P694 Late shunt closure: is it the only cause of pulmonary hypertension after surgical repair?

Atrial septal defects (ASD) may be a cause of pulmonary hypertension (PH) specially when they are only detected in adulthood. Sinus venosus type ASD are rare, with an estimated prevalence of 4-11%, and frequently they are associated with anomalous venous return of the right superior pulmonary vein (RSPV). Surgical closure is safe and effective, and it is associated with normal life expectancy when performed before age 25; the risk of PH is higher in untreated defects or late closure. Clinical case The authors present the case of a 74-years old female patient with previous diagnosis of a sinus venosus type ASD. Closure of the shunt and correction of venous return was performed when the patient was 36. Follow up in the following years was normal, and the patient was discharged from the congenital surgical center. The patient was referred to our PH unit due to symptomatic PH for etiological investigation (PSAP of 70 mmHg in transthoracic echocardiogram). After excluding PH related to left heart disease and lung disease, the most likely cause was pulmonary arterial hypertension due to late closure of left to right shunt, but complete investigation was performed. A transesophageal echocardiogram showed dilatation of right heart chambers and a communication of 36 mm at the high atrial septum between the RSPV and superior vena cava entrance with spontaneous left to right shunt. A severe dilation of coronary sinus (maximal dimension 33.4mm) suggestive of persistent left superior vena cava (PLSVC) was also found. A cardiac magnetic resonance was performed showing dilated right chambers, abnormal drainage of right superior pulmonary vein to right atrium, a dilated coronary sinus with a PLSVC and Qp/Qs 1.7. Right heart catheterization showed a mean pulmonary artery pressure of 25 mmHg with normal pulmonary vascular resistance (2.4 UWood) suggesting that the intracardiac shunt is the responsible for the PH with reversible pulmonary vascular disease. The patient was proposed to surgical repair. Conclusion The authors present a rare clinical case of an undiagnosed persisting sinus venous ASD after surgical repair. Failure of shunt closure led to the development of PH, emphasizing the need to maintain lifelong follow up of these patients in specialized centers. Abstract P694 Figure.