Catheter tip assembled with a spring

Abstract

A catheter tip that provides longitudinal flexibility, pushability and radial rigidity thereby improving deliverability is provided. The catheter tip includes a spring-like element to provide longitudinal flexibility and pushability to the catheter tip. The spring-like element may also provide radial support to the distal edge of the catheter tip. Alternatively, a radially rigid distal end may also be included distal of the spring-like element. The apparatus may be used with any interventional catheter system, but is particularly suitable for use with balloon-expandable stent systems and balloon-angioplasty systems, where flexibility of the catheter tip and minimal flaring of the distal edge of the catheter tip is desirable.

What is claimed is: 
     
         1 . A flexible and pushable catheter tip having a proximal end and a distal end, comprising:
 a longitudinally flexible tube;   a spring-like element located inside of said longitudinally flexible tube, said spring-like element and said longitudinally flexible tube extending along a common longitudinal axis of the catheter tip; and   a distal end portion located at the distal end of the catheter tip, the distal end portion extending distal of the spring-like element.   
     
     
         2 . A flexible and pushable catheter tip having a proximal end and a distal end, comprising:
 a longitudinally flexible tube; and   a spring-like element located inside of said longitudinally flexible tube, said spring-like element and said longitudinally flexible tube extending along a common longitudinal axis of the catheter tip,   wherein the spring-like element extends to a distal edge of the distal end of the catheter tip.   
     
     
         3 . The catheter tip of  claim 1  or  2 , wherein said longitudinally flexible tube is a flexible polymer material. 
     
     
         4 . The catheter tip of  claim 3 , wherein said spring-like element is embedded in the flexible polymer material. 
     
     
         5 . The catheter tip of  claim 4 , wherein the flexible polymer material is selected from the group consisting of: block co-polymer, polyether block amide (PEBA), and polyurethane. 
     
     
         6 . The catheter tip of  claim 1  or  2 , wherein said spring-like element is non-compressible in a direction along the common longitudinal axis. 
     
     
         7 . The catheter tip of  claim 1  or  2 , wherein said spring-like element is an extension spring. 
     
     
         8 . The catheter tip of  claim 1  or  2 , wherein said spring-like element comprises a region of tightly packed coils. 
     
     
         9 . The catheter tip of  claim 1  or  2 , wherein said spring-like element provides at least one of pushability and radial rigidity to said catheter tip, and wherein a material of the spring-like element is selected from the group consisting of: stainless steel, cobalt chromium, and nitinol. 
     
     
         10 . The catheter tip of  claim 1  or  2 , wherein said spring-like element tapers distally with a decreasing diameter taper. 
     
     
         11 . The catheter tip of  claim 1  or  2 , wherein said spring-like element does not taper, said spring-like element having a single diameter from its proximal to distal end. 
     
     
         12 . The catheter tip of  claim 1 , wherein the distal end portion provides radial rigidity to the catheter tip, and wherein a material of the distal end portion is selected from the group consisting of: polyamide, nylon, PEBA, and a co-polymer material. 
     
     
         13 . The catheter tip of  claim 1  or  2 , further comprising a spacer portion located at a proximal end of said spring-like element, said spacer portion bridging a distance between a distal end of a balloon and the proximal end said spring-like element, wherein said spacer portion is said longitudinally flexible tube. 
     
     
         14 . The catheter tip of  claim 1 , wherein the longitudinally flexible tube extends beyond a distal end of the spring-like element, and wherein the longitudinally flexible tube is contiguous with a proximal end of the distal end portion. 
     
     
         15 . The catheter tip of  claim 1 , wherein the distal end portion tapers distally to a distal edge of the catheter tip with a decreasing diameter taper. 
     
     
         16 . The catheter tip of  claim 1 , wherein the spring-like element is positioned about 0.5 mm proximal of a distal edge of the catheter tip. 
     
     
         17 . The catheter tip of  claim 1 , wherein the distal end portion is contiguous with said longitudinally flexible tube. 
     
     
         18 . The catheter tip of  claim 1 , wherein the distal end portion is contiguous with said spring-like element. 
     
     
         19 . The catheter tip of  claim 2 , wherein a distal end portion at the distal end of the catheter tip is a distal end of said spring-like element, wherein said spring-like element provides radial rigidity to the distal end portion of the catheter tip. 
     
     
         20 . The catheter tip of  claim 1  or  2 , wherein the spring-like element is an accordion plastic tube. 
     
     
         21 . The catheter tip of  claim 1  or  2 , wherein the spring-like element includes a radiopaque material. 
     
     
         22 . The catheter tip of  claim 1  or  2 , wherein the spring-like element is configured to allow flexibility of the catheter tip to bend along the common longitudinal axis. 
     
     
         23 . The catheter tip of  claim 1  or  2 , wherein the distal end of the catheter tip is open. 
     
     
         24 . A catheter, comprising: a proximal end; a distal end; a balloon having a proximal shoulder and a distal shoulder; and the catheter tip of  claim 1  or  2 ; wherein said balloon is mounted on said catheter proximal of said catheter tip. 
     
     
         25 . The catheter of  claim 24 , wherein said catheter tip includes a spacer portion between a proximal edge of said spring-like element and said distal shoulder of said balloon.