Patent attributes
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.
