Evolution of Patients with Pulmonary Arterial Hypertension Starting Macitentan After the Discontinuation of Other Endothelin-Receptor Antagonists: Results of a Retrospective Study

Background Macitentan is the latest endothelin-receptor antagonist (ERA) approved for the treatment of pulmonary arterial hypertension (PAH), presenting enhanced properties over previous ERAs. Objective We describe the clinical and echocardiographic evolution of patients with PAH who started macitentan after discontinuing bosentan/ambrisentan. Methods This was a retrospective series of patients with different etiologies who started macitentan after the suspension of other ERAs under routine clinical practice at five Spanish hospitals. World Health Organization functional class (WHO-FC), 6-min walk distance (6MWD), levels of N-terminal prohormone of brain natriuretic peptide (NT-proBNP), and cardiac imaging data were collected and described at baseline (before macitentan initiation) and after 3, 6, and 12 months, when available. Results In total, 12 patients (ten women; mean age 65.63 +/- 13.27 years) were observed. At baseline, most patients were receiving concomitant PAH medications, and five patients were classed as WHO-FC III. After 3 months of macitentan treatment, WHO-FC had improved in four patients, 6MWD increased in eight patients, and NT-proBNP levels and right atrial area were lowered in seven and eight patients, respectively. Similar results were observed after 6 and 12 months. Macitentan was well-tolerated, with no PAH hospitalizations, septostomies, transplants, or deaths registered. Conclusions Our results suggest that switching to macitentan in patients with PAH who discontinued bosentan/ambrisentan was well-tolerated and effective. Further studies are needed to confirm these observations.