Balloon catheter with improved pushability

Abstract

Rapid exchange angioplasty catheters and methods of constructing rapid exchange angioplasty catheters including features that provide good pushability and kink resistance. In an illustrative embodiment, a catheter is provided, the illustrative catheter including a proximal hypotube section, which connects to a more distal braided catheter section. The braided catheter section connects to a midshaft portion that includes a guidewire entry port. Distal of the midshaft portion is a distal section having a balloon disposed thereon. An inflation lumen extends the length of the catheter, while a guidewire lumen extends only from the guidewire entry port to the distal end of the catheter. Optionally, a core wire may extend across the joint from the hypotube, to the braided catheter section, and past the guidewire entry port.

What is claimed is: 
     
         1 . A rapid exchange catheter comprising:
 an elongated shaft having a proximal end and a distal end, the elongated shaft including:
 a hypotube having a proximal end and a distal end; 
 a midshaft portion having a proximal end and a distal end, the midshaft portion being attached near its proximal end to a location near the distal end of the hypotube, the midshaft portion including a coiled member; and 
 a distal portion including an inner tubular member and an outer tubular member surrounding the inner tubular member, a short guidewire lumen being defined by the inner tubular member and an inflation lumen being defined between the inner tubular member and the outer tubular member, the distal portion being attached to the midshaft portion and extending distally therefrom; 
 wherein the midshaft portion includes a flared portion and a tab prior to being attached to the distal portion such that when the midshaft portion and the distal portion are attached at a port joint the inner tubular member extends along an exterior surface of the tab to provide a proximal guidewire port; 
   a balloon disposed near the distal end of the elongated shaft; and   a core wire attached to the hypotube and extending distally of the distal end of the hypotube and across the location at which the proximal end of the midshaft portion is attached to the distal end of the hypotube.   
     
     
         2 . The rapid exchange catheter of  claim 1 , wherein the core wire extends distally beyond the proximal guidewire port. 
     
     
         3 . The rapid exchange catheter of  claim 1 , wherein the core wire is tapered. 
     
     
         4 . The rapid exchange catheter of  claim 1 , wherein the midshaft portion includes a polymeric outer layer surrounding the coiled member. 
     
     
         5 . The rapid exchange catheter of  claim 1 , further comprising a polymeric tubular member extending between the port joint and a distal end of the coiled member. 
     
     
         6 . The rapid exchange catheter of  claim 1 , wherein the hypotube includes a crimp to attach the core wire to the hypotube. 
     
     
         7 . The rapid exchange catheter of  claim 1 , wherein a proximal end of the inner tubular member is skived at an angle. 
     
     
         8 . The rapid exchange catheter of  claim 7 , wherein the angle is about 60°. 
     
     
         9 . The rapid exchange catheter of  claim 1 , wherein the inner tubular member extends through the balloon to a distal tip. 
     
     
         10 . A rapid exchange catheter comprising:
 an elongated shaft having a proximal end and a distal end, the elongated shaft including:
 a hypotube having a proximal end and a distal end; 
 a midshaft portion having a proximal end and a distal end, the midshaft portion being attached near its proximal end to a location near the distal end of the hypotube, the midshaft portion including a coiled member; and 
 a distal portion including an inner tubular member and an outer tubular member surrounding the inner tubular member, a short guidewire lumen being defined by the inner tubular member and an inflation lumen being defined between the inner tubular member and the outer tubular member, the distal portion being attached to the midshaft portion and extending distally therefrom; 
 wherein the midshaft portion includes polymeric member extending distal of the coiled member, the polymeric member including a flared portion and a tab prior to being attached to the distal portion such that when the midshaft portion and the distal portion are attached at a port joint the inner tubular member extends along an exterior surface of the tab to provide a proximal guidewire port; 
   a balloon disposed near the distal end of the elongated shaft; and   a core wire attached to the hypotube and extending distally of the distal end of the hypotube and across the location at which the proximal end of the midshaft portion is attached to the distal end of the hypotube.   
     
     
         11 . The rapid exchange catheter of  claim 10 , wherein the core wire extends distally beyond the proximal guidewire port. 
     
     
         12 . The rapid exchange catheter of  claim 10 , wherein the core wire is tapered. 
     
     
         13 . The rapid exchange catheter of  claim 10 , wherein the hypotube includes a crimp to attach the core wire to the hypotube. 
     
     
         14 . The rapid exchange catheter of  claim 1 , wherein a proximal end of the inner tubular member is skived at an angle. 
     
     
         15 . The rapid exchange catheter of  claim 14 , wherein the angle is about 60°. 
     
     
         16 . The rapid exchange catheter of  claim 10 , wherein the inner tubular member extends through the balloon to a distal tip.