Abstract
OBJECTIVE: The purpose of this study was to identify patients at particularly high risk for major amputation after emergent infrainguinal bypass to help tailor postoperative and long-term patient management. METHODS: In the Vascular Quality Initiative, we identified 2126 patients who underwent emergent infrainguinal artery bypass. Two primary outcomes were investigated: major ipsilateral amputation above the ankle level during the index hospitalization and major amputation above the ankle at any time after emergent infrainguinal bypass surgery (perioperative and postdischarge combined). Binary logistic regression analysis was performed for each outcome using variables that achieved a univariable P value of ≤.10. We then determined which variables have a multivariable association for the outcomes as defined by a regression P value of ≤.05. A risk score was then created for the outcome of amputation after emergent infrainguinal bypass using weighted beta-coefficient. Variables with a multivariable P value of ≤.05 were included in the risk score and weighted based on their respective regression beta-coefficient in a point scale. RESULTS: Overall, 17.1% of patients (368/2126) underwent major amputation at some point in follow-up after emergent infrainguinal artery bypass. The mean follow-up duration on the amputation variable was 261 days with the 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 infrainguinal arterial bypass were home status in top 10% (most deprived) of Area Deprivation Index, prior infrainguinal 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 comorbidities, insurance status, race, and gender. There is steep progression in amputation rate ranging from 5% at scores of 0 and 1 to >60% for scores in of >10. Area under the curve analysis revealed a value of 0.706. CONCLUSIONS: Patients living in the most disadvantaged socioeconomic neighborhoods have an increased risk of amputation after emergent infrainguinal arterial bypass independent of baseline comorbidities and perioperative events. Baseline comorbidities are not impactful regarding amputation rates after emergent infrainguinal bypass surgery. The need for bypass revision or thrombectomy during the index hospitalization is the most impactful factor toward 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.