Short-Term Hemodynamic Response to Pulmonary Vasodilator Therapy in Children with Ventricular Septal Defect–Associated Pulmonary Arterial Hypertension: A Prospective Longitudinal Cohort Study

Abstract

Objectives: To evaluate the short-term hemodynamic response to pulmonary vasodilator therapy in pediatric patients with VSD-associated pulmonary arterial hypertension. Methodology: This prospective longitudinal cohort study was conducted at the Pediatric Department of the National Institute of Cardiovascular Diseases (NICVD) between January and June 2025. Thirty consecutive children aged 1–18 years with VSD-associated PAH and pulmonary vascular resistance (PVR) > 8 Wood units were enrolled. Patients received either single or dual pulmonary vasodilator therapy and underwent invasive hemodynamic assessment at baseline and after six months of treatment. Results: Of the 30 patients analyzed, 18 (60%) received single-agent therapy and 12 (40%) received dual therapy. Mean pulmonary artery pressure decreased significantly from 79.3 ± 15.3 mmHg to 72.6 ± 13.6 mmHg (p < 0.001). Pulmonary vascular resistance declined from 15.3 ± 7.2 to 11.7 ± 4.9 Wood units (p < 0.001), and pulmonary vascular resistance index decreased from 14.6 ± 5.6 to 10.4 ± 3.2 (p < 0.001). Arterial oxygen saturation improved from 89.5% to 91.8% (p = 0.002). Systemic hemodynamic parameters remained stable. Conclusion: Pulmonary vasodilator therapy was associated with significant short-term improvement in pulmonary hemodynamics and oxygenation in children with VSD-associated PAH. While these findings suggest potential benefit as a medical optimization strategy, the small sample size and non-randomized design limit generalizability. Larger, multicenter studies are required to confirm long-term safety and clinical outcomes.