Levosimendan in Patients with Low Cardiac Output Syndrome After Cardiac Surgery: A Substudy of the Multicenter Randomized CHEETAH Trial

Objective: To test the hypothesis that levosimendan administration in patients with low cardiac output syndrome after cardiac surgery is associated with improved long-term (5-year follow-up) outcomes. Design: Single-center subanalysis of the multicenter randomized CHEETAH trial. Setting: Cardiac surgery department of a tertiary hospital. Participants: A total of 134 adult patients requiring hemodynamic support for a cardiac index <2.5 L/min/m² after cardiac surgery with cardiopulmonary bypass (CPB). Interventions: Patients were randomized (1:1 ratio) to receive levosimendan (continuous infusion with a starting dose of 0.05 μg/kg/min) or placebo, in addition to standard inotropic care. Measurements and Main Results: The primary endpoint was long-term mortality (1-5 years) after randomization. Secondary outcomes were hemodynamic parameters, need for inotropic support, acute kidney injury (AKI), need for renal replacement therapy, duration of mechanical ventilation, intensive care unit (ICU) and hospital stay, and 30-day mortality. No significant between-group difference in long-term mortality (5 years) was observed (hazard ratio, 1.59; 95% confidence interval, 0.81 to 3.11; p = 0.17). There were no significant differences in secondary outcomes, except for the difference in the mean pulmonary artery pressure at 4 to 6 hours after randomization, which was lower in the levosimendan group compared to the placebo group (median, 24 [interquartile range (IQR), 21.8-28] mmHg vs 26 [IQR, 22.2-33] mmHg; p = 0.019). Conclusions: Among patients requiring hemodynamic support after cardiac surgery with CPB, perioperative levosimendan infusion did not affect long-term survival (1-5 years) compared with placebo. Levosimendan also had no effect on major clinical outcomes such as AKI, ICU stay, hospital stay, and 30-day mortality.