Initial lactic acid as a predictor of mortality in acute fulminant myocarditis patients undergoing heart transplantation

초록

Background: Fulminant myocarditis (FM) is a catastrophic condition frequently requiring extracorporeal membrane oxygenation (ECMO) and occasionally heart transplantation (HTPL). Data regarding outcomes after HTPL in FM are limited. Lactic acid is a known marker of tissue perfusion and prognostic indicator in cardiovascular diseases. This study evaluated the prognostic value of initial lactic acid in FM patients who underwent HTPL. Methods: Clinical data were retrospectively collected from 8 centers in Korea (2001–2021). Among FM patients receiving ECMO, those who subsequently underwent HTPL were analyzed for 180-day mortality. Receiver operating characteristic (ROC) analysis identified the optimal cutoff value of initial lactic acid for predicting 180-day mortality, and Kaplan–Meier (KM) analysis compared survival between groups. Results: Thirty-one patients underwent HTPL for FM (mean age 45 ± 14 years; 61% male). The cumulative 180-day mortality was 22.6%. ROC analysis demonstrated an AUC of 0.78 (p = 0.025), with an optimal cutoff of 3.75 mmol/L. Based on this threshold, 20 patients had lactate < 3.75 mmol/L and 11 had ≥ 3.75 mmol/L (mean 2.3 ± 0.9 vs 7.5 ± 3.5 mmol/L, p = 0.001). Baseline clinical, laboratory, and echocardiographic characteristics showed no significant differences between the two lactate groups. Patients with higher lactate exhibited significantly poorer survival (log-rank p = 0.012); Cox proportional hazards analysis revealed HR 6.31 (95% CI 1.22–32.8, p = 0.028). Conclusion: Among FM patients requiring HTPL, overall mortality remained substantial. Elevated initial lactic acid (≥ 3.75 mmol/L) was independently associated with worse 180-day survival, underscoring its prognostic importance. Early lactate assessment may aid risk stratification and postoperative management in this critically ill population.