ObjectiveTo test the hypothesis that levosimendan administration to patients with low-cardiac-output syndrome after cardiac surgery is associated with improved long-term (5-year follow-up) outcome. DesignSingle-center subanalysis of the multicenter randomized CHEETAH trial. SettingCardiac surgery department of a tertiary hospital. ParticipantsA total of 134 adult patients requiring hemodynamic support for cardiac index <2.5 L/min/m2 after cardiac surgery with cardiopulmonary bypass (CPB). InterventionsPatients were randomized (1:1 ratio) to receive levosimendan (continuous infusion with starting dose of 0.05 μg/kg/min) or placebo, in addition to standard inotropic care. Measurements and Main ResultsThe primary endpoint was long-term mortality (1-5 years) after randomization. Secondary outcomes were the following: hemodynamic parameters, need for inotropic support (VIS), acute kidney injury (AKI), need for renal-replacement therapy, duration of mechanical ventilation, ICU and hospital stay, 30-day mortality. No significant between-group difference in long-term mortality (5-year) was observed (hazard ratio, 1.59; 95% CI, 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 4-6 hours after randomization, which was lower in the levosimendan group (24 [21.8, 28] mmHg versus placebo 26 [22.2, 33] mmHg, p = 0.019). ConclusionsAmong patients requiring hemodynamic support after cardiac surgery with CPB, perioperative levosimendan infusion does 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, 30-day mortality.