Abstract: A tissue anchor is provided that includes a proximal head at a proximal end of the tissue anchor, and a helical tissue-coupling element disposed about a longitudinal axis thereof, extending to the proximal head, and having a distal tissue-penetrating tip. The helical tissue-coupling element includes a first helical portion and a second helical portion more distal than the first axial portion. The first and the second helical portions of the helical tissue-coupling element have a first axial stiffness and a second axial stiffness, respectively. The second axial stiffness is greater than the first axial stiffness, such that if excessive tension is applied to the helical tissue-coupling element, the helical tissue-coupling element generally elongates along the first helical portion before along the second helical portion, such that the first helical portion serves as a mechanical fuse that reduces force applied to the second helical portion.

Abstract: A tissue anchor is provided for delivery in a constrained state within a deployment tool. The tissue anchor includes a tissue-coupling element; a flexible elongate tension member, which includes (a) a distal portion that is fixed to a site on the tissue-coupling element, and (b) a proximal portion, which is slidably disposed through a passage defined by the tissue anchor; and a load-limiting element, which is attached to the flexible elongate tension member. The load-limiting element and the passage are sized and shaped such that the size and shape of the passage prevent proximal movement of the load-limiting element past the passage, such that the load-limiting element limits a total load that can be applied to the tissue-coupling element by the flexible elongate tension member.

Abstract: A method is provided for reducing tricuspid valve regurgitation of a patient. The method includes implanting a first tissue anchor at a first implantation site in cardiac tissue in the vicinity of the tricuspid valve of the patient, and implanting a second tissue anchor at a second implantation site in cardiac tissue of the patient opposite the first implantation site across the tricuspid valve. Using a spool that winds therewithin at least a portion of a longitudinal member that couples the first and the second tissue anchors together, tension is applied between the first and the second tissue anchors to alter the geometry of the tricuspid valve by rotating the spool.

Abstract: Apparatus is provided that includes a tissue anchor, which (a) includes a helical tissue-coupling element which has a distal tissue-penetrating tip at a distal end of the tissue anchor, and which is configured to be advanced into soft tissue, and (b) is shaped so as to define a longitudinal channel extending to the distal end of the tissue anchor. The apparatus further includes a depth-finding tool, which includes a radiopaque bead that is axially moveable along the channel so as to serve as a marker indicating a depth of penetration of the tissue-coupling element into the soft tissue.

Abstract: A tissue anchor (200, 258, 300) includes a shaft (122), a tissue-coupling element (128), and a flexible elongate tension member (202). The tissue-coupling element (128) includes a wire (150), which is shaped as an open loop (154) having more than one turn when the tissue anchor (200, 258, 300) is unconstrained. The tension member (202) includes a distal portion (204) that is fixed to a site (206) on the open loop (154), a proximal portion (208), which has a longitudinal segment (209) that runs alongside at least a portion (210) of the shaft (122), and a crossing portion (212), which (i) is disposed between the distal and the proximal N portions (204, 208) along the tension member (202), and (ii) crosses at least a portion of the open loop (154) when the tissue anchor (200, 258, 300) is unconstrained.

Abstract: Apparatus is provided that includes a tissue anchor, which (a) includes a helical tissue-coupling element which has a distal tissue-penetrating tip at a distal end of the tissue anchor, and is configured to be advanced into soft tissue, and (b) is shaped so as to define a longitudinal channel extending to the distal end of the tissue anchor. The apparatus further includes (a) a depth-finding tool, which includes a radiopaque bead, which is shaped so as to define a hole therethrough, and which is positioned within and axially moveable along the channel so as to serve as a marker indicating a depth of penetration of the tissue-coupling element into the soft tissue, and (b) and a shaft that is removably positioned within the channel, such that the shaft passes through the hole of the bead, and such that the bead is axially moveable along the shaft and along the channel.

Abstract: A torque-delivering cable is provided, which includes a first coupling. The torque-delivering cable and the first coupling are shaped so as to collectively define a first passage therethrough. A tissue anchor is further provided, which includes a tissue-engaging element and a second coupling, which second coupling is shaped so as to define a second passage therethrough. The first and the second couplings are interlockingly coupleable to each other.

Abstract: A method is provided including making an opening (300) through an atrial septum (302) at a septal site (304) at least 5 mm from a fossa ovalis (330). A first tissue anchor (204) is endovascularly advanced to a left-atrial site (306) on an annulus of a mitral valve (310) or a wall of a left atrium (308) above the annulus. The first tissue anchor (204) is implanted at the left-atrial site (306). A second tissue anchor (24) is endovascularly advanced to a right-atrial site (320) on an annulus of a tricuspid valve (207) or a wall of a right atrium (200) above the annulus. The second tissue (24) anchor is implanted at the right-atrial site (320). The left-atrial site (306) and the right-atrial site (320) are approximated by tensioning a tether (22) that passes through the opening (300) of the atrial septum (302) and connects the first and the second tissue anchors (204, 24). Other embodiments are also described.

Abstract: A method is provided for repairing the tricuspid valve of a patient using tension. A radially-expandable stent is implanted in a coronary sinus of the patient. A tissue anchor is implanted in tissue in the vicinity of the tricuspid valve. The tricuspid valve is repaired by applying tension between the radially-expandable stent and the tissue anchor using a flexible longitudinal member that connects the radially-expandable stent and the tissue anchor.

Abstract: Apparatus is provided that includes a tissue anchor, which (a) comprises a helical tissue-coupling element which has a distal tissue-penetrating tip at a distal end of the tissue anchor, and which is configured to be advanced into soft tissue, and (b) is shaped so as to define a longitudinal channel extending to the distal end of the helical tissue-coupling element. The apparatus further includes a depth-finding tool, which comprises a radiopaque bead that is axially moveable along the channel so as to serve as a marker indicating a depth of penetration of the tissue-coupling element into the soft tissue.

Abstract: A method is provided of reducing tricuspid valve regurgitation of a patient. A first tissue anchor is implanted at a first implantation site in cardiac tissue in the vicinity of the tricuspid valve of the patient. A second tissue anchor is implanted at a second implantation site of the patient, different from the first implantation site. After the first and the second tissue anchors have been implanted, a longitudinal member that couples the first and the second tissue anchors together is longitudinally deflected.

Abstract: A tissue anchor includes a shaft, a tissue-coupling element, and a flexible elongate tension member. The tissue-coupling element includes a wire, which is shaped as an open loop having more than one turn when the tissue anchor is unconstrained. The tension member includes a distal portion that is fixed to a site on the open loop, a proximal portion, which has a longitudinal segment that runs alongside at least a portion of the shaft, and a crossing portion, which (i) is disposed between the distal and the proximal portions along the tension member, and (ii) crosses at least a portion of the open loop when the tissue anchor is unconstrained. The tissue anchor is configured to allow relative axial motion between the at least a portion of the shaft and the longitudinal segment of the proximal portion of the tension member when the tissue anchor is unconstrained.

Abstract: A method is provided that includes implanting (a) a venous first tissue anchor in a vein selected from the group of veins consisting of: a superior vena cava and an inferior vena cava, (b) an atrial second tissue anchor at an atrial site selected from the group of sites consisting of: an annulus of a tricuspid valve, and a wall of a right atrium of a heart above the annulus of the tricuspid valve, (c) a venous third tissue anchor in a coronary sinus, and (d) one or more tethers, which connect the venous first tissue anchor, the atrial second tissue anchor, and the venous third tissue anchor. A size of a tricuspid orifice is reduced by tensioning the one or more tethers. Other embodiments are also described.

Abstract: A method is provided that includes implanting (a) a first venous tissue anchor in a superior vena cava, an inferior vena cava, or a coronary sinus, (b) exactly two atrial tissue anchors, which consist of second and third atrial tissue anchors, at respective different atrial sites, each of which sites is selected from: an annulus of a tricuspid valve, and a wall of a right atrium of a heart above the annulus, and (c) a pulley system, which includes (i) a pulley, which is connected to the second atrial tissue anchor, and (ii) a tether, which (A) is connected to the first venous tissue anchor and the third atrial tissue anchor, (B) is moveable through the pulley, and (C) has a length, measured between the first venous and the third atrial tissue anchors, of at least 30 mm. A size of a tricuspid orifice is reduced by tensioning the tether.

Abstract: Apparatus is provided for use with a guidewire, the apparatus including a tissue anchor, and a tool for facilitating implanting of the tissue anchor. The tool includes a sheath, and an atraumatic tip, which is removably engaged to a distal end of the sheath, and which is shaped so as to define a body that defines a recess for housing the tissue anchor during guiding of the tool through vasculature of a patient.

Abstract: Apparatus is provided that includes first and second tissue-engaging elements, and first and second flexible longitudinal members, coupled at respective first end portions thereof to the first and the second tissue-engaging elements, respectively. The apparatus further includes a first flexible-longitudinal-member-coupling element coupled to a second end portion of the first flexible longitudinal member, a second flexible-longitudinal-member-coupling element coupled to a second end portion of the second flexible longitudinal member, and a flexible longitudinal guide member reversibly coupled to the first flexible-longitudinal-member-coupling element. The first and second flexible-longitudinal-member-coupling elements are configured to be couplable together to couple together the first and the second flexible longitudinal elements. Other applications are also described.

Abstract: A radially-expandable stent (20) is shaped so as to define one or more tether interfaces (50), a lower-securement portion (56), and a higher-securement portion (64). The lower-securement portion (56) extends (a) along at least a contiguous lower-securement axial segment (58) of the stent (20) and (b) circumferentially around a contiguous lower-securement circumferential portion (60) of the stent (20), which lower-securement axial segment (58) and lower-securement circumferential portion (60) include the one or more tether interfaces (50). The higher-securement portion (64) extends (a) along at least a contiguous higher-securement axial segment (65) of the stent (20) and (b) circumferentially around between 215 and 330 degrees of a circumference (C), at all circumferential locations other than those of the lower-securement circumferential portion (60).

Abstract: Apparatus is provided including a radially-expandable percutaneous implant shaped so as to define a tension-distributing element. A flexible longitudinal member is coupled at a first portion thereof to at least a portion of the percutaneous implant via the tension-distributing element. The tension-distributing element is configured to distribute tension applied by the flexible longitudinal member along a longitudinal length of the percutaneous implant.

Abstract: A tissue anchor (20) comprises a helical tissue-coupling element (30) disposed about a longitudinal axis (32) thereof and having a distal tissue-penetrating tip (34). The helical tissue-coupling element (30) has: a first axial stiffness along a first axial portion (60) of the helical tissue-coupling element (30); a second axial stiffness along a second axial portion (62) of the helical tissue-coupling element (30) more distal than the first axial portion (60), which second axial stiffness is greater than the first axial stiffness; and a third axial stiffness along a third axial portion (64) more distal than the second axial portion (62), which third axial stiffness is less than the second axial stiffness. Other embodiments are also described.

Abstract: Apparatus is provided, including a radially-expandable percutaneous implant, a tissue anchor, and a connecting element shaped so as to provide an annular loop surrounding a proximal portion of the tissue anchor in a manner which enables rotation of the anchor about a central longitudinal axis thereof when surrounded by the annular loop. The apparatus also includes a flexible longitudinal member coupled at a first portion thereof to at least a portion of the percutaneous implant and at a second portion to the connecting element. The annular loop of the connecting element facilitates rotation of the tissue anchor about the central longitudinal axis such that the anchor can rotate about the central longitudinal axis with respect to the annular loop, the flexible longitudinal member, and the percutaneous implant. Other applications are also described.