Factors Associated with Urgent Amputation Status and Its Impact on Mortality.

OBJECTIVES: Thirty-day mortality is higher after urgent major lower extremity amputations compared to elective lower extremity amputations. This study aims to identify factors associated with urgent amputations and to examine their impact on perioperative outcomes and long-term mortality.

METHODS: Patients undergoing major lower limb amputation from 2013-2020 in the Vascular Quality Initiative (VQI) were included. Urgent amputation was defined as occurring within 72 hours of admission. Associations with sociodemographic characteristics, comorbidities, and outcomes including postoperative complication, inpatient death, and long-term survival were compared using univariable tests and multivariable logistic regression. Long-term survival between groups was compared using Kaplan-Meier analysis.

RESULTS: Of the 12,874 patients included, 4,850 (37.7%) had urgent and 8,024 (62.3%) had elective amputations. Nonwhite patients required urgent amputation more often than white patients (39.8% vs 37.9%, P=0.03). A higher proportion of Medicaid and self-pay patients presented urgently (Medicaid:13.0% vs 11.0%; self-pay: 3.4% vs 2.5%, P< 0.001). Patients requiring urgent amputation were less often taking aspirin (55.6% vs 60.1%, P<0.001) or statin (62.2% vs 67.2%, P<0.001), had fewer prior revascularization procedures (41.0% vs 48.8%, P<0.001), and were of higher ASA class 4-5 (50.9% vs 40.1%, P<0.001). Urgent amputations were more commonly for uncontrolled infection (48.1% vs 29.4%, P< 0.001) or acute limb ischemia (14.3% vs 6.2%, P<0.001). Post-operative complications were higher after urgent amputations (34.7% vs 16.6%, P<0.001), including need for return to operating room (23.8% vs 8.4%, P< 0.001) and need for higher revision (15.2% vs 4.5%, P<0.001). Inpatient mortality was higher after urgent amputation (8.9% vs 5.4%, P<0.001). Multivariable analysis revealed non-white race, self-pay, homelessness, current smoking, ASA class 4-5, and amputations for uncontrolled infection or acute limb ischemia were associated with urgent status, whereas living in a nursing home or prior revascularization were protective. Further, urgent amputation was associated with an increased odds of postoperative complication or death (OR 1.86 [1.69-2.04], P<0.001) as well as long-term mortality (OR: 1.24 [1.13-1.35], P<0.001). Kaplan-Meier analysis corroborated that elective status was associated with improvement of long-term survival.

CONCLUSIONS: Patients requiring urgent amputations are more often nonwhite, uninsured, and less frequently had prior revascularization procedures, revealing disparities in access to care. Urgency was associated with a higher post-operative complication rate, as well as increased long-term mortality. Efforts should be directed towards reducing these disparities to improve outcomes following amputation.