High compliance, high strength catheter balloons useful for treatment of gastrointestinal lesions

A method of forming a balloon for a medical device comprising:

• radially expanding tubing of thermoplastic polymer material under elevated blowing pressure greater than 50 psi at an elevated blowing temperature to form the balloon to have a first diameter at 3 atm inflation pressure,
• annealing the formed balloon prior to sterilization of the medical device at an elevated annealing temperature less than or equal to the blowing temperature, and at an annealing pressure which in the range of 0–20 psi, for a time sufficient to shrink the formed balloon to have a second diameter at 3 atm inflation pressure which is less than 90% of the first diameter, and then
• pressurizing the balloon in a fixed diameter form, said fixed diameter being greater than said second diameter but no more than 90% of said first diameter, at a pressure above the annealing pressure but no more than 50 psi and a temperature not less than said annealing temperature and not greater than said blowing temperature for a time to provide the balloon with a final diameter at 3 atm inflation pressure which is greater than said second diameter but not more than 90% of said first diameter.