Effect of balloon pulmonary angioplasty on chronic thromboembolic pulmonary hypertension: an assessment of the learning curve in a Japanese university hospital.

Balloon pulmonary angioplasty (BPA) is an innovative treatment for chronic thromboembolic pulmonary hypertension (CTEPH). We retrospectively examined the clinical outcomes and complications of BPA at Yokohama City University Hospital (YCUH) between 2012 and 2018. In 2012, we began to conduct BPA sessions in 46 patients with inoperable CTEPH; 34 completed the BPA scheme and the follow-up plan. A longitudinal sub-analysis was performed with cohorts 1 and 2 receiving BPA before and after April 2015. Significant improvements in the mean pulmonary arterial pressure, pulmonary vascular resistance, and other parameters were detected after BPA. The total rate of thoracic complications was 25%. Specifically, the increase in SaO and home oxygen therapy discontinuation rate, and oral riociguat discontinuation rate was significantly higher in cohort 2 (+ 7.7, 75, and 59%) compared to cohort 1 (+ 3.1, 27, and 10%) (P < 0.05). Moreover, the need for non-invasive positive pressure ventilation was significantly lower: 0% (cohort 2) vs. 7% (cohort 1) (P < 0.05). The BPA sessions conducted at the YCUH resulted in significant improvements in patients with CTEPH. This study demonstrates a clear learning curve regarding the effectiveness of BPA both in normalizing SaO and facilitating the cessation of home oxygen therapy, as well as in reducing the incidence of severe complications.