Pulmonary Artery Elastic Properties After Balloon Pulmonary Angioplasty in Patients With Inoperable Chronic Thromboembolic Pulmonary Hypertension

A significant proportion of the right ventricular afterload is determined by the elastic properties of the pulmonary artery (PA). We aimed to assess the effect of balloon pulmonary angioplasty (BPA) on PA elastic properties in patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH). We enrolled adult patients with CTEPH treated with BPA and controls without PH. Total PA compliance (CPa) was calculated as stroke volume/PA pulse pressure. PA distensibility (DC) and compliance (CC) coefficients were assessed by intravascular ultrasound to denote local elastic properties of the treated PA segments. We performed 103 BPA sessions in 17 patients with CTEPH (5 men [29%], aged 66 [64 to 73] years) who were followed for 6 (5 to 7) months after the last BPA. The median time between BPA sessions was 39 (28 to 52) days. The CPa, CC, and DC were lower in patients with CTEPH than in controls without PH (n = 10). Complete BPA treatment led to increase of CPa from 1.02 (0.70 to 1.39) to 2.08 (1.49 to 2.39) mL/mm Hg (P < 0.001) at the 6-month follow up, and this increase was in proportion to a decrease in pulmonary vascular resistance (PVR) (R2 = 0.74; P = 0.001). CPa increased immediately after BPA session by 0.13 (–0.05; 0.33) mL/mm Hg (P = 0.001) and remained unchanged until the next BPA session. CC and DC exhibited no immediate change after catheter balloon inflation (Δ=0 [–0.03; 0.02] mm2/mm Hg, P = 0.52, and Δ = 0 [–0.13; 0.13] %/mm Hg, P = 0.91, respectively) and remained unchanged at the 6-month follow-up. BPA improved total CPa in proportion to a decrease in PVR despite no improvement in local elastic properties of the treated PA segments. Une proportion importante de la postcharge du ventricule droit est déterminée par les propriétés élastiques de l’artère pulmonaire (AP). Nous avions pour objectif d’évaluer l’effet de l’angioplastie pulmonaire par ballonnet (APB) sur les propriétés élastiques de l’AP chez des patients qui présentaient une hypertension pulmonaire thromboembolique chronique (HPTC) inopérable. Nous avons recruté des patients adultes atteints d’HPTC inopérable et traités au moyen d’une APB ainsi que des témoins non atteints d’hypertension pulmonaire (HP). La compliance totale de l’AP (CAP) a été calculée en divisant le débit systolique par la pression différentielle de l’AP. Les coefficients de distensibilité (CD) et de compliance (CC) de l’AP ont été évalués par échographie intravasculaire pour que les propriétés élastiques lo