Optimal Endpoint for Balloon Pulmonary Angioplasty Based on Distal Pulmonary Artery Pressure Waveforms.

BACKGROUND: Balloon pulmonary angioplasty (BPA) is an established therapy for chronic thromboembolic pulmonary hypertension (CTEPH), but its optimal lesion-specific endpoint remains unclear. This study aimed to clarify the optimal endpoint for pressure-guided BPA (PG-BPA) based on the distal pulmonary artery pressure waveform (Pd-WF). METHODS AND RESULTS: We retrospectively analyzed 23 patients with CTEPH who underwent 118 PG-BPA sessions involving 424 lesions. The pressure ratio (PR; i.e., the distal-to-proximal mean pulmonary artery pressure ratio) and Pd-WF were evaluated for each lesion. Complete arterialization of the Pd-WF (Pd-CA), defined as a distal-to-proximal pulse pressure ratio >0.5, was used as the physiological endpoint. PR improved significantly from a median of 0.52 (interquartile range [IQR] 0.39-0.66) to 0.80 (IQR 0.73-0.89) after balloon dilatation (P<0.001), and Pd-CA was achieved in 63.9% of lesions. Significant decreases were seen in both mean pulmonary artery pressure (median 34 [IQR 26-50] to 19 [IQR 18-25] mmHg) and pulmonary vascular resistance (median 8.3 (IQR 5.6-13.6) to 2.7 (IQR 2.1-4.0 Wood units; both P<0.0001). The number of lesions achieving Pd-CA correlated with the percentage reduction in pulmonary vascular resistance (r=-0.52, P=0.011). Receiver operating characteristic analysis identified a PR cut-off value of 0.77 for predicting Pd-CA (area under the curve 0.86; P<0.0001). CONCLUSIONS: Pd-CA may represent an optimal physiological endpoint for PG-BPA and enable lesion-level optimization beyond angiographic assessment alone.