A vibrational catheter for disrupting obstructions in lumens such as blood vessels includes an elongate flexible catheter body having a proximal end, a distal end and at least one lumen extending longitudinally therethrough, a vibrational transmission member extending longitudinally through the lumen of the catheter body and having a proximal end and a distal end, and a transition connector attached to the proximal end of the vibrational transmission member for coupling the transmission member with a vibrational energy source. The transition connector includes a bore into which the proximal end of the vibrational transmission member extends. The proximal end of the vibrational transmission member is attached within the bore of the transition connector with variable attachment forces such that the transition connector exerts a lowest amount of attachment force on an attached distal-most portion of the vibrational transmission member housed within the bore.