Tissue Anchors

Abstract

Apparatus is provided that includes an implantable tissue anchor for delivery in a constrained state within a deployment tool. The implantable tissue anchor includes an anchor shaft and a tissue-coupling element, which extends from a distal end of the anchor shaft. The tissue-coupling element includes a wire and a tip, which is fixed to a distal end of the wire, and has, at a widest longitudinal site along the tip, a greatest tip outer cross-sectional area that equals at least 150% of an average wire cross-sectional area of the wire. The tissue-coupling element is shaped as an open shape that is generally orthogonal to the anchor shaft when the tissue anchor is unconstrained by the deployment tool. Other embodiments are also described.

1 - 34 . (canceled) 
     
     
         35 . Apparatus comprising an implantable tissue anchor for delivery in a constrained state within a deployment tool, the implantable tissue anchor comprising:
 an anchor shaft; and   a tissue-coupling element, which (a) extends from a distal end of the anchor shaft, (b) comprises a wire and a tip, which is fixed to a distal end of the wire, and has, at a widest longitudinal site along the tip, a greatest tip outer cross-sectional area that equals at least 150% of an average wire cross-sectional area of the wire, and (c) is shaped as an open shape that is generally orthogonal to the anchor shaft when the tissue anchor is unconstrained by the deployment tool.   
     
     
         36 . The apparatus according to  claim 35 , wherein the greatest tip outer cross-sectional area equals at least 200% of the average anchoring-element outer cross-sectional area. 
     
     
         37 . The apparatus according to  claim 35 , wherein the greatest tip outer cross-sectional area is greater than 1 mm2. 
     
     
         38 . The apparatus according to  claim 35 , wherein the tip comprises a frustoconical portion. 
     
     
         39 . The apparatus according to  claim 35 , wherein the anchor shaft has a central longitudinal axis that is straight when the tissue anchor is unconstrained by the deployment tool. 
     
     
         40 . The apparatus according to  claim 35 , wherein the anchor shaft and the tissue-coupling element are integral to one another. 
     
     
         41 . The apparatus according to  claim 35 , wherein the open shape is an open loop having more than one turn when the tissue anchor is unconstrained by the deployment tool. 
     
     
         42 . The apparatus according to  claim 41 , wherein the open loop is shaped as a spiral when the tissue anchor is unconstrained by the deployment tool. 
     
     
         43 . The apparatus according to  claim 42 , wherein the spiral is shaped as an elliptical spiral when the tissue anchor is unconstrained by the deployment tool. 
     
     
         44 . The apparatus according to  claim 41 , wherein the wire extends from the distal end of the anchor shaft at a radially-outer end of the open loop when the tissue anchor is unconstrained by the deployment tool. 
     
     
         45 . The apparatus according to  claim 35 , wherein when the tissue anchor is unconstrained by the deployment tool, if the tissue-coupling element were to be projected onto a plane that is perpendicular to a central longitudinal axis of the anchor shaft, the open shape would surround between 170 and 355 degrees of a point in the plane, wherein the point falls on a projection onto the plane of a line segment that terminates at (a) a site at the distal end of the wire and (b) a proximal end of the tissue-coupling element. 
     
     
         46 . The apparatus according to  claim 35 , wherein the wire comprises a shape-memory alloy that causes the wire to automatically transition to the open shape when released from being constrained by the deployment tool to being unconstrained by the deployment tool. 
     
     
         47 . The apparatus according to  claim 35 , wherein the tissue anchor is a first tissue anchor, and wherein the apparatus further comprises:
 a second tissue anchor, which is separate and distinct from the first tissue anchor; and   one or more tethers that couple the first tissue anchor to the second tissue anchor.   
     
     
         48 . A method comprising:
 introducing, during a transcatheter procedure, an implantable tissue anchor into a cardiac chamber of a heart of a subject, while a tissue-coupling element of the tissue anchor is constrained by a deployment tool, the tissue-coupling element (i) extending from a distal end of an anchor shaft of the tissue anchor, and (ii) including a wire and a tip, which is fixed to a distal end of the wire, and has, at a widest longitudinal site along the tip, a greatest tip outer cross-sectional area that equals at least 150% of an average wire cross-sectional area of the wire;   delivering the tissue-coupling element through a wall of the heart; and   at least partially releasing the tissue anchor from the deployment tool such that the tissue-coupling element is unconstrained by the deployment tool, and the tissue-coupling element is shaped as an open shape that is generally orthogonal to the anchor shaft.   
     
     
         49 . The method according to  claim 48 , wherein the greatest tip outer cross-sectional area equals at least 200% of the average anchoring-element outer cross-sectional area. 
     
     
         50 . The method according to  claim 48 , wherein the greatest tip outer cross-sectional area is greater than 1 mm2. 
     
     
         51 . The method according to  claim 48 , wherein the open shape is an open loop having more than one turn when the tissue anchor is unconstrained by the deployment tool. 
     
     
         52 . The method according to  claim 48 , wherein the anchor shaft has a central longitudinal axis that is straight when the tissue anchor is unconstrained by the deployment tool. 
     
     
         53 . The method according to  claim 48 , wherein the anchor shaft and the tissue-coupling element are integral to one another. 
     
     
         54 . The apparatus according to  claim 48 , wherein when the tissue anchor is unconstrained by the deployment tool, if the tissue-coupling element were to be projected onto a plane that is perpendicular to a central longitudinal axis of the anchor shaft, the open shape would surround between 170 and 355 degrees of a point in the plane, wherein the point falls on a projection onto the plane of a line segment that terminates at (a) a site at the distal end of the wire and (b) a proximal end of the tissue-coupling element. 
     
     
         55 . The method according to  claim 48 , wherein the wire includes a shape-memory alloy that causes the wire to automatically transition to the open shape when released from being constrained by the deployment tool to being unconstrained by the deployment tool. 
     
     
         56 . The method according to  claim 48 , wherein the tissue anchor is a first tissue anchor, and wherein the method further comprises:
 implanting a second tissue anchor in the subject, which second tissue anchor is separate and distinct from the first tissue anchor; and   facilitating repair of an atrioventricular valve of the subject by applying tension to one or more tethers that couple the first tissue anchor to the second tissue anchor.