An angiographic study of ischemia as a determinant of neovascularization in arteriovenous reversal

The results of recent studies by ourselves and others have demonstrated the feasibility of revascularizing severely ischemic limbs by means of staged arteriovenous reversal at the popliteal level. The results of investigations we did, both clinically and in an animal model, revealed the development of an intense vascular network in the region of the arteriovenous anastomosis as an important component of the revascularization process. To determine the role of ischemia in this process, four groups consisting of three dogs each underwent a popliteal artery to vein anastomosis. In group I, there was no ischemia; group II, distal ischemia only; group III, partial ischemia, and group IV, total ischemia. Angiography at four weeks in all dogs demonstrated that the intense neovascular network seen in previous studies developed only in the limbs of the dogs in group IV. We conclude that the neovascular process seen after creation of arteriovenous reversal develops as a response to severe ischemia. Further studies are needed to better characterize the nature of these vessels, and it is our hope that, in doing so, means of enhancing development of these vessels in order to indirectly revascularize otherwise unsalvagable extremities will be realized.