Tricuspid valve repair using tension

A stent system comprising:

• a percutaneous implant comprising:
• a first radially-expandable stent, which has proximal and distal ends, and comprises a first plurality of nitinol mechanical structural elements, which are arranged so as to have a radially compressed state and to form a first tubular structure having a lumen when the first stent is in a radially-expanded state sized to contact tissue;
• a second radially-expandable stent, which comprises a second plurality of nitinol mechanical structural elements, which are arranged so as to form a second tubular structure when the second stent is in a radially-expanded state, and which are shaped so as to provide a plurality of struts located adjacent to the first stent, is the second stent shaped so as to be longitudinally disposed within, and longitudinally aligned with, the lumen of the first stent such that when the second stent is in its radially-expanded state the plurality of struts extend to and engage at predetermined locations with the first plurality of mechanical structural elements of the first stent in order to limit relative longitudinal movement between the first stent and the second stent;
• and
• a nitinol tension-distributing element located at the distal end of the first stent, the tension-distributing element having a longitudinal length of at least 15% of, and less than an entirety of, a longitudinal length of the first stent;
• a flexible longitudinal member, which couples a tissue anchor to the first tension distributing element of the percutaneous implant, the tension-distributing element distributing tension of the flexible longitudinal member to the percutaneous implant;
• a tissue-anchor assembly, comprising:
• the tissue anchor, which is configured to be implanted at least in part in cardiac tissue;
• and
• first and second coupling elements, which are (a) shaped so as to define a curved channel and a protrusion slidably disposed within the curved channel, and (b) configured to lock and limit movement of the flexible longitudinal member by movement of the protrusion within the curved channel, the movement caused by relative rotation of the first and the second coupling elements;
• a sheath, which is configured to deliver the first stent while the first plurality of mechanical structural elements are in the radially compressed state, wherein the first stent is configured to assume its radially-expanded state when the sheath is retracted in a distal to proximal direction;
• and
• a torque-delivery tool, which is configured to deliver the tissue anchor to the cardiac tissue.