Apparatus is provided, comprising (1) a guide member, (2) a tissue-adjustment mechanism having (a) an upper surface and a lower surface, (b) at least one first opening at the upper surface, (c) at least one second opening at the lower surface, and (4) a channel extending between the first and second openings, the channel facilitating advancement of the tissue-adjustment mechanism along the guide member； and (3) at least one repair chord coupled at a first portion thereof to the tissue-adjustment mechanism and having at least a first end that is configured to be coupled to a portion of tissue of a patient, the repair chord being configured to adjust a distance between the portion of tissue and the tissue-adjustment mechanism, in response to adjustment of the repair chord by the tissue-adjustment mechanism. Other embodiments are also described.
