Limb loss after lower extremity bypass.

BACKGROUND

Infrainguinal bypass now has a limb salvage rate approaching 90% at 10 years. This study helps elucidate the causes of limb loss despite bypass surgery.

METHODS

A retrospective chart review of all patients undergoing a major lower extremity amputation after attempted bypass surgery.

RESULTS

Between July 1987 and January 1997, 67 major amputations (52 below knee, 15 above knee) followed infrainguinal bypass for limb salvage in 64 patients. Of these patients, 53 (83%) were diabetic and 10 (16%) were on dialysis. The etiology of limb loss included thrombosed bypass (n = 33, 49%), lack of limb salvage despite patent bypass (n = 23, 34%), intraoperative bypass failure (n = 6, 9%), and exposed/infected bypass (n = 5, 8%). The 23 patients with patent grafts required amputations because of hindfoot necrosis (n = 6), persistent forefoot necrosis (n = 6), acute diabetic foot infection (n = 6), and various other reasons (n = 5). Using life-table analysis, survival for the whole group was 56% at 12 months and 17% at 48 months. Patients with limb loss despite a patent bypass fared the worst with survival of 21% at 2 years.

CONCLUSIONS

Bypass thrombosis caused half of the amputations after limb salvage surgery. A patent bypass was functioning at the time of amputation in another third. Survival after failure of limb salvage was abysmal, especially in patients with patent bypasses.