Learning curve and analysis of curative effects after balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension

To the Editor: Chronic thromboembolic pulmonary hypertension (CTEPH) is a chronic progressive disease in which pulmonary artery pressure (PAP) increases and eventually leads to right heart failure and death. Balloon pulmonary angioplasty (BPA) is a new and effective treatment for CTEPH patients who are unsuitable for surgery or who develop recurrent or persistent pulmonary hypertension after pulmonary endarterectomy (PEA). Continuous variables with normal distribution were presented as mean ± standard deviation and compared by independent samples t test, and the multiple groups were compared via one-way analysis of variance. [41.87 ± 15.26] mmHg), pulmonary vascular resistance (PVR) (6.50 [3.40, 9.10] WOOD units [WU] vs. 8.78 [5.30, 15.95] WU), brain natriuretic peptide precursor (proBNP) (140.30 [57.76, 601.20] ng/L vs. 387.90 [101.80, 2004.00] ng/L) and World Health Organization (WHO) functional classification (WHO FC) (2.00 [2.00, 2.00] vs. 2.00 [2.00, 3.00]) significantly decreased after the last BPA session (all P