Catheter distal tip design and method of making

Abstract

A catheter comprises a catheter shaft having a distal tip, the distal tip having an inner surface and an outer surface, the inner surface having a rounded profile. The catheter may be made by rounding the inner surface of the distal tip.

1 . A catheter comprising: 
 a catheter shaft and a distal tip, the distal tip having a proximal end and a distal end, the distal tip having an inner surface and an outer surface, and in a longitudinal cross-sectional profile view of the distal tip, the inner surface curves towards the outer surface at the distal end and is substantially straight proximal the distal end, and the outer surface curves toward the inner surface or the outer surface remains substantially unchanged at the distal end and is substantially straight proximal the distal end.    
     
     
         2 . (canceled)  
     
     
         3 . The catheter of  claim 1 , the inner surface having a first circumference at the distal tip and a second circumference proximal the distal tip, wherein the first circumference at the distal tip is at least 10% larger than the second circumference proximal the distal tip.  
     
     
         4 . The catheter of  claim 1  wherein the distal tip is formed from at least one member selected from the group consisting of polyolefins, polyamides, polyurethanes, polyimides, polyesters, silicones, rubbery block copolymers, latex, copolymers thereof and mixtures thereof.  
     
     
         5 . The catheter of  claim 1  wherein the distal tip is formed from a block copolymer.  
     
     
         6 . The catheter of  claim 1  wherein said distal tip is formed of a polymeric material which is softer than said polymeric material from which said catheter shaft is formed as measured by a Shore Durometer scale.  
     
     
         7 . The catheter of  claim 1  wherein said distal tip is formed from a polymeric material which has a hardness which is equal to or greater than the polymeric material from which the catheter shaft is formed as measured by a Shore Durometer scale.  
     
     
         8 . The catheter of  claim 1  wherein the curvature of the outer surface substantially mirrors the curvature of the inner surface.  
     
     
         9 . A method of manufacturing a catheter shaft having a distal tip, the distal tip having an inner surface and an outer surface, the method comprising the steps of: 
 providing said catheter shaft and said distal tip; and    rounding the inner surface of the distal tip such that the circumference of the inner surface increases in a longitudinal direction toward the distal tip.    
     
     
         10 . The method of  claim 9  further comprising the step of rounding the outer surface of the distal tip.  
     
     
         11 . The method of  claim 9  wherein the rounding step comprises laser ablation of material from the surface.  
     
     
         12 . The method of  claim 11  wherein said laser is an ultraviolet laser.  
     
     
         13 . The method of  claim 11  wherein said laser produces UV radiation having a wavelength of about 450 nm or less.  
     
     
         14 . The method of  claim 11  wherein said laser produces UV radiation having a wavelength of about 351 nm or less.  
     
     
         15 . The method of  claim 9  wherein the distal tip is integral with said catheter shaft.  
     
     
         16 . The method of  claim 9  wherein the distal tip is formed separately from said catheter shaft and the method further comprises the steps of disposing the distal tip on the catheter shaft.  
     
     
         17 . The catheter of  claim 5  wherein said block copolymer has styrene end-blocks and diene mid-blocks.