Apparatus and methods for cryogenically ablating tissue and adjusting cryogenic ablation regions

A cryogenic ablation apparatus, comprising:

• a support member;
• a cryogenic ablation element including a first balloon extending from the support member and having a first shape, and a second balloon extending from the support member and having a second shape different than the first shape, the second balloon wrapping around at least a portion of the first balloon;
• and
• an adjustment element including a first tube having and a proximal end and a distal end positioned within and opening into an interior of the second balloon to supply a refrigerant to the second balloon, the adjustment element including a second tube having a proximal end and a distal end being positioned within and opening into an interior of the second balloon to exhaust spent refrigerant therefrom, a cryogenic ablation region being defined between the respective distal end openings of the first and second tubes, the ablation region being adjustable by movement of at least one of the first and second tubes within the second balloon.