(12) United States Patent ao) Patent No.: Us 7,357,797 B2
Ryba (45) Date of Patent: Apr. 15,2008
(51) Int. CI.
A61B 18/18 (2006.01)
(52) U.S. CI 606/21; 606/23
(58) Field of Classification Search 606/20 26
See application file for complete search history.
A cryoablation device having a temperature control system includes an elongated catheter tube that has a central lumen and is formed with a closed distal tip. The distal end of a refrigerant supply line is positioned in the central lumen and distanced from the catheter tube's distal tip to establish an expansion chamber therebetween. A return line, which can be established between the supply line and the catheter tube, is provided to exhaust expanded refrigerant from the chamber. The temperature control system includes a valve that is positioned at a predetermined location along the return line. The valve is adjustable to vary a pressure within the return line to control the operational temperature at the distal tip of the catheter tube. Specifically, the valve can be used to reduce the pressure in the return line to thereby increase the tip temperature, and vice versa.
20 Claims, 2 Drawing Sheets