Hiding in plain sight: Is late diagnosis of a small patent ductus arteriosus the underlying cause of severe pulmonary arterial hypertension?

Background. Patent ductus arteriosus (PDA) is uncommon in adulthood, and clinical impact depends on ductal size and pulmonary vascular remodelling. Case report. A 19-year-old female, born at term and with a known history of asthma, was referred to Cardiology Department with progressive dyspnoea. Initial evaluation—including clinical examination, electrocardiogram, chest radiography—raised the suspicion of a congenital heart disease. Transthoracic echocardiography detected a small PDA and signs of severe pulmonary hypertension (PH). ECG-gated contrast-enhanced computed tomography and cardiac magnetic resonance confirmed a 2.3 mm by 3.6 mm PDA connecting the left pulmonary artery to the descending aorta. Right heart catheterization showed a bidirectional shunt (Qp/Qs=1), supra-systemic pulmonary pressures (123/52/79 mmHg) after temporary balloon occlusion, an elevated pulmonary vascular resistance of 13.95 WU), and a pulmonary artery wedge pressure of 7 mmHg—findings consistent with severe pulmonary arterial hypertension (PAH). Given the presence of severe PAH, PDA closure was considered inadvisable, and treatment with pulmonary vasodilators was initiated. After thoroughly evaluating