Rapid Exchange Balloon Catheter and Method for Making Same

Abstract

A rapid exchange balloon catheter having a proximal end and a distal end, the catheter including a tubular metal shaft body extending from the proximal end along a majority of the total length and having an inflation lumen arranged therein, a plastics distal end portion bonded to the metal body in extension thereof, the distal end portion being provided with an inflation lumen in communication with a balloon, and a guide wire lumen, the guide wire lumen extending from a proximal side port to a distal end opening. To reduce the resistance to kinking, the metal body includes a transitional region having reduced stiffness at the position of bonding to the plastics distal end portion compared to a more proximal position along the metal body.

1 . A method for manufacturing a rapid exchange balloon catheter comprising the steps of:
 providing a tubular metal shaft body with an inflation lumen arranged therein;   providing a plastics distal end portion, the distal end portion being provided with an inflation lumen in communication with a balloon, and a guide wire lumen, the guide wire lumen extending from a side port to a distal end opening;   subjecting an end of the tubular metal shaft body to a processing step adapted to locally reduce the stiffness of an end region of the tubular metal shaft body to provide a transitional region; and   bonding the plastics distal end portion onto the transitional region.   
     
     
         2 . The method according to  claim 1 , wherein prior to the processing step any one or any combination of the composition, shape and dimension of the tubular metal shaft body is substantially unchanging along its length. 
     
     
         3 . The method according to  claim 1 , wherein the tubular metal shaft body is made of a superelastic alloy, and wherein the processing step involves heat treating the transitional region at temperatures of 300-600° C. for a period of 10 seconds to 24 hours. 
     
     
         4 . The method according to  claim 1 , wherein the processing step comprises heat treating the transitional region at temperatures of about 540-550° C. for about 20 hours. 
     
     
         5 . The method according to  claim 1 , wherein the processing step comprises heat treating the transitional region at temperatures of about 520-600° C. for about 30 minutes to 24 hours. 
     
     
         6 . The method according to  claim 1 , comprising maintaining a region of the tubular metal shaft body other than the transitional region at about room temperature during the processing step. 
     
     
         7 . The method according to  claim 1 , wherein the processing step comprises heat treatment comprising dipping the transitional region into a heated salt bath. 
     
     
         8 . The method according to  claim 1 , wherein the processing step comprises heat treatment comprising electrical resistance heating, laser heating, using a jet of hot inert gas, using an induction coil or combinations thereof. 
     
     
         9 . The method according to  claim 1 , comprising providing the plastics portion having an inner diameter that is larger than an outer diameter of the tubular metal body and sliding the plastics portion onto the tubular metal portion before bonding thereto. 
     
     
         10 . The method according to  claim 1 , wherein bonding the plastics distal end portion onto the transitional region comprises gluing. 
     
     
         11 . The method according to  claim 1 , wherein bonding the plastics distal end portion onto the transitional region comprises thermal bonding. 
     
     
         12 . The method according to  claim 1 , wherein the processing step provides the transitional region having a bending stiffness, wherein a bending stiffness of the metal body at a proximal position is at least twice as high as a bending stiffness of the metal body at the distal end of the transitional region. 
     
     
         13 . The method according to  claim 1 , wherein the processing step provides the transitional region having a bending stiffness, wherein a bending stiffness of the metal body at a proximal position is at least four times as high as a bending stiffness of the metal body at the distal end of the transitional region. 
     
     
         14 . The method according to  claim 1 , wherein the processing step provides the transitional region having a bending stiffness, wherein a bending stiffness of the metal body at a proximal position is at least eight times as high as a bending stiffness of the metal body at the distal end of the transitional region. 
     
     
         15 . The method according to  claim 1 , wherein the processing step provides the transitional region having a bending stiffness, wherein a bending stiffness of the metal body at a proximal position is at least twenty times as high as a bending stiffness of the metal body at the distal end of the transitional region. 
     
     
         16 . The method according to  claim 1 , further comprising providing weakenings in the transitional region. 
     
     
         17 . The method according to  claim 1 , further comprising providing cutouts in the transitional region. 
     
     
         18 . The method according to  claim 1 , further comprising providing a reduced wall thickness in the transitional region.