Catheter balloon liner with variable thickness and method for making same

Abstract

A method of making a catheter balloon, and a balloon catheter formed thereby, in which a layer of a catheter balloon is formed by providing a tubular member to serve as a non porous liner for cooperation with a polymeric tube, and enlarging radially a central or working section of the tubular member such that a first end of the tubular member is smaller in the radial direction with respect to the working section. The tubular member may also have a thickness at the working section that is less than a thickness of the first and second end portions. The first end section of the tubular member is bonded to a catheter shaft having a first outer diameter to form at least a portion of a skirt section of the balloon, and the second end section is bonded to the catheter shaft having a second outer diameter to form a portion of a skirt section, where the skirt sections have an improved high rupture pressure.

1 .- 10 . (canceled)  
     
     
         11 . A method for forming a balloon liner of a balloon catheter comprising the steps of: 
 a) providing an tubular liner of substantially constant thickness and substantially constant inner diameter along a longitudinal direction, the tubular liner having a proximal section, a middle section, and a distal section, and;    b) expanding the inner diameter of the tubular liner along the proximal and middle sections while maintaining an original inner diameter of the tubular liner at the distal section.    
     
     
         12 . The method for forming a balloon liner of  claim 11  further comprising reducing a thickness of the tubular liner at the middle section while preserving the original thickness of the tubular liner at the distal section.  
     
     
         13 . The method for forming a balloon liner of  claim 12  further comprising maintaining the thickness of the tubular liner at the proximal section.  
     
     
         14 . The method for forming a balloon liner of  claim 11  where the step of expanding the inner diameter of the tubular liner further comprises placing the tubular liner of constant thickness and constant inner diameter on a mandrel having a first section comprising a constant outer diameter and a second section comprising a radially expanding tapered section, and heating the tubular liner to stabilize a shape of the liner to conform with the shape of the mandrel.  
     
     
         15 . The method for forming a balloon liner of  claim 14  further comprising reducing the thickness of the tubular liner along a section of the liner coinciding with a portion of the radially expanding tapered section of the mandrel.  
     
     
         16 . The method for forming a balloon liner of  claim 15  wherein the step of reducing the thickness of the liner comprises an application of selective heating of the tubular liner while located on the mandrel.  
     
     
         17 . The method for forming a balloon liner of  claim 15  wherein the step of reducing the thickness of the liner comprises positioning a hypotube within the mandrel and expelling a gas during the formation of the liner at the section of the liner to be thinned to reduce the thickness of the liner at the section.  
     
     
         18 . The method for forming a balloon liner of  claim 11  wherein the mandrel is selected to have a first outer diameter at a first end coinciding with an outer diameter of a catheter shaft at a first end, and wherein the mandrel is further selected to have a second outer diameter at a second end coinciding with an outer diameter of a catheter shaft at a second end, where the outer diameter of the catheter shaft at the first end is greater than the outer diameter of the catheter shaft at the second end.  
     
     
         19 . A method of forming a balloon catheter having an elongated catheter shaft with an inflation lumen, and a tubular, essentially wingless balloon with a polymeric outer layer and a polymeric inner layer and an interior in fluid communication with the inflation lumen such that the balloon inflates from a noninflated configuration to an inflated configuration, comprising: 
 a) positioning over the catheter shaft a polymeric tubular member forming the inner layer of the balloon, the inner layer tubular member having a wall thickness along a distal end section which is thicker than along at least a middle section and having an inner diameter along the distal end section which is smaller than along a middle section and along a proximal end section, and positioning a polymeric tubular member forming the outer layer of the balloon on the inner layer tubular member, the outer layer tubular member having a proximal end section on the inner layer tubular member proximal end section and a distal end section on the inner layer tubular member distal end section, and a wall thickness which does not vary from the proximal end section to a middle section of the outer tubular member, such that the inner layer tubular member wall thickness varies along a nonvarying wall thickness portion of the outer layer tubular member; and    b) bonding at least a portion of the proximal and distal end sections of the inner layer tubular member to the underlying section of the shaft and to the overlying proximal and distal end sections of the outer layer tubular member, to thereby form the balloon bonded to the catheter shaft, such that the bonded balloon has a proximal skirt section and a distal skirt section sealingly secured to the shaft, and an inflatable section extending between the proximal and distal skirt sections.    
     
     
         20 . The method of  claim 19  wherein the wall thickness of the inner layer tubular member along the distal end section is thicker than along the proximal end section thereof in b), and including bonding the inner layer to the outer layer along the inflatable section of the balloon.