Balloon catheter and method for facilitating increased radial expansion

A medical catheter for performing angioplasty with a balloon having increased radial expansion to provide a larger effective inflated profile,

• while exhibiting a relatively small deflated profile adapted for percutaneous insertion, comprising:
• a balloon catheter adapted to be inserted within the vasculature of a patient, said catheter defining an inflation lumen and a guidewire lumen, said balloon catheter having proximal and distal ends, a substantially inelastic balloon disposed near said distal end, a shaft member extending through said balloon, and an outer shaft surrounding said shaft member, the outer shaft member being sealed to a proximal and distal end of the balloon, said inflation lumen being defined by an annular space between said outer shaft and said shaft member, and communicating with an interior of the balloon to conduct a pressurized fluid from outside the patient into the interior of the balloon, thereby to inflate the balloon from a deflated profile to an inflated profile;
• wherein the balloon is adapted to expand to a first inflated shape when the balloon is an initial length, and to impart a compressive force on the outer shaft member at the proximal and distal ends of the balloon sealed to the outer shaft member as the pressurized fluid inflates the balloon;
• and
• wherein the outer shaft member is adapted to collapse and shorten upon inflation of the balloon, thereby shortening the balloon and allowing a portion of said balloon to expand wider than said first inflated shape.

A balloon catheter for use by a health care professional in performing a medical procedure, comprising:

• a tubular shaft having proximal and distal ends, and an outer shaft surrounding said tubular shaft, an inflation lumen being defined by an annular space between said outer shaft and said shaft member;
• a substantially inelastic balloon having an initial length and being disposed near said tubular shaft distal end;
• wherein said inflation lumen is in fluid communication with the interior of said balloon and is adapted to conduct a pressurized fluid from said tubular shaft proximal end into an interior of said balloon to inflate said balloon;
• and
• wherein said balloon is adapted to expand to a first inflated profile while said balloon is said initial length, and is adapted to longitudinally shorten upon inflation, thereby allowing a portion of said balloon to radially expand wider said first inflated profile.

A method of performing an interventional medical therapy procedure in the body of a patient, comprising the steps of:

• a) providing a balloon catheter having a proximal hub coupled with a shaft member and an outer tubular shaft surrounding said shaft member, and a substantially inelastic balloon disposed near a distal end of the tubular shaft, said balloon catheter having an inflation lumen communicating with the balloon being defined by an annular space between said outer tubular shaft and said shaft member;
• b) inserting the balloon catheter within the body of said patient;
• c) conducting a pressurized fluid from said proximal hub through said inflation lumen into the interior of the balloon;
• d) inflating the balloon from a deflated profile to a first inflated profile;
• e) causing said balloon to shorten and further expand to a second inflated profile that is wider than said first inflated profile.