Patent ID: 7556642

Claim:
A balloon dilatation catheter for medically treating a patient, comprising: a high-strength proximal tube having proximal and distal ends, and defining a proximal portion of an inflation lumen; a hub affixed to the proximal end of the high-strength proximal tube; a distal shaft assembly; a balloon affixed to the distal shaft assembly near its distal end, the distal shaft assembly defining a distal portion of the inflation lumen in fluid communication with the proximal portion of the inflation lumen of the proximal tube, such that the proximal and distal portion of the inflation lumen together define the inflation lumen extending from an inflation port near a proximal end of the catheter to a distal inflation port where the inflation lumen opens into the balloon, the distal shaft assembly further defining a guidewire lumen extending from a distal guidewire port near a distal end of the catheter to a proximal guidewire port near a transition between the proximal tube and the distal shaft assembly, the distal shaft assembly having a flexibility greater than the proximal tube; wherein at least a portion of the distal shaft assembly includes an inner tubular body and an outer tubular bodies; wherein the inner tubular body defines at least a portion of the guidewire lumen, and an annular space between the inner and outer tubular bodies defines a portion of the inflation lumen; and a stiffening wire positioned across the transition, providing flexible bending strain relief; the stiffening wire having a portion near its distal end affixed to the inner and outer tubular bodies in a stiffening wire seal area, and the stiffening wire having a proximal end including a most proximal tip, said proximal end extending into and floating within a distal portion of the proximal portion of the inflation lumen defined by the proximal tube, such that said proximal end is not affixed to the proximal tube at any location.