Preliminary study of individualized therapy for ventricular septal defect with severe pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a serious complication of congenital heart disease (CHD) with a left-to-right shunt, particularly ventricular septal defect (VSD). In patients presenting with severe PAH, therapeutic decision-making remains challenging because precise and individualized assessment criteria are lacking. In current clinical practice, treatment strategies are often based mainly on isolated hemodynamic parameters obtained by right heart catheterization (RHC), which may not fully reflect disease severity or reversibility.

This study aimed to explore an individualized treatment strategy for patients with severe VSD-PAH by analyzing the relationships among peripheral arterial oxygen saturation (SaO₂), pulmonary vascular resistance (PVR), pulmonary-to-systemic blood flow ratio (Qp/Qs), and pulmonary-to-systemic pressure ratio (Pp/Pa).

We retrospectively analyzed 121 patients with isolated VSD and severe PAH admitted to our center between 2010 and 2020. All patients underwent RHC. Correlations between SaO₂ and PVR, Qp/Qs, and Pp/Pa were assessed using Spearman correlation analysis. Patients were stratified according to SaO₂ levels, and treatment strategies were compared across different hemodynamic profiles using Fisher's exact test. Based on these findings, we established a scoring system integrating SaO₂, PVR, Qp/Qs, and Pp/Pa, and categorized total scores to examine their association with actual treatment strategies.

The distribution of treatment strategies differed significantly across combinations of SaO₂ and PVR, whereas Qp/Qs and Pp/Pa provided limited additional discrimination when SaO₂ exceeded 93%. The proposed scoring system was associated with observed treatment patterns: patients with total scores ≥ 60 were predominantly managed surgically (with or without preoperative medical therapy), whereas those with scores <40 were mainly treated with medical therapy alone (93.7%). Intermediate score ranges were associated with mixed treatment patterns.

Combining SaO₂ with RHC-derived parameters provides a more comprehensive and individualized assessment of disease severity in VSD-PAH than hemodynamics alone. The proposed multidimensional scoring system may provide a hypothesis-generating framework for cardiovascular specialists.