The Ptmc balloon catheter design exhibits five uniquely different inflation stages. These stages are described below:

Stage 1:

Balloon completely deflated

Allows catheter advancement and passage through the atrial septum.

Stage 2:

Distal portion partially inflated

When a small volume of dilute contrast medium is injected, the distal portion of the balloon inflates first. The balloon may float across the mitral valve, like a thermodilution catheter

Stage 3:
Distal portion completely inflated

When a larger volume of dilute contrast is injected, the distal portion inflates completely. This aids in seating the balloon on the valve.

Stage 4:
Hourglass shape

A latex band placed at the center of the balloon constricts inflation. Consequently, when additional dilute contrast medium is injected, the balloon shape resembles an hourglass. This unique shape centers the balloon on the valve and prevents

Stage 5:
Full Inflation

Further injection will inflate the balloon to its full extent. The force of this expansion is used to achieve valvuloplasty.