[Severe cardiotoxic characteristics associated with allogeneic hematopoietic stem cell transplantation preconditioning in patients with aplastic anemia]

Objective: To delineate the clinical characteristics and outcomes associated with severe cardiac toxicity during the preconditioning phase of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with aplastic anemia (AA). Methods: This retrospective case series study included 31 patients with severe AA who underwent allo-HSCT and were diagnosed with severe cardiac toxicity at the Hematology Department of Peking University People's Hospital from August 2012 to June 2022. The clinical manifestations of severe cardiac toxicity observed during the preconditioning process were assessed. Patient survival was assessed using the Kaplan-Meier method. Results: In this cohort of 31 patients, the median follow-up period was 9 days (range: 4-365 days). Severe cardiac toxicity manifested within 6 days after the initial cyclophosphamide (Cy) administration. Twenty patients died within 30 days of initiating Cy preconditioning, of which 16 patients died due to severe cardiac toxicity within 25 days. Patients whose cardiac function improved within 30 days post-preconditioning showed a median survival duration of 222 days (n=11). Troponin I (TNI) levels in patients who died within 30 days of initiating Cy preconditioning began increasing on day 5 post-Cy, peaking sharply by day 9 after a notable rise on day 8. B-type natriuretic peptide (BNP) levels in patients who died within 30 days of initiating Cy preconditioning started to rise from day 1, stabilized between days 2 and 5, and then doubled daily from days 6 to 8, remaining elevated thereafter. Notably, the initial increases in BNP and TNI correlated with electrocardiogram (ECG) signs of low voltage and T-wave inversion in 83.87% of cases (n=26). Most patients (n=28, 90.32%) were administered corticosteroid therapy. In those with restored cardiac function, the ejection fraction returned to >50% within 30 days of initiating Cy preconditioning. Conclusions: Patients with severe cardiac toxicity during the preconditioning phase of allo-HSCT typically exhibit early, sustained, and marked elevations in myocardial damage markers, including BNP and TNI, accompanied by ECG abnormalities following Cy administration, with BNP often increasing first. These indicators are associated with rapid disease progression and high mortality. Prompt initiation of treatment upon clinical diagnosis is critical for improving survival outcomes.