Balloon catheter with improved column strength and torque transmission

Abstract

A balloon catheter capable of delivering torque and pushing through obstructions includes a relatively weak balloon segment of a catheter and rotatable asymmetric tip. A reinforcement sleeve increases column strength and torque transmission to push the balloon and rotate the tip to facilitate passage through said obstructions. The tip is preferably asymmetric around its axis, usually being beveled, and the reinforcement slide includes a slide lock mechanism which increases shaft flexibility after balloon deployment.

What is claimed is: 
     
         1 . A method for dilatating a lesion in a blood vessel, said method comprising:
 providing a catheter having an inner member, a distal tip, a reinforcement sleeve, and an inflatable balloon connected at a distal end to the inner member and at a proximal end to the reinforcement sleeve;   advancing the catheter through a patient's vasculature by pushing a proximal end of the inner member to transmit force to the distal tip through both the inner member and the reinforcement sleeve, while both the inner member and sleeve remain engaged with the distal tip, to position the balloon at the lesion; and   inflating the balloon within the lesion such that the balloon radially expands and elongates and the reinforcement sleeve separates from the distal tip to accommodate such balloon elongation.   
     
     
         2 . A method as in  claim 1 , further comprising rotating the catheter about its axis as it is being advanced, wherein rotational torque is transmitted to the distal tip through both the inner member and the reinforcement sleeve. 
     
     
         3 . A method as in  claim 2 , wherein the distal tip has a beveled and which is reoriented relative to a luminal obstruction in the vasculature as the catheter is rotated. 
     
     
         4 . A method as in  claim 3 , wherein the distal tip is asymmetrically beveled so that the distal tip can be rotationally oriented relative to the luminal obstruction. 
     
     
         5 . A method as in  claim 1 , wherein a distal region of the reinforcement sleeve is tapered within the balloon to reduce the crossing profile of the balloon. 
     
     
         6 . A method as in  claim 5 , wherein the reinforcement sleeve has a substantially uniform diameter over the distal region. 
     
     
         7 . A method as in  claim 1 , wherein the inner member comprises a hypotube over at least a portion of its length. 
     
     
         8 . A method as in  claim 1 , wherein the inner member comprises a polymer tube over at least a portion of its length. 
     
     
         9 . A method as in  claim 8 , wherein polymer tube is reinforced. 
     
     
         10 . A method as in  claim 1 , wherein the reinforcement sleeve comprises a polymer tube over at least a portion of its length. 
     
     
         11 . A method as in  claim 10 , wherein the polymer tube is reinforced. 
     
     
         12 . A method as in  claim 1 , wherein the balloon has a distal construction which defines an annular channel which receives the distal end of the reinforcement sleeve.  13  A method as in  claim 1 , wherein the distal tip is a separate component attached to the distal end of the inner member 
     
     
         14 . A method as in  claim 1 , wherein the distal end of the balloon is attached to the proximal surface of the distal tip. 
     
     
         15 . A method as in  claim 14 , wherein the balloon has a collar region at its distal end which is attached to the distal tip.