Effect of Balloon Pulmonary Angioplasty on Homogenization of Lung Perfusion Blood Volume by Dual-Energy Computed Tomography in Patients with Chronic Thromboembolic Pulmonary Hypertension.

OBJECTIVE: Balloon pulmonary angioplasty (BPA) is used to treat patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH); the goal is to improve pulmonary perfusion. We aimed to evaluate lung perfusion blood volume (PBV) with haemodynamic and exercise-capacity parameters to assess the efficacy of BPA in the treatment of CTEPH. METHODS: We retrospectively studied 33 patients over a 6-year period. DECT pulmonary angiography was performed before and after BPA. DECT provided iodine distribution maps; whole-lung and regional PBV images and quantification were generated using post-processing software. A mosaic pattern suggesting perfusion inhomogeneity is typical in CTEPH. Hypothetically, BPA treatment would promote homogenization that would be reflected in the calculated standard deviation. RESULTS: Lung perfusion images showed decreased heterogeneity after BPA. There was a significant difference before and after BPA in the whole-lung PBV and in the regional standard deviation for pulmonary arterial pressure (R = 0.37, p = 0.032 and R = 0.57, p = 0.006), pulmonary vascular resistance (R = 0.51, p = 0.023 and R = 0.60, p = 0.002), transtricuspid pressure gradient (R = 0.50, p = 0.0028 and R = 0.61, p = 0.0001), brain natriuretic peptide (R = 0.54, p = 0.0012 and R = 0.46, p = 0.0078), and 6-min walking distance (R = 0.59, p = 0.003 and R = 0.26, p = 0.14). The effects were especially pronounced after the first BPA procedure. CONCLUSION: Decreased lung heterogeneity may suggest BPA efficacy in treating CTEPH. After BPA treatment, improved lung PBV and improved regional standard deviation showed a strong positive correlation with haemodynamic parameters and exercise capacity, which also suggests that BPA is effective in treating CTEPH.