Optimal conduit choice for open lower extremity bypass in critical limb threatening ischemia

Outline: Open bypass surgery remains a major tool for limb salvage in chronic limb threatening ischemia (CLTI). While rest pain and tissue loss both fall into the category of CLTI, goals of revascularization are markedly different for each context. Rest pain mandates long term patency considerations. Tissue loss, on the other hand, requires consideration of infection risks and patency enough to heal the wound. Of the major conduit options, autologous saphenous vein (SVG) continues to be the conduit of choice given both superior patency and low risk of infection. When SVG is not available or not available in appropriate length, arm vein, small saphenous vein, and spliced combinations of these have acceptable patency rates. Heparin bonded PTFE and Dacron grafts are prosthetic conduits with excellent patency rates when vein is not available. For infected wounds without other options, cryovein continues to provide acceptable patency for limb salvage. Creation of a bypass is only part of CLTI management. Appropriate post-operative surveillance with noninvasive studies including ankle-brachial index (ABI) and duplex ultrasound can alert to impending graft failure, with a drop in ABI of .15 and velocity ratios of 3 or more suggestive of significant stenoses. Anticoagulation has only been shown in limited contexts (such as poor conduit, poor outflow) to offer some patency benefit, however findings from the VOYAGER trial was a major breakthrough, showing reduction in composite outcome of major adverse limb, cardiac, and cerebrovascular events in revascularized patients taking low dose rivaroxaban in conjunction with aspirin, without significant increase in bleeding risk.