Catheter having improved curve retention and method of manufacture

Abstract

The present invention provides a polymeric treatment for curved regions in shaft assemblies that increases curve retention without affecting the flexibility within these regions. More specifically, the present invention modifies the underlying crystalline morphology of a polymer in order to decrease crystal fracturing. In particular, the present invention treats polymeric materials suitable for catheter construction with a nucleating agent.

What is claimed is:  
     
         1 . A catheter shaft comprising: 
 a polymeric tubular member having a lumen extending the length therein, wherein the tubular member includes a pre-formed bend along a portion of the length of the tubular member, wherein the polymeric material forming at least a portion of the pre-formed bend includes a sufficient quantity of a nucleating agent dispersed therein.    
     
     
         2 . The catheter shaft of  claim 1 , wherein the polymeric material is selected from the group consisting of polyamide, polyethylene terephthalate, polyetheretherketone, polyimide, polyetherimide and polyether block amide and mixtures thereof.  
     
     
         3 . The catheter shaft of  claim 1 , wherein the nucleating agent is selected from the group consisting of talc, silica, kaolin, molybdenum disulfide, iron sulfide, titanium dioxide, sodium phenylphosphanate and mixtures thereof.  
     
     
         4 . The catheter shaft of  claim 1 , wherein the nucleating agent is selected from the group consisting of sodium p-tert-butylbenzoate, monton wax, montanic ester salts, salts of monocarboxylic acids and polycarboxylic acids and mixtures thereof.  
     
     
         5 . The catheter shaft of  claim 1 , wherein the nucleating agent is selected from the group consisting of an ethylene and an acrylic ester copolymer, a fumeric acid polymer, ethylene, propylene, 1,4-hexadiene, norbornadiene and mixtures thereof.  
     
     
         6 . The catheter shaft of  claim 1 , wherein the nucleating agent is present in a concentration of about 0.01% to 1.0% by weight.  
     
     
         7 . The catheter shaft of  claim 1 , wherein the catheter shaft is a portion of a guide catheter.  
     
     
         8 . The catheter shaft of  claim 1 , wherein the catheter shaft is a portion of a vascular catheter.  
     
     
         9 . The catheter shaft of  claim 1 , wherein the catheter shaft is a portion of a biliary catheter.  
     
     
         10 . A catheter shaft comprising: 
 a tubular member having a lumen extending the length therein, wherein the tubular member further comprises at least two segments having differing rigidities, wherein at least one of the segments of the tubular member has a pre-formed bend extending over at least a portion of the length thereof which includes a polymer in a portion of said pre-formed bend having a sufficient quantity of a nucleating agent dispersed therein.    
     
     
         11 . The catheter shaft of  claim 10 , wherein the polymeric material is selected from the group consisting of polyamide, polyethylene terephthalate, polyetheretherketone, polyimide, polyetherimide and polyether block amide and mixtures thereof.  
     
     
         12 . The catheter shaft of  claim 10 , wherein the nucleating agent is selected from the group consisting of talc, silica, kaolin, molybdenum disulfide, iron sulfide, titanium dioxide, sodium phenyl phosphanate and mixtures thereof.  
     
     
         13 . The catheter shaft of  claim 10 , wherein the nucleating agent is selected form the group consisting of sodium p-tert-butyl benzoate, monton wax, montanic ester salts, salts of monocarboxylic acids and polycarboxylic acids and mixtures thereof.  
     
     
         14 . The catheter shaft of  claim 10 , wherein the nucleating agent is selected from the group consisting of an ethylene and an acrylic ester copolymer, a fumeric acid polymer, ethylene, propylene, 1,4-hexadiene, norbornadiene and mixtures thereof.  
     
     
         15 . The catheter shaft of  claim 10 , wherein the nucleating agent is present in a concentration of about 0.01% to about 1.0% by weight.  
     
     
         16 . The catheter shaft of  claim 10 , wherein the catheter shaft is a portion of a guide catheter.  
     
     
         17 . The catheter shaft of  claim 10 , wherein the catheter shaft is a portion of a vascular catheter.  
     
     
         18 . The catheter shaft of  claim 10 , wherein the catheter shaft is a portion of a biliary catheter.  
     
     
         19 . A process for improving curve retention in catheters having a pre-formed curve, the process comprising: 
 providing a polymeric material;    providing a nucleating agent;    admixing the nucleating agent with the polymeric material; and    extruding the admixed polymeric material and forming a catheter shaft having a pre-formed curve along a portion of the catheter shaft's length.    
     
     
         20 . The process of  claim 19 , wherein the pre-formed curve is formed prior to cooling the extruded polymeric material, followed by cooling the pre-formed curve.  
     
     
         21 . The process of  claim 19 , wherein the pre-formed curve is formed subsequent to cooling the extruded polymeric material in a further step comprising heating a portion of the catheter shaft and forming the pre-formed curve, followed by cooling.