Effect of Ascorbic Acid on Postoperative Acute Kidney Injury in Coronary Artery Bypass Graft Patients: A Pilot Study

Background: Even minor postoperative reductions in renal function influence the outcome of cardiac surgery. The mechanisms of postoperative renal injury in cardiac surgery are multifactorial and include ischemia-reperfusion injury. The study investigates the effect of the antioxidant ascorbic acid on the postoperative acute kidney injury after elective CABG surgery. Methods: A prospective randomized single-center trial was conducted in on-pump coronary artery bypass patients. The patients in the ascorbic acid group received 2 grams of ascorbic acid 24 hours and 2 hours preoperatively and 1 gram twice daily five days after the surgery. Postoperatively, the subjects were monitored for renal dysfunction and other complications. Results: 100 patients were included, with 50 patients in each study group. The groups were well matched for baseline demographics, preoperative medications, comorbidities, and had similar intraoperative characteristics. The incidence of postoperative acute kidney injury in the ascorbic acid group was 16% and 14% in the control group ( P = .779). The groups also did not differ in peak postoperative serum creatinine (83 [33] µmol/L versus 83 [39] µmol/L; P = .434), the lowest postoperative creatinine clearance (96.40 ± 35.78 mL/min versus 90.89 ± 36.18 mL/min; P = .766), and time from surgery to the onset of peak postoperative serum creatinine (1.64 ± 1.34 days versus 1.92 ± 1.54 days; P = .393). There was no dialysis required in any patient. Conclusion: The results of this study did not demonstrate a significant protective effect of ascorbic acid on the incidence of postoperative acute renal injury in elective on-pump CABG patients.