Association of Pericardial Tamponade With Initiation of Sotatercept in a Patient With Eisenmenger Syndrome.

Eisenmenger syndrome (ES) represents an advanced stage of pulmonary arterial hypertension (PAH) associated with congenital heart disease. It is characterized by elevated pulmonary vascular resistance, with a right-to-left shunt and resting hypoxemia. ES is associated with high morbidity and mortality. Sotatercept, an activin-signaling inhibitor recently approved for PAH, has demonstrated meaningful hemodynamic and clinical benefits; however, post-approval experience has raised concern for an association with pericardial effusion. We report a 21-year-old woman with ES secondary to an unrepaired patent ductus arteriosus, who developed a hemodynamically significant pericardial effusion 84 days after initiating sotatercept. She presented with tamponade physiology requiring urgent pericardiocentesis and drain placement. An extensive evaluation revealed no obvious alternative etiology. A review of the published literature identified 39 cases of pericardial effusion associated with sotatercept, with more than half occurring in patients with connective tissue-associated PAH. This case highlights potential susceptibility in complex physiologic states such as ES and emphasizes the importance of close surveillance.