Serial ultrasonographic monitoring during defibrotide treatment of sinusoidal obstruction syndrome after hematopoietic stem cell transplantation: a longitudinal study of treatment response

Purpose: This study evaluated serial ultrasonographic (US) changes during defibrotide therapy for sinusoidal obstruction syndrome (SOS) after hematopoietic stem cell transplantation, identifying parameters whose temporal trajectories differed by treatment response.Methods: This retrospective study included adults treated with defibrotide for SOS between January 2015 and August 2024 with baseline US and at least one follow-up US examination.Response was defined a priori as total bilirubin <2 mg/dL with resolution of SOS-related multiorgan dysfunction.US was repeated weekly until response assessment.HokUS-10 parameters and additional US findings were analyzed using generalized estimating equations and linear mixed-effects models to test the group-by-time interaction.The fully adjusted model was primary, with a minimal model used for sensitivity analysis.P-values were adjusted using the Benjamini-Hochberg procedure.Results: Among 39 patients (23 responders [59.0%] and 16 non-responders [41.0%]; median defibrotide duration, 23 days), only HokUS-10 score showed a significant group-by-time interaction after multiple-testing adjustment in both models, declining more rapidly among responders (fully adjusted model: β=-0.048;95% confidence interval [CI], -0.083 to -0.013; P=0.017; minimal model: β=-0.053;95% CI, -0.087 to -0.019; P=0.006).The odds of hepatofugal portal vein flow decreased faster among responders in the fully adjusted model (odds ratio [OR], 0.92; 95% CI, 0.85 to 0.99; P=0.032), whereas the association was directionally similar but non-significant in the minimal model (OR, 0.95; 95% CI, 0.88 to 1.02; P=0.162).Hepatic artery resistive index ≥0.75 was not significantly associated with differential temporal change.Conclusion: Serial US trajectories differed by treatment response.Longitudinal HokUS-10 changes may help distinguish defibrotide responders from non-responders.