflets LF remain in position between elements 20, 40 surrounded by openings O (also referred to herein as orifices) which result from the diastolic pressure gradient. Advantageously, leaflets LF are coapted such that their proximal or upstream surfaces face each other in a vertical orientation, parallel to the direction of blood flow through the valve. The upstream surfaces may be brought together so as to be in contactAtty Docket No. ABTEVA-0064PCT with one another or may be held slightly apart but will preferably be maintained in the vertical orientation in which the upstream surfaces face each other at the point of coaptation. This simulates the double orifice geometry of a standard surgical bow-tie repair. Color Doppler echo will show if the regurgitation of the valve has been reduced. If the resulting flow pattern is satisfactory, the leaflets LF may be fixed together in this orientation. If the resulting color Doppler image shows insufficient improvement in valve regurgitation, fixation device 112 may be repositioned. This may be repeated until an optimal result is produced wherein the leaflets LF are held in place.

[0115] FIGS. 4A-19C depict a fixation device 112 according to another embodiment of the present disclosure. Fixation device 112 may generally include a pair of distal elements 120, a pair of proximal elements 140, a coupling member 160, an actuation mechanism 113, and a stud 131. Distal elements 120 may include elongate arms 121 in which each arm has a proximal end portion 121a, which may be rotatably connected to the coupling member 160, and a free end 121b, as best shown in FIG. 4A. Free ends 121b may each have a rounded shape to minimize interference with and trauma to surrounding tissue structures according to one example. In one example, each free end 121b defines a curvature extending about two axes 126, 127. The first axis 126 may be a longitudinal axis of each respective arm 121. Additionally, arms 121 may each include an engagement surface 125 that may also be curved about first axis 126 and may extend at least partially along a length of arm 121 to the free end 121b. Thus, in some examples, engagement surfaces 125 may each have a cupped or concave shape which may maximize contact area engagement with tissue and may assist in grasping and holding valve leaflets. Such cupped or concave shape may further allow arms 121 to nest around shaft 111 of interventional tool 110 while in the closed position to minimize the profile of device 112. Thus, arms 121 may be at least partially cupped or curved inwardly about their longitudinal axes 126 which may form a concavity extending along axis 126 which may nest proximal elements 140 when in a lowered position thereof. The second axis 127 about which each free end 121b may be curved may extend perpendicular to first axis 126, as is also shown in FIG. 4A. The curvature about this second axis 127 may be a reverse curvature located at the most distal portion of free ends 121b. In addition to the dual curvature, free ends 121b may flare outwardly at their respective longitudinal edges. It is believed that both the reverse curvature and flare help create an atraumatic configuration that minimizes trauma to the tissue engaged therewith.Atty Docket No. ABTEVA-0064PCT

[0116] In the nonlimiting embodiment depicted, a transverse width across engagement surfaces 125 (which is in the direction of second axis 127 and determines the width of tissue engaged) may be at least about 2 mm, 3-10 mm in some examples, and about 4-6 mm in some examples. Tn some embodiments, a wider engagement may be desired wherein the engagement surfaces 125 are larger, for example about 2 cm, or multiple fixation devices 112 may be used adjacent to each other. Arms 121 may also have a length of about 6-12 mm (defined along first axis 126), and engagement surfaces 125 may be configured to engage a length of tissue of about 4-10 mm along the longitudinal axis 126 of arms 121 according to some examples. Also, as shown in the illustrated example, each arm 121 may include a plurality of openings 128 to enhance grip and to promote tissue ingrowth following implantation.

[0117] In one example, actuation mechanism 113 may include two link members or legs 130. Legs 130 may be comprised of a rigid or semi-rigid metal or polymer such as Elgiloy®, cobalt chromium or stainless steel, however any suitable material may be used. Each leg 130 may have a first end 132, which may be rotatably joined with one of the distal elements 120 at a riveted joint 135, and a second end 134, which may be rotatably joined with stud 131, as shown in FIG. 4A. Although the depicted embodiment shows both legs 130 pinned to stud 131 by a single rivet 135, it is also contemplated that each leg 130 may be individually attached to the stud 131 by a separate rivet, pin or the like. In other embodiments of actuation mechanism 113, actuation mechanism 113 may include a base 139, and second ends 134 of legs 130 may be rotatably joined with base 169, such as by one or more riveted joints 135, as best shown in FIG. 10B. An actuator rod 170 of delivery system 600 may be joinable with actuation mechanism 113 directly, such as via direct connection with base 139, or indirectly, such as via connection with stud 131, which itself may extend from base 139. In either of these embodiments, actuator rod 170 may be axially extendable and retractable in a proximal-distal direction to actuate actuation mechanism 1 13 and consequently rotate distal elements 120 between open, closed, and inverted positions, which are described further below. Additionally, coupling member 160, stud 131, and / or base 169 may comprise a center portion or center body of fixation device, for example.

[0118] Proximal elements 140 may, in some examples, be flexible, resilient, and cantilevered from a center of fixation device 112. For example, FIGS. 5 A and 5B depict a gripping device 114 according to an embodiment of the present disclosure that may generallyAtty Docket No. ABTEVA-0064PCT include a pair of proximal elements 140, a base section 150, and a pair of arm bend features 153 partitioning proximal elements 140 from base section 150.

[0119] Proximal elements 140 may be in the form of elongate arms 141 that each extend along a longitudinal axis A2 from a first end portion or fixed end 141 a to a second end portion or free end 141b, as shown in FIG. 5A. Each proximal element 140 may also have opposed side edges 142 that define a width transverse to the longitudinal axis A2. Such width may be less than the width of a corresponding distal element 120 such that proximal element 140 may be recessed within the concavity formed by engagement surface 125 of distal element 120 when proximal element 140 is moved into a lowered position, as described in more detail below.

[0120] Proximal elements 140 may also each have a first side or proximal side 143 and a second side or distal side 144. In one example, proximal elements 140 may include a plurality of openings 146 that may extend from proximal side 143 to distal side 144, as shown in FIG. 5 A. Such openings 146 may be used to couple a proximal element line, which is discussed further below, to a proximal element 140 for raising and lowering proximal element 140. Each proximal element 140 may also include one or more frictional elements 145 extending from distal side 144. For example, each proximal element 140 may include one or more rows of frictional elements 145 where frictional elements 145 in each row may be aligned in a direction transverse to longitudinal axis A2. Frictional elements 145 in such rows may also be aligned with frictional elements 145 in other rows in a lengthwise direction thereby forming columns of frictional elements 145. For example, in the embodiment depicted in FIGS. 5 A and 5B, each proximal element 145 may include four rows of two frictional elements 145. In other words, two columns of four frictional elements 145. In other embodiments, proximal elements 140 may include one to six rows of two to six frictional elements 145 per row, for example. However, in other embodiments, frictional elements 145 may be arranged in an offset relationship in a lengthwise and / or transverse direction such that at least some frictional elements 145 are not aligned with another frictional element 145 in such directions.

[0121] Frictional elements 145 may comprise frictional protrusions or tines having tapering pointed tips extending from distal side 144 of proximal elements 140. Frictional elements 145 may also be angled toward fixed end 141a of proximal element 140 which may help prevent frictional elements 145 from inadvertently snaring tissue during repositioning of fixation device 112. In one example, frictional elements 145 may be integral with or connected to a distal surface 144 of a proximal element 140 and protrude therefrom. In another example,Atty Docket No. ABTEVA-0064PCT as shown in FIG. 5A, frictional elements 145 may be formed from side edges 142, such as by cutting and bending the base material forming proximal elements 140, for example. It may be appreciated that 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. However, it should be noted that some types of frictional elements that can be utilized may permanently alter or cause some trauma to the tissue engaged. Thus, it is preferable that frictional elements 145 be atraumatic and generally frictional rather than penetrative so as to not injure or otherwise affect the tissue in a clinically significant way.

[0122] Base section 150 may be connected to a center portion or center body of fixation device 112 such that proximal elements 140 extend outwardly therefrom. For example, base section 150 may be coupled to coupling member 160. In the embodiment depicted, base section 150 may include a first member 152, a second member 154, and a third member 156. First and third members 152, 156 may be connected to second member 154 to form a generally U-shaped or box-shaped structure which may allow a locking mechanism (discussed below) to be positioned between first and third members 152, 156. However, other shapes may be formed, such as a V-shape, a crescent shape, or semicircular, for example. In some embodiments, first and third members 152, 156 may be connected to second member 154 via base bend features 157, for example. Also, second member 154 may include an opening 158 extending therethrough for receipt of stud 131 and / or actuator rod 170, as shown in FIG. 5A.

[0123] Arm bend features 153 may couple a respective proximal element 140 and base section 150. For example, an arm bend feature 153 can couple a proximal element 140 to first member 152 of base section 150, and another arm bend feature 153 can coupled the other proximal element 140 to third member 156 of base section 150. As shown, am bend features 153 may form a living hinge about which proximal elements 140 may bend relative to base section 150. In this regard, arm bend features 153 may be integral with proximal elements 140 and base section 150 and may bias proximal elements 140 to a relaxed position. As illustrated in FIG. 5B, proximal elements 140 may form a relaxed angle 149 formed between proximal sides 143 of each proximal element 140. Such relaxed angle 149 is formed when proximal elements 140 are in the relaxed position and may form an angle of about 85 degrees to 200 degrees (+ / - 5 degrees). For example, proximal elements 140 may form a relaxed angle of 180 degrees in the relaxed position. In another example, proximal elements 140 may form a relaxed angle of 185 degrees in the relaxed position. Although the embodiment depicted illustratesAtty Docket No. ABTEVA-0064PCT bend features 153 as living hinges, in other embodiments bend features 153 may comprise a biased hinge that modularly connects proximal elements 140 to base section 150. For example, proximal elements 140 may be separately formed from base section 150 and modularly connected to base section 150 via arm bend features 153 which may each comprise a spring biased hinge biasing a respective proximal element 140 to the relaxed position, for example.

[0124] Arm bend features 153 may also each include an elongate opening extending 151 along the longitudinal axis A2 which may furcate each arm bend feature 153, as illustrated in FIG. 5 A. Such an elongated opening 151 may have a uniform width extending along axis A2. However, in some embodiments, such as the embodiment depicted, elongate opening 151 may form a bowling-pin shape such that a width of opening 151 is narrower at one end (e.g., the end closest to free end 141b) than the other end (e.g., the end furthers from free end 141b) and is wider somewhere in between. Elongate opening 151 may also not be relegated to just arm bend feature 153 but may also extend from arm bend feature 153 to proximal element 140 and / or base body 150. The elongate opening 151 and corresponding furcation of arm bend features 153 may be configured (e.g., in size, shape, spacing, position, etc.) so as to provide the desired resiliency, fatigue resistance, and / or flexibility at the coinciding arm bend features 153.

[0125] Base bend features 1 10 and arm bend features 1 12 may be configured to give gripping device 116 a bent configuration when gripping device is in a relaxed state (i.e., when proximal elements are in the relaxed position), such that when gripping device 114 is forced into a stressed state (e.g., by bending proximal elements at one or more of the base and / or arm In the exemplary embodiment depicted, gripping device 114 may be formed from a metallic sheet of a spring-like material, such as a shape-memory metal (e.g., Nitinol) which may provide the bias of proximal elements 140 toward the relaxed position. Alternatively, gripping device 114 could be molded from a biocompatible polymer. Each proximal element 112 may, in one example, be configured to be at least partially recessed within the concavity of the distal element 120 when no tissue is present. When fixation device 112 is in the open position, each proximal element 140 may be separated from the engagement surface 125 near free end 121b of arm 121 and may slope toward engagement surface 125 near free end 121b with the free end 141b of proximal element 140 contacting engagement surface 125, as illustrated in FIGS. 4A and 11B. This arrangement may be facilitated by the dimensions of base section 150. For example, increasing or decreasing the respective lengths of first, second, and third members 152, 154, 156 of base section 150 may increase or decrease the separation distance between aAtty Docket No. ABTEVA-0064PCT proximal element 140 and corresponding distal element 120 which may help accommodate a valve leaflet or other tissues of varying thicknesses. Further examples of gripping devices that may be utilized in fixation device 112 are described in more detail in U.S. Patent No. 11 ,096,691 , the disclosure of which is incorporated by reference herein in its entirety.

[0126] In other embodiments proximal elements may be connected to or otherwise extend from distal elements rather than from a center of fixation device, like that of fixation device 112. For example, FIGS. 6A and 6B depict a gripping device 214 according to another embodiment of the present disclosure that may generally include a first arm 240, a second arm 250, and an arm bend feature 260 partitioning first arm 240 from second arm 250. Gripping device 214 may be made from a shape-memory-metal material, such as Nitinol, for example.

[0127] First arm 240 may constitute a proximal element of fixation device 112, like that of and as an alternative to proximal element 140 and may include one or more frictional elements 245 which may be similar to frictional elements 145 discussed above. Thus, a plurality of frictional elements 245 may extend from a distal side of first arm 240 such as in one or more rows and / or columns. In the embodiment depicted, a single row of three frictional elements 245 may be provided near a free end 241b of first arm 240. But, as mentioned above, first arm 240 may have any number of frictional elements 245, such as two, four, or six, for example. First arm 240 may also include a pair of elongate members 247 offset from each other to form a space 248 therebetween. Such space 248 may be configured to receive second arm 250, for example. Additionally, first arm 240 may include one or more openings 246, such as near free end 241b, as shown in FIG. 6A. Such opening 246 may be configured to receive a proximal element line for raising and lowering first arm 240.

[0128] Second arm 250 may be in the form of a beam or other elongate structure. Second arm 250 (also referred to herein as base section) may be configured to couple to a distal element 120. For example, in the embodiment depicted in FIGS. 6A and 6B, second arm 250 may be curved in a plane transverse to its longitudinal axis. For example, second arm 250 may be semi-cylindrical such that it may have a semi-circular profile. Thus, second arm 250 may have a convex surface 255 configured to conform to the cupped curvature of engagement surface 125 of a corresponding distal element 120. FIG. 6B illustrates second arm 250 coupled to proximal engagement surface 125 of distal element 120 such that it is generally recessed within distal element 120 and free ends 241b, 251b of first and second arms 240, 250 point in the general direction toward free end 121b of distal element 120. Thus, in some embodiments,Atty Docket No. ABTEVA-0064PCT second arm 250 may have a width configured to be positioned within the concavity of distal element 120 and secure to proximal engagement surface 125. In other embodiments, a second arm 250’ of an alternative gripping device 214’ may not be concave and may instead have a planar surface corresponding to a planar engagement surface 125’ of an alternative distal element 120’ and secured thereto, as illustrated in FIG. 6C. In further embodiments, distal element 120 may include a recess or pocket for receipt and securement of second arm 250, such as in a press-fit manner, for example. Second arm 250 may be secured to distal element 120 in any number of ways, such as via one or more sutures, welding, press-fit, fastener (e.g., rivet or screw) or the like. For example, a rivet, screw, or suture may pass through one or more openings 257 in second arm 250 and into distal element 120. A tissue fixation device, such tissue fixation device 112, may include a pair of gripping devices 214 with one coupled to each distal element 120 as mentioned above.

[0129] Arm bend feature 260 may be coupled to a fixed end 241 of first arm 240 and a fixed end 251a of second arm 250 such that first and second arms 240, 250 extend in the same general direction and may form a V-shape when first arm 240 is in an exemplary open or raised position, as illustrated in FIGS. 6B and 6C. As shown, arm bend feature 260 may form a living hinge about which first arm 240 may bend relative to second arm 250. In this regard, arm bend feature 260 may be integral with first arm 240 and second arm 250 so as to form a monolithic structure and may bias first arm 240 to a relaxed position. Such relaxed position may include second arm 250 extending through space 248 between elongate members 247 of first arm 240 to form an X-shape. However, it should be noted that such position can generally only be achieved when gripping device 214 is not coupled to distal element 120 as the presence of distal element 120 would prevent second arm 250 from passing into space 248. It should also be appreciated that in some embodiments of gripping device 214, arm bend feature 260 may be a spring loaded or otherwise biased hinge coupling separately formed first and second arms 240, 250.

[0130] Fixation device 114 may also have a covering 117, as shown in FIG. 4B. As depicted, covering 117 may encapsulate distal elements 120 and actuation mechanism 113. Thus, engagement surfaces 125 may be covered by covering 117 which may help minimize trauma on tissues and enhance primary fixation via additional friction to assist in grasping. Additionally, covering 117 on engagement surfaces 125 may facilitate tissue ingrowth to provide for secondary fixation to ensure long-term security. Covering 117 may be loosely fittedAtty Docket No. ABTEVA-0064PCT and / or may be flexible such that device 112 can freely move to various positions all the while covering 117 conforms to the contours of the device 112 and remains securely attached thereto. It may be appreciated that the covering 117 may cover specific parts of fixation device 112 while leaving other parts exposed. For example, proximal elements 140 may be exposed, while distal elements 120 and actuation mechanism 113 may be covered. However, in some embodiments, proximal elements 140 may be covered with covering 117 to enhance grip and tissue ingrowth following implantation. Preferably, when a covering 117 is used in combination with frictional elements 145 or other frictional features, such as those extending from proximal elements 140, such features may protrude through such covering 117 so as to contact any tissue engaged by proximal elements 140.

[0131] Covering 117 may be comprised of any biocompatible material, such as polyethylene terepthalate, polyester, cotton, polyurethane, expanded polytetrafluoroethylene (ePTFE), silicon, or various polymers or fibers and have any suitable form, such as a fabric (woven or unwoven), mesh, textured weave, felt, looped or porous structure. Generally, covering 117 has a low profile so as not to interfere with delivery through an introducer sheath or with grasping and coapting of leaflets or tissue. Covering 117 may alternatively be comprised of a polymer or other suitable materials dipped, sprayed, coated, or otherwise adhered to the surfaces of the fixation device 112. Optionally, a polymer coating may include pores or contours to assist in grasping the tissue and / or to promote tissue ingrowth. Any of the coverings 117 may optionally include drugs, antibiotics, anti-thrombosis agents, or anti-platelet agents such as heparin, COUMADIN® (Warfarin Sodium), to name a few. These agents may, for example, be impregnated in or coated on the coverings 117. These agents may then be delivered to the grasped tissues surrounding tissues and / or bloodstream for therapeutic effects.

[0132] FIGS. 7A-7C depict an exemplary coupling system 115 between fixation device 112 and delivery system shaft 111. As mentioned above, once the leaflets of a target valve are coapted in the desired arrangement, fixation device 112 may then be detached from delivery system 600 and left behind as an implant to hold the leaflets together in the coapted position. Such detachment may occur between coupling member 160 of fixation device 112 and a distal end of delivery shaft 111. Thus, coupling member 160 may be configured to be releasably coupled to shaft 1 11. Coupling member 160 may be disposed at a center of fixation device 112 and may extend proximally along it’s the longitudinal axis of fixation device 112. In the coupling system 115 depicted, shaft 111 may form a tubular upper shaft with a first matingAtty Docket No. ABTEVA-0064PCT surface 163 formed at a distal end thereof, and coupling member 160 may form a detachable lower tubular shaft with a second mating surface 162 formed at a proximal end thereof. Mating surfaces 162, 163 may be correspondingly shaped so that they interlock and form a joining line 165 when merged together, as shown in FIG. 7B. In this regard, mating surfaces 162, 163 may have any shape or curvature which allows or facilitates interlocking and later detachment. For example, in the depicted embodiment, mating surfaces 162, 163 define a joining line 165 with an S-shaped curvature.

[0133] Coupling system 115 may also include actuator rod 170 and stud 131 (or alternatively base 139) such that fixation device 112 may also be releasably coupled to delivery system 600 via connection between actuator rod 170 and stud 131. When shaft 111 is coupled to coupling member 160, they may collectively form an axial channel. Actuator rod 170 may pass through this channel to bridge the joining line 165, as shown in FIG. 7B. Actuator rod 170 may comprise a proximal extremity 171, a distal extremity 172, and a joiner 174. Distal extremity 172 may be smaller in diameter than proximal extremity 171 and may be optionally surrounded by a coil 173 which may serve to bias joiner 174 in a proximal direction. However, in some embodiments, actuator rod 170 may not have coil 173 or proximal and distal extremities 171 , 172 of differing diameters. Joiner 174 may be removably coupled with stud 131 of fixation device 112 via any one of various possible release mechanisms. For example, in the embodiment depicted, joiner 174 may be threadedly connected to stud 131 of fixation device 112. In this regard, joiner 174 may have internal threads 175 which mate with external threads 133 on stud 131. Alternatively, joiner 174 may have external threads which mate with internal threads of stud 131. As described previously, stud 131 may be connected with distal elements 120 so that advancement and retraction of stud 131, by means of actuator rod 170, manipulates distal elements 120. It is also contemplated that joiner 174 may be directly threadedly engaged with base 139 where no stud 131 is provided. Once detachment of fixation device 112 is desired, actuator rod 170 may be rotated until threads 175 of joiner 174 disengage threads 133 of stud 131. Actuator rod 170 may then be retracted to a position above mating surfaces 162, 163 which in turn allows coupling member 160 to separate from shaft 111 along joining line 165, as illustrated in FIG. 7C.

[0134] FIGS. 8A and 8B illustrate an alternative example of a coupling system. In this exemplary coupling system 315, shaft 311 of the delivery system (e.g., delivery system 600) may be releasably coupled with coupling member 360 via a detent mechanism, for example. InAtty Docket No. ABTEVA-0064PCT this regard, shaft 311 may form an upper tubular shaft with detent mechanism features and coupling member 360 may form a lower tubular shaft with detent mechanism features configured to releasably connect with the detent mechanism features of shaft 311. In the embodiment depicted, the detent mechanism may include one or more spring arms 361 integrally formed on shaft 311 and one or more receptacles 362 sized to receive spring arms 361 within coupling member 360. However, shaft 311 may include receptacles 362, while coupling member 360 may include spring arms 361, for example. As shown, spring arms 361 may have a flange-like engagement element 363 at a distal end thereof and are preferably biased inwardly, i.e., toward an interior shaft 311, as shown in FIG. 8B. Receptacles or apertures 362 may be configured to receive and mate with respective engagement elements 363 of spring arms 361, as shown in FIG. 8 A. Receptacles 362 may extend all the way through the wall of coupling member 360 and may be sized to snuggly fit both engagement elements 362. A snuggly fitting rod (such as actuator rod 370) may extend through shaft 311 and coupling member 360 and may outwardly deflecting the inwardly biased spring arm(s) 361 such that the engagement elements 363 are pushed into respective engagement with a corresponding receptacle 362 thereby coupling the shaft 311 to coupling member 360, as shown in the example of FIG. 8A. When desirable to detach fixation device 1 12 from delivery system 600, actuator rod 370 may be retracted to a position above spring ami(s) 361 and engagement features 363 thereof. This allows the inwardly biased spring arms 361 and corresponding engagement elements 363 to disengage from receptacles 362 thereby detaching shaft 31 1 and coupling member 360. As mentioned above, actuator rod 370 may be threadedly engaged to stud 131. Thus, actuator rod 370 may first be rotated to unthread its threads 375 from stud 131 and then retracted to release coupling member 360 according to an example of the disclosure.

[0135] As mentioned above, fixation device 112 may, in one example, be actuated through multiple positions within a mammalian body during a transcatheter procedure such as by extending and retracting actuator rod 170 when coupled to stud 131 and / or base 139. FIGS. 9A-9B, 10A-10B, 11A-1 IB, 12A-12B, and FIGS. 13A-13B illustrate several of these possible positions and in a sequence that may be utilized during a transcatheter procedure.

[0136] FIGS. A and 9B depict fixation device 112 in an example of a closed position or delivery position. Fixation device 112 may assume the closed position when being delivered through a guide catheter or sheath 3300 of steerable guide system 5, as shown in FIG. 9A. InAtty Docket No. ABTEVA-0064PCT the closed position, the opposed pair of distal elements 120 may be positioned so that engagement surfaces 125 thereof face each other. The cupped or concave shape of each ami 121 in this example allows arms 121 to surround shaft 111 and optionally contact each other on opposite sides of shaft 1 11. This provides a low profile for fixation device 1 12 so that it is readily passable through a delivery catheter 3300 and through any anatomical structures, such as those within the cardiovascular system.

[0137] FIGS. 10A-10B depict fixation device 112 in an example of an open position. Fixation device 112 may assume the open position for capturing and grasping leaflets of a heart valve. In an open position, distal elements 120 may be rotated so that engagement surfaces 125 thereof face a first direction such that engagement surfaces 125 are disposed at an acute angle relative to shaft 111. For example, the acute angle formed between each engagement surface 125 and shaft may be 45 degrees to 90 degrees. Stated differently, in the open position, engagement surfaces 125 of distal elements 120 may be oriented 90 degrees to 180 degrees relative to each other. However, it is generally preferable for arms to be positioned 120 degrees relative to each other (and 60 degrees relative to shaft 111) for capturing leaflets. Movement of fixation device 112 from the closed position to the open position may be achieved by advancing stud 131 distally relative to coupling member 160 by distally advancing actuator rod 170. Conversely, fixation device 112 may be moved from the open position to the closed position by retracting actuator rod 170 and retracting stud 131 proximally, according to one example of the disclosure.

[0138] As shown in FIG. 10B, proximal elements 140 (or proximal elements 240) may be in a raised or insertion position when fixation device 112 is in the open position to facilitate insertion of leaflets between distal and proximal elements 120, 140 for their capture. Proximal elements 140 are, in one example, biased toward distal elements 120. In this regard, proximal elements 140 may be moved inwardly toward shaft 111 and held against shaft 111 with the aid of proximal element lines 101 which can be in the form of sutures, wires, nitinol wire, rods, cables, polymeric lines, or other suitable structures, as shown in FIG. 10A. Thus, FIGS. 10A and 10B depict fixation device 112 in an insertion configuration in which proximal elements 140 are in a raised position and distal elements 120 are in an open position.

[0139] Once fixation device 112 has been positioned in a desired location against the valve leaflets, the leaflets may then be captured between proximal elements 140 and distal elements 120. FIGS. 11A and 11B illustrate fixation device 112 in an example of such aAtty Docket No. ABTEVA-0064PCT position. Here, proximal elements 140 are lowered toward engagement surfaces 125 so that proximal elements 140 are in a lowered or capture position, and the leaflets are held between distal and proximal elements 120, 140. Proximal elements 140 are, in one example, lowered into the lowered position while distal elements 120 remain in the open position. Thus, fixation device 112, as shown in FIGS. 11 A and 1 IB is in an example of a capture configuration which may be similar to the insertion configuration of FIGS. 10A and 10B, but with the difference being that proximal elements 140 are now lowered toward distal elements 120 by releasing tension on proximal element lines 101 to compress the leaflet tissue therebetween. At any time, the proximal elements 140 may be raised and the distal elements 120 adjusted or inverted to reposition fixation device 112 if regurgitation is not sufficiently reduced according to one example of the disclosure.

[0140] FIGS. 12A-12B depict an example of an inverted position of fixation device 112. Fixation device 112 may assume the inverted position to aid in repositioning or removal of fixation device 112. In one example of the inverted position, distal elements 120 may be further rotated from the open position, which may be achieved by advancing stud 131 further relative to the open position, so that the engagement surfaces 125 of distal elements 120 face outwardly, and free ends 121b point distally. Additionally, in some examples, engagement surfaces 125 of each arm 121 may form an obtuse angle relative to shaft 111. For example, the obtuse angle formed between each engagement surface 125 and shaft 111 may be 135 degrees to 180 degrees. Stated differently, in the inverted position, engagement surfaces 125 of distal elements 120 may be oriented 270 degrees to 360 degrees relative to each other.

[0141] Also, as shown in FIG. 12B, in one example proximal elements 140 are in their raised position against shaft 111 while distal elements 120 are in the inverted position by exerting tension on the proximal element lines 101. Thus, a relatively large space may be created between proximal and distal elements 140, 18 for repositioning. In addition, the inverted position allows withdrawal of the fixation device 112 through the valve while minimizing trauma to the leaflets. Engagement surfaces 125 provide an atraumatic surface for deflecting tissue as the fixation device is retracted proximally. It should be further noted that tines 145 of proximal elements 140 may, in some examples, be angled slightly in the distal direction (away from the free ends of the proximal elements 140), reducing the risk that tines 145 will catch on or lacerate tissue as fixation device 112 is withdrawn and while proximal elements 140 are in the raised position.Atty Docket No. ABTEVA-0064PCT

[0142] After the leaflets have been captured between distal and proximal elements 120,140, distal elements 120 may be relumed to or toward the closed position where they may be locked in place. An example of such locking is described further below. FIG. 13A illustrates fixation device 112 in the closed position wherein the leaflets (not shown) are captured and coapted. In one example, this is achieved by retraction of the stud 131 proximally relative to coupling member 160 so that the legs 130 of the actuation mechanism 113 apply an upwards force to distal elements 120 which in turn rotate distal elements 120 so that engagement surfaces 125 again face one another, similar to that of FIGS. 9A and 9B, and so that distal elements 120 rotate proximal elements 140 in a direction toward shaft 111. However, because the leaflets are captured between distal and proximal elements 120, 140, it may be desirable to keep distal elements 120 at about 20 degrees to 60 degrees relative to each other so as to limit the amount of tension and stress on the native tissue. Thus, while fixation device 1 12 may be returned to the closed position, such closed position may not be as closed as in the initial delivery position.

[0143] As shown in FIG. 13B, fixation device 112 may then be released from shaft 111 of delivery system 600 while in the closed position. As mentioned, fixation device 112 may be releasably coupled to delivery system 600 via a coupling system (e.g., coupling system 1 15 or 315). When the coupling structures of such coupling system are released, proximal element lines 101 may remain attached to proximal elements 140 following detachment to function as a tether to keep the fixation device 112 connected with the delivery catheter 610 (see FIG. 16) for reconnection and repositioning. However, in other embodiments, proximal elements lines 101 may be released prior to release of fixation device 112 or concurrently with the release of fixation device 112, as described in more detail below.

[0144] FIG. 13C illustrates a released fixation device 112 in an example of a closed position. As shown, coupling member 160 remains separated from shaft 11 1 of delivery system 600, and proximal elements 140 are deployed so that tissue (not shown) may reside between proximal elements 140 and distal elements 120.

[0145] As mentioned above, proximal element lines or actuators 101 may be releasably coupled to proximal elements 140. In some examples, proximal element lines 101 may pass through an opening in proximal elements 140, such as openings 146 and 246 in the case of proximal element 240. In other examples, eyelets, which may be formed from one or more lengths of suture, may be coupled to proximal elements 140 and proximal element lines 101Atty Docket No. ABTEVA-0064PCT may pass through such eyelets. Thus, proximal element lines 101 may be released from proximal elements 140 prior to, concurrent with, or after release of fixation device 112 from delivery system 600 according to various examples.

[0146] Tn an exemplary embodiment of interventional tool 1 10, as shown in FIG. 14, a plurality of proximal element lines 101a, 101b may extend through corresponding lumens 614a, 614b of shaft 111 of delivery system 600 (see FIG. 16) and may be coupled to proximal elements 140 of fixation device 112. Each of proximal element lines 101a and 101b may be elongated flexible threads, wire, cable, sutures, or lines extending through shaft 111, looped through proximal elements 140, and extending back through shaft 111 to a delivery device handle of delivery system 600. When detachment is desired, one end of each proximal element line 101a, 101b may be released from delivery system 600, and the other end pulled to draw the free end distally through shaft 111 and through proximal element 140 thereby releasing it. Also, in this arrangement, proximal element lines 101a and 101b may be independently or concurrently manipulated so as to independently or concurrently raise and lower proximal elements 140, respectively.

[0147] In another example, interventional tool 110’ may be configured, as shown in FIG. 15 with respect to certain components thereof, such that proximal elements 140 may alternatively be supported by a single proximal element line 101 which may extend through both of the proximal elements 140. In this arrangement both proximal elements 140 may be raised and lowered concurrently by action of a single proximal element line 101. Whether proximal elements 140 are manipulated individually by separate proximal element lines 101 or jointly by a single proximal element line 101, the proximal element lines 101 may extend directly through openings (e.g., openings 146, 246) of the proximal elements 140 and / or through a layer or portion of a covering 117 on proximal elements 140, or through a suture loop / eyelet above or below a covering 117, for example.

[0148] In a further example, interventional tool 110” may be configured, as shown in FIG. 16, such that each proximal element line 101a, 101b may be releasably engaged with structures that are activated by removal of the actuator rod 170 that passes through coupling member 160 and shaft 111 such that release of proximal element lines 101a, 101b occurs concurrently with the release of fixation device 112 from delivery system 600. Thus, in one example, which is depicted in FIG. 16, each proximal element line 101a, 101b may have a first end portion 103a (e.g. , proximal end portion), which may be coupled to an actuator of a deliveryAtty Docket No. ABTEVA-0064PCT system handle, a second end portion 103b (e.g., distal end portion) which may be releasably engages to shaft 111 via actuator rod 170, and an intermediate portion 103c which may be coupled to a proximal element 140. As described above and as illustrated in FIG. 7A, stud 131 may be releasably attached to actuator rod 170 which passes through coupling member 160 and shaft 111 of delivery system 600. In this way, actuator rod 170 is connectable with fixation device 112 and acts to manipulate fixation device 112 so as to move it through its various positions, which are described above. After the leaflets have been coapted, actuator rod 170 may be removed proximally from stud 131 which may thereby also release coupling member 160 from shaft 111, as described with respect to FIGS. 7A-7C and also FIGS. 8A and 8B with respect to coupling system 315. This action of actuator rod 170 may be utilized to release distal end portion 103b of each of proximal element lines 101a, 101b.

[0149] Exemplary features which may be implemented in interventional tool 110” to facilitate release of proximal element lines 101a, 101b in this manner are shown in FIGS. 17A- 17G. As depicted, an actuator rod 470 may be used as an anchor to restrict proximal movement of one or more proximal element lines 401. Proximal element line 401 has a distal end portion 403b which may include a catch element 405 (or catch), for example a trumpet 405 having a cone shape (see FIG. 17D) or other shapes, such as a ball 405’ having a spherical shape (see FIG. 17G), which can be sized to be received within shaft 411. As shown in the example of FIGS. 17B, shaft 411 may have spring arms 461 like that of the coupling system 315 of FIGS. 8A and 8B for releasing device 112 from shaft 411. However, shaft 411 may also have mating surfaces of FIGS. 7A and 7C. In any event, a portion of shaft 411 proximal of spring arms 461 (or mating elements 463), may have two slots 412a and 412b defined therein. Slot 412a can define holes 414a and 414b and slot 412b can define holes 414c and 414d. Holes 414a and 414c can be sized to receive catch element 405 of a pair of proximal element lines 401, respectively, therethrough and into slots 412a and 412b, respectively. Holes 414b and 414d can be sized to prevent catch element 405 of proximal element lines 401, respectively, from extending beyond slots 412a and 412b, respectively. The configuration of slots 412a and 412b and holes 414a-414d can allow for easier manufacture of the features in shaft 411. Slots 412a and 412b can be drilled to ensure that slots 412a and 412b do not pass the entire way through shaft 41 1. In this example configuration, catch elements 405 of proximal element lines 401 can be maintained within shaft 411 to manage the slack of proximal element lines 401.Atty Docket No. ABTEVA-0064PCT

[0150] In one example, catch element 405 of proximal element line 401 can be inserted into slot 412a through hole 414a beyond a longitudinal axis of shaft 411 and toward hole 414b, and catch element 405 of proximal element line 401 can be inserted into slot 412b through hole 414c beyond the longitudinal axis of shaft 41 1 and toward hole 414d prior to the insertion and coupling of the actuator rod 470 (which passes through shaft 411) with stud 131 of fixation device 112. With actuator rod 470 extending through shaft 411, actuator rod 470 may directly engage catch elements 405 of lines a plurality of proximal element lines 401 thereby preventing their movement back out along the path through which they were inserted. For example, trumpets 405 can be inhibited from being advanced through holes 414b and 414d, respectively, and can be prevented from being pulled past actuator rod 470 and through holes 414a and 414c, respectively. Accordingly, the second end portions 403b of proximal element lines 401 can be held in place relative to shaft 414. Once the actuator rod 470 is decoupled from stud 131 and subsequently retracted, movement of catch elements 405 at the distal end portions of proximal element lines 401 is no longer restricted and proximal element lines 401 are free to move. Upon proximal retraction, proximal element lines 401 can thread through holes 414a and 414c, respectively, and decouple from the proximal elements 140.

[0151] In accordance with one example of the disclosed subject matter, slots 412a and 412b can be drilled at an angle towards the distal end of shaft 411 (see FIGS. 17E and 17F), e.g., with hole 414b formed distal to hole 414a on one side, and hole 414d formed distal to hole 141c on the other side. This example configuration of slots 412a and 412b can provide easier deployment of a plurality of proximal element lines 401 and can reduce friction.

[0152] Prior to securing second end portion 403b of each proximal element line 401 with the shaft 411, each proximal element line 401 can be coupled with a respective proximal element 140, such as in the manner described above with respect to FIG. 16. Thus, when proximal element lines 401 are actuated proximally, proximal element lines 401 can move proximal elements 140 relative to distal elements 120, thereby moving proximal elements 140 between their respective raised and lowered positions.

[0153] As mentioned above, fixation device 112 optionally includes a locking mechanism e.g., locking mechanism 116) for locking device 112 in a particular position, such as in any one of the aforementioned open, closed, and inverted positions or any position therebetween. It may be appreciated that according to various examples, locking mechanism 116 may be configured for both locking and unlocking which correspondingly allows deviceAtty Docket No. ABTEVA-0064PCT112 to be both locked and unlocked. As described in more detail below with respect to various locking mechanism examples, such locking mechanisms may have components disposed between coupling member 160 and base 139 which may be configured to selectively arrest proximal-distal movement of stud 131 / base 1 9 which consequently arrests movement of distal elements 120. Such locking mechanisms may help provide end user control of the final arm angle of fixation device 112 for tailored and optimal results for each patient. Additionally, such locking mechanisms may bring the leaflets and annulus together which may result in beneficial dimensional changes of the target valve which can prevent adverse remodeling of the heart, particularly for patients with heart failure.

[0154] FIGS. 14, 15, and 16A-16C illustrate an embodiment of the locking mechanism 116. Locking mechanism 116 generally includes a housing 181, one or more wedging elements 180, a release harness 190, and a biasing member 189. Housing 181may be positioned distal to coupling member 160 and may be free-floating, coupled to, or integral with coupling member 160, such as at a distal end thereof. Housing 181 may form a window 183 which may be defined at opposite sides with sloping or tapered surfaces 185 which slope inwardly toward stud 131 in a proximal to distal direction. Wedging elements 180 may be in the form of rolling elements, such as a pair of barbells, disposed on opposite sides of stud 131 and between sloping surfaces 185, as shown in FIGS. 18A and 18B. Each barbell 180 may have a pair of generally cylindrical caps 182 and a shaft 184 therebetween, as illustrated in the barbell cross-section of FIG. 16A. Barbells 180 and stud 131 are preferably comprised of cobalt chromium or stainless steel, however any suitable material may be used. Biasing member 189 may be a spring, such as a leaf spring, for example, and may be positioned at a proximal end of housing 181 between sloping surfaces 185 and proximal to barbells 180 such that spring 189 bears on barbells 180 and biases them in a distal direction. Thus, when barbells 180 are pushed distally by spring 189, they are correspondingly pushed inwardly and wedged against stud 131 by sloping surfaces 185, as illustrated by FIG. 18 A, which depicts barbells 180 in a proximal and unlocked position, and FIG. 18B, which depicts barbells 180 in a distal and locked position.

[0155] As shown in FIGS. 14, 15, and 18C, release harness 190 may be in the form of a ridged wire or rod that may extend proximally from stud 131 toward a proximal end of fixation device 112 and at opposite sides thereof. In this regard, release harness 190 may form a first portion or front portion 192a and a second portion or rear portion 192b. Each of first and second portions 192a, 192b may include a crest or closed proximal end 194 through which aAtty Docket No. ABTEVA-0064PCT lock line 102 may be threaded and engaged, as described below. Release harness 190 may also form hooked distal ends 196a, 196b which may extend between first and second portions 192a, 192b and between sloping surfaces 185 and stud 131, as shown in FIGS. 18A and 18B. Thus, hooked ends 196a and 196b may be moveable proximally-distally within window 183 formed between sloped surfaces 185 and stud 131. Additionally, hooked ends 196a and 196b may be positioned distal of barbells 180 such that pulling up on harness 190 moves hooked ends 196a, 196b proximally so as to push the respective barbells 180 against the bias of spring 189 and move them to their unlocked position.

[0156] Movement of harness 190 may be performed by one or more lock line 102 which may be coupled to harness 190 by such as by threading lock line 102 through and engaging one or more of proximal ends 194 of first and second portions 192a, 192b thereof, as shown in FIGS. 14 and 15. Such lock line 102 may have a first end 102a fixedly secured to a delivery system handle of delivery system 600 and a second end 102b releasably secured to a delivery system handle, as described in more detail below. In this regard, tension can be selectively applied to lock line 102 to unlock and lock locking mechanism 116. Also, lock line 102 can be released from release harness 190 prior to, concurrently with, or after release of fixation device 112 from delivery system 600 which may be achieved by releasing the second end 102b from delivery system handle and pulling lock line 102 and its second end through shaft 111. Lock line 102 may be comprised of any suitable material, typically wire, nitinol wire, cable, suture, or thread, to name a few. In addition, lock line 102 may include a coating, such as parylene. Parylene is a vapor deposited pinhole free protective film which is conformal and biocompatible. It is inert and protects against moisture, chemicals, and electrical charge.

[0157] When an upwards force is applied to harness 190 by the lock line 102, hooked ends 196a, 196b may raise barbells 180 against spring 189, as shown in FIG. 18A. This may draw barbells 180 up along sloping surface 185 which un wedges barbells 180 from against stud 131. In this position, stud 131 is free to move. Thus, when lock line 102 is tensioned to raise or lift harness 1 0, locking mechanism 116 is in an unlocked position wherein stud 131 is free to move actuation mechanism 113 and therefore distal elements 120 to any desired position. Releasing tension in lock line 102 may, on the other hand, transition the locking mechanism 116 to a locked position, as shown in FIG. 18B. Thus, by releasing the upwards force on barbells 180 by hooked ends 192a, 192b, spring 189 forces barbells 180 downwards and wedges barbells 180 between a sloping surface 185 and stud 131. This restricts motion of studAtty Docket No. ABTEVA-0064PCT131, which in turn locks actuation mechanism 113 and therefore distal elements 120 in place. In addition, stud 131 may include one or more grooves or indentations 137 which may receive shaft 184 of each barbell 180. This may provide more rapid and positive locking by causing barbells 180 to settle in a definite position, increase the stability of locking mechanism 116 by further preventing movement of barbells 180, as well as tangible indication to the user that each barbell 180 has reached a locking position. In addition, grooves 137 may be used to indicate the relative position of distal elements 120, particularly the distance between distal elements 120. For example, each groove 137 may be positioned to correspond with a 0.5- or 1.0-mm decrease in distance between distal elements 120. As stud 131 is moved, barbells 180 may contact grooves 137, and by counting the number of grooves 137 that are felt as stud 131 is moved, the user can determine the distance between distal elements 120 and can provide the desired degree of coaptation based upon leaflet thickness, geometry, spacing, blood flow dynamics and other factors. Thus, grooves 137 may provide tactile feedback to the user.

[0158] Locking mechanism 116 allows fixation device 112 to remain in an unlocked position when attached to delivery system 600 during grasping and repositioning and then maintain a locked position when left behind as an implant. It may be appreciated, however, that locking mechanism 1 16 may be repeatedly locked and unlocked throughout the placement of the fixation device 112 if desired. Once the final placement is determined, lock line 102 may be removed and fixation device 112 may be left behind.

[0159] FIGS. 19A-19C depict a locking mechanism 516 according to another embodiment of the present disclosure that may be incorporated into a fixation device 112 of the disclosure. In this embodiment, locking mechanism 516 also includes a housing 581, a spring 589, a release harness 590, and a wedging element 500. However, instead of sloping surfaces 185 as present in the example of locking element 116, housing 185 may include generally parallel sidewalls 585 and may include a finger or protrusion 587 extending from one of sidewalls 585 toward stud 131, as best shown in FIG. 19C. Such finger 587 may slope in a distal direction and may define a proximal notch 588. Also, as shown in FIG. 19C, first hooked end 596a of release harness 590 may be positioned distal of finger 587.

[0160] Furthermore, wedging element may comprise a binding lever or binding plate 500. As shown in FIG. 19B, binding plate 500 may have an oblong shape that may extend lengthwise between a first end 501 and a second end 502 thereof. An aperture 504 may be formed between first and second ends 501, 502 and may extend from a top planar surface 508Atty Docket No. ABTEVA-0064PCT through a botom planar surface 506 of binding plate 500. Binding plate 500 may be positioned between sidewalls 406 so that stud 131 passes through aperture 504 and so that first end 501 of binding plate 500 is positioned within notch 588 proximal of finger 587, as best shown in FIG. 19C. Thus, finger 587 may be positioned between first end 501 of binding plate 500 and first hooked end 596a of released harness 590. Also, spring 589 may be positioned proximal to binding plate 500 and provide downward or distal bias thereto. Binding plate 500 and stud 131 may be comprised of any suitable material. In some embodiments, binding plate 500 may have a higher hardness than stud 131. In other embodiments, binding plate 500 may be comprised of a flexible or semi-flexible material. Such flexibility may allow slight movement of stud 131 in the proximal and distal directions, therefore allowing slight movement of distal elements 120 when locking mechanism 516 is in the locked position. This may allow fixation device 112 to adjust in response to dynamic cardiac forces.

[0161] FIGS. 19A and 19C illustrate binding plate 500 in a locked position or configuration. In this regard, spring 589 pushes binding plate 500 in a distal direction. However, because first end 501 of binding plate 501 is positioned within notch 588, axial movement of first end 501 toward a distal end of housing 581 is prohibited while axial movement of second end 502 of binding plate 500 is permitted. Thus, finger 587 obstructs first end 501 from axial movement and creates a lever type movement of binding plate 500. Moreover, finger 587 obstructs first hooked end 596a of release harness 590 from axial movement resulting in a side-to-side pivoting of release harness 590 upon tension of lock line 102. This pivoting movement correspondingly results in second hooked end 596b of release harness moving proximally and controlling movement of second end 502 of binding plate 500. As such, when an upwards force is applied to harness 590 by lock line 102, second hooked end 596b of release harness 590 raises second end 502 of plate 500 against spring 589 so that planar surfaces 506, 508 of binding plate 500 become oriented substantially perpendicular to stud 131. This aligns aperture 504 with stud 131 allowing free movement of stud 131 in the proximal- distal direction. Thus, in this state, locking mechanism 516 is unlocked wherein stud 131 is free to move actuation mechanism 113 and therefore distal elements 120 to any desired position.

[0162] Release of harness 590 by lock line 102 transitions locking mechanism 516 back to the locked position. By releasing the upwards force on second end 502 of binding plate 500, spring 589 forces second end 502 of biding plate 500 downwards, which misaligns apertureAtty Docket No. ABTEVA-0064PCT504 relative to stud 531, and correspondingly wedges binding plate 500 against stud 131, as best shown in FIG. 19C. This arrests movement of stud 131, which in turn locks actuation mechanism 113 and therefore distal elements 120 in place. It may be appreciated that binding plate 500 may have any suitable form to function as described above. For example, plate 500 may have a variety of shapes with or without planar surfaces 506, 508 and / or the aperture 504 may be of a variety of shapes and positioned in a variety of locations, to name a few. For example, binding plate 500 may not have a through-hole, like that of aperture 504, but may rather have a notch such that binding plate 500 does not encircle stud 131 but rather partially surrounds it. Further, it may be appreciated that any number of binding plates 500 may be present. Each binding plate 500, in this regard, may provide an additional binding location which may enhance lock performance.

[0163] While the above-described nonlimiting examples of fixation device 112 may utilize a push-to-open, pull-to-close mechanism for opening and closing distal elements 120, it should be understood that a pull-to-open, push-to-close mechanism may alternatively be provided. For example, distal elements 120 may be coupled at their proximal ends to stud 131 rather than to coupling member 160, and legs 130 may be coupled at their proximal ends to coupling member 160 rather than to stud 131 . Tn this example, when stud 131 is pushed distally relative to coupling member 160, distal elements 120 may close, while pulling on stud 131 proximally toward coupling member 160 may open distal elements 120. Regardless, the aforementioned locking mechanism examples may be configured to arrest stud to lock distal elements 120 in the desired position, as described.

[0164] It is to be understood that the fixation devices and components thereof described above are provided as examples are not to be considered as limiting to fixation devices suitable for use with other aspects of the disclosure.

[0165] 1'he above-described examples of fixation device 112 may be utilized in a TEER procedure or any other tissue approximation procedures (e.g., procedures involving cardiac and non-cardiac tissues). A TEER procedure is a minimally invasive interventional procedure that aims to approximate cardiac valvular leaflets to reduce valvular regurgitation particularly in the mitral and triscupid valves. One of the challenges of this type of procedure is ensuring that the valve leaflets are adequately inserted into the fixation device, such as fixation device 112, for example, so that when the fixation device is deployed, it remains secured to the tissue and sufficiently reduces regurgitation. Current TEER techniques typically rely onAtty Docket No. ABTEVA-0064PCT echocardiography and fluoroscopy for visualization which typically capture fixed views of the target valve. Such visualization modalities, however, have inherent limitations that present challenges making leaflet capture and grasping one of, if not the most, challenging aspects of a TEER procedure. Tn particular, technique and technological limitations make it difficult to visually observe the leaflets within the fixation device during and after deployment so that the surgeon cannot directly observe how much leaflet is inserted into the fixation device or whether a leaflet has been captured at all. Thus, surgeons typically assess leaflet capture through circumstantial observations that are heavily reliant on surgeon experience. For example, an operator may observe changes in movements of the leaflets and reductions in backflow via color doppler to estimate the adequacy of leaflet capture.

[0166] Difficulties in visualizing leaflet capture can potentially lead to poor leaflet securement and ultimately single leaflet device attachment (“SLDA”), in which only a single leaflet is captured by the fixation device, or complete detachment (i.e., implant embolization). For example, if a leaflet is not inserted far enough between a proximal element and a distal element (i.e., shallow leaflet insertion), the proximal and distal elements may not be able to grasp the tissue with enough force to retain the tissue potentially resulting in leaflet slippage and ultimately SEDA or implant embolization. Thus, it generally is not sufficient to just capture valve tissue between proximal and distal elements. Rather, the capture should be of such quality to ensure the fixation device remains attached to the leaflet. The quality of tissue capture can be influenced by a number of factors, one of which being the magnitude of the pinch force applied to the tissue.

[0167] Finite element analysis has been performed to quantify the pinch force within corresponding proximal and distal elements to help determine how deep a leaflet may be inserted to achieve an adequality high probability that a leaflet will be permanently captured with limited or otherwise acceptable risk of SLDA or embolization. The force distribution resulting from this analysis for a first clamp 104 comprised of distal element 120 and proximal element 140 is shown in FIG. 20A and for a second, longer clamp 104’ comprised of distal element 120’ and proximal element 140’ is shown in FIG. 20B. As shown, the majority of the generated pinch force is applied to the tissue when approximately more than 50% of a maximum leaflet insertion depth is achieved. Thus, leaflet security is ensured, and leaflet capture is sufficient when a leaflet LF is inserted between proximal and distal elements to a depth of more than 50% of a maximum insertion depth. The maximum insertion depth Lgrip,Atty Docket No. ABTEVA-0064PCT as depicted in FIGS. 20A and 20B, is the maximum length along which a leaflet LF can be captured between the proximal and distal elements, such as proximal elements 120, 120’ and distal elements 140, 140’. The maximum insertion depth Lgrip may be measured between a crotch 105 (taking into account any fabric covering on the fixation device) formed between fixed ends 121a, 141a and free ends 121b, 141b of the respective distal elements 120, 120’ and proximal elements 140, 140’. Crotch 105 defines a closed end of clamps 104 and 104’. Free ends 121b, 141b define an open end of clamps 104 and 104’. Although distal and proximal elements 120, 120’, 140, 140’ typically capture tissue when each distal element 120, 120’ is at about 60 degrees relative to a longitudinal axis defined by shaft 111 (see FIG. 11B) (120 degrees relative each other) and are then moved to a final, closed position of 5 to 15 degrees (10 to 30 degrees relative each other), it should be noted that the pinch force generally does not change with the angle of the clamp 104, 104’ up to about the initial capture angle of 60 degrees. Thus, the pinch force will be approximately the same throughout the range of motion from initial capture to the final, closed position.

[0168] FIG. 21A illustrates an impedance system 700 according to an embodiment of the present disclosure. Impedance system 700 generally includes an impedance control unit 701 , a plurality of electrodes 702, and an interface 706 between the electrodes 702 and the control unit 701. As described further below, impedance system 700 may be integrated into a medical system or medical implant and may be configured to measure impedance of biological tissue within a patient.

[0169] Impedance is a measure of opposition to the flow of electrical cunent in a circuit. In an AC circuit, impedance varies with frequency and is a combination of both resistance R and reactance, which includes inductive reactance XL and capacitive reactance Xc. Impedance in an AC circuit is given by the formula: z = 7R2+ (xL- xcyIn a DC circuit, since the current does not oscillate (i.e., the frequency is zero), the reactance is effectively zero, and thus the impedance reduces to the circuit’s resistance R. Thus, the term “impedance” as used throughout the following discussion of various examples is not limited to AC circuits.

[0170] Impedance control unit 701 includes a power source 703 and a measurement module 710. Power source 703 may be configured to provide AC power and / or DC power. Thus, in one example, power source 703 is configured to deliver AC power. In anotherAtty Docket No. ABTEVA-0064PCT example, power source 703 is configured to deliver DC power. In a further example, power source 703 is configured to deliver AC power and DC power. In this example, power source 703 may be configured to have an AC mode and a DC mode and may be configured to switch between AC mode and DC mode either automatically or through manual operation.

[0171] In the examples in which power source 703 provides DC power, power source 703 provides a constant current or voltage for impedance measurements which focus purely on the resistive properties of biological tissue. This configuration may be beneficial when binary outputs are desired, such as whether the electrodes 702 are in contact with tissue or not in contact with tissue. The use of DC power can help ensure stable and reliable operation and consistent measurements.

[0172] In the examples in which power source 703 provides AC power, power source 703 may be configured to provide a single frequency or a range of frequencies for impedance measurement. In such examples, the use of AC power may help determine when electrodes 702 are in contact or not in contact with tissue and to distinguish between the types of tissue the electrodes 702 are in contact with. Thus, AC operation of control unit 701 may measure both the resistive and reactive components of a tissue’s impedance, which is sometimes referred to as bioimpedance.

[0173] The impedance of tissue varies between different types of tissue primarily due to differences in cellular structure and composition. The electrical properties of biological tissues are influenced by the makeup of cell membranes, intracellular fluids, and extracellular fluids, each contributing to the overall resistance and reactance of the tissue. Cell membranes function as natural capacitors, storing electrical charge and affecting the reactive component of impedance. Tissues with a higher concentration of cells, such as the heart's leaflet tissues, exhibit greater capacitance due to the large number of cell membranes compared to other tissues with lower cell concentrations, such as the chordae tendineae (“chordae”), which influences how electrical signals propagate.

[0174] Tissues respond differently to various frequencies, allowing for distinct impedance characteristics to be observed across a range of frequencies. For example, at low frequencies (e.g., 10 Hz to 10 kHz), impedance measurements primarily reflect the resistance of the tissue. At these frequencies, cell membranes act as barriers to current flow which directs current through the extracellular matrix. This characteristic allows for the assessment of the density and integrity of both the cellular structures and the extracellular components within theAtty Docket No. ABTEVA-0064PCT tissue, facilitating the distinction between different types of tissue. For instance, valve leaflets contain a rich extracellular matrix, which provides conductive pathways for current to How. In contrast, the chordae are primarily composed of collagen fibers with lower cellular density and a less conductive extracellular matrix. Thus, at low frequencies, valve leaflets typically exhibit lower impedance than the chordae. As a result, impedance values measured from the chordae are generally higher due to their fibrous nature and lower capacitance. This distinction not only enables differentiation between valve leaflets and chordae but also highlights potential use cases in optimizing implant placement. Specifically, in disease states such as Barlow’s or other valve morphological abnormalities, similar impedance-based technologies could facilitate precise implant positioning to avoid targeting specific tissue types. Such differences enable the distinction between valve leaflets and chordae at low frequencies.

[0175] Distinguishing between these tissues may also be possible at higher frequencies (e.g., 10 kHz to 10 MHz). At these frequencies, current can penetrate the cell membranes, allowing it to travel through both the intracellular and extracellular environments, which provides insight into the reactive components of impedance. Since valve leaflets have a higher concentration of cells and a rich extracellular matrix, they may exhibit a greater reduction in impedance at higher frequencies, where the current interacts more with intracellular fluids and membrane capacitance. In contrast, the chordae, with their lower cellular density and more fibrous, collagen-rich structure, may exhibit less change in impedance because their extracellular matrix and overall composition contribute less to capacitive behavior. As a result, the difference in impedance between the valve leaflets and chordae becomes may be pronounced at higher frequencies, further enabling tissue differentiation. Such differentiation may become even clearer when traversing between low and high frequencies and observing the resulting impedance response.

[0176] Power source 703 may be configured to provide a single frequency. In one example, power source 703 may provide AC power at a single frequency in the low frequency range (e.g., 10 Hz to 10 kHz). In another example, power source 703 may provide AC power at a single frequency in the high frequency range (e.g., 10 kHz to 10 MHz).

[0177] Alternatively or additionally, power source 703 may be configured to vary frequency. In one example, power source 703 may vary frequency within the low frequency range (e.g., 10 Hz to 10 kHz). In another example, power source 703 may vary frequency within the high frequency range (e.g., 10 kHz to 10 MHz). In a further example, power source 703Atty Docket No. ABTEVA-0064PCT may vary frequency between these ranges. As such, impedance system 700 may take advantage of the change of cellular behavior in the low and high frequency ranges and the transition between these ranges to help identify the type of tissue in contact with electrodes 702.

[0178] The impedance measurement module 710 is configured to measure the resulting response of the tissue after a known current or voltage is applied by power source 703 to the tissue via electrodes 702. In some examples, measurement module 710 may include one or more processors 712 and a memory 714, as shown in FIG. 21B. Processor 712 can be any conventional processor, such as a commercially available CPU. Alternatively, processor 712 can be a dedicated component such as an application specific integrated circuit ("ASIC") or other hardware -based processor. Memory 714 may include data that can be retrieved, manipulated or stored by processor 712. Memory 714 can be of any non-transitory type capable of storing information accessible by processor 712, such as a hard-drive, memory card, ROM, RAM, write-capable, and read-only memories.

[0179] In examples where power supply 703 provides DC power, measurement module 710 is enabled to assess resistive impedance of tissue in contact with electrodes 702. In this configuration, measurement module 710 may employ signal processing techniques, including noise filtering and amplification, to ensure that low-level signals from biological tissues are accurately captured. Additionally, measurement module 710 may be configured to compensate for parasitic resistances and electrode contact impedance, for example, ensuring precise and reliable impedance measurements across different operating conditions.

[0180] In examples where power supply 703 provides AC power, measurement module 710 is enabled for single-frequency and / or multifrequency measurements for assessment of tissue impedance at a single frequency and / or across a spectrum of frequencies. In this regard, measurement module 710 may be configured to analyze both resistive (real) and reactive (imaginary) components of impedance. This may involve phase shift analysis and Fourier transform techniques to decompose the incoming signals into their frequency components. This is particularly advantageous for investigating the electrical properties of tissues, as the resistance and reactive components of tissues can vary with frequency. Measurement module 710 may also be configured to calculate parameters such as phase angle and impedance magnitude, providing a comprehensive understanding of tissue characteristics.

[0181] As shown in FIG. 2 IB, measurement module 710 may also be configured to interface with a display 720 (e.g., a monitor having a screen, a touchscreen, a projector, aAtty Docket No. ABTEVA-0064PCT television, or other device that is operable to display information) to output impedance measurement results to a surgeon. Such results may be in the form of waveforms or in the form of interpretations of the impedance signals to simplify the surgeon’s decision-making process. For example, memory 714 may include a database of impedance measurements for various types of tissues, and processor 712 may be configured to compare this database to measured impedances during a procedure to assess the type of tissue in contact with electrodes 702. The results of this comparison can be provided to the surgeon in lieu of or in addition to the raw impedance signals.

[0182] The electrodes 702 may be surface electrodes configured as contact pads that interface with biological tissue for impedance measurement. Electrodes 702 may be made from one or more of various conductive, biocompatible materials, ensuring a low-impedance connection with the tissue. For example, electrodes 702 may be constructed from one or more metal materials (e.g., gold, platinum, silver, or silver chloride (AgCl)), carbon-based materials (e.g., graphene or carbon nanotubes), and / or conductive polymers (e.g., polypyrrole). As described in more detail below, impedance system 700 may include al least two electrodes, such as a first electrode 702a and a second electrode 702b (see FIGS. 21C and 21D), forming an electrode pair that creates an open electrical circuit until tissue contact closes the circuit. Starting with an open electrical circuit before tissue is contacted may be advantageous in that it may minimize noise, may provide a clear indication of when tissue contact occurs, and may enhance safety by preventing unintended current flow. Furthermore, as the circuit is closed and more tissue contact is initiated (e.g., when additional tissue is compressed between the contacts), the signal strength increases. This configuration correlates signal strength to the degree of tissue contact, offering enhanced feedback and a clearer picture of tissue interaction with electrodes 702a, 702b and any structure underlying electrodes 702a, 702b.

[0183] In some examples, the electrode pair includes an anode and a cathode. For example, first electrode 702a may be a cathode, and second electrode 702b may be an anode. In another example, first electrode 702a may be an anode, and second electrode 702b may be a cathode. In such examples, the anode and cathode may be made from the same material. Alternatively, the anode and cathode may be made from different materials.

[0184] In one example of impedance system 700, electrodes, such as first and second electrodes 702a, 702b, may be standalone electrodes, as depicted in FIG. 21C. In this regard, electrodes 702a, 702b may be separately connected to a medical device, such as through theAtty Docket No. ABTEVA-0064PCT use of non-conductive connectors and / or adhesives (e.g., silicone adhesive). Insulated conductors 704a, 704b (e.g., leads or traces) are connected to each electrode 702a for carrying signals between electrodes 702a, 702b and impedance control unit 700.

[0185] Tn another example of impedance system 700, electrodes, such as first and second electrodes 702a, 702b, may be collectively disposed on a substrate 705, as depicted in FIG. 2 ID. Substrate 705 may be permanently connected to a medical device, such as an implant, or may be removably connected to a medical device so that the substrate 705 and electrodes 702a, 702b may be removed from the medical device after implantation. Substrate 705 may be a printed circuit board (“PCB”) or be made from flexible, biocompatible materials such as silicone or medical-grade polymers. Electrical conductors 704a, 704b may extend from electrodes 702a, 702b and through or on substrate 705. This configuration may also facilitate the construction of an electrode array that includes more than one pair of electrodes 702. An array configuration may enable the distinction of different tissue patterns along the array through the opening and closing of individual circuits. This could provide a "map" of the tissue rather than a binary presence of tissue, offering more detailed diagnostic or placement information.

[0186] The interface 706 between electrodes 702 and impedance control unit 701 may be a hardwired interface or a wireless interface, for example. In a hardwired configuration, interface 706 may include one or more conductors, such as conductors 704a, 704b, which may carry electrical signals between electrodes 702 and impedance control unit 701. Such configuration enables stable and reliable signal transmission with minimal noise interference. In a wireless configuration, interface 706 may additionally or alternatively include transmitters, receivers, and / or transceivers which may be enabled with any one of various wireless protocols (e.g., Bluetooth Tow Energy (“BLE”), Near Field Communication (“NFC”), or Zigbee) to transmit signals from electrodes 702 to impedance control unit 701.

[0187] Impedance system 700 may be integrated with a medical device, such as the fixation device 1012 depicted in FIG. 22A. Fixation device 1012 is similar to fixation device 112. In this regard fixation device 1012 includes a pair of distal elements 1020, a pair of proximal elements 1040, and a center portion that includes a coupling member 1060 for coupling to a delivery catheter shaft 1011. However, it should be understood that fixation device 1012 can be any of the aforementioned fixation devices and variations thereof. ForAtty Docket No. ABTEVA-0064PCT example, fixation device 102 can include proximal elements 140 of FIGS. 5 A and 5B or proximal elements 240 of FIGS. 6A-6C.

[0188] In one example, impedance system 700 may be fully encapsulated within fixation device 1012. For example, electrodes 702 may be positioned on proximal elements 1040 and / or distal elements 1020, as described further below, and impedance control unit 701 may be coupled to the center portion of fixation device 1012, such as coupling member 1060. Control unit 1060 may be configured to communicate with one or more external devices, such as display 720, via a wireless protocol, for example.

[0189] In another example, electrodes 702 may be positioned on proximal elements 1040 and / or distal elements 1020, as described further below, and an impedance control unit 701 may be positioned external to the patient and separate from fixation device 1012 such that electrodes 702 communicate wirelessly with impedance control unit 701.

[0190] Impedance system 700 may alternatively be integrated with a medical system, such as the interventional system 1010 depicted in FIGS. 22A and 22B. Interventional system 1010 includes fixation device 1012 and a delivery system 1050. Delivery system 1050 generally includes a delivery device handle 1051 and delivery catheter 1052 extending from handle 1051 . Delivery device handle 1051 includes a plurality of controls 1053a, 1053b, 1053c for controlling fixation device 1012, such as proximal elements 1040 and distal elements 1020, and for disconnecting fixation device 1012 from a shaft 1011 of catheter 1052 so as to leave fixation device 1012 within a patient as an implant.

[0191] In one example, electrodes 702 may be placed on proximal elements 1040 and / or distal elements 1020, as described further below, and control unit 701 may be coupled to delivery device handle 1051, such as embedded therein or separately connected (e.g., via a cable). In this example, interface 706 between impedance control unit 701 and electrodes 702 may be a hardwired interface which may extend from implant 1012, through catheter 1052 to catheter handle 1051. For example, gripper lines 1001 may be comprised of insulating wiring which may extend through catheter and have the dual functions of providing an electrical connection between electrodes 702 and control unit 701 and raising and lowering proximal elements 1040. Alternatively, electric conductors (e.g., leads or traces) may extend through catheter 1052 and into a center portion of fixation device 1012 across a coupling mechanism thereof. When fixation device 1012 is disconnected from delivery catheter 1052 during a procedure, electrodes 702 may be removed from fixation device 1012. Alternatively, interfaceAtty Docket No. ABTEVA-0064PCT706 between electrodes 702 and control unit 701 may be disconnected and electrodes 702 may be left within fixation device 1012 after disconnection between catheter 1052 and fixation device 1012.

[0192] FIGS. 23 A and 23B depict one example of a disconnectable interface at a coupling mechanism 1015 (or coupler) between delivery catheter 1052 and implant 1012. In this example, delivery system 1050 includes an actuator rod 1070 like actuator rod 370 for actuating distal elements 1020. Delivery catheter 1052 includes a shaft 1011, like shaft 311, with two or more spring arms 1061 which are inwardly biased. Spring arms 1060 include projections or feet 1063 extending outwardly therefrom. Fixation device 1012 includes a coupling member 1060, like coupling member 360. Coupling member 1060 includes receptacles or apertures 1062 which are configured to receive projections 1063 for connection between shaft 1011 and coupling member 1060. As depicted, actuator rod 1070 extends distally through shaft 1011 and coupling member 1060 to urge spring arms 1061 outwardly which moves spring arms 1061 into engagement with coupling member 1060 and projections 1063 into receptacles 1062. Actuator rod 1070 is moveable proximally to a position proximal relative to spring arms 1061 which allows the bias of spring arms 1061 to move spring arms 1061 inwardly and disengage coupling member 1060 and thereby disconnect shaft 101 1 from fixation device 1012.

[0193] Shaft 1070 includes conductors 1003 (e.g., leads or traces) extending through catheter 1052 to delivery catheter handle 1051 and which may be coupled to impedance control unit 701. Coupling member 1060 includes conductors 1009 (e.g., leads or traces) which extend through fixation device 1012 and are connected to electrodes 702. Spring arms 1061 include electrical terminals or contact pads 1005 on an exterior thereof. Coupling member 1060 includes electrical terminals or contact pads 1007 on an interior thereof. Such terminals 1005, 1007 are connected to the respective conductors 1003, 1009 of shaft 1011 and coupling member 1060. When actuator rod 1070 moves distally within shaft 1011 and coupling member 1060, spring arms 1061 move outwardly such that terminals 1005 of shaft 1011 contact terminals 1007 of coupling member 1060 thereby forming an electrical connection and electrically coupling control unit 701 with electrodes 702. When actuator rod 1070 moves proximally to disconnect shaft 1011 from coupling member 1060, spring arms 1061 move inwardly severing the electrical connection between terminals 1005, 1007 of shaft 1011 and coupling member 1060.Atty Docket No. ABTEVA-0064PCT

[0194] As mentioned, impedance control unit 701 may be disposed in delivery device handle 1051. In this example, control unit 701 may be coupled via a cable or otherwise to other external devices, such as display 720. In another example, delivery device handle 1051 may include a display coupled to impedance control unit 700. For example, as shown in FIG. 22B, such display may be an LED array 1055 that turns on or off when electrodes 702 come into contact with tissue to indicate to the surgeon that leaflet tissue has been captured by fixation device 1012. In some examples, control unit 701 may interrogate what kind of tissue is captured such that if undesired tissue, such as chordae, are contacted, LED array 1055 will not activate while desired tissue, such as leaflets, will activate LED array 1055.

[0195] Impedance control unit 701 can also be positioned external to delivery system 1050. In such example, impedance control unit 701 may be coupled to hardwiring within delivery system 1050 via a cable or otherwise so as to electrically couple control unit 701 with electrodes 702.

[0196] Electrodes may be coupled to proximal elements 1040 and / or distal elements 1020 of fixation device 1012 in any one of various configurations. FIGS. 24A-32 depict exemplary electrode configurations. In such configurations, electrodes 702 may be separately coupled to proximal elements 1040 or distal elements 1020 such as that described with respect to FIG. 21C. Alternatively, electrodes 702 may be coupled to a substrate, such as substrate 705, and the substrate may be coupled to proximal elements 1040 or distal elements 1020 such that electrodes 702 are removable therefrom or permanently coupled so as to be left implanted with fixation device 1012. Additionally, in some examples, proximal elements 1020 and / or distal elements 1040 may include a covering 1017. Electrodes 702 may be coupled to such covering 1017 such that electrodes 702 are exposed on the covering 702. In another example, electrodes 702 may be connected to directly the proximal elements 1020 or distal elements 1040 and may be exposed through openings within the covering 1017 such that tissue may contact the electrodes 702 through the covering 1017.

[0197] In each of the following exemplary configurations, at least two electrodes 702 are coupled to each proximal element 1040 and / or each distal element 1040 to form an electrode pair. Impedance system 700 is configured such that an electrode pair forms an open electrical circuit and tissue contact with the electrode pair closes the electrical circuit resulting in an impedance response. If tissue does not contact electrodes 702 or contacts only one electrode 702 of an electrode pair, the electrical circuit remains open.Atty Docket No. ABTEVA-0064PCT

[0198] In one example configuration shown in FIGS. 24A-24D, a first electrode 702a and a second electrode 702b are coupled to a proximal element and conductors 704a, 704b extend therefrom toward a center of fixation device, such as fixation device 1012. Proximal element 1040 may include an elongate body 1041 and a plurality of frictional elements 1045 extending from opposing edges 1042 of elongate body 1041. First and second electrodes 702a, 702bin this example are coupled to elongate body 1041. First electrode 702a is positioned between a free end or second end 1041b of proximal element 1040 and a midline ML of proximal element 1040. Midline ML is located at 50% of the grip length Lgrip of proximal element 1040. Second electrode 702b is positioned between a fixed end or first end 1041a of proximal element 1040 and the midline ML. In this configuration, positioning second electrode 702b between midline ML and fixed end 1041a allows electrodes 702a, 702b to detect when a leaflet has reached beyond the threshold 50% grip length Lgrip which indicates to the surgeon that a quality capture has been achieved.

[0199] In operation, where a leaflet, such as first leaflet LI depicted in FIG. 22A, is not in contact with either electrode 702a, 702b, such as when proximal element 1040 is in a raised position or is in contact with only first electrode 702a but not second electrode 702b, the electrical circuit remains open indicating that the leaflet LF1 has not reached the second electrode 702b. Thus, an impedance signal indicates a first impedance value 751 as shown in FIG.24D. When a leaflet, such as leaflet L2 shown in FIG. 22A, comes into contact with second electrode 702b, the electrical circuit closes indicating that the leaflet LF2 has reached beyond the midline ML and a quality grasp has been achieved. Thus, an impedance signal indicates a second impedance value 752 as shown in FIG. 24D. Since the electrical circuit remains open when proximal element 1040 is raised or when the leaflet is only in contact with first electrode 702a, first impedance value 751 is greater than second impedance value 752 in which the circuit is closed. Second impedance value 752 may be interrogated by measuring module 710 to determine the type of tissue (e.g., leaflet tissue or chordae) that is in contact with first and second electrodes 702a, 702b, as described above. It is recognized that blood in the environment could affect the open circuit by contributing noise, but once the tissue is grasped, the direct contact of the tissue will primarily overcome the interference from the blood signal. To mitigate the effect of blood and enhance signal clarity, a solution could be pumped through a delivery system to displace blood from the vicinity of the sensors, further reducing noise andAtty Docket No. ABTEVA-0064PCT improving measurement accuracy. Additionally, the spacing of the electrodes or other design variables may be optimized to ensure an open circuit is maintained in the presence of blood.

[0200] In another example configuration shown in FIG. 25, first and second electrodes 702a, 702b are coupled to the elongate body 1141 of proximal element 1 140. First electrode 702a is positioned between a free end or second end 1141b of proximal element 1140 and a midline ML of proximal element 1140. Second electrode 704b is positioned at the midline ML.

[0201] In further example configuration shown in FIG. 26, first and second electrodes 702a, 702b are coupled to elongate body 1241 of proximal element 1240. First electrode 701a is positioned at the midline ML. Second electrode 702b is positioned between a fixed end or first end 1241a of proximal element 1240 and the midline ML.

[0202] In another example configuration shown in FIG. 27, first and second electrodes 702a, 702b are each coupled to a corresponding frictional element 1345a, 1345b of the proximal element 1340. First electrode 702a and second electrode 702b may be positioned at any of the positions described above but instead on a frictional element. Alternatively, as shown, first and second electrodes 702a, 702bmay be aligned in a direction transverse to a longitudinal axis LA of proximal element 1340 and coupled to frictional elements 1345a, 1345b at opposite sides of proximal element 1340. For example, first and second electrodes 702a, 702b may be located at the midline ML or between the midline ML and a fixed end or first end 1341a of proximal element 1340. Conductors 704a, 704b may extend from the respective frictional elements 1345a, 1345b and along proximal element 1340 to a center of the fixation device.

[0203] In further example configuration shown in FIG. 28, first electrode 702a is coupled to the elongate body 1441 of the proximal element 1440 and second electrode 702b is coupled to a frictional element 1445 of proximal element 1440. Alternatively, first electrode 702a may be coupled to a frictional element 1445, and second electrode 702b may be coupled to elongate body 1441. Positioning electrodes 702a, 702b on frictional elements may help ensure electrode contact with tissue particularly through a covering, such as covering 1017.

[0204] In another example configuration shown in FIGS. 29A-29D, a first electrode 702a, a second electrode 702b, and a third electrode 702c are coupled to a proximal element 1540, such as to the elongate body 1541 thereof. First electrode 702 is positioned between a free end or second end 1541b of proximal element 1540 and a midline ML of proximal element 1540. Second electrode 702b is positioned at the midline ML. Third electrode 702c isAtty Docket No. ABTEVA-0064PCT positioned between the midline ML and a fixed end or first end 1541a of proximal element 1540. In one implementation of this example, first electrode 702a and second electrode 702b may form an electrode pair, and first electrode 702a and second electrode 702c may form a second electrode pair such that second and third electrodes 702b, 702c are arranged in parallel. In this regard, first electrode 702a may be an anode, and second and third electrodes 702a, 702b may each be cathodes, or vice versa. As shown in FIG. 26B, when tissue only contacts first electrode 702a or does not contact any of electrodes 702a, 702b, and 702c, the electrical circuit is open. When tissue contacts first and second electrodes 702a, 702b but not third electrode 702c, the electrical circuit closes between first and second electrodes 702a, 702b to form a series electrical circuit inducing an impedance response indicating that the leaflet has reached the midline ML but not beyond the midline ML to the third electrode 702c. When tissue contacts first, second, and third electrodes 702a, 702b, 702c, the electrical circuit closes between the parallel circuits inducing an impedance response that differs from the series electrical circuit indicating tissue has reached beyond the midline ML to the third electrode 702c.

[0205] In another implementation of the example of FIG.29A, first and second electrodes 702a, 702b may form a first electrode pair, and second electrode 702b and third electrode 702c may form a second electrode pair such that two series electrical circuits like that of FIGS. 24B and 24C may be formed. In this regard, first electrode 702a may be a cathode and second electrode 702b may be an anode, and third electrode 702c may be a cathode, or vice versa.

[0206] In a further example configuration shown in FIG. 30, a first electrode 702a, a second electrode 702b, a third electrode 702c, and a fourth electrode 704d are coupled to a proximal element 1640, such as to the elongate body 1641 thereof. First and second electrodes 702a, 702b are positioned between a free end or second end 1641b of proximal element 1640 and a midline ML of proximal element 1640. Third electrode 702c is positioned at the midline ML. Fourth electrode 704d is positioned between the midline ML and a fixed end or first end 1641a of proximal element 1640. First and third electrodes 702a, 702c may form a first electrode pair, and second and fourth electrodes 702b, 702d may form a second electrode pair each pair forming a series electrical circuit like that of FIGS. 24B and 24C. Thus, when tissue contacts first, second, and third electrodes 702a, 702b, 702c but not fourth electrode 702d, the first series electrical circuit will close, while the second series electrical circuit will remainAtty Docket No. ABTEVA-0064PCT open indicating that the tissue has not reached beyond the midline ML to the fourth electrode 702d.

[0207] Each of the above-described electrode configurations may help determine the depth of tissue insertion within a fixation device and incorporating more than two electrodes 702 in a proximal element, such as in the examples of FIGS. 29 and 30, may help provide further resolution regarding the depth of tissue insertion. Further, the type of tissue may be determined based on the measured impedance, as described above with respect to impedance system 700.

[0208] Additionally or alternatively, electrodes 702 may be coupled to a distal element. In one example configuration shown in FIG. 30, a first and second electrode 702a, 702b may be coupled to an engagement surface 1725 of a distal element 1720, such as within a depressed portion of engagement surface 1725, for example. The depicted configuration is like that of FIG. 24A for proximal element 1040 in that first electrode 702a is positioned between a free end or second end 1721b of distal element 1720 and a midline ML of a grip length LgiPof distal element, and second electrode 702b is positioned between a fixed end or first end 1721a of distal element 1720 and the midline ML. It may be advantageous to couple electrodes 702 to distal element 1720 as an impedance response may be initiated prior to the lowering of a proximal element to indicate to the surgeon that tissue is positioned far enough along distal element 1720 that gripping can be initiated. Thus, it may be further advantageous to also couple electrodes to a proximal element, such as in any of the aforementioned configurations, for further confirmation that tissue has been engaged by the proximal element.

[0209] Although FIG. 31 depicts an electrode arrangement on distal element 1720 similar to that of proximal element of FIG. 24A, it should be understood that electrodes 702a, 702b may be arranged on distal element in any of the configurations described above with respect to proximal elements of FIGS. 25 and 26. Additionally, distal element 1720 may include more than two electrodes in arrangements like that of proximal elements of FIGS. 2 A and 30.

[0210] In some implementations, a distal element 1820 may have wing portions 1824a. 1824b extending outwardly therefrom, as shown in FIG. 31. Such wing portions 702a, 702b may increase the width of distal element 1820 for increased contact area. One or more electrodes 702a, 702b may be positioned on wing portions 1824a, 1824b. For example, a first electrode 702a may be located on a first wing portion 1824a, and second electrode 702b mayAtty Docket No. ABTEVA-0064PCT be positioned on a second wing portion 1824b. First and second electrodes 702a, 702b may be aligned in a direction transverse to longitudinal axis LA as described with respect to FIGS. 27 and 28, or may be staggered along longitudinal axis LA, such as in any of the aforementioned arrangements on the proximal elements of FIGS. 24A, 25, and 26.

[0211] Additionally or alternatively, electrodes 702 may be positioned along a central axis of the fixation device. FIG. 33 depicts a distal portion of an interventional tool 1910 which includes a delivery catheter shaft 1911 and a fixation device 1912. In one example, fixation device 1912 includes a central portion 1960 and a plurality of electrodes 702a, 702b coupled to central portion 1960. Such electrodes 702a, 702b may be arranged in pairs and positioned at opposite sides of central portion 1911 so as to detect tissue extending from each distal element and proximal element pair. In this example, central portion 1960 is a coupling member (e.g., coupling member 160 or 260) which is configured to releasably couple to delivery catheter shaft 1911.

[0212] In another example, a plurality of electrodes 702a, 702b is coupled to delivery catheter shaft 1911, as also illustrated in FIG. 33. In this example, such electrodes 702a, 702b may be arranged in pairs and positioned at opposite sides of shaft 1911 so as to detect tissue extending from each distal element and proximal element pair. Additionally, the electrodes 702a, 702b may be positioned at longitudinally spaced-apart positions along the delivery catheter shaft 1911, similar to the electrode configurations described above with respect to proximal and distal elements. In this configuration, as tissue is inserted between the proximal and distal elements, the tissue advances along the catheter shaft and progressively contacts the electrodes to provide depth sensing capability. For example, first electrode 702a may be positioned proximally and second electrode 702b may be positioned distally, such that contact with only the first electrode indicates partial insertion and contact with both electrodes indicates adequate insertion depth. The electrodes may be spaced apart by 3 mm to 10 mm, corresponding to a desired minimum insertion depth.

[0213] In a further example, electrode pairs 702a, 702b may be coupled to both central portion 1960 and delivery catheter shaft 1911, as illustrated in FIG. 33. Each of these examples may provide certain benefits. For example, by placing electrodes 702a, 702b along a central axis of a fixation device or interventional tool (e.g., fixation device 1912 and interventional tool 1910), system 700 may help determine concentricity of the tissue about such central axis and whether there are equal amounts of tissue opposing sides of the fixation device or tool. FullAtty Docket No. ABTEVA-0064PCT engagement of tissue on either side of a fixation device is indicative of a perpendicular arrangement with respect to the tissue which is an optimal arrangement. Asymmetric engagement, on the other hand, is indicative of implant tilt, which may not be optimal for inhibiting regurgitative flow. Axial placement of electrodes can help determine the degree of tilt and whether regrasping may be necessary.

[0214] Although each of the foregoing example electrode configurations on proximal and distal elements are shown and described as being on a single proximal element or a single distal element, it should be understood that in a fixation device, such as fixation device 1012, the same electrode configurations may be implemented on the other proximal and distal element in the fixation device. Additionally, it should be understood that electrodes can be positioned on any one or more of the aforementioned proximal elements, distal elements, center portions, and delivery catheter shafts which can provide redundancy and a mapping of the internal conditions at the fixation device.

[0215] Examples

[0216] The following describes examples of the present disclosure:

[0217] As illustrated in FIG. 34, an exemplary fixation device 2012 includes a center portion 2060, a first distal element 2020, a first proximal element 2040, a first electrode 2002a, and a second electrode 2002b. The first and second electrodes 2002a, 2002b are coupled to either first distal element 2020 or the first proximal element 2040. First and second electrodes 2002a, 2002b at least partially form an electrical circuit. When tissue contacts first electrode 2002a and not the second electrode 2002b, the circuit is an open circuit configured to generate a first impedance response. When tissue contacts first and second electrodes 2002a, 2002b, the circuit is a closed circuit configured to generate a second impedance response. The first impedance response has a first impedance value greater than a second impedance value of the second impedance response.

[0218] In some implementations of the center portion 2060 may additionally or alternatively include first and second electrodes 2002a, 2002b. Center portion 2060 may include a coupling member (e.g., coupling member 160, 360, or 1060). Additionally or alternatively, center portion 2060 may include a stud (e.g., stud 131). Additionally or alternatively, center portion 2060 may include a base (e.g., base 139). Additionally or alternatively, center portion 2060 may include a locking mechanism (e.g., locking mechanism 116 01- 516).Atty Docket No. ABTEVA-0064PCT

[0219] In some implementations of first distal element 2020, first distal element 2020 may be any one of the distal elements described above (e.g., distal element 120, 1720, or 1820). First distal element 2020 may extend from center portion 2060 and may be moveable between an open position and a closed position. First distal element 2020 may have a first end 2021 a, a second end 2021b, and a length extending therebetween. The first and second electrodes 2002a, 2002b may be disposed on first distal element 2020 between first and second ends 2021a, 2021b thereof. Second end 2021b of fixation device 2020 may be a free end, and first distal element 2020 may have a midline equidistant between free end 2021b and the fixed end 2021a.

[0220] In some implementations of fixation device 2012, first electrode 2002a may be positioned between the free end 2021b and the midline of first distal element 2020, and the second electrode 2002b may be positioned between the midline and fixed 2021a end of distal element 2020.

[0221] In some implementations of fixation device 2012, first electrode 2002a may be positioned between free end 2021b and the midline of first distal element 2020, and second electrode 2002b may be positioned at the midline of first distal element 2020.

[0222] In some implementations of fixation device 2012, first electrode 2002a may be positioned at the midline of first distal element 2020, and second electrode 2002b may be positioned between the midline and fixed end 2021a of first distal element 2020.

[0223] In some implementations of fixation device 2012, first electrode 2002a and second electrode 2002b may each be disposed at the midline of first distal element 2020.

[0224] In some implementations of fixation device 2012, the distal element 2020 may also include an elongate body and first and second wing portions (e.g., wing portions 1824a and 1824b) extending outwardly therefrom.

[0225] In some implementations of fixation device 2012, first electrode 2002a may be coupled to the first wing portion, and second electrode 2002b may be coupled to the second wing portion.

[0226] In some implementations of fixation device 2012, the first electrode 2002a may be coupled to the elongate body of first distal element 2020, and second electrode 2002b may be coupled to the first wing portion of first distal element 2020.

[0227] In some implementations of fixation device 2012, fixation device 2012 may also include a third electrode (e.g., electrode 702c).Atty Docket No. ABTEVA-0064PCT

[0228] In some implementations of fixation device 2012, the first electrode may be positioned between the free end and the midline of the first distal element, the second electrode may be positioned at the midline of the first distal element, and the third electrode may be positioned between the midline and the fixed end of the first distal element.

[0229] In some implementations of fixation device 2012, the first electrode and the second electrode may form a first series circuit, and the first electrode and the third electrode may form a second series circuit.

[0230] In some implementations of fixation device 2012, the first series circuit may be configured as an open circuit when tissue only contacts the first electrode, and a closed circuit when tissue contacts the first and second electrodes.

[0231] In some implementations of fixation device 2012, the second series circuit may be configured as an open circuit when tissue only contacts the first electrode or only the first and second electrodes and not the third electrode, and as a closed circuit when tissue contacts the first electrode and the third electrode.

[0232] In some implementations of fixation device 2012, the second and third electrodes may be in parallel.

[0233] In some implementations of fixation device 2012, fixation device may additionally include a fourth electrode (e.g., electrode 704d). The first and second electrodes may be positioned between the free end and the midline of the first distal element. The third electrode may be positioned at the midline of the first distal element. The fourth electrode may be positioned between the midline and the fixed end of the first distal element. The first and third electrodes may form a first series circuit, and the second and fourth electrodes may form a second series circuit.

[0234] In some implementations of first proximal element 2040, first proximal element 2040 may be any of the proximal elements described above (e.g., proximal element 140, 240, 1040, 1140, 1240, 1340, 1440, 1540, or 1640). First proximal element 2040 may be moveable relative to first distal element 2020 between a first position and a second position. First proximal element 2020 may have a first end 2041a, a second end 2041b, and a length extending therebetween. First and second electrodes 2002a, 2002b may be disposed on first proximal element 2040 between first and second ends 2041a, 2041b thereof. First end 2041a of proximal element 2040 may be a fixed end, the second end 2041b of first proximal element 2040 may be a free end, and first proximal element 2040 may have a midline equidistant between freeAtty Docket No. ABTEVA-0064PCT end 2041b and fixed end 2041a. First proximal element 2040 may also include an elongate body and a plurality of frictional elements 2045 extending from the elongate body.

[0235] In some implementations of fixation device 2012, first electrode 2002a may be positioned between free end 2041 b and the midline of first proximal element 2040, and second electrode 2002b may be positioned between the midline and fixed end 2021a of first proximal element 2040.

[0236] In some implementations of fixation device 2012, first electrode 2002a may be positioned between free end 2041b and the midline of first proximal element 2040, and second electrode 2002b may be positioned at the midline of first proximal element 2040.

[0237] In some implementations of fixation device 2012, first electrode 2002a may be positioned at the midline of first proximal element 2040, and the second electrode may be positioned between the midline and fixed end 2041a of first proximal element 2040.

[0238] In some implementations of fixation device 2012, first electrode 2002a and second electrode 2002b may each be disposed at the midline of proximal element 2040.

[0239] In some implementations of fixation device 2012, first electrode 2002a may be coupled to a first frictional element 2045 of first proximal element 2040, and second electrode 2002b may be coupled to second frictional element 2045 of first proximal element 2040.

[0240] In some implementations of fixation device 2012, first electrode 2002a may be coupled to the elongate body, and second electrode 2002b may be coupled to one of the frictional elements 2045.

[0241] In some implementations of fixation device 2012, fixation device 2012 further included a third electrode (e.g., electrode 702c).

[0242] In some implementations of fixation device 2012, first electrode 2002a may be positioned between free end 2041b and the midline of proximal element 2040, second electrode 2002b may be positioned at the midline of proximal element 2040, and the third electrode may be positioned between the midline and fixed end 2041a of the proximal element.

[0243] In some implementations of fixation device 2012, first electrode 2002a and second electrode 2002b may form a first series circuit, and first electrode 2002a and the third electrode may form a second series circuit.

[0244] In some implementations of fixation device 2012, the first series circuit may be configured as an open circuit when tissue only contacts first electrode 2002a, and a closed circuit when tissue contacts first and second electrodes 2002a, 2004b.Atty Docket No. ABTEVA-0064PCT

[0245] In some implementations of fixation device 2012, the second series circuit may be configured as an open circuit when tissue only contacts first electrode 2002a or only first and second electrodes 2002a, 2002b and not the third electrode, and as a closed circuit when tissue contacts the first electrode 2002a and the third electrode.

[0246] In some implementations of fixation device 2012, second electrode 2002b and the third electrode may be arranged in parallel.

[0247] In some implementations of fixation device 2012, fixation device 20212 may also include a fourth electrode (e.g., electrode 704d). The first and second electrodes 2002a, 2002b may be positioned between free end 2041b and the midline of first proximal element 2040. The third electrode may be positioned at the midline of first proximal element 2040. The fourth electrode may be positioned between the midline and fixed end 2041a of first proximal element 2040. The first electrode 2002a and the third electrode may form a first series circuit, and the second electrode 2002b and the fourth electrode may form a second series circuit.

[0248] In some implementations of fixation device 2012, both first distal element 2020 the first proximal element 2040 have a first electrode 2002a and a second electrode 2002b.

[0249] In some implementations of fixation device 2012, first electrode 2002a may be a cathode or an anode, and second electrode 2002b may be the other of an anode or cathode.

[0250] FIG. 35 illustrates an exemplary fixation device 2112 which is the same as fixation device 2012 with the exception that it includes a second distal element 2120b and a second proximal element 2140b. Additionally, first and second electrodes 2102a, 2102b may be positioned on one of the second distal element 2120b or second proximal element 2140b as described above with respect to fixation device 2012.

[0251] FIG. 36 illustrates an exemplary method 2200 of the present disclosure.

[0252] In some implementations of the exemplary method 2200, the method may include delivering 2202 a fixation device to a target valve within a heart. The fixation device may be any of the fixation devices described above. The target valve may be a tricuspid valve or a mitral valve, for example. Additionally, in some implementations, the fixation device may be delivered to any target tissue, other than a cardiac valve.

[0253] In some implementations of the exemplary method 2200, the method may also include directing 2204 a first leaflet (or first tissue) into a space between a first proximal element and a first distal element of the fixation device.Atty Docket No. ABTEVA-0064PCT

[0254] In some implementations of the exemplary method 2200, the method may also include transmitting 2206 an AC signal from a power source to first and second electrodes coupled to one of the first proximal element and distal element. This may include transmitting the AC signal from a delivery device handle through a delivery catheter to the fixation device.

[0255] In some implementations of the exemplary method 2200, the method may include modulating 2208 a frequency of the AC signal within a range of frequencies. In one example, the range of frequencies may be 10 Hz to 10 kHz. In another example, the range of frequencies is 10 kHz to 10 MHz.

[0256] In some implementations of the exemplary method 2200, the method may include measuring 2210 an impedance response from the first and second electrodes.

[0257] In some implementations of the exemplary method 2200, the method may include determining 2212 a depth of insertion of the first leaflet (or tissue) between the first proximal element and the first distal element based on the impedance response where contact with only the first electrode generates a first impedance response having a first impedance value and contact with the first and second electrode generates a second impedance response having a second impedance value less than that of the first impedance value.

[0258] In some implementations of the exemplary method 2200, the method further includes determining 2214 the type of tissue in contact with the first and second electrodes based on the measured impedance response across the range of frequencies. This may include analyzing resistive and reactive components of impedance the impedance response.

[0259] The paragraphs below address various embodiments of the disclosure.

[0260] Paragraph A: According to an aspect of the disclosure, a fixation device 3000 is shown in FIG. 37A. The fixation device 3000 includes a center portion 3010, a first distal element 3020, and a first proximal element 3030. Non-limiting examples of fixation devices are described above (e.g., fixation device 110, 1012, 2012) and shown in the figures (e.g., FIGS. 11A-11B, 16, 34). The first distal element 3020 is coupled to the center portion 3010 and extends therefrom and is moveable between an open position and a closed position. The first distal element 3020 has a first end, a second end, and a length extending therebetween. The first proximal element 3030 is disposed opposite the first distal element 3020 and is moveable relative to the first distal element 3020 between a first position and a second position. The first proximal element 3030 has a first end, a second end, and a length extending therebetween. The fixation device 3000 includes first and second electrodes 3040, 3042 disposed on one of theAtty Docket No. ABTEVA-0064PCT first distal element 3020 and first proximal element 3030 between the first and second ends thereof. The first and second electrodes 3040, 3042 at least partially form a circuit 3044. The circuit 3044 is an open circuit generating a first impedance response when tissue contacts the first electrode 3040 and not the second electrode 3042. The circuit 3044 is a closed circuit generating a second impedance response when tissue contacts the first and second electrodes 3040, 3042. The first impedance response has a first impedance value greater than a second impedance value of the second impedance response. Representative examples of these portions of fixation device 3000 are shown in FIG. 37A.

[0261] Paragraph B: In the fixation device 3000 of Paragraph A, and as shown in FIG. 37B, the first end of the first proximal element 3030 may be a fixed end 3031, the second end of the first proximal element 3030 may be a free end 3032, and the first proximal element 3030 may have a midline 3033 equidistant between the free end 3032 and the fixed end 3031. A positional indicator extending between the free end 3032, midline 3033, and fixed end 3031 indicates the relative positions along the first proximal element 3030 at which the first and second electrodes 3040, 3042 may be disposed. In one example, the first electrode 3040 is positioned between the free end 3032 and the midline 3033 of the first proximal element 3030, and the second electrode 3042 is positioned between the midline 3033 and the fixed end 3031 of the first proximal element 3030. In another example, the first electrode 3040 is positioned between the free end 3032 and the midline 3033 of the first proximal element 3030, and the second electrode 3042 is positioned at the midline 3033 of the first proximal element 3030. In a further example, the first electrode 3040 is positioned at the midline 3033 of the first proximal element 3030, and the second electrode 3042 is positioned between the midline 3033 and the fixed end 3031 of the first proximal element 3030. In yet another example, the first electrode 3040 and the second electrode 3042 are each disposed at the midline 3033 of the first proximal element 3030. Representative examples of these portions of fixation device 3000 are shown in FIG. 37B.

[0262] Paragraph C: In the fixation device 3000 of any of Paragraphs A-B, and as shown in FIG. 37C, the first proximal element 3030 may include an elongate body 3034 and a plurality of frictional elements 3035 extending from the elongate body 3034. Non-limiting examples of frictional elements are described above (e.g., frictional elements 145, 245, 1045, 2045) and shown in the figures (e.g., FIGS. 2A-2B, 3A-3B, 5). In one example, the first electrode 3040 is coupled to a first frictional element 3035a, and the second electrode 3042 isAtty Docket No. ABTEVA-0064PCT coupled to a second frictional element 3035b. Representative examples of these portions of fixation device 3000 are shown in FIG. 37C.

[0263] Paragraph D: In the fixation device 3000 of Paragraph C, and as shown in FIG. 37D, the first electrode 3040 may be coupled to the elongate body 3034, and the second electrode 3042 may be coupled to one of the frictional elements 3035. Representative examples of these portions of fixation device 3000 are shown in FIG. 37D.

[0264] Paragraph E: In the fixation device 3000 of any of Paragraphs A-D, the first electrode 3040 may be a cathode or an anode, and the second electrode 3042 may be the other of an anode or cathode. The designation of cathode and anode indicates the polarity of the electrodes during impedance measurement.

[0265] Paragraph F: In the fixation device 3000 of any of Paragraphs A-E, and as shown in FIG. 37E, the fixation device 3000 may further include a third electrode 3050. The first electrode 3040 may be positioned between the free end 3032 and the midline 3033 of the first proximal element 3030. The second electrode 3042 may be positioned at the midline 3033 of the first proximal element 3030. The third electrode 3050 may be positioned between the midline 3033 and the fixed end 3031 of the first proximal element 3030. Representative examples of these portions of fixation device 3000 are shown in FIG. 37E.

[0266] Paragraph G: In the fixation device 3000 of Paragraph F, and as shown in FIG. 37F, the first electrode 3040 and the second electrode 3042 may form a first series circuit 3052, and the first electrode 3040 and the third electrode 3050 may form a second series circuit 3054. Representative examples of these portions of fixation device 3000 are shown in FIG. 37F.

[0267] Paragraph H: In the fixation device 3000 of Paragraph G, and as shown in FIGS. 37G and 37H, the first series circuit 3052 may be configured as an open circuit when tissue only contacts the first electrode 3040, and as a closed circuit when tissue contacts the first and second electrodes 3040, 3042. The second series circuit 3054 may be configured as an open circuit when tissue only contacts the first electrode 3040 or only the first and second electrodes 3040, 3042 and not the third electrode 3050, and as a closed circuit when tissue contacts the first electrode 3040 and the third electrode 3050. Representative examples of the first series circuit 3052 in open and closed circuit configurations are shown in FIG. 37G. Representative examples of the second series circuit 3054 in open and closed circuit configurations are shown in FIG. 37H.Atty Docket No. ABTEVA-0064PCT

[0268] Paragraph I: In the fixation device 3000 of Paragraph F, and as shown in FIG. 371, the second electrode 3042 and third electrode 3050 may be arranged in parallel 3056. This parallel arrangement allows for redundant sensing capability at different positions along the first proximal element 3030. Representative examples of these portions of fixation device 3000 are shown in FIG. 371.

[0269] Paragraph I: In the fixation device 3000 of any of Paragraphs A-I, and as shown in FIG. 37J, the fixation device 3000 may further include a third electrode 3050 and a fourth electrode 3058. The first and second electrodes 3040, 3042 may be positioned between the free end 3032 and the midline 3033 of the first proximal element 3030. The third electrode 3050 may be positioned at the midline 3033 of the first proximal element 3030. The fourth electrode 3058 may be positioned between the midline 3033 and the fixed end 3031 of the first proximal element 3030. The first electrode 3040 and the third electrode 3050 may form a first series circuit 3052. The second electrode 3042 and the fourth electrode 3058 may form a second series circuit 3054. Representative examples of these portions of fixation device 3000 are shown in FIG. 37.1.

[0270] Paragraph K: In the fixation device 3000 of Paragraph A, and as shown in FIG. 37K, the first and second electrodes 3040, 3042 may alternatively be disposed on the first distal element 3020 rather than on the first proximal element 3030. The first end of the first distal element 3020 may be a fixed end 3021. the second end of the first distal element 3020 may be a free end 3022, and the first distal element 3020 may have a midline 3023 equidistant between the free end 3022 and the fixed end 3021. A positional indicator extending between the free end 3022, midline 3023, and fixed end 3021 indicates the relative positions along the first distal element 3020 at which the first and second electrodes 3040, 3042 may be disposed. In one example, the first electrode 3040 is positioned between the free end 3022 and the midline 3023 of the first distal element 3020, and the second electrode 3042 is positioned between the midline 3023 and the fixed end 3021 of the first distal element 3020. In another example, the first electrode 3040 is positioned between the free end 3022 and the midline 3023 of the first distal element 3020, and the second electrode 3042 is positioned at the midline 3023 of the first distal element 3020. In a further example, the first electrode 3040 is positioned at the midline 3023 of the first distal element 3020, and the second electrode 3042 is positioned between the midline 3023 and the fixed end 3021 of the first distal element 3020. In yet another example, the first electrode 3040 and the second electrode 3042 are each disposed at the midline 3023 of the firstAtty Docket No. ABTEVA-0064PCT distal element 3020. Representative examples of these portions of fixation device 3000 are shown in FIG. 37K.

[0271] Paragraph L: In the fixation device 3000 of Paragraph A. and as shown in FIG. 37L, the first distal element 3020 may include an elongate body 3024 and first and second wing portions 3025, 3026 extending outwardly therefrom. Non-limiting examples of wing portions are described above (e.g., wing portions on distal elements 1720, 1820) and shown in the figures (e.g., FIGS. 28-29). In one example, the first electrode 3040 is coupled to the first wing portion 3025, and the second electrode 3042 is coupled to the second wing portion 3026. Representative examples of these portions of fixation device 3000 are shown in FIG. 37L.

[0272] Paragraph M: In the fixation device 3000 of Paragraph L, and as shown in FIG. 37M, the first electrode 3040 may be coupled to the elongate body 3024 of the first distal element 3020, and the second electrode 3042 may be coupled to the first wing portion 3025 of the first distal element 3020. Representative examples of these portions of fixation device 3000 are shown in FIG. 37M.

[0273] Paragraph N: In the fixation device 3000 of any of Paragraphs K-M, the first electrode 3040 may be a cathode or an anode, and the second electrode 3042 may be the other of an anode or cathode. The designation of cathode and anode indicates the polarity of the electrodes during impedance measurement when the electrodes are disposed on the first distal element 3020.

[0274] Paragraph O: In the fixation device 3000 of Paragraph K, and as shown in FIG. 37N, the fixation device 3000 may further include a third electrode 3050 disposed on the first distal element 3020. The first electrode 3040 may be positioned between the free end 3022 and the midline 3023 of the first distal element 3020. The second electrode 3042 may be positioned at the midline 3023 of the first distal element 3020. The third electrode 3050 may be positioned between the midline 3023 and the fixed end 3021 of the first distal element 3020. Representative examples of these portions of fixation device 3000 are shown in FIG. 37N.

[0275] Paragraph P: In the fixation device 3000 of Paragraph O, and as shown in FIG. 370, the first electrode 3040 and the second electrode 3042 may form a first series circuit 3052, and the first electrode 3040 and the third electrode 3050 may form a second series circuit 3054. Representative examples of these portions of fixation device 3000 are shown in FIG. 370.

[0276] Paragraph Q: In the fixation device 3000 of Paragraph P, and as shown in FIGS. 37P and 37Q, the first series circuit 3052 may be configured as an open circuit when tissueAtty Docket No. ABTEVA-0064PCT only contacts the first electrode 3040, and as a closed circuit when tissue contacts the first and second electrodes 3040, 3042. The second series circuit 3054 may be configured as an open circuit when tissue only contacts the first electrode 3040 or only the first and second electrodes 3040, 3042 and not the third electrode 3050, and as a closed circuit when tissue contacts the first electrode 3040 and the third electrode 3050. Representative examples of the first series circuit 3052 in open and closed circuit configurations are shown in FIG. 37P. Representative examples of the second series circuit 3054 in open and closed circuit configurations are shown in FIG. 37Q.

[0277] Paragraph R: In the fixation device 3000 of Paragraph O, and as shown in FIG. 37R, the second electrode 3042 and third electrode 3050 may be arranged in parallel 3056. This parallel arrangement allows for redundant sensing capability at different positions along the first distal element 3020. Representative examples of these portions of fixation device 3000 are shown in FIG. 37R.

[0278] Paragraph S: In the fixation device 3000 of Paragraph K, and as shown in FIG. 37S, the fixation device 3000 may further include a third electrode 3050 and a fourth electrode 3058 disposed on the first distal element 3020. The first and second electrodes 3040, 3042 may be positioned between the free end 3022 and the midline 3023 of the first distal element 3020. The third electrode 3050 may be positioned at the midline 3023 of the first distal element 3020. The fourth electrode 3058 may be positioned between the midline 3023 and the fixed end 3021 of the first distal element 3020. The first electrode 3040 and the third electrode 3050 may form a first series circuit 3052. The second electrode 3042 and the fourth electrode 3058 may form a second series circuit 3054. Representative examples of these portions of fixation device 3000 are shown in FIG. 37S.

[0279] Paragraph T: In the fixation device 3000 of any of Paragraphs A-S, and as shown in FIG. 371', the fixation device 3000 may further include a second distal element 3060 extending from the center portion 3010, and a second proximal element 3070 disposed opposite the second distal element 3060. Non-limiting examples of fixation devices with second distal and proximal elements are described above (e.g., fixation device 2112) and shown in the figures (e.g., FIG. 35). The second distal element 3060 and second proximal element 3070 may be configured similarly to the first distal element 3020 and first proximal element 3030, and may optionally include additional electrodes for redundant impedance sensing. Representative examples of these portions of fixation device 3000 are shown in FIG. 37T.Atty Docket No. ABTEVA-0064PCT

[0280] Paragraph U: According to another aspect of the disclosure, an interventional system 3100 is shown in FIG. 37U. The interventional system 3100 includes the fixation device 3000 of any one of Paragraphs A-T, a delivery system 3102, and a control unit 3108. The delivery system 3102 has a delivery device handle 3104 and a delivery catheter 3106 extending from the delivery device handle 3104. Non- limiting examples of delivery systems are described above (e.g., delivery system 600, delivery device 700) and shown in the figures (e.g., FIGS. 11A-11B, 21A). The fixation device 3000 is coupleable to the delivery catheter 3106. The control unit 3108 is in communication with the first and second electrodes 3040, 3042 of the fixation device 3000. The interventional system 3100 may further include an interface 3110 between the first and second electrodes 3040, 3042 and the control unit 3108. The interface 3110 may be a hardwired interface extending from the fixation device 3000 and through the delivery catheter 3106 to the delivery device handle 3104. Alternatively, the interface 3110 may be a wireless interface configured with a wireless protocol of one of Bluetooth Low Energy, Near Field Communication, and Zigbee. Representative examples of these portions of interventional system 3100 are shown in FIG. 37U.

[0281] Paragraph V: In the interventional system 3100 of Paragraph U, and as shown in FIG. 37V, the delivery catheter 3106 and the fixation device 3000 may include a coupler 3112 configured to disconnect the fixation device 3000 from the delivery catheter 3106 and to disconnect the interface 3110. The coupler 3112 may include a shaft 3114 having a plurality of spring arms 3116 each having a first electrical terminal 3118 and an actuator rod 3120 extendable through the shaft 3114. The fixation device 3000 may include a coupling member 3122 having second electrical terminals 3124 corresponding with the first electrical terminals 3118. Moving the actuator rod 3120 in a first direction urges the spring arms 3116 into engagement with the coupling member 3122 and the first electrical terminals 3118 into engagement with the second electrical terminals 3124. Moving the actuator rod 3120 in a second direction disengages the spring arms 31 16 from the coupling member 3122 and the first electrical terminals 3118 from the second electrical terminals 3124. Representative examples of these portions of interventional system 3100 are shown in FIG. 37 V.

[0282] Paragraph W: In the interventional system 3100 of any of Paragraphs U-V, and as shown in FIG. 37W, the control unit 3108 may include a power source 3126 and a measurement module 3128. The power source 3126 may be configured to deliver an AC signal to the first and second electrodes 3040, 3042 within a range of frequencies, and theAtty Docket No. ABTEVA-0064PCT measurement module 3128 may be configured to determine a type of tissue in contact with the first and second electrodes 3040, 3042 based on an impedance response detectable by the measurement module 3128. Alternatively, the power source 3126 may be configured to deliver a DC signal to the first and second electrodes 3040, 3042, and the measurement module 3128 may be configured to measure resistive impedance of tissue in contact with the first and second electrodes 3040, 3042. The range of frequencies for the AC signal may be 10 Hz to 10 kHz, or alternatively 10 kHz to 10 MHz. The control unit 3108 may be disposed within the delivery device handle 3104. Representative examples of these portions of interventional system 3100 are shown in FIG. 37W.

[0283] Paragraph X: In the interventional system 3100 of Paragraph W, and as shown in FIG. 37X, the measurement module 3128 may be coupled to a display 3130. The display 3130 may be disposed within the delivery device handle 3104. The measurement module 3128 may be configured to transmit output signals indicative of the first and second impedance responses to the display 3130. The display 3130 may be configured to provide at least one of visual indicators, audio alerts, or haptic feedback signals based on the first and second impedance responses. Representative examples of these portions of interventional system 3100 are shown in FIG. 37X.

[0284] Paragraph Y: According to another aspect of the disclosure, an alternative interventional system 3100 is shown in FIG. 37Y. The interventional system 3100 includes a delivery system 3102 having a delivery device handle 3104 and a delivery catheter 3106 extending from the delivery device handle 3104. The interventional system 3100 includes a fixation device 3000 having a center portion 3010, a first distal element 3020 coupled to the center portion 3010 and extending therefrom and being moveable between an open position and a closed position, and a first proximal element 3030 disposed opposite the first distal element 3020 and being moveable relative to the first distal element 3020 to capture tissue therebetween. The fixation device 3000 is coupleable to the delivery catheter 3106. The interventional system 3100 includes a control unit 3108 and first and second electrodes 3040, 3042 coupled to the delivery catheter 3106 and in communication with the control unit 3108. The first and second electrodes 3040, 3042 at least partially form a circuit 3044. The circuit 3044 is an open circuit generating a first impedance response when tissue contacts the first electrode 3040 and not the second electrode 3042, and the circuit 3044 is a closed circuit generating a second impedance response when tissue contacts the first and second electrodesAtty Docket No. ABTEVA-0064PCT3040, 3042. The first impedance response has a first impedance value greater than a second impedance value of the second impedance response. The interventional system 3100 may further include an interface 3110 between the first and second electrodes 3040, 3042 and the control unit 3108. The interface 3110 may be a hardwired interface extending through the delivery catheter 3106 to the delivery device handle 3104, or the interface 3110 may be a wireless interface configured with a wireless protocol of one of Bluetooth Low Energy, Near Field Communication, and Zigbee. Representative examples of these portions of interventional system 3100 are shown in FIG. 37 Y.

[0285] Paragraph Z: In the interventional system 3100 of Paragraph Y, and as shown in FIG. 37Z, the control unit 3108 may include a power source 3126 and a measurement module 3128. In one example, the power source 3126 is configured to deliver an AC signal to the first and second electrodes 3040, 3042 within a range of frequencies, and the measurement module 3128 is configured to determine a type of tissue in contact with the first and second electrodes 3040, 3042 based on an impedance response detectable by the measurement module 3128. The range of frequencies may be 10 Hz to 10 MHz. In another example, the power source 3126 is configured to deliver a DC signal to the first and second electrodes 3040, 3042, and the measurement module 3128 is configured to measure resistive impedance of tissue in contact with the first and second electrodes 3040, 3042. The AC signal configuration and the DC signal configuration represent alternative implementations of the control unit 3108. Representative examples of these portions of interventional system 3100 are shown in FIG. 37Z.

[0286] Paragraph AA: In the interventional system 3100 of any of Paragraphs Y-Z, and as shown in FIG. 37AA, the measurement module 3128 may be coupled to a display 3130. The display 3130 may be configured to provide at least one of visual indicators, audio alerts, or haptic feedback signals based on the first and second impedance responses. Additionally, the display 3130 may be configured to provide real-time visual feedback 3132 indicative of a depth of tissue insertion between the first proximal element 3030 and the first distal element 3020 during insertion of tissue. The real-time visual feedback 3132 may indicate the position of tissue relative to the fixation device 3000 to assist the clinician in achieving optimal tissue capture during the procedure. Representative examples of these portions of interventional system 3100 are shown in FIG. 37AA.

[0287] Although the subject matter disclosed herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrativeAtty Docket No. ABTEVA-0064PCT of the principles and applications set forth in this disclosure. It is therefore to be understood that numerous modifications may be made to the exemplary embodiments and that other arrangements may be devised, such as combining one or more features of one embodiment with another embodiment or features from a plurality of embodiments, as an example. Thus, the exemplary embodiments herein are not intended to be exhaustive or to limit the disclosed subject matter to such embodiments.

Claims

Atty Docket No. ABTEVA-0064PCTCLAIMS1. A fixation device comprising: a center portion; a first distal element coupled to the center portion and extending therefrom and being moveable between an open position and a closed position, the first distal element having a first end, a second end, and a length extending therebetween; a first proximal clement disposed opposite the first distal clement and being moveable relative to the first distal element between a first position and a second position, the first proximal element having a first end, a second end, and a length extending therebetween; and first and second electrodes disposed on one of the first distal element and first proximal element between the first and second ends thereof and at least partially forming a circuit, wherein the circuit is an open circuit generating a first impedance response when tissue contacts the first electrode and not the second electrode, and the circuit is a closed circuit generating a second impedance response when tissue contacts the first and second electrodes, the first impedance response having a first impedance value greater than a second impedance value of the second impedance response.

2. The fixation device of claim 1, wherein the first end of the first proximal element is a fixed end, the second end of the first proximal element is a free end, and the first proximal element has a midline equidistant between the free end and the fixed end.

3. The fixation device of claim 2, wherein the first electrode is positioned between the free end and the midline of the first proximal element, and the second electrode is positioned between the midline and the fixed end of the first proximal element.

4. The fixation device of claim 2, wherein the first electrode is positioned between the free end and the midline of the first proximal element, and the second electrode is positioned at the midline of the first proximal element.

5. The fixation device of claim 2, wherein the first electrode is positioned at the midline of the first proximal element, and the second electrode is positioned between the midline and the fixed end of the first proximal element.

6. The fixation device of claim 2, wherein the first electrode and the second electrode are each disposed at the midline of the first proximal element.Atty Docket No. ABTEVA-0064PCT7. The fixation device of any one of claims 1-6, wherein the first proximal element includes an elongate body and a plurality of frictional elements extending from the elongate body.

8. The fixation device of claim 7, wherein the first electrode is coupled to a first frictional element, and the second electrode is coupled to a second frictional element.

9. The fixation device of claim 7, wherein the first electrode is coupled to the elongate body, and the second electrode is coupled to one of the frictional elements.

10. The fixation device of any one of claims 2-6, wherein the first electrode is a cathode or an anode, and the second electrode is the other of an anode or cathode.

11. The fixation device of any one of claims 2-6, further comprising a third electrode, the first electrode being positioned between the free end and the midline of the first proximal element, the second electrode being positioned at the midline of the first proximal element, and the third electrode being positioned between the midline and the fixed end of the first proximal element.

12. The fixation device of claim 11, wherein the first electrode and the second electrode form a first series circuit, and the first electrode and the third electrode form a second series circuit.

13. The fixation device of any one of claims 11 and 12, wherein the first series circuit is configured as an open circuit when tissue only contacts the first electrode, and a closed circuit when tissue contacts the first and second electrodes.

14. The fixation device of claim 13, wherein the second series circuit is configured as an open circuit when tissue only contacts the first electrode or only the first and second electrodes and not the third electrode, and as a closed circuit when tissue contacts the first electrode and the third electrode.

15. I’he fixation device of claim 11, wherein the second and third electrodes are in parallel.

16. The fixation device of any one of claims 2-6, further comprising a third electrode and a fourth electrode, the first and second electrodes being positioned between the free end and the midline of the first proximal element, the third electrode being positioned at the midline of the first proximal element, and the fourth electrode being positioned between the midline and the fixed end of the first proximal element, the first and third electrodes forming a first series circuit, and the second and fourth electrodes forming a second series circuit.Atty Docket No. ABTEVA-0064PCT17. The fixation device of claim 1, wherein the first end of the first distal element is a fixed end, the second end of the first distal element is a free end, and the first distal element has a midline equidistant between the free end and the fixed end.

18. The fixation device of claim 17, wherein the first electrode is positioned between the free end and the midline of the first distal element, and the second electrode is positioned between the midline and the fixed end of the first distal element.

19. The fixation device of claim 17, wherein the first electrode is positioned between the free end and the midline of the first distal element, and the second electrode is positioned at the midline of the first distal element.

20. The fixation device of claim 17, wherein the first electrode is positioned at the midline of the first distal element, and the second electrode is positioned between the midline and the fixed end of the first distal element.

21. The fixation device of claim 17, wherein the first electrode and the second electrode are each disposed at the midline of the first distal element.

22. The fixation device of claim 1, wherein the first distal element includes an elongate body and first and second wing portions extending outwardly therefrom.

23. The fixation device of claim 22, wherein the first electrode is coupled to the first wing portion, and the second electrode is coupled to the second wing portion.

24. The fixation device of claim 22, wherein the first electrode is coupled to the elongate body of the first distal element, and the second electrode is coupled to the first wing portion of the first distal element.

25. The fixation device of any one of claims 17-24, wherein the first electrode is a cathode or an anode, and the second electrode is the other of an anode or cathode.

26. The fixation device of claim 17, further comprising a third electrode, the first electrode being positioned between the free end and the midline of the first distal element, the second electrode being positioned at the midline of the first distal element, and the third electrode being positioned between the midline and the fixed end of the first distal element.

27. The fixation device of claim 26, wherein the first electrode and the second electrode form a first series circuit, and the first electrode and the third electrode form a second series circuit.Atty Docket No. ABTEVA-0064PCT28. The fixation device of claim 27, wherein the first series circuit is configured as an open circuit when tissue only contacts the first electrode, and a closed circuit when tissue contacts the first and second electrodes.

29. The fixation device of claim 27, wherein the second series circuit is configured as an open circuit when tissue only contacts the first electrode or only the first and second electrodes and not the third electrode, and as a closed circuit when tissue contacts the first electrode and the third electrode.

30. The fixation device of claim 26, wherein the second and third electrodes are in parallel.

31. The fixation device of claim 17, further comprising a third electrode and a fourth electrode, the first and second electrodes being positioned between the free end and the midline of the first distal element, the third electrode being positioned at the midline of the first distal element, and the fourth electrode being positioned between the midline and the fixed end of the first distal element, the first and third electrodes forming a first series circuit, and the second and fourth electrodes forming a second series circuit.

32. The fixation device as in any of the preceding claims, further comprising a second distal element extending from the center portion, and a second proximal element disposed opposite the second distal element.

33. An interventional system comprising: the fixation device of any one of claims 1-32: a delivery system having a delivery device handle and a delivery catheter extending from the delivery device handle, wherein the fixation device is coupleable to the delivery catheter; and a control unit in communication with the first and second electrodes of the fixation device.

34. The system of claim 33, further comprising an interface between the first and second electrodes and the control unit.

35. The system of claim 34, wherein the interface is a hardwired interface extending from the fixation device and through the delivery catheter to the delivery device handle.

36. The system of claim 35, wherein the delivery catheter and the fixation device comprise a coupler configured to disconnect the fixation device from the delivery catheter and to disconnect the interface.Atty Docket No. ABTEVA-0064PCT37. The system of claim 36, wherein: the delivery catheter includes a shaft having a plurality of spring amis each having a first electrical terminal and an actuator rod extendable through the shaft, and the fixation device includes a coupling member having second electrical terminals corresponding with the first electrical terminals, wherein moving the actuator rod in a first direction urges the spring arms into engagement with the coupling member and the first electrical terminals into engagement with the second electrical terminals, and moving the actuator rod in a second direction disengages the spring arms from the coupling member and the first electrical terminals from the second electrical terminals.

38. The system of claim 34, wherein the interface is a wireless interface configured with a wireless protocol of one of Bluetooth Low Energy, Near Field Communication, and Zigbee.

39. The system of any one of claims 33-38, wherein the control unit includes a power source and a measurement module.

40. The system of claim 39, wherein the power source is configured to deliver an AC signal to the first and second electrodes within a range of frequencies, and the measurement module is configured to determine a type of tissue in contact with the first and second electrodes based on an impedance response detectable by the measurement module.

41. The system of claim 40, wherein the range of frequencies is 10 Hz to 10 kHz.

42. The system of claim 40, wherein the range of frequencies is 10 kHz to 10 MHz.

43. The system of any one of claims 39-42, wherein the control unit is disposed within the delivery device handle.

44. The system of any one of claims 39-43, wherein the measurement module is coupled to a display, the display being disposed within the delivery device handle, and the measurement module is configured to transmit output signals indicative of the first and second impedance response to the display.

45. An interventional system comprising: a delivery system having a delivery device handle and a delivery catheter extending from the delivery device handle; a fixation device having a center portion, a first distal element coupled to the center portion and extending therefrom and being moveable between an open position and a closed position, and a first proximal element disposed opposite the first distal element and beingAtty Docket No. ABTEVA-0064PCT moveable relative to the first distal element to capture tissue therebetween, wherein the fixation device is coupleable to the delivery catheter; a control unit; and first and second electrodes coupled to the delivery catheter and in communication with the control unit, the first and second electrodes at least partially forming a circuit, wherein the circuit is an open circuit generating a first impedance response when tissue contacts the first electrode and not the second electrode, and the circuit is a closed circuit generating a second impedance response when tissue contacts the first and second electrodes, the first impedance response having a first impedance value greater than a second impedance value of the second impedance response.

46. The system of claim 45, further comprising an interface between the first and second electrodes and the control unit.

47. The system of claim 46, wherein the interface is a hardwired interface extending through the delivery catheter to the delivery device handle.

48. The system of claim 46, wherein the interface is a wireless interface configured with a wireless protocol of one of Bluetooth Low Energy, Near Field Communication, and Zigbee.

49. The system of any one of claims 45-48, wherein the control unit includes a power source configured to deliver an AC signal to the first and second electrodes within a range of frequencies, and a measurement module configured to determine a type of tissue in contact with the first and second electrodes based on an impedance response detectable by the measurement module.

50. The system of any one of claims 45-48, wherein the power source is configured to deliver a DC signal to the first and second electrodes, and the measurement module is configured to measure resistive impedance of tissue in contact with the first and second electrodes.

51. The system of any one of claims 45-48, wherein the display is configured to provide at least one of visual indicators, audio alerts, or haptic feedback signals based on the first and second impedance responses.

52. The system of any one of claims 45-48, wherein the display is configured to provide real-time visual feedback indicative of a depth of tissue insertion between the first proximal element and the first distal element during insertion of tissue.

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