Risk Factors for Target Vessel Re-intervention After Balloon Pulmonary Angioplasty in Inoperable Chronic Thromboembolic Pulmonary Hypertension.

PURPOSE: This study aims to identify the risk factors of re-intervention on targeted vessels after balloon pulmonary angioplasty (BPA) in patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH). MATERIALS AND METHODS: We retrospectively analyzed consecutive patients with inoperable CTEPH undergoing BPA at a single center. Targeted vessels and patients were classified according to whether re-intervention occurred. Mixed-effects logistic regression with a patient-level random intercept was used to identify predictors of re-intervention. The optimal threshold was determined by ROC analysis. Time to re-intervention was described by vessel-level Kaplan-Meier curves, and model performance was evaluated using the C-statistic, bootstrap internal validation, calibration plots, and decision-curve analysis. RESULTS: We enrolled 62 patients with inoperable CTEPH who underwent 168 BPA sessions and 412 targeted vessels. Re-intervention occurred in 98/412 vessels (23.8%) across 32/62 patients (51.6%). In mixed-effects logistic regression, percent diameter stenosis remained independently associated with re-intervention (OR = 1.38, 95% CI 1.23-1.54, p = 0.023), and pulmonary flow grade showed a strong graded association (p < 0.001). The combined model (percent diameter stenosis + pulmonary flow grade) showed good discrimination for re-intervention (AUC = 0.81, 95% CI 0.75-0.86). Kaplan-Meier curves demonstrated higher re-intervention rates in vessels with higher percent diameter stenosis and in those with pulmonary flow grade 0-1 (both log-rank p < 0.001). The combined model also had acceptable calibration and greater net benefit than percent diameter stenosis or pulmonary flow grade alone. CONCLUSIONS: Baseline pulmonary flow grade and percent diameter stenosis independently predict re-intervention after BPA. Vessels lacking high-grade flow and exhibiting greater stenosis may benefit from closer follow-up and staged dilatation strategies.