Balloon catheter having a shaft with a variable stiffness inner tubular member

A method of making a balloon catheter, comprising:

• a) assembling an elongated shaft having a proximal end, a distal end, an inflation lumen, and a guidewire lumen by placing an inner tubular member within at least a distal section of an outer tubular member, so that the inner tubular member defines the guidewire lumen and the outer tubular member defines the inflation lumen, the inner tubular member having a proximal portion with an axial compression stiffness less than an axial compression stiffness of a distal portion of the inner tubular member;
• b) bonding a portion of the inner tubular member to the outer tubular member at or distally adjacent a junction between the proximal and distal portions of the inner tubular member, to form a bonded portion along which an outer surface of the inner tubular member is bonded to an inner surface of the outer tubular member;
• c) bonding a proximal end of a balloon to the distal end of the outer tubular member so that the balloon has an interior in fluid communication with the inflation lumen;
• and
• d) bonding a distal end of the balloon to the distal portion of the inner tubular member to form the balloon catheter.