Abstract
BACKGROUND: Open surgery on the thoracic aorta is associated with a variable and often pronounced postoperative inflammatory response, which contributes to organ injury and prolonged intensive care unit (ICU) stays. Various anti-inflammatory strategies have been proposed as a way to modulate this response and therefore improve clinical outcomes. The SUSTAIN-CSX randomized controlled trial investigated the effect of perioperative high-dose selenium supplementation on mortality and organ dysfunction in cardiac surgery patients. In this post hoc analysis, we examined its effect on 30-day mortality and organ dysfunction in patients undergoing open thoracic aortic surgery. METHODS: We conducted a post hoc analysis of patients who underwent open thoracic aortic surgery within the SUSTAIN-CSX trial, a multicenter randomized controlled trial evaluating perioperative intravenous high-dose selenium supplementation in cardiac surgery. The selenium regimen consisted of 2,000 µg sodium selenite at anesthesia induction, 2,000 µg immediately postoperatively, and 1,000 µg daily for up to 10 days in the ICU. Patients treated with endovascular interventions of the thoracic aorta were excluded. RESULTS: A total of 287 patients were included, with 144 randomized to selenium and 143 to placebo. The primary outcome, 30-day mortality, did not differ significantly between groups (selenium 2.8% vs. placebo 3.5%; P=0.73). Clinically relevant postoperative atrial fibrillation (POAF) occurred more frequently in the selenium group (selenium 18.1% vs. placebo 10.5%; P=0.03). Non-cardiac organ dysfunction, including acute kidney injury (AKI), postoperative delirium and Sequential Organ Failure Assessment (SOFA) scores, was comparable between groups. Postoperative inflammatory and organ injury markers were overall comparable, although patients receiving selenium showed a non-significant trend toward lower creatine kinase-myocardial band (CK-MB) levels (selenium 18.9 µg/L vs. placebo 28.3 µg/L; P=0.07). Six-month survival, ICU and hospital length of stay, readmission rates, and measures of functional recovery did not differ between groups. CONCLUSIONS: Perioperative intravenous high-dose selenium supplementation did not improve 30-day mortality and was associated with an increased incidence of clinically relevant POAF in this exploratory subgroup analysis. Routine selenium supplementation in this setting cannot be recommended.