An endovascular near critical fluid based cryoablation catheter for creating an elongated lengthwise-continuous lesion in tissue comprises an elongated shaft, a flexible distal tissue treatment section, and a distal tip. A plurality of flexible tubes extend through the distal treatment section to transport a near critical fluid to and from the distal tip. The distal treatment section is controllably articulated to match the contour of an anatomical region to be treated. In embodiments the distal treatment section includes a superelastic material and assumes a pre-set shape when released from an outer sleeve member. When the catheter is activated, heat is transferred between a target tissue and the distal treatment section of the catheter thereby creating the elongated lengthwise-continuous lesion in the tissue.
