The Effect of Neuraxial Versus General Anesthesia on Outcomes of Infrainguinal Bypasses in Vascular Quality Initiative-Medicare-linked Database

Background: Neuraxial anesthesia (NA) has been hypothesized to decrease postoperative complications and reduce mortality. However, studies regarding the impact of anesthesia type on outcomes of infrainguinal bypass (IIB) have demonstrated mixed results. In this multiinstitutional study, we aimed to investigate the association of NA versus general anesthesia (GA) and perioperative and 1-year outcomes of IIBs. Methods: The Vascular Quality InitiativedMedicare-linked database was queried for all patients that received IIB between 2011 and 2019. Patients undergoing concomitant suprainguinal bypass or endovascular interventions were excluded. Two cohorts, NA and GA were compared. Primary outcomes included postoperative complications, estimated blood loss of >500 mL, need for red blood cell transfusion, prolonged length of stay, and 30-day mortality. Secondary outcomes included 1-year freedom from all-cause mortality, reintervention, amputation, and 1year amputation-free survival. Chi-square test, logistic regression, and one-to-one propensity score matching based on 33 variables were used to analyze the perioperative outcomes. Kaplan-Meier survival and Cox regression analyses were used to analyze 1-year outcomes. Results: A total of 28,443 patients (NA = 875, 3.1%; GA = 27,568, 96.9%) were included in the study. Patients undergoing NA were more likely to be older, have chronic obstructive pulmonary disease, and receive preoperative aspirin, while patients undergoing GA were more likely to receive preoperative P2Y12 inhibitor, have history of prior lower extremity arterial intervention, undergo urgent/emergent bypass, undergo infrageniculate bypass and receive nonautogenous conduit. Propensity score matching produced 2 well-matched cohorts (706 pairs) and revealed significant greater rates of estimated blood loss >500 mL (relative risk = 1.4 [95% confidence interval: 1.1-1.9]; P = 0.014) and need for red blood cell transfusion (relative risk = 1.3 [95% confidence interval: 1.0-1.5]; P = 0.013) for patients undergoing IIB with GA. The type of anesthesia was not associated with 30-day mortality and postoperative complications. There were no significant differences in 1-year outcomes when stratified by anesthesia type, both in unmatched and matched cohorts. Conclusions: In this multi -institutional study, we have shown that patients undergoing IIB by GA have greater blood loss and require more transfusions compared to NA. However, NA anes- thesia did not offer benefit in reducing postoperative mortality and complications. There were no differences in outcomes up to 1 year of follow-up. Neuraxial anesthesia (NA) and GA are equally safe for IIBs.