Subclinical myocardial changes after hematopoietic stem cell transplantation: limited predictive value of early biomarkers and strain imaging

BACKGROUND: Cardiotoxicity is a relevant late complication after hematopoietic stem cell transplantation. Early identification of subclinical myocardial injury could allow preventive interventions, yet the optimal diagnostic approach in this setting remains undefined. OBJECTIVES: To evaluate the incidence of subclinical myocardial damage through cardiac biomarkers and echocardiography in adult HSCT recipients, and to determine their association with subsequent clinical cardiotoxicity. METHODS: This prospective, single-center study enrolled 158 adult patients undergoing HSCT between 2017 and 2020. NT-proBNP, troponins, and CK-MB were measured at baseline, post-infusion, day 14, and day 30. Echocardiography was performed at baseline and day 30. Subclinical myocardial damage was defined as the presence of asymptomatic myocardial injury during chemotherapy, as evidenced by new biomarker elevation and/or a relative decline > 15% in global longitudinal strain from baseline. Clinical cardiotoxicity was assessed at 1 year. RESULTS: During the first 100 days, 79.7% of patients exhibited NT-proBNP elevation, whereas troponins and CK-MB remained unchanged. A ≥ 15% GLS reduction occurred in 14.6% of cases, without correlation to NT-proBNP changes (p = 0.3). Subclinical myocardial damage was detected in 83.5% of patients and was associated with older age and females but not with prior anthracycline exposure or conditioning regimen. At 1 year, the cumulative incidence of clinical cardiotoxicity was 4.4%, with no predictive association with early biomarker or strain alterations. CONCLUSIONS: Subclinical myocardial alterations are frequent during the early post-HSCT period but lack predictive value for subsequent clinical cardiotoxicity. NT-proBNP elevation and GLS reduction likely represent transient myocardial stress rather than irreversible injury. Routine early post-transplant biomarker and strain monitoring may have limited clinical utility.