A method is provided including introducing, during a transcatheter procedure, a 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 is delivered distally through a cardiac wall. The tissue anchor is at least partially released from the deployment tool such that the tissue-coupling element is unconstrained by the deployment tool. After the tissue-coupling element is delivered through the cardiac wall and the tissue anchor is at least partially released from the deployment tool, whether the tissue-coupling element overlies a coronary blood vessel is ascertained, and, if the tissue-coupling element overlies the coronary blood vessel, the tissue anchor is rotated until the tissue-coupling element no longer overlies the coronary blood vessel. Thereafter, the tissue-coupling element is proximally pulled by applying tension to the tissue anchor. Other embodiments are also described.