Clinical Predictors and Outcomes Associated with Postoperative Delirium Following Infrainguinal Bypass Surgery

Abstract

Post-operative delirium (POD) is common yet often underdiagnosed following vascular surgery. Elderly patients with advanced peripheral artery disease may be at particular risk for POD yet understanding of the clinical predictors and impact of POD is incomplete. We sought to identify POD predictors and associated resource utilization after infrainguinal lower extremity bypass. This single center retrospective analysis included all infrainguinal bypass cases performed for peripheral arterial disease from 2012-2020. The primary outcome was inpatient POD. Delirium sequelae were also evaluated. Key secondary outcomes were length of stay, nonhome discharge, readmission, 30-day amputation, post-operative myocardial infarction, mortality, and 2-year survival. Regression analysis was used to evaluate risk factors for delirium in addition to association with 2-year survival and amputation free survival. Among 420 subjects undergoing infrainguinal lower extremity bypass, 105 (25%) developed POD. Individuals with POD were older and more likely to have non-elective surgery (P<0.05). On multivariable analysis, independent predictors of POD were age 60-89years old, chronic limb threatening ischemia, female sex, and nonelective procedure. Consultations for POD took place for 25 cases (24%); 13 (52%) were with pharmacists, and only 4 (16%) resulted in recommendations. The average length of stay for those with POD was higher (17days vs. 9days; P<0.001). POD was associated with increased non-home discharge (61.8% vs. 22.1%; P<0.001), 30-day major amputation (6.7% vs. 1.6%; P<0.01), 30-day postoperative myocardial infarction (11.4% vs. 4.1%; P<0.01), and 90-day mortality (7.6% vs. 2.9%; P=0.03). Survival at 2years was lower in those with delirium (89% vs. 75%; P<0.001). In a Cox proportional hazards model, delirium was independently associated with decreased survival (HR=2.0; 95% CI=1.15-3.38; P=0.014) and decreased major-amputation free survival (HR=1.9; 95% CI=1.18-2.96; P=0.007). POD is common following infrainguinal lower extremity bypass and is associated with other adverse post-operative outcomes and increased resource utilization, including increased hospital length of stay, nonhome discharge, and worse 2-year survival. Future studies should evaluate the role of routine multidisciplinary care for high-risk patients to improve perioperative outcomes for vulnerable older adults undergoing infrainguinal lower extremity bypass.