Extravascular Recanalization of Chronic Total Occlusions
Subintimal revascularization is a mainstay of therapy for lower extremity interventions. This stems from the realization that true lumen traversal is not always possible, subintimal revascularization has a high technical success rate, and the subintimal space may confer advantages over a heavily calcified true lumen. Most commonly in the tibial vasculature, there are times when subintimal recanalization is not possible because the wire and catheter may leave the subintimal plane and enter the periadventitial tissue. Although this is not intentional, exit from the vessel historically results in a technical failure because future passes of the wire and catheter are likely to follow suit, as evidenced by extravasation on contrast injection. This chapter describes two techniques to salvage this scenario and accept an extravascular tract for revascularization: the Outback® extravascular revascularization technique and the percutaneous gun-sight extravascular revascularization technique.