Dilation catheter with a smooth transition between a stiff proximal portion and a flexible distal portion

摘要

A balloon dilatation having a catheter shaft with inner and outer tubular members with the proximal portion of the inner tubular member being formed of a pseudoelastic NiTi alloy having an A.sub.f at or below body temperature. The austenite phase is stable at body temperature exhibits a stress induced transformation, to the martensite phase which has a much lower modulus of elasticity than the austenite phase. The distal portion of the inner tubular member is formed of a flexible plastic material. The junction of the proximal and distal portions of the inner tubular member is preferably supported by a transition sleeve formed of a high strength plastic such as polyimide to provide a smoother transition between the proxima and distal portions of the inner tubular member and in turn the proximal and distal portion of the catheter shaft.