Right Ventricular Adaptation after Pulmonary Endarterectomy and Balloon Pulmonary Angioplasty in Chronic Thromboembolic Pulmonary Hypertension: A comparative Cardiac MRI-Based Study

Background Chronic thromboembolic pulmonary hypertension (CTEPH) is associated with elevated right ventricular (RV) afterload and progressive RV remodeling. Balloon pulmonary angioplasty (BPA) has emerged as an established and increasingly used alternative to pulmonary endarterectomy (PEA). This study aimed to evaluate hemodynamic, functional and structural cardiac responses to PEA and BPA, with specific focus on RV reverse remodeling. Methods In this prospective, multicenter cohort study, 93 patients with CTEPH (PEA; n=50, BPA; n=43) from the Netherlands and Denmark underwent cardiac magnetic resonance imaging, right heart catheterization, exercise testing and biomarker assessment at baseline and 6-months post-intervention. Longitudinal changes were assessed with repeated-measures ANOVA. A subgroup underwent analysis at 18 months. Results BPA patients were older (68.9±10.1 versus 62.4±11.1 years, p = 0.004), and used more PH medication. PEA-treated patients had higher RV mass index at baseline (40.1±13.5 versus 32.9±12.2 g·m −2 ; p=0.017), and consistently higher relative RV wall thickness at baseline and follow-up (both 0.4±0.1 versus 0.3±0.1; p <0.001). Both interventions improved RV afterload, function and exercise capacity (all p <0.05). Larger hemodynamic improvement after PEA (mPAP and PVR; p-interaction≤0.001) was accompanied by more pronounced RV reverse remodeling, including lower follow-up indexed RV volumes (RVEDVi; 76.2±16.8 versus 92.2±20.2 mL·m −2 ; p <0.001 and RVESVi; 39.0±15.6 versus 49.0±18.8 mL·m −2 ; p=0.014). Conclusions In this multicenter European study, both therapies resulted in significant RV reverse remodeling. PEA was associated with larger absolute reductions in indexed RV mass and volumes than BPA. However, remodeling sensitivity to unloading appeared broadly similar across treatments. Despite favorable outcomes following both treatments, our findings emphasize the need for randomized controlled studies, to optimize treatment strategies for operable and inoperable patients.