Stent deploying catheter system and balloon catheter

Abstract

An intravascular catheter system for properly implanting a stent in a body lumen generally comprising a catheter having an elongated shaft with an inflatable balloon formed of compliant material and a stent mounted on the working length of the balloon. The balloon material is compliant within the working range of the balloon to provide substantial radial expansion. The wingless radially expansive balloon expands in a uniform manner, thereby producing uniform expansion and implantation of the stent. Another embodiment is directed to a balloon catheter having a semi-compliant balloon formed at least in part of a block copolymer.

What is claimed:  
     
         1 . A catheter system for implanting a stent in a patient's body comprising: 
 a) a catheter having an elongated shaft with proximal and distal ends and an inflation lumen extending within at least a portion of a distal shaft section to a location spaced proximally from the distal end;    b) an essentially wingless radially expansive uninflated balloon formed of compliant polymeric material, mounted on the distal section of the catheter shaft, with an interior chamber in fluid communication with the inflation lumen; and    c) an expandable stent disposed about and mounted onto the uninflated balloon so that radial expansion of the balloon within the working range expands the stent mounted thereon and implants the stent in the body.    
     
     
         2 . The intravascular catheter system of  claim 1  wherein the compliant material has an elongation at failure at room temperature of at least about 300%.  
     
     
         3 . The intravascular catheter system of  claim 1  wherein the compliant material has an elongation at failure at room temperature of at least about 500%.  
     
     
         4 . The intravascular catheter system of  claim 1  wherein the compliant material has a Shore durometer hardness of about 50A to about 75D.  
     
     
         5 . The intravascular catheter system of  claim 1  wherein the compliant material has a Shore durometer hardness of about 60A to about 65D.  
     
     
         6 . The catheter system of  claim 1  wherein the balloon is formed of elastomeric material.  
     
     
         7 . The intravascular catheter system of  claim 6  wherein the balloon is formed of an elastomeric material selected from the group consisting of latex, silicone, polyurethane, polyolefin elastomer, flexible polyvinyl chloride, ethylene vinyl acetate, ethylene methylacrylate, ethylene ethylacrylate, styrene butadiene styrene, and ethylene propylene diene rubber.  
     
     
         8 . The intravascular catheter system of  claim 1  wherein the balloon is formed of a thermoplastic aromatic polyether polyurethane.  
     
     
         9 . The intravascular catheter system of  claim 8  wherein the balloon has a hoop strength of about 10,000 psi to about 20,000 psi.  
     
     
         10 . A method of implanting a stent within a patient's body, comprising: 
 a) providing a catheter system for implanting a stent in a patient's body, comprising: 
 i) a catheter having an elongated shaft with proximal and distal ends and an inflation lumen extending within at least a distal shaft section to a location spaced proximally from the distal end;  
 ii) an essentially wingless radially expansive uninflated balloon formed of compliant polymeric material, mounted on the distal section of the catheter shaft, with an interior chamber in fluid communication with the inflation lumen; and  
 iii) an expandable stent disposed about and mounted onto the uninflated balloon so that radial expansion of the balloon within the working range expands the stent mounted thereon and implants the stent in the body;  
   b) inserting the catheter system into the patient's body;    c) inflating the balloon to produce uniform radial expansion of the balloon and the stent mounted thereon; and    d) radially retracting the balloon to a wingless shape and removing the catheter from the patient's body, with the stent remaining within the patient's body.    
     
     
         11 . The method of  claim 10  further including the step of advancing the catheter system to a desired region within a lumen of the patient's body.  
     
     
         12 . The method of  claim 10  further including the step of radially expanding the balloon by delivering inflation fluid through the inflation lumen to the balloon interior chamber.  
     
     
         13 . The method the  claim 10  wherein the compliant polymeric material is a thermoplastic aromatic polyether polyurethane, and during step (d), the balloon elastically recoils to a preinflation radial and axial size.  
     
     
         14 . A balloon catheter, comprising 
 a) an elongated shaft having a proximal end, a distal end, and at least one lumen therein; and    b) a semi-compliant balloon formed at least in part of a polyurethane block copolymer.    
     
     
         15 . The balloon catheter of  claim 14  wherein the balloon has a compliance of less than about 0.045 mm/atm within an inflation pressure range of about 6 atm to about 19 atm.  
     
     
         16 . The balloon catheter of  claim 14  wherein the balloon has a compliance of about 0.025 mm/atm to about 0.04 mm/atm within an inflation pressure range of about 6 atm to about 19 atm.  
     
     
         17 . The balloon catheter of  claim 14  wherein the balloon has a compliance of about 0.025 mm/atm to about 0.03 mm/atm within an inflation pressure range of about 10 atm to about 19 atm.  
     
     
         18 . The balloon catheter of  claim 14  wherein the balloon has a percent radial expansion of less than about 4% at an inflation pressure of about 150 psi.  
     
     
         19 . The balloon catheter of  claim 14  wherein the balloon has a percent radial expansion of about 1.5% to about 4% at an inflation pressure of about 150 psi.  
     
     
         20 . The balloon catheter of  claim 14  wherein the balloon is axially noncompliant.  
     
     
         21 . The balloon catheter of  claim 14  wherein the polyurethane block copolymer has a flexural modulus of about 150,000 psi to about 300,000 psi.  
     
     
         22 . The balloon catheter of  claim 14  wherein the polyurethane block copolymer has a hardness of about 55 Shore D to about 75 Shore D.  
     
     
         23 . A balloon catheter, comprising 
 a) an elongated shaft having a proximal end, a distal end, and at least one lumen therein; and    b) an axially noncompliant balloon formed at least in part of a block copolymer.    
     
     
         24 . The balloon catheter of  claim 23  wherein the balloon has an axial compliance of about 0.1 mm/atm to about 0.25 mm/atm within an inflation pressure range of about 6 atm to about 14 atm.  
     
     
         25 . The balloon catheter of  claim 23  wherein the balloon has a length which increases by less than about 5% to about 15% within an inflation pressure range of about 6 atm to about 14 atm.  
     
     
         26 . The balloon catheter of  claim 23  wherein the block copolymer comprises a polyurethane block copolymer.  
     
     
         27 . A method of making a semi-compliant balloon for a catheter. comprising 
 a) extruding a tubular product having a first outer diameter and a first inner diameter, formed at least in part of a block copolymer;    b) heating the tubular product at a first elevated temperature and radially expanding the tubular product to a second outer diameter    c) heating the expanded tubular product at a second elevated temperature not less than the first elevated temperature; and    d) cooling the expanded tubular product to form the semi-compliant balloon.    
     
     
         28 . The method of  claim 27  wherein the semi-compliant balloon has a percent radial expansion of less than about 4% at an inflation pressure of about 150 psi, and heating the tubular product comprises displacing a heating member along a length of the tubular product at a first rate to apply heat to portions of the tubular product adjacent to the heating member.  
     
     
         29 . The method of  claim 27  wherein heating the expanded tubular product comprises displacing a heating member along a length of the tubular product at a second rate to apply heat to portions of the tubular product adjacent to the heating member.  
     
     
         30 . The method of  claim 29  wherein the first rate is greater than the second rate.  
     
     
         31 . The method of  claim 27  wherein the balloon has a percent radial expansion of about 1.5% to about 4% at an inflation pressure of about 150 psi.  
     
     
         32 . The method of  claim 27  wherein the balloon has a compliance of less than about 0.045 mm/atm within an inflation pressure range of about 6 atm to about 19 atm.  
     
     
         33 . The method of  claim 27  wherein the balloon has a compliance of about 0.025 mm/atm to about 0.03 within an inflation pressure range of about 10 atm to about 19 atm.  
     
     
         34 . The method of  claim 27  wherein the first elevated temperature is about 90 to about 105° C.  
     
     
         35 . The method of  claim 27  wherein the second elevated temperature is about 110 to about 140° C.  
     
     
         36 . The method of  claim 27  wherein the tubular product is radially expanded to the second outer diameter which is about 7 to about 8 times the first inner diameter of the tubular product.  
     
     
         37 . The method of  claim 27  including axially elongating the tubular product.  
     
     
         38 . The method of  claim 27  wherein the tubular product is expanded by subjecting the tubular product to an expansion pressure, and the expanded tubular product is heated at the second elevated temperature at the expansion pressure.  
     
     
         39 . The method of  claim 38  wherein the expanded tubular product is cooled at the expansion pressure.  
     
     
         40 . The method of  claim 27  wherein the block copolymer comprises a polyurethane block copolymer.  
     
     
         41 . The method of  claim 27  wherein the semi-compliant balloon is axially noncompliant.  
     
     
         42 . A balloon catheter, comprising: 
 a) an elongated shaft having a proximal end, a distal end, and at least one lumen therein; and    b) a noncompliant balloon formed at least in part of a polyurethane block copolymer.