Pulmonary Artery Denervation for Medication Refractory Pulmonary Hypertension (PARPH Study)　- Study Protocol for a Prospective, Open-Label, Single-Arm Clinical Trial.

Background: Despite the development of effective pulmonary vasodilators, the prognosis for patients with pulmonary hypertension (PH) remains poor, particularly in medication-refractory patients. Catheter-based pulmonary artery denervation (PADN) is an emerging therapeutic strategy targeting the sympathetic nervous system in various types of PH. However, data on its safety and efficacy in refractory patients with PH who truly require non-pharmacotherapy are lacking. Here, we describe a phase II, investigator-initiated, open-label, single-arm trial (Japan Registry of Clinical Trials jRCTs052200017) to evaluate the efficacy and safety of PADN over a 2-year observation period. Methods and Results: Twenty participants will be enrolled and will undergo PADN. The primary endpoint is the time from PADN to the first occurrence of the composite events of death, lung transplantation, and worsening of PH. The safety endpoints are the occurrence of adverse events related to PADN and bradycardia requiring treatment. The exploratory endpoints include right ventricular function evaluated using cardiac magnetic resonance imaging and Short Form-36 score. Conclusions: The findings of this study will lead to the adoption of PADN for patients with limited treatment options.