Patent ID: 7357797

Claim:
A cryoablation device having a temperature control system, said device comprising: a refrigerant supply unit; an elongated catheter tube having a central lumen and formed with a closed distal tip; a supply line having a proximal end connected to said refrigerant supply unit and a distal end disposed in the central lumen of said catheter tube and distanced from the distal tip thereof; a flow restrictor positioned at the distal end of said supply line to bound an expansion chamber between said flow restrictor and the closed distal tip of said catheter tube, with said flow restrictor delivering a refrigerant from said refrigerant supply unit to the expansion chamber for expansion therein; a return line in fluid communication with the expansion chamber for exhausting refrigerant from the expansion chamber, with said return line having a first end bounding the expansion chamber and a second end, wherein said return line defines an unobstructed path between the first end and the second end; and a valve positioned at the second end of the return line, said valve being adjustable to vary a pressure in the return line to control a temperature at the distal tip of the catheter tube; wherein said valve is positioned at an extracorporeal location during a cryoablation procedure to establish an unrestricted flow between the flow restrictor and the extracorporeal valve.