Positionable valvuloplasty catheter

1. A method of operating a balloon catheter comprising:

A. advancing a balloon catheter to a valve, said balloon catheter having a balloon disposed at a distal end of an elongated shaft, said balloon having a distal bulb, a proximal bulb, and a waist located between said distal bulb and said proximal bulb, said balloon extending through an annulus of the valve from a first side to an opposite second side of the annulus,

B. said distal bulb being formed from a noncompliant material, said proximal bulb being formed from a material more compliant than said noncompliant material of said distal bulb,

C. inflating said balloon to a first pressure ranging from zero to 0.5 atmospheres to inflate said distal bulb to a fully inflated distal bulb diameter, said proximal bulb having a maximum diameter smaller than said fully inflated distal bulb diameter at the first pressure,

D. positioning said balloon with the waist being positioned in the annulus of the valve and the distal bulb being adjacent to the annulus of the valve at the second side,

E. further inflating said balloon to a second pressure that is larger than said first pressure thereby expanding said proximal bulb to a fully inflated proximal bulb diameter, said proximal bulb expanding against leaflets of the valve,

F. said fully inflated proximal bulb diameter and said fully inflated distal bulb diameter being larger than a waist diameter.

2. The method of operating a balloon catheter of claim 1 , wherein said waist is formed from an noncompliant material, said waist achieving a fully expanded waist diameter at said first pressure.

3. The method of operating a balloon catheter of claim 1 , wherein said waist is formed from a material more compliant than said noncompliant material of said distal bulb, said waist achieving a fully expanded waist diameter at said second pressure.

4. The method of claim 1 , wherein a wall structure for said waist contains a braided fibers such that an axial length for said waist becomes smaller as said pressure is increased from said first pressure to said second pressure.

5. A method of operating a balloon catheter comprising:

A. advancing a balloon catheter to a valve, said balloon catheter having a balloon disposed at a distal end of an elongated shaft, said balloon having a distal bulb, a proximal bulb, and a waist located between said distal bulb and said proximal bulb, said balloon extending through an annulus of the valve from a first side to an opposite second side of the annulus,

B. said distal bulb being formed from a noncompliant material, said proximal bulb being formed from a material that is more compliant than said noncompliant material of said distal bulb,

C. inflating said distal bulb to a first pressure of zero atmospheres; said distal bulb forming a fully inflated distal bulb diameter, said distal bulb having a larger distal bulb diameter than a first maximum diameter of said proximal bulb at said first pressure;

D. positioning said balloon with the waist being positioned in the annulus of the valve and said distal bulb being in contact with the annulus of said valve at the second side,

E. inflating said proximal bulb to a second pressure that is higher than said first pressure, said proximal bulb forming a second maximum diameter that is larger than said first maximum diameter,

F. inflating said waist to said second pressure, said waist having a fully inflated waist diameter that is smaller than said fully inflated distal bulb diameter and smaller than said second maximum diameter of said proximal bulb.

6. The method of operating a balloon catheter of claim 5 , wherein said waist is formed from an noncompliant material, said waist achieving said fully expanded waist diameter at said first pressure.

7. The method of operating a balloon catheter of claim 5 , wherein said waist is formed from a material more compliant than said noncompliant material of said distal bulb, said waist achieving said fully expanded waist diameter at said second pressure.

8. A method of operating a balloon catheter comprising:

A. advancing a balloon catheter to a valve, said balloon catheter having a balloon disposed at a distal end of an elongated shaft, said balloon having a distal bulb, a proximal bulb, and a waist located between said distal bulb and said proximal bulb, said balloon extending through an annulus of the valve from a first side to an opposite second side of the annulus,

B. said distal bulb being formed from a noncompliant material,

C. inflating said distal bulb to a first pressure of zero atmospheres; said distal bulb forming a fully inflated distal bulb diameter, said distal bulb having a larger distal bulb diameter than a first maximum diameter of said proximal bulb at said first pressure;

D. positioning said balloon in such a position that said waist is located in the annulus of the valve and said distal bulb contacts the annulus of said valve at the second side,

E. inflating said proximal bulb to a second pressure that is higher than said first pressure to contact and dilate leaflets of the valve,

F. inflating said waist to said second pressure, said waist having a fully inflated waist diameter that is smaller than said fully inflated distal bulb diameter.

9. The method of operating a balloon catheter of claim 8 , wherein said waist is formed from an noncompliant material, said waist achieving said fully expanded waist diameter at said first pressure.

10. The method of operating a balloon catheter of claim 8 , wherein said waist is formed from a material more compliant than said noncompliant material of said distal bulb, said waist achieving said fully expanded waist diameter at said second pressure.