Treatment effect prediction using CT after balloon pulmonary angioplasty in chronic thromboembolic pulmonary hypertension

Objective: To evaluate whether the change in computed tomography pulmonary angiography (CTPA) metrics after balloon pulmonary angioplasty (BPA) can predict treatment effect in chronic thromboembolic pulmonary hypertension (CTEPH) patients. Methods: This study included 82 CTEPH patients who underwent both CTPA and right heart catheterization (RHC) before and at the scheduled time of 6 months after BPA. The diameters of the main pulmonary artery (dPA), ascending aorta (dAA), right atrium (dRA), right ventricular free wall thickness (dRVW), and right and left ventricles (dRV, dLV) were measured on CTPA. The correlation of the New York Heart Association functional class (NYHA FC), 6-minute walking distance (6MWD), brain natriuretic peptide (BNP) level, and calculated CT metrics with a decrease in mean pulmonary artery pressure (ΔmPAP) using RHC (used as the reference for BPA effect) was investigated. Using multiple regression analysis, independent variables were also identified. Results: In univariate analysis, clinical indicators (NYHA FC, 6MWD, and BNP level) improved significantly after BPA and were significantly correlated with ΔmPAP (p < 0.01). In the univariate analysis of CTPA parameters, dPA, dRA, dPA/dAA ratio, dRVW, and dRV/dLV ratio decreased significantly and were significantly correlated with ΔmPAP (p < 0.01). Multivariate analysis demonstrated that decreased dPA (p = 0.001) and decreased dRA (p = 0.039) on CTPA were independent predictive factors of ΔmPAP. Conclusions: Decreased dPA and dRA on CTPA could predict a decrease in mPAP after BPA, thus potentially eliminating unnecessary invasive catheterization. Key Points: • The reduction in mean pulmonary artery pressure after balloon pulmonary angioplasty in CTEPH patients was significantly correlated with the clinical indices improvement and CTPA parameter decrease. • The decreased diameter of the main pulmonary artery and the decreased diameter of the right atrium on CTPA were independent predictors of mean pulmonary artery pressure reduction.