Effect of High-Dose Selenium on Postoperative Organ Dysfunction and Mortality in Cardiac Surgery Patients: The SUSTAIN CSX Randomized Clinical Trial

IMPORTANCE: Selenium contributes to antioxidative, anti-inflammatory, and immunomodulatory pathways, which may improve outcomes in patients at high risk of organ dysfunctions after cardiac surgery. OBJECTIVE: To assess the ability of high-dose intravenous sodium selenite treatment to reduce postoperative organ dysfunction and mortality in cardiac surgery patients. DESIGN, SETTING, AND PARTICIPANTS: This multicenter, randomized, double-blind, placebo-controlled trial took place at 23 sites in Germany and Canada from January 2015 to January 2021. Adult cardiac surgery patients with a European System for Cardiac Operative Risk Evaluation II score–predicted mortality of 5% or more or planned combined surgical procedures were randomized. INTERVENTIONS: Patients were randomly assigned (1:1) by a web-based system to receive either perioperative intravenous high-dose selenium supplementation of 2000 μg/L of sodium selenite prior to cardiopulmonary bypass, 2000 μg/L immediately postoperatively, and 1000 μg/L each day in intensive care for a maximum of 10 days or placebo. MAIN OUTCOMES AND MEASURES: The primary end point was a composite of the numbers of days alive and free from organ dysfunction during the first 30 days following cardiac surgery. RESULTS: A total of 1416 adult cardiac surgery patients were analyzed (mean [SD] age, 68.2 [10.4] years; 1043 [74.8%] male). The median (IQR) predicted 30-day mortality by European System for Cardiac Operative Risk Evaluation II score was 8.7% (5.6%-14.9%), and most patients had combined coronary revascularization and valvular procedures. Selenium did not increase the number of persistent organ dysfunction–free and alive days over the first 30 postoperative days (median [IQR], 29 [28-30] vs 29 [28-30]; P = .45). The 30-day mortality rates were 4.2% in the selenium and 5.0% in the placebo group (odds ratio, 0.82; 95% CI, 0.50-1.36; P = .44). Safety outcomes did not differ between the groups. CONCLUSIONS AND RELEVANCE: In high-risk cardiac surgery patients, perioperative administration of high-dose intravenous sodium selenite did not reduce morbidity or mortality. The present data do not support the routine perioperative use of selenium for patients undergoing cardiac surgery. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02002247