Increased risk of mortality after lower extremity bypass in individuals with acute kidney injury in the Vascular Quality Initiative.

OBJECTIVE: The development of acute kidney injury (AKI) and its effect on prognosis after lower extremity bypass (LEB) surgery have not been well described. We determined risk factors associated with AKI in patients undergoing infrainguinal LEB surgery and whether individuals with AKI are at increased risk for cardiovascular events and mortality.

METHODS: Data for 12,907 operations entered in the Vascular Quality Initiative (VQI) registry from January 2012 through April 2015 were retrospectively reviewed. Procedures performed on patients not on dialysis before the surgery with perioperative assessments of renal function were eligible for the study. AKI was defined as a postoperative increase in serum creatinine ≥0.5 mg/dL or new dialysis requirement. Logistic regression was performed to determine the effect of AKI on the risk of in-hospital cardiovascular events, including myocardial infarction, stroke, congestive heart failure, or arrhythmias, and mortality. Cox proportional hazards regression was performed to determine the risk of long-term mortality (median follow-up of 11.5 months).

RESULTS: AKI developed after 507 (4%) of the 12,907 operations performed in 11,859 patients. After adjustment for demographic, clinical, and perioperative variables, AKI was associated with an increased risk of in-hospital cardiovascular events (odds ratio, 2.50; 95% confidence interval [CI], 1.91-3.28) and in-hospital mortality (odds ratio, 6.96; 95% CI, 3.94-12.31). Risk of mortality persisted over the course of follow-up (hazard ratio, 1.98; 95% CI, 1.58-2.47).

CONCLUSIONS: AKI after LEB is associated with an increased risk of cardiovascular events and all-cause mortality. Further study should evaluate whether preoperative interventions before LEB can be effectively applied for at-risk patients to reduce the incidence of AKI and its associated morbidity and mortality.