Methods and apparatus for cryo-therapy

Abstract

Methods and apparatus for cryo-therapy are disclosed herein. This includes a hollow guidewire disposed within a catheter having helical loops contacting tissue. A coolant delivery tube disposed within can have a coolant delivered from a proximal end into the guidewire lumen. The coolant flows back proximally through the guidewire while cooling the guidewire surface and cooling or cryogenically ablating the contacting tissue. To minimize guidewire exposure to surrounding fluids or tissue, insulative barriers can be attached to the guidewire. A coolant delivery tube and return lumen can be integrated from a single extrusion in various configurations. Expandable balloons can also be used to expand the loops of the guidewire to contact the tissue. Also, helical loops with a coolant delivery tube or stem disposed longitudinally within the loops can be used and the loops can also have a variable collapsible cooling region.

1 . An apparatus for thermally treating a hollow body organ comprising:
 a catheter having a proximal end and a distal end and defining at least one lumen therebetween;   a guidewire defining at least one passageway therein, wherein the guidewire is configured to have a first configuration when disposed within the lumen and a second radially extended configuration when withdrawn from the lumen; and   a delivery tube disposable within the guidewire passageway for transporting a fluid, wherein the delivery tube defines at least one exit port near a distal end of the delivery tube through which the fluid passes.