Method of making a balloon dilation catheter shaft having end transition

A method of making a catheter comprising:

• positioning an inner tubular member in the bore of an outer tubular member, the inner tubular member extending beyond the distal end of the outer tubular member wherein the outer tubular member and inner tubular member are formed from weldable thermoplastic materials and wherein the inner tubular member has a bore defining a guidewire lumen and wherein an annular space between the outside surface of the inner tubular member and the inside surface of the outer tubular member define a first inflation/deflation lumen;
• inserting a first mandrel into the bore of the inner tubular member adjacent the distal end of the outer tubular member;
• inserting at least one second mandrel into the annular space between the inner tubular member and the outer tubular member adjacent the distal end of the outer tubular member;
• welding the outer tubular member to the inner tubular member at the distal end of the outer tubular member to form a transition neck, wherein the thermoplastic materials of the outer tubular member and inner tubular member are bonded around the second mandrel;
• and
• removing the second mandrel from the transition neck to form a second inflation/deflation lumen, the second inflation/deflation lumen extending from the first inflation/deflation lumen and opening at the distal end of the transition neck.

A method of making a catheter from an inner tubular member positioned in an outer tubular member so as to define a first inflation/deflation lumen, the inner tubular member extending beyond the distal end of the outer tubular member and defining a guidewire lumen, comprising:

• inserting a first mandrel into the inner tubular member adjacent the distal end of the outer tubular member;
• inserting at least one second mandrel into the inflation lumen adjacent the distal end of the outer tubular member;
• bonding the outer tubular member to the inner tubular member at the distal end of the outer tubular member to form a transition neck;
• and
• removing the second mandrel from the transition neck to form a second inflation/deflation lumen extending from the first inflation/deflation lumen and opening at the distal end of the transition neck.