Effect of memantine on post-operative cognitive dysfunction after cardiac surgeries: a randomized clinical trial

BACKGROUND: Post-operative cognitive dysfunction (POCD) is an important complication of cardiac surgeries. Glutamate plays a critical role in physiologic and pathologic conditions in the brain. Due to the role of glutamate in ischemia, this study is designed to identify the effect of memantine in prevention of POCD early and late after cardiac surgeries. METHODS: In this randomized clinical trial, 172 patients with ages 45–75 years old who underwent elective cardiac surgery were enrolled. For patients in memantine group, 5 mg of memantine per day administered at least 48 h before surgery and increased to 10 mg per day during the first 24 h after surgery and continued for 3 months. A brief Wechsler memory test (WMT) was administered before, three to 5 days after, and 3 months after surgery for both groups. RESULTS: Both groups demonstrate standard pattern of cognitive dysfunction after surgery and in follow up. Pre- and post-operative WMT score showed significant improvement in memantine compared to control group (P < 0.001) both in unadjusted and adjusted with confounding factor analysis. Unadjusted pre-, post-operative, and follow up WMT score improved significantly after 3 months in memantine group (P = 0.006). CONCLUSION: Pre-operative administration of memantine protects patients from POCD following cardiac surgeries. In addition, it improves cognitive function 3 months after surgery. TRIAL REGISTRATION: The trial was registered in the Iranian Registry of Clinical Trials (registration number: IRCT201303168698N12). GRAPHICAL ABSTRACT: Memantin effect on POCD. [Image: see text]