Characteristics of High-Risk Patients Receiving Levosimendan After Pediatric Congenital Heart Surgery

Objectives: To characterize the clinical profile and outcomes of pediatric patients receiving rescue levosimendan for refractory circulatory failure after congenital heart surgery rather than to evaluate treatment efficacy.
Methods: This retrospective single-center cohort study included pediatric patients who received postoperative levosimendan between January 2023 and December 2024 for persistent circulatory failure despite optimized conventional inotropic therapy. Demographic, operative, and postoperative variables, including vasoactive-inotropic score (VIS) at levosimendan initiation and extracorporeal membrane oxygenation (ECMO) requirement, were analyzed. Multivariable logistic regression was used to explore factors associated with in-hospital mortality.
Results: Thirty-nine patients received rescue levosimendan; one was excluded because of interhospital transfer before final outcome assessment, leaving 38 patients for analysis. Most procedures were of high complexity (STAT Mortality Category 4–5, 71.1%). In-hospital mortality was 34.2% (13/38). Non-survivors had higher VIS at levosimendan initiation (median, 22 vs. 17; p=0.048) and more frequently required ECMO support (84.6% vs. 20.0%; p<0.001). Delayed sternal closure was performed in 36.8% of patients. In multivariable analysis, ECMO requirement remained strongly associated with mortality (OR, 17.8; 95% CI, 3.4–92.1; p=0.001), whereas VIS was not statistically significant after adjustment. Conclusion: Pediatric patients receiving rescue levosimendan after congenital heart surgery represent a high-risk subgroup with advanced circulatory failure and substantial mortality. Rescue levosimendan use may therefore serve as a clinical marker of severe postoperative hemo-dynamic deterioration rather than an isolated determinant of outcome.

Keywords: ECMO, congenital heart surgery, levosimendan, low cardiac output syndrome, vasoactive-inotropic score