MATERIALS AND METHODS: This prospective study constituted a nested sub-study of the SUSTAIN CSX trial, a double-blinded, randomized, placebo-controlled multicenter trial to investigate the impact of high-dose selenium supplementation on high-risk cardiac surgery patients' postoperative recovery. Functional recovery was assessed by 6-min walk distance, Short Form-36 (SF-36) and Barthel Index questionnaires.

KEY FINDINGS: 174 patients were included in this sub-study. The mean age (SD) was 67.3 (8.9) years, and 78.7 % of the patients were male. The mean (SD) predicted 30-day mortality by the European System for Cardiac Operative Risk Evaluation II score was 12.6 % (9.4 %). There was no difference at hospital discharge and after three months in the 6-min walk distance between the selenium and placebo groups (131 m [IQR: not performed - 269] vs. 160 m [IQR: not performed - 252], p = 0.80 and 400 m [IQR: 299-461] vs. 375 m [IQR: 65-441], p = 0.48). The SF-36 and Barthel Index assessments also revealed no clinically meaningful differences between the selenium and placebo groups.

METHODS AND ANALYSIS: The NeST Registry is designed as a product registry that would provide information on the use and safety of NeuroAiD in clinical practice. An online NeST Registry was set up to allow easy entry and retrieval of essential information including demographics, medical conditions, clinical assessments of neurological, functional and cognitive state, compliance, concomitant medications, and side effects, if any, among patients on NeuroAiD. Patients who are taking or have been prescribed NeuroAiD may be included. Participation is voluntary. Data collected are similar to information obtained during standard care and are prospectively entered by the participating physicians at baseline (before initialisation of NeuroAiD) and during subsequent visits. The primary outcome assessed is safety (ie, non-serious and serious adverse event), while compliance and neurological status over time are secondary outcomes. The in-person follow-up assessments are timed with clinical appointments. Anonymised data will be extracted and collectively analysed. Initial target sample size for the registry is 2000. Analysis will be performed after every 500 participants entered with completed follow-up information.

ETHICS AND DISSEMINATION: Doctors who prescribe NeuroAiD will be introduced to the registry by local partners. The central coordinator of the registry will discuss the protocol and requirements for implementation with doctors who show interest. Currently, the registry has been approved by the Ethics Committees of Universiti Kebangsaan Malaysia (Malaysia) and National Brain Center (Indonesia). In addition, for other countries, Ethics Committee approval will be obtained in accordance with local requirements.