Percutaneous tissue anchor techniques

A system for use with a tissue of a subject, the system comprising:

• (i) a tissue anchor, comprising:
• an engaging head, comprising a coupling eyelet that defines an eyelet plane, and
• a helical tissue-coupling element, reversibly anchorable to the tissue, and having a central helix axis that lies on the eyelet plane;
• (ii) an anchor driver, configured to anchor the tissue anchor to the tissue by rotating the tissue anchor about the central helix axis by applying a rotational force to the eyelet, the anchor driver comprising:
• a casing that defines a slot, the slot defining a slot plane, and dimensioned to receive at least part of the eyelet therein in a manner in which the eyelet plane is coplanar with the slot plane, and
• a detent, configured to reversibly inhibit movement of the eyelet with respect to the slot;
• and
• (iii) an anchor-retrieval tool, transluminally advanceable independently of the anchor driver, the anchor-retrieval tool comprising:
• at a distal portion, an anchor-engaging-element actuator, and an anchor-engaging element comprising a curved arm, and configured to be coupled to the tissue anchor by moving through the eyelet, and
• at a proximal portion of the anchor-retrieval tool, a retrieval-tool controller configured to control the anchor-engaging-element actuator,
• wherein:
• the system has at least two states:
• (1) an uncoupled state in which the anchor-engaging element is not in contact with the tissue anchor, and
• (2) an articulatably-coupled state in which:
• the engaging head at least in part inhibits movement of the anchor-engaging element away from the tissue anchor, and
• the distal portion is deflectable with respect to the tissue anchor;
• the anchor-engaging-element actuator is configured to facilitate transition of the system from the uncoupled state to the articulatably-coupled state;
• and
• in at least one of the at least two states, the anchor-retrieval tool is configured, while coupled to the tissue anchor, to apply a rotational de-anchoring force to the tissue anchor.