Patent ID: 8715274

Claim:
A method of operating a cryotherapy balloon catheter, the method comprising: providing a cryotherapy balloon catheter with a controller; regulating with the controller, during a first phase, a pressure source to inflate a first distal balloon portion of the cryotherapy balloon catheter, independently of a release of cryogenic fluid into the first distal balloon portion, to develop a first pressure inside the first distal balloon portion; starting a flow of cryogenic fluid to the first distal balloon portion and a corresponding flow of exhaust from the first distal balloon portion; and regulating with the controller, during a second phase, flow of cryogenic fluid to and exhaust from the first distal balloon portion to a) cause a temperature inside the first distal balloon portion to reach a value sufficient to deliver therapeutic levels of cryotherapy, and b) maintain a second-phase pressure that is within a threshold value of the initial pressure.