Background: Over the past decade, balloon pulmonary angioplasty (BPA) for chronic thromboembolic pulmonary hypertension has shown improved outcomes with procedural refinement in expert hospitals with high procedural volume. Whether the outcomes of BPA are reproducible in hospitals with limited procedural volumes remains unknown. The Japan BPA registry was designed to assess the outcomes of contemporary BPA from a nationwide perspective, including hospitals with low treatment volume.
Methods: This prospective multicenter registry enrolled 1202 consecutive patients with chronic thromboembolic pulmonary hypertension who underwent BPA at 44 hospitals between April 2018 and March 2023. We assessed the efficacy and safety of BPA and survival rates, comparing high- and low-volume hospitals based on the BPA center definition (≥50 procedures per year) from the seventh World Symposium on Pulmonary Hypertension.
Results: A total of 5207 procedures were performed. Thirty-five low-volume hospitals (79.5%) performed 40.8% of all BPA procedures. BPA significantly improved symptoms, clinical parameters, and hemodynamics (55.6% reduction in pulmonary vascular resistance), with 0.2% periprocedural BPA-related mortality. Severe lung injury (0.3%), balloon overdilatation (0.67%), and mechanical ventilation (0.3%) were less common in high-volume hospitals than in low-volume hospitals (1.3%, 1.7%, and 1.5%, respectively; P<0.001). In the Kaplan-Meier analysis, the survival rate of all patients at 3 years was 94.7% (95% CI, 92.5%-96.3%). Multivariable Cox regression analysis showed an increased mortality risk with higher right atrial pressure, and high-volume hospitals were associated with a reduced mortality risk.
Conclusions: This nationwide registry demonstrated the outcomes of contemporary BPA in patients with chronic thromboembolic pulmonary hypertension. No significant differences were observed in efficacy and periprocedural mortality between low- and high-volume hospitals. However, the significantly lower rate of severe complications in high-volume hospitals indicates that BPA may be safer in high-volume hospitals.
Keywords: angioplasty, balloon; hospitals, high-volume; hospitals, low-volume; hypertension, pulmonary; vascular resistance.