A medical device comprising: a manipulation assembly having a distal portion configured to be intravascularly positioned within a blood vessel lumen, the manipulation assembly comprising: an elongate tubular member, the tubular member having a proximal portion, a distal portion, and a lumen extending therein; and a joining element located at the distal portion of the elongate tubular member, the joining element having a proximal-end surface , a distal end surface opposite the proximal end surface , and a lumen extending from the proximal end surface to the distal end surface of the joining element ; and an interventional element comprising a proximally located attachment portion having a distal engagement feature comprising a proximal-facing surface , a proximal engagement feature comprising a distal-facing surface , and a retention region therebetween, wherein the distal and proximal engagement features each protrude outwardly with respect to the retention region , characterized in that the retention region is positioned within the lumen of the joining element such that the distal-facing surface of the proximal engagement feature is positioned to abut the proximal end surface of the joining element and thereby limit distal translation of the interventional element relative to the joining element and the proximal-facing surface of the distal engagement feature is positioned to abut the distal end surface of the joining element and thereby limit proximal translation of the interventional element relative to the joining element . a manipulation assembly having a distal portion configured to be intravascularly positioned within a blood vessel lumen, the manipulation assembly comprising: an elongate tubular member, the tubular member having a proximal portion, a distal portion, and a lumen extending therein; and a joining element located at the distal portion of the elongate tubular member, the joining element having a proximal-end surface , a distal end surface opposite the proximal end surface , and a lumen extending from the proximal end surface to the distal end surface of the joining element ; and an elongate tubular member, the tubular member having a proximal portion, a distal portion, and a lumen extending therein; and a joining element located at the distal portion of the elongate tubular member, the joining element having a proximal-end surface , a distal end surface opposite the proximal end surface , and a lumen extending from the proximal end surface to the distal end surface of the joining element ; and an interventional element comprising a proximally located attachment portion having a distal engagement feature comprising a proximal-facing surface , a proximal engagement feature comprising a distal-facing surface , and a retention region therebetween, wherein the distal and proximal engagement features each protrude outwardly with respect to the retention region , characterized in that the retention region is positioned within the lumen of the joining element such that the distal-facing surface of the proximal engagement feature is positioned to abut the proximal end surface of the joining element and thereby limit distal translation of the interventional element relative to the joining element and the proximal-facing surface of the distal engagement feature is positioned to abut the distal end surface of the joining element and thereby limit proximal translation of the interventional element relative to the joining element . <EOS>