Eisenmenger Syndrome After Delayed Atrial Septal Defect Closure at High Altitude: A Case Report

Objective: Congenital defects / diseases Background: Eisenmenger syndrome develops from untreated or late-repaired cardiac shunts, causing irreversible pulmonaryvascular remodeling and systemic symptoms. Although timely repair has nearly eradicated Eisenmenger syndrome in high-income regions, delayed diagnosis in middle-income countries, especially when combined with chronic high-altitude hypobaric hypoxia, such as at approximately 2800 m (9186 ft) in the Ecuadorian Andes, can accelerate pulmonary hypertension through hypoxic vasoconstriction and erythrocytosis. We report a case of Eisenmenger syndrome 2 decades after surgical atrial septal defect closure. Case Report: A 46-year-old woman living at high altitude presented with severe cyanosis and heart failure 22 years after atrial septal defect closure. She had marked hypoxemia and secondary erythrocytosis. Echocardiography showed suprasystemic pulmonary artery pressure, severe right-chamber dilation, and reduced right ventricular systolic function. Right-heart catheterization confirmed Eisenmenger physiology with severe pulmonary-vascular resistance and low cardiac index. Chest computed tomography showed marked pulmonary artery enlargement without thromboembolic disease. Multidisciplinary management included bosentan 125 mg twice daily, tadalafil 10 mg once daily, nocturnal oxygen, diuretics, and anticoagulation, resulting in symptomatic stabilization and discharge on day 4. Transplant evaluation was initiated. Conclusions: Delayed atrial septal defect repair at high altitude can lead to irreversible Eisenmenger syndrome, for which current therapy is palliative. Early defect recognition and closure, congenital heart screening, and access to pulmonary vasodilators and transplant programs are imperative in resource-constrained mountainous regions.