ObjectiveThe purpose of this study is to identify patients at particularly high risk for major amputation following emergent infra-inguinal bypass to help tailor postoperative and long-term patient management. MethodsIn the Vascular Quality Initiative, we identified 2126 patients who underwent emergent infra-inguinal artery bypass. Two primary outcomes were investigated : major ipsilateral amputation above the ankle level during index hospitalization and major amputation above the ankle at any time after emergent infra-inguinal bypass surgery (perioperative and post discharge combined). Binary logistic regression analysis was performed for each outcome utilizing variables which achieved a univariable P value < .10. We then determined which variables have a multivariable association for the outcomes as defined by a regression P value of .05 or less. A risk score was then created for the outcome of amputation after emergent infra-inguinal bypass using weighted beta-coefficient. Variables with a multivariable P-value < .05 were included in the risks score and weighted based on their respective regression beta-coefficient in a point scale. ResultsOverall, 17.1% (368/2126) of patients experienced major amputation at some point in follow up after emergent infra-inguinal artery bypass. Mean follow up duration on the amputation variable was 261 days with end point being time of amputation or time of last follow up data on the amputation variable. Variables with a significant multivariable association (P<.05) with major amputation at any point after emergent infra-inguinal arterial bypass were : home status in top 10% (most deprived) of area deprivation index; prior infra-inguinal ipsilateral arterial bypass; prior ipsilateral endovascular arterial intervention; prosthetic bypass conduit; postoperative skin/soft tissue infection; and postoperative need to revise or thrombectomize bypass. Pertinent negatives on multivariable analysis included all baseline co-morbidities, insurance status, race, and gender. There is steep progression in amputation rate ranging from 5% at scores of 0 and 1 to over 60% for scores in excess of 10. AUC analysis revealed a value of .706. ConclusionsPatients living in the most disadvantaged socioeconomic neighborhoods have an increased risk of amputation following emergent infra-inguinal arterial bypass independent of baseline co-morbidities and perioperative events. Baseline co-morbidities are not impactful regarding amputation rates after emergent infra-inguinal bypass surgery. The need for bypass revision or thrombectomy during index hospitalization is the most impactful factor towards amputation after emergency bypass. A risk score with quality accuracy has been developed to help identify patients at particularly high likelihood of limb loss which may aid in counseling regarding heightened vigilance in postoperative and long term follow up care.