Apparatus and methods are described, including a catheter shaped to define a catheter lumen. A wall of the catheter comprises a braided portion, and is shaped to define first and second longitudinally-running channels therethrough. A distal portion of the catheter is shaped to define first and second lateral openings, which are approximately equidistant from the distal end of the catheter. A flexible longitudinal member passes (a) from a proximal portion of the catheter to the distal portion of the catheter via the first channel, (b) out of the first channel via the first lateral opening, (b) into the second channel via the second lateral opening, and (c) from the distal portion of the catheter to the proximal portion of the catheter via the second channel. Other applications are also described.
