Reduced material tip for catheter and method of forming same

Abstract

Method for fabricating a catheter including providing an inner tubular member formed from a first polymeric material, the inner tubular member having a distal section, a distal end, and a lumen defined therein by a first inner diameter; necking down at least a portion of the distal section of the inner tubular member to form a necked tip having a second inner diameter; and removing a portion of polymeric material from an inner surface along the necked tip to define a third inner diameter for the necked tip. The method can include positioning the distal section of the inner tubular member in a balloon having a working length, a distal neck, and a distal leg, with the distal end of the inner tubular member extending distally beyond a distal end of the distal leg, and coupling the distal leg of the balloon to at least a portion of the distal section of the inner tubular member.

1 . A method of fabricating a catheter, comprising:
 providing an inner tubular member formed from a first polymeric material, the inner tubular member having a distal section, a distal end, and a lumen defined therein by a first inner diameter;   necking down at least a portion of the distal section of the inner tubular member to form a necked tip having a second inner diameter; and   removing a portion of polymeric material from an inner surface along the necked tip to define a third inner diameter for the necked tip.   
     
     
         2 . The method of  claim 1 , wherein the second inner diameter is less than the first inner diameter. 
     
     
         3 . The method of  claim 1 , wherein the third inner diameter is about equal to the first inner diameter. 
     
     
         4 . The method of  claim 1 , wherein the inner tubular member is necked down on a stepped mandrel having a first portion with a first outer diameter and a second portion having a second outer diameter, the second outer diameter being about equal to the second inner diameter. 
     
     
         5 . The method of  claim 1 , wherein the tubular member is necked down using a hot die having an inner diameter, wherein the necked tip has an outer diameter about equal to the inner diameter of the hot die. 
     
     
         6 . The method of  claim 1 , wherein the portion of polymeric material removed from the inner surface along the necked tip is removed by a rotary device. 
     
     
         7 . The method of  claim 1 , wherein the portion of polymeric material removed from the inner surface along the necked tip is removed by milling or laser ablation. 
     
     
         8 . The method of  claim 1 , further comprising monitoring the necked tip to determine a removal depth; and
 terminating removing the portion of polymeric material from the inner surface along the necked tip when the removal depth reaches a predetermined threshold.   
     
     
         9 . The method of  claim 1 , wherein the polymeric material comprises a material selected from the group consisting of nylon, polyurethane, polyethylene, co-polyamide such as Pebax (polyether block amide), polyester, or co-polyester. 
     
     
         10 . The method of  claim 1 , wherein the inner tubular member is a multilayer tubular member comprising a first layer, a second layer, and a third layer, further wherein the second layer is an outer layer relative to the first layer and the third layer is an outer layer relative to the second layer. 
     
     
         11 . The method of  claim 1 , further comprising positioning the distal section of the inner tubular member in a balloon having a working length, a distal neck, and a distal leg, with the distal end of the inner tubular member extending distally beyond a distal end of the distal leg, and coupling the distal leg of the balloon to at least a portion of the distal section of the inner tubular member. 
     
     
         12 . The method of  claim 11 , wherein the balloon comprises a material selected from the group consisting of nylon, polyurethane, polyethylene, co-polyamide such as Pebax (polyether block amide), polyester, or co-polyester. 
     
     
         13 . The method of  claim 11 , further comprising forming the balloon by:
 melt-extruding a thermoplastic polymeric material to form a tube having a tube lumen and cooling the extruded tube to a temperature less than an elevated temperature of the melt-extrusion;   placing the extruded tube within a capture member; and   biaxially orienting the polymeric material of the extruded tube by radially expanding the extruded tube with pressurized media in the tube lumen and axially stretching the extruded tube with a load applied to at least one end of the tube.   
     
     
         14 . The method of  claim 11 , wherein the balloon is a multilayer balloon comprising a first layer and a second layer, further wherein the second layer is an outer layer relative to the first layer. 
     
     
         15 . The method of  claim 14 , wherein the first layer comprises a first material having a first durometer hardness and the second layer comprises a second material having a second durometer hardness, the second duromoter hardness being greater that the first durometer hardness. 
     
     
         16 . The method of  claim 14 , wherein the first layer comprises a first material having a first durometer between about 55 D and about 63 D. 
     
     
         17 . The method of  claim 16 , wherein the first material comprises polyether block amide. 
     
     
         18 . The method of  claim 14 , wherein the second layer comprises a second material having a durometer between about 70 D and 72 D. 
     
     
         19 . The method of  claim 18 , wherein the second material comprises polyether block amide. 
     
     
         20 . A catheter having a monolithic distal tip prepared by a process comprising:
 providing an inner tubular member formed from a first polymeric material, the inner tubular member having a distal section, a distal end, and a lumen defined therein by a first inner diameter;   necking down at least a portion of the distal section of the inner tubular member to form a necked tip having a second inner diameter; and   removing a portion of polymeric material from an inner surface along the necked tip to define a third inner diameter for the necked tip.   
     
     
         21 . The catheter of  claim 20 , wherein the third inner diameter is about equal to the first inner diameter. 
     
     
         22 . The catheter of  claim 20 , wherein the first polymeric material comprises a material selected from the group consisting of nylon, polyurethane, polyethylene, co-polyamide such as Pebax (polyether block amide), polyester, or co-polyester. 
     
     
         23 . The catheter of  claim 20 , further comprising positioning the distal section of the inner tubular member in a balloon having a working length, a distal neck, and a distal leg, with the distal end of the inner tubular member extending distally beyond a distal end of the distal leg;
 and coupling the distal leg of the balloon to at least a portion of the distal section of the inner tubular member.