Method of reducing rigidity of angioplasty balloon sections

Abstract

A dilatation balloon is fabricated according to a process that forms cavities and indentations in the balloon and/or catheter sections. A length of tubing is axially elongated and radially expanded in a form to provide the requisite biaxial orientation and strength. Then, an excimer laser or another type of laser or mechanical material removal tool is used to remove the polymeric material, virtually without thermal effects. Cavities in the sleeve sections of the balloon are defined and if desired, indentations in the cone sections are defined. Material removal, particularly near the balloon sleeves enables a thinner, more flexible bonding area between the catheter shaft and the balloon. Further, the indentations along the cone sections enables tighter wrapping of the balloon for a reduced delivery profile. Rigidity near the sleeves is reduced for better maneuverability of the catheter in tortuous passageways.

What is claimed is: 
     
         1 . An expandable balloon configured to be bonded to a catheter shaft, comprising:
 a proximal cone section, a distal cone section, and a medial section disposed therebetween, the distal cone section having a maximum thickness; and   a proximal sleeve section disposed proximal the proximal cone section and a distal sleeve section disposed distal the distal cone section, the proximal and distal sleeve sections each having a wall with an inner surface, an outer surface and a thickness defined therebetween,   wherein the distal sleeve section has a portion of polymeric material removed from the inner surface of the wall to define a reduced thickness less than the maximum thickness of the distal cone section.   
     
     
         2 . The expandable balloon configured to be bonded to a catheter shaft of  claim 1 , wherein the reduced thickness is configured to provide a reduced bonding profile when bonded to the catheter shaft. 
     
     
         3 . The expandable balloon configured to be bonded to a catheter shaft of  claim 1 , wherein the portion of polymeric material is removed by milling the wall of the distal sleeve section. 
     
     
         4 . The expandable balloon configured to be bonded to a catheter shaft of  claim 1 , wherein the portion of polymeric material is removed by at least one technique selected from the group consisting of laser ablation, mechanical grinding, drilling, chemical or mechanical etching and any combination thereof. 
     
     
         5 . The expandable balloon configured to be bonded to a catheter shaft of  claim 1 , wherein the portion of polymeric material is removed by cutting circumferentially about the distal sleeve section. 
     
     
         6 . The expandable balloon configured to be bonded to a catheter shaft of  claim 1 , wherein the portion of polymeric material is removed by cutting spirally about the distal sleeve section. 
     
     
         7 . The expandable balloon configured to be bonded to a catheter shaft of  claim 1 , wherein the portion of polymeric material is removed at a generally constant depth from the inner surface along a length of the distal sleeve section. 
     
     
         8 . The expandable balloon configured to be bonded to a catheter shaft of  claim 1 , wherein the portion of polymeric material is removed at a varied depth from the inner surface along a length of the distal sleeve section. 
     
     
         9 . The expandable balloon configured to be bonded to a catheter shaft of  claim 1 , wherein the distal sleeve section further includes an edge, and wherein the portion of polymeric material is removed from the inner surface along a longitudinal length from the edge. 
     
     
         10 . The expandable balloon configured to be bonded to a catheter shaft of  claim 1 , wherein the distal sleeve section has a length and wherein the portion of polymeric material is removed along the entire length. 
     
     
         11 . The expandable balloon configured to be bonded to a catheter shaft of  claim 1 , wherein at least one of the proximal cone section or the distal cone section has a portion of polymeric material removed to define at least one indentation along a length thereof. 
     
     
         12 . The expandable balloon configured to be bonded to a catheter shaft of  claim 11 , wherein the at least one of the proximal cone section or the distal cone section includes a wall having a cone thickness, the medial section includes a wall having a medial thickness, and the at least one indentation includes a depth extending into the wall of the proximal cone section or the distal cone section defining a second reduced thickness along a section of the wall of the at least one of the proximal cone section or the distal cone section. 
     
     
         13 . The expandable balloon configured to be bonded to a catheter shaft of  claim 12 , wherein the second reduced thickness is substantially equal to the medial thickness of the medial section. 
     
     
         14 . The expandable balloon configured to be bonded to a catheter shaft of  claim 12 , wherein the second reduced thickness is greater than or equal to the medial thickness of the medial section. 
     
     
         15 . The expandable balloon configured to be bonded to a catheter shaft of  claim 11 , wherein the portion of material removed from the at least one of the proximal cone section or the distal cone section is removed by at least one technique selected from the group consisting of laser ablation, mechanical grinding, milling, blasting, drilling, chemical or mechanical etching and any combination thereof. 
     
     
         16 . The expandable balloon configured to be bonded to a catheter shaft of  claim 1 , wherein the portion of polymeric material removed from the inner surface of the wall of the distal sleeve section defines the reduced thickness along an entire length thereof. 
     
     
         17 . The expandable balloon configured to be bonded to a catheter shaft of  claim 7 , wherein the length of the distal sleeve section is an entire length of the distal sleeve section. 
     
     
         18 . The expandable balloon configured to be bonded to a catheter shaft of  claim 1 , wherein the polymeric material comprises at least one of nylon or polyether block amide. 
     
     
         19 . The expandable balloon configured to be bonded to a catheter shaft of  claim 1 , wherein the distal cone section has a first thickness proximate the medial section and the maximum thickness is proximate the distal sleeve section. 
     
     
         20 . An expandable balloon configured to be bonded to a catheter shaft, comprising:
 a proximal cone section, distal cone section, and a medial section disposed therebetween, the distal cone section having a first maximum thickness; and   a proximal sleeve section disposed proximal the proximal cone section and a distal sleeve section disposed distal the distal cone section, the proximal and distal sleeve sections each having a wall with an inner surface, an outer surface and a thickness defined therebetween;   wherein the distal sleeve section has a reduced thickness less than the maximum thickness of the distal cone section,   wherein the reduced thickness is formed by removing a portion of polymeric material from the inner surface of the wall of the distal sleeve section.   
     
     
         21 . The expandable balloon configured to be bonded to a catheter shaft of  claim 20 , wherein the reduced thickness is configured to provide a reduced bonding profile when bonded to the catheter shaft. 
     
     
         22 . The expandable balloon configured to be bonded to a catheter shaft of  claim 20 , wherein removing a portion of polymeric material includes milling the wall of the at least one of the proximal sleeve section or the distal sleeve section. 
     
     
         23 . The expandable balloon configured to be bonded to a catheter shaft of  claim 20 , wherein the polymeric material is removed at a generally constant depth from the inner surface along a length of the distal sleeve section. 
     
     
         24 . The expandable balloon configured to be bonded to a catheter shaft of  claim 23 , wherein the length of the distal sleeve section is an entire length of the distal sleeve section. 
     
     
         25 . The expandable balloon configured to be bonded to a catheter shaft f of  claim 20 , wherein the distal cone section has a first thickness proximate the medial section and the maximum thickness is proximate the distal sleeve section. 
     
     
         26 . A method for forming an expandable balloon configured to be bonded to a catheter shaft, comprising:
 providing a balloon formed from polymeric material, the balloon having
 a proximal cone section, distal cone section, and a medial section disposed therebetween, the distal cone section having a first maximum thickness; 
 a proximal sleeve section disposed proximal the proximal cone section and a distal sleeve section disposed distal the distal cone section, the proximal and distal sleeve sections each having a wall with an inner surface, an outer surface and a thickness defined therebetween; and 
   removing a portion of polymeric material from the inner surface of the wall of the distal sleeve section to define a reduced thickness less than the maximum thickness of the distal cone section.   
     
     
         27 . The method of  claim 26 , wherein removing the polymeric material includes milling the wall of the at least one of the proximal sleeve section or the distal sleeve section. 
     
     
         28 . The method of  claim 26 , wherein the polymeric material is removed at a generally constant depth from the inner surface along a length of the distal sleeve section. 
     
     
         29 . The method of  claim 28 , wherein the length of the distal sleeve section is an entire length of the distal sleeve section. 
     
     
         30 . The method of  claim 26 , wherein the distal cone section has a first thickness proximate the medial section and the maximum thickness is proximate the distal sleeve section.