Cryogenic medical device with high pressure resistance tip

Abstract

The present invention provides a medical device to cold treat desired regions. An injection tube with an open distal end is disposed inside of a catheter tube, defining a return lumen therein. A supply of cryogenic fluid, regulated by a controller mechanism coupled to the device, flows through the injection tube and into the distal tip portion of the catheter tube, whereupon the fluid is returned from the catheter through the return lumen. The expansion and evaporation of cryogenic fluid inside the device serves to cool the surrounding areas external to and proximate the distal end of the device. An additional restriction tube is provided in the length of the catheter tube to regulate the pressure of the flow of cryogen therethrough so as to create higher operating pressures in the distal end of the device and thereby enhance the cooling power and temperature stability of the device at a lower range of fluid flow rates without reaching the triple point of the cryogenic fluid.