Patient selection and improved technical factors in small-vessel bypass procedures of the lower extremity.

Thirty-two small-vessel bypasses were constructed as limb-salvage procedures. The one month patency rate was 72 percent and the one year cumulative patency rate was 55 percent. Preoperative, intraoperative, and postoperative angiography was performed in most cases and the results correlated with the ultimate fate of the graft. Preoperative angiography is critical in determining the location of a suitable small vessel, including the peroneal artery, and the quality of the runoff. Intraoperative angiography is required to delineate correctable intraoperative defects usually appearing at the distal anastomotic area. Additionally, failure to demonstrate runoff or a pedal arch can help support a decision not to re-explore a graft should early closure occur. Postoperative angiography is essential to validate clinical success with graft patency and function. It also serves to discover potential graft defects that might otherwise lead to closure and potential limb loss. Selected cases of failed small-vessel bypass grafts may be salvaged by thrombectomy with or without graft revision. Small-vessel bypass is generally contraindicated if there is extensive tissue necrosis and infection extending into the proximal foot. In cases where the necrotizing infection is localized, particularly to the forefoot, then open drainage, debridement, or amputation should be performed together with small-vessel bypass. Finally, the risks indigenous to small-vessel bypass procedures demand optimal patient selection and exquisite operative technique.