Acute limb ischemia (ALI) remains one of the most challenging emergencies in vascular surgery. Historically, outcomes after interventions for ALI have been associated with high rates of morbidity and mortality. The purpose of this study was to determine contemporary outcomes after lower extremity bypass (LEB) performed for ALI. All patients undergoing infrainguinal LEB between 2003 and 2011 within hospitals comprising the Vascular Study Group of New England (VSGNE) were identified. Patients were stratified according to whether the indication for LEB was ALI. Primary end points included bypass graft occlusion, major amputation, and mortality at 1 year postoperatively as determined by Kaplan-Meier life-table analyses. Multivariable Cox proportional hazards models were constructed to evaluate independent predictors of mortality and major amputation at 1 year. Of 5712 LEB procedures, 323 (5.7%) were performed for ALI. Patients undergoing LEB for ALI were similar in age (66 vs 67 years; P = .084) and gender (68% male vs 69% female; P = .617), but were less likely to be taking aspirin (63% vs 75%, P < .0001) or a statin (55% vs 68%; P < .0001). Patients with ALI were more likely to be current smokers (49% vs 39%; P < .0001), and to have had a prior ipsilateral bypass (33% vs 24%; P = .004) or a prior ipsilateral percutaneous intervention (41% vs 29%, P = .001). Bypasses performed for ALI were longer in duration (270 vs 244 minutes; P < .0001), had greater blood loss (363 vs 272 mL; P < .0001), and more commonly used prosthetic conduits (41% vs 33%; P = .003). ALI patients experienced increased in-hospital major adverse events, including myocardial infarction, congestive heart failure, deterioration in renal function, and respiratory complications (Table). Patients who underwent LEB for ALI had no difference in rates of graft occlusion, but did have significantly higher rates of limb loss and mortality at 1 year (Table). On multivariate analysis, ALI was an independent predictor of major amputation (HR, 2.16; CI, 1.38-3.40; P = .001) and mortality (HR, 1.41; CI, 1.09-1.83; P = .009) at 1 year.TableAcute limb ischemia (n=323)All other indications (n=5389)P-valueIn-hospital complicationsAny in-hospital major adverse event19.8%11.6%<.0001Myocardial infarction7.5%3.6%0.001CHF5.6%3.3%0.03Deterioration in renal function6.6%5.4%0.001Respiratory3.7%1.4%0.004One-year complicationsGraft occlusion18.1%18.5%0.77Major amputation22.4%9.7%<0.0001Mortality20.9%13.1%<0.0001 Open table in a new tab Patients who present with ALI represent a less medically optimized subgroup within the population of patients undergoing LEB. These patients may be expected to have more complex operations, followed by increased rates of perioperative adverse events. In addition, despite equivalent graft patency rates, patients undergoing LEB for ALI have significantly higher rates of amputation and mortality at 1 year.