Effect of Ascorbic Acid on Cardiac Surgery-Associated Acute Kidney Injury Incidence.

OBJECTIVES: Acute kidney injury (AKI) is associated with higher perioperative mortality and morbidity. Oxidative stress has been proposed as a cause of postoperative AKI. Ascorbic acid (AA) supplementation was suggested as a novel and promising antioxidant. The aim of this study was to evaluate the capability of AA to reduce the incidence of postoperative AKI in cardiac surgery patients. METHODS: A prospective randomized trial was conducted in patients scheduled for on-pump cardiac surgery. Subjects in the AA group received 2 g of AA intravenously during the induction of anesthesia, 2 g before aortic cross-clamp removal and 1 g every 8 hours for five postoperative days (the JERICA protocol). Postoperatively, the patients were monitored for AKI and other complications. Malondialdehyde levels were monitored in a subpopulation of 100 patients to evaluate the effect of AA on oxidative stress level. RESULTS: The AA and control group consisted of 163 and 169 patients, respectively. The groups were well matched for baseline demographics and had similar intraoperative characteristics. The incidence of AKI in the AA and control group was 20.9 and 28.4%, respectively (p = 0.127). The estimated glomerular filtration rate did not differ between the study groups in the entire postoperative period. There was a trend toward higher malondialdehyde values with statistical significance on postoperative day 1 and lower in-hospital mortality in the AA group (0.6 vs. 4.1%, p = 0.067). CONCLUSION: Our results do not support the effectiveness of AA supplementation in reducing the incidence of postoperative AKI in on-pump cardiac surgery patients. CLINICAL REGISTRATION NUMBER: This study was registered with the ISRCTN Registry under the trial registration number ISRCTN98572043.

Perioperative ascorbic acid supplementation does not reduce the incidence of postoperative atrial fibrillation in on-pump coronary artery bypass graft patients.

BACKGROUND: Atrial fibrillation is the most common arrhythmia following cardiac surgery. It is associated with increased hemodynamic instability, systemic embolization, and complications linked to anticoagulant therapy. Oxidative stress and consequent electrophysiological remodeling have been proposed as a cause of postoperative atrial fibrillation. Ascorbic acid supplementation was suggested as a novel and effective preventive agent. The aim of this study was to evaluate the capability of ascorbic acid to reduce the incidence of postoperative atrial fibrillation in coronary artery bypass grafting (CABG) patients. METHODS: A prospective randomized single-center trial was conducted in patients scheduled for an elective on-pump CABG surgery. Subjects in the ascorbic acid group received 2g of ascorbic acid 24h and 2h before the surgery and 1g twice a day for five days after the surgery. Postoperatively, the patients were monitored for atrial fibrillation and other complications. RESULTS: The ascorbic acid group consisted of 52 patients and the control group included 53 patients. The groups were well matched for baseline demographics, preoperative medications, comorbidities, and had similar intraoperative characteristics. The incidence of atrial fibrillation in the ascorbic acid group was 13.5% and 18.9% in the control group (p=0.314). No difference was found between groups in the time of occurrence of atrial fibrillation (3.71±1.89 vs. 2.91±1.58 days after the surgery; p=0.342). There was also no difference in the other observed postoperative complications. CONCLUSIONS: The results of this study do not support the effectiveness of ascorbic acid supplementation in reducing the incidence of postoperative atrial fibrillation in elective on-pump CABG patients.