A Meta-Analysis of Randomized and Observational Studies: Aspirin Protects from Cardiac Surgery-Associated Acute Kidney Injury

Abstract

Background: Antiplatelet therapy is critical in the management of coronary artery diseases. For patients undergoing cardiac surgeries, including coronary artery bypass graft (CABG) and valve replacement, controversy remains in preoperative antiplatelet therapy concerning risk of bleeding. For safety concern, aspirin is recommended to be withdrawn 5 to 10 days before a cardiac surgery. Recent studies, however, indicate that preoperative aspirin may have a protective effect on cardiac surgery-associated acute kidney injury (CSA-AKI). Objective: To estimate the efficacy of preoperative aspirin in preventing CSA-AKI. Methods and results: Eligible studies included randomized controlled trials (RCTs) and observational studies (OSs) of patients, who had undergone CABG, valve replacement, or combined surgery. These studies compared preoperative aspirin with placebo/no aspirin and reported the least incidence of CSA-AKI. One RCT and five OSs met the inclusion criteria. Data retrieved suggested that aspirin prescribed within five days before cardiac surgery decreased post-operative renal failure [odds ratio (OR), 0.67; 95% confidence interval (CI), 0.50-0.89; P < 0.01] and 30-day mortality (OR, 0.64; 95% CI, 0.53-0.77; P < 0.01). One RCT and three OSs suggested aspirin protected from major adverse cardiocerebral events (MACE) (OR, 0.88; 95% CI, 0.76-1.01; P = 0.07). One RCT and two OSs suggested aspirin did not increase risk of re-exploration for bleeding (OR, 1.01; 95% CI, 0.76-1.34; P = 0.95). Conclusion: Preoperative low-dose aspirin decreases post-operative CSA-AKI, mortality, and MACE without increasing the risk of re-exploration. But most of the studies are observational. They lack a uniformed standard on prescription of aspirin and outcomes measurement. No stratification analysis is performed concerning different types of surgical procedures and comorbidities. More randomized controlled trials are necessary to confirm the efficacy and safety of preoperative aspirin prescription.