Long-term effect of subcutaneous treprostinil in patients with pulmonary hypertension: rationale and design of the phase IV, multicentre, observational TREPAR-HP study

Background: Pulmonary hypertension (PH) is a chronic, progressive condition with high morbidity and mortality due to right heart (RH) failure. Prognosis depends on RH adaptability and remodelling in response to increased pulmonary arterial pressure. There is little information regarding risk variables and prognostic factors in the Argentinian population, current risk scores have not been validated, and its impact on free-event survival is still unknown. Prostacyclin analogues are the first-line treatment for high-risk patients. However, there is limited evidence on its clinical benefits, long-term effects, and impact on RH remodelling in the Argentinian population.Methods: The study was designed as a national, multicentre, prospective, observational, phase IV study including 100 patients with pulmonary arterial hypertension or chronic thromboembolic pulmonary hypertension, treated with subcutaneous treprostinil and followed up for 48 months. The study will be conducted in parallel with the patients' standard management and treatment in each centre. The primary objective is to assess the long-term improvement or reversal of RH remodelling (RHRR) parameters obtained by echocardiography. Secondary objectives include the evaluation of the prognostic value of RHRR parameters and the rate of clinical events, the treatment effect in terms of pulmonary vascular resistance, right ventricle systolic function, morbidity and all-cause mortality, quality of life, and safety and tolerability.Conclusions: This study will help to determine the clinical benefits, long-term effects, and impact on RH remodelling of prostacyclin analogues in Argentina.Trial registration: The trial was registered at Registro Nacional de Investigaciones en Salud (RENIS) in Argentina (https://sisa.msal.gov.ar/sisa/#sisa; registration number IS003303).