Use of Regional Anesthesia for Lower Extremity Amputation May Reduce the Need for Perioperative Vasopressors: A Propensity Score-Matched Observational Study

Abstract

Purpose: Lower extremity amputation (LEA) is associated with a high risk of postoperative mortality. The effect of type of anesthesia on postoperative mortality has been studied in various surgeries. However, data for guiding the selection of optimal anesthesia for LEA are limited. This study aimed to determine the effect of anesthesia type on perioperative outcomes in patients with diabetes and/or peripheral vascular disease undergoing LEA.

Patients and methods: We reviewed the medical records of patients who underwent LEA at our center between September 2007 and August 2017, who were grouped according to use of general anesthesia (GA) or regional anesthesia (RA). Primary outcomes were 30-day and 90-day mortality. Secondary outcomes were postoperative morbidity, intraoperative events, postoperative intensive care unit admission, and postoperative length of stay. Propensity score-matched cohort design was used to control for potentially confounding factors, including patient demographics, comorbidities, medications, and type of surgery.

Results: Five hundred and nineteen patients (75% male, mean age 65 years) were identified to have received GA (n=227) or RA (n=292) for above-knee amputation (1.5%), below-knee amputation (16%), or more minor amputation (82.5%). Before propensity score matching, there was an association of GA with coronary artery disease (44% [GA] vs 34.5% [RA], p=0.028), peripheral arterial disease (73.1% vs 60.2%, p=0.002), and preoperative treatment with aspirin and clopidogrel (68.7% vs 55.1%, p=0.001; 63% vs 41.8%, p<0.001, respectively). Propensity score matching produced a cohort of 342 patients equally divided between GA and RA. There was no significant between-group difference in 30-day (3.5% vs 2.9%, p=0.737) or 90-day (6.4% vs 4.6%, p=0.474) mortality or postoperative morbidity. However, postoperative ICU admission (14.6% vs 7%, p=0.032), intraoperative hypotension (61.4% vs 14.6%, p<0.001), and vasopressor use (52% vs 14%, p<0.001) were more common with GA than with RA.

Conclusion: Type of anesthesia did not significantly affect mortality or morbidity after LEA. However, intraoperative hypotension, vasopressor use, and postoperative ICU admission rates were lower with RA.