Soft Tip Balloon Catheter

Abstract

Method for fabricating a balloon catheter including providing an inner tubular member having a distal section and a distal end with a lumen extending therein and forming a balloon having a distal leg with a first segment having a first diameter and a first wall thickness and a second segment having a second wall thickness. The second diameter is greater than the first diameter and the first wall thickness is greater than the second wall thickness. The distal end section of the inner tubular member can be positioned in the balloon and bonded to the first segment while reducing the diameter of the second segment. Method also provided for fabricating a multilayer balloon catheter including removing at least a portion of an outer layer from the distal leg of the balloon.

1 . A balloon catheter having a monolithic distal tip, prepared by a process comprising the steps of:
 providing an inner tubular member having a distal section, a distal end, and a lumen extending therein;   forming a balloon having a working length, a distal neck, and a distal leg, the distal leg having a first segment with a first diameter and first wall thickness and a second segment with a second diameter and second wall thickness, the second diameter being larger than the first diameter and the second wall thickness being thinner than the first wall thickness;   positioning the distal end of the inner tubular member in the balloon, with the first segment of the distal leg disposed proximate the distal section of the inner tubular member and the second segment of the distal leg extending distally beyond the distal end of the inner tubular member;   heating the distal leg of the balloon to bond at least a portion of the first segment to the distal section of the inner tubular member and to reduce the second diameter of the second segment of the distal leg.   
     
     
         2 . A method of fabricating a multilayer balloon catheter, comprising:
 providing an inner tubular member having a distal section, a distal end, and a lumen extending therein;   forming a multilayer balloon having at least a first layer and a second layer, a working length, a distal neck, and a distal leg, the distal leg having a first segment and a second segment, wherein the first layer is made of a first polymer material having a first durometer, wherein the second layer is made of a second polymer material having a second durometer, the second durometer being greater than the first durometer, and wherein the second layer is an outer layer relative to the first layer;   removing at least a portion of the second layer from the second segment of distal leg of the balloon;   positioning the distal section of the inner tubular member in the balloon, with at least the second segment of the distal leg extending beyond the distal end of the inner tubular member; and   bonding the inner tubular member to the first distal leg segment of the balloon.   
     
     
         3 . The method of  claim 2 , wherein removing at least a portion of the second layer further includes removing at least a portion of the second layer from the first segment. 
     
     
         4 . The method of  claim 2 , wherein the first layer comprises a material having a durometer between about 55D and about 63D. 
     
     
         5 . The method of  claim 4 , wherein the material of the first layer is selected from the group consisting of polyurethane, polyethylene, co-polyamide, polyester, and co-polyester. 
     
     
         6 . The method of  claim 4 , wherein the material of the first layer comprises polyether block amide. 
     
     
         7 . The method of  claim 2 , wherein the second layer comprises a material having a durometer between about 70D and 72D. 
     
     
         8 . The method of  claim 7 , wherein the material of the second layer is selected from the group consisting of polyamide, polyurethane, polyethylene, co-polyamide, polyester, and co-polyester. 
     
     
         9 . The material in  claim 8 , wherein the material of the second layer comprises polyether block amide or polyamide. 
     
     
         10 . The method of  claim 2  wherein the at least a portion of the second layer is removed with a rotary device. 
     
     
         11 . The method of  claim 2 , wherein the at least a portion of the second layer is removed by milling or laser ablation. 
     
     
         12 . The method of  claim 2 , further comprising monitoring the second layer to determine a removal depth; and
 terminating the removing at least a portion of the second layer when the removal depth reaches a predetermined threshold.   
     
     
         13 . The method of  claim 2 , wherein removing the at least a portion is performed after bonding the inner tubular member to the first distal leg segment of the balloon 
     
     
         14 . The method of  claim 2 , further comprising:
 positioning a mandrel in the lumen of the inner tubular member, the mandrel extending beyond the second segment of the distal leg of the balloon;   positioning a heat shrink tubing around at least a portion of the first and second segments of the distal leg of the balloon; and   heating the heat shrink tubing and first and second segments of the distal leg of the balloon, to bond at least a portion of the first segment to the distal section of the inner tubular member.