Abstract
A 31-yr-old female patient previously diagnosed with idiopathic pulmonary arterial hypertension (PAH) was referred to our centre for further evaluation. Cardiac magnetic resonance imaging (MRI) and echocardiography revealed a superior sinus venosus atrial septal defect (ASD) with partial anomalous pulmonary venous drainage. Following re-diagnosis, surgical repair was considered. Despite a disproportionately high mean pulmonary artery pressure (P(pa)) of 47 mmHg relative to the patient's age and defect, the decision to operate was based on the absence of oxygen desaturation (either at rest or during exercise), cyanosis or abnormally elevated haemoglobin. Other operability criteria included normal sinus rhythm at rest, vasoreactivity and a pulmonary to systemic blood flow ratio of 1.9 at rest. Surgical repair and continued advanced therapy with bosentan 125 mg b.i.d. and aspirin 75 mg o.d. proved successful, with post-operative improvements in exercise capacity and dyspnoea, and a reduction in P(pa) to 25 mmHg. Keen to start a family, the risks of pregnancy were discussed. This case illustrates the importance of secondary PAH in sinus venosus ASD and the need to exclude a sinus venosus ASD in unexplained right ventricular dilatation. Access to expertise in congenital heart disease and use of cardiac MRI can improve diagnosis and, in turn, treatment decisions.