Abstract Rationale Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare but potentially curable form of pulmonary hypertension caused by organized thrombotic obstruction of the pulmonary arteries, leading to elevated pulmonary arterial pressure, vascular remodeling, and right ventricular (RV) overload. Balloon pulmonary angioplasty (BPA) improves pulmonary hemodynamics, oxygenation, dyspnea, and prognosis. However, improvements in dyspnea may not be explained solely by hemodynamic relief, as several reports suggest accompanying pulmonary function improvement. The underlying mechanisms remain unclear, and no study has evaluated lung volume changes using imaging analysis. AIM: To evaluate changes in lung, cardiac, pulmonary vascular volumes, and pulmonary function pre- and post-BPA in patients with CTEPH. Methods This single-center retrospective study included patients with CTEPH who underwent BPA and chest computed tomography pre- and post-treatment. Patients with prior pulmonary endarterectomy or worsening comorbidities were excluded. Lung and pulmonary vascular volumes were analyzed using Synapse VINCENT (FUJIFILM, Japan), RV volumes by cardiac magnetic resonance imaging. Pre- and post-BPA values were compared using the Wilcoxon signed-rank test, and correlations between percentage changes were analyzed using Spearman’s rank correlation. Results Ten patients (3 women; mean age 63.4 ± 10.6 years; 40% nonsmokers) were included, with a mean of 6.1 ± 1.7 BPA sessions. Mean pulmonary arterial pressure decreased from 41.8 ± 8.1 to 19.5 ± 4.0 mmHg, and pulmonary vascular resistance from 8.6 ± 2.3 to 3.1 ± 0.9 WU. Total lung volume increased from 4278 ± 1194 to 4572 ± 1078 mL, mainly in the right lower, left upper, and left lower lobes. Pulmonary arterial volume decreased from 129.5 ± 48.7 to 115.5 ± 38.6 mL. RV end-diastolic and end-systolic volumes decreased from 226.3 ± 116.2 to 147.1 ± 51.0 mL and from 172.4 ± 117.5 to 89.3 ± 43.9 mL, respectively. Percent predicted vital capacity and total lung capacity improved from 97.8 ± 11.7 to 104.3 ± 14.2% and from 102.8 ± 7.4 to 107.6 ± 11.3%, whereas percent predicted forced expiratory volume 1 second did not change. Increases in right lower lobe volume correlated with decreases in RV end-diastolic (ρ = 0.850) and end-systolic (ρ = 0.833) volume. No significant correlation was found between pulmonary arterial and lung volume changes. Conclusions In patients with CTEPH who completed BPA, improvement in pulmonary function may be partly associated with increased lung volume resulting from RV volume reduction. This abstract is funded by: None
Wakazono et al. (Fri,) studied this question.