Abstract
BACKGROUND: This study aimed to assess the effect of oral melatonin consumption on improving heart function and reducing postoperative complications in patients undergoing coronary artery bypass grafting (CABG) surgery. METHODS: A total of 60 CABG patients in the postoperative period were included in this randomized, double-blind, placebo-controlled trial. The patients were divided into three groups: Group 1 (n = 20, 5 mg melatonin), Group 2 (n = 20, 10 mg melatonin), and the placebo group (n = 20). The patients were discharged about 8 to 10 days after the surgery. Blood samples were taken from all the patients before and after the intervention (for 60 days), and Biochemical parameters including creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH), malondialdehyde (MDA), tumor necrosis factor alpha (TNF-α), total antioxidant capacity (TAC), nitric oxide (NO) assessed. Echocardiography and the measurement of systolic and diastolic blood pressure were also performed on participants. RESULTS: Our results showed that melatonin treatment significantly increased the ejection fraction (%EF) and TAC levels in both the treatment groups compared to the placebo group (P < 0.05). Moreover, the levels of inflammatory and oxidative biomarkers, including TNF-α, MDA, and NO, decreased in the intervention group significantly (P < 0.05). In the placebo group, %EF decreased significantly (P = 0.042), while MDA increased (P < 0.001) and TAC decreased (P = 0.002). No significant changes were observed in LDH and CK-MB levels. The comparison of serum biomarkers between the two treatment groups showed that 10 mg of melatonin was more effective than 5 mg, but the difference was not significant (P > 0.05). CONCLUSION: The present study showed that as a potential antioxidant, melatonin could alleviate oxidative stress and inflammation associated with CABG and is essential in improving overall heart function. TRIAL REGISTRATION: IRCT20111119008129N14, first trial registration date: 01/08/2023.