Abstract: A shaft is shown having inner and outer members in interfering contact along their length, at least one of which comprises a wire, at least a portion of which is superelastic, to achieve substantial mechanical fidelity and resistance to damage. An ultrasound imaging catheter has a hollow catheter shaft, an ultrasound transducer in the shaft, and a drive shaft that rotates the transducer. The shaft comprises at least one metal coil having characteristic elastic deformation under stress in the range of about 3% to 9%, while a restraint means prevents torsional deflection of the coil. A drive shaft having a coil surrounded by a tube, a coil bonded to an inner coaxial cable, and an inner and outer coil that interfere with one another are shown. A superelastic coil is formed by continuously winding a wire about a mandrel, heating a region of the wire to render it superelastic, and after cooling, removing it from the mandrel.

Abstract: A kink resistant balloon catheter for insertion into a bodily conduit. The catheter (10) includes a shaft (20), a radiopaque distal tip (35), a dilatation balloon (33) between the shaft and the distal tip, and a removable core wire (40). The shaft includes a kink resistant, cross-wound multifilar (CWMF) coil (21) enclosed by a polymeric sleeve (22) and defining a central lumen (28) for delivery of a fluid inflation medium for inflating the balloon. A fixed core wire (36) interconnects the CWMF coil and the distal tip. In a method for widening constricted bodily passages using the novel balloon catheter, the removable core wire is inserted to assist positioning of the catheter, and is removed to permit rapid inflation and deflation of the balloon.