Patency and limb salvage after infrainguinal bypass with severely compromised ("Blind") outflow

Hypothesis: Infrainguinal graft patency and limb salvage are adversely affected by severely compromised outflow. Design: Retrospective review of all infrainguinal bypass procedures performed at a single institution during a 5-year period. Setting: University teaching hospital. Patients: Two hundred seventy-four patients underwent infrainguinal bypass for limb salvage (351 grafts in 307 limbs). Interventions: All infrainguinal bypasses originated from a femoral artery. The distal anastomosis in 279 grafts was located in an artery with at least 1 patent outflow vessel with anatomically normal end-artery runoff (Society for Vascular Surgery/International Society for Cardiovascular Surgery ad hoc committee runoff score, 1-9). The distal anastomosis of 72 grafts was located in an artery with only collateral outflow ("blind bypass"; runoff score, 10). Main Outcome Measures: Perioperative morbidity and mortality, primary-assisted and secondary graft patency, limb salvage, and survival. Results: All data are presented as mean ± SEM. Patients undergoing blind bypass were older (age, 70 ± 2 vs 66 ± 1 years; p <.05) and had a higher incidence of hypertension (90% vs 70%; P <.05) and end-stage renal disease (24% vs 13%; P <.05). Comparing patients undergoing blind bypass to bypass with at least 1 patent outflow vessel, there were no differences in the use of nonautogenous conduits (50% vs 59%; P = .21) or postoperative warfarin (30% vs 32%; P = .69), or in perioperative mortality rates (2.7% vs 3.2%; P = .79). After a median follow-up of 13 months (range, 0-60 months), 2-year secondary graft patency for the entire group was 63% ± 4%. The secondary patency rate of blind bypass grafts was no different from that of grafts with at least 1 patent outflow vessel (67% ± 7% vs 64% ± 4%; P was not significant). However, the 2-year limb salvage rate in limbs with blind outflow was significantly worse than in limbs with at least 1 patent outflow vessel (67% ± 7% vs 76% ± 3%; P = .04). Conclusion: Acceptable long-term patency rates can be achieved in infrainguinal bypass grafts with blind outflow, although blind outflow remains a marker for subsequent limb loss in the chronically ischemic leg.