Chronic Occlusion of the Superior Vena Cava Resulting in Cyanosis in an Adult

A 42-year-old man presented to his local hospital with sepsis. He was cyanotic and had finger clubbing with oxygen saturation of 85% to 90%. A computed tomographic pulmonary angiogram led to an initial diagnosis of left-sided superior vena cava and partial anomalous pulmonary venous drainage. He had been generally well but always had limited exercise capacity (New York Heart Association class 2) and mild cyanosis and finger clubbing had been noted previously but had never been investigated. He was reviewed at an adult congenital center, and his symptoms were thought to be inconsistent with partial anomalous pulmonary venous drainage and left-sided superior vena cava. An echocardiogram raised suspicion for abnormal drainage of the SVC, and bubble echocardiography showed early and complete opacification of the left atrium and left ventricle after contrast injection in the left arm. There was late but significant filling of the right atrium and right ventricle, but this was less dense, signifying a right to left shunt. A cardiac magnetic resonance imaging demonstrated complete occlusion of the right SVC (Figure [A]). The brachiocephalic vein and other head and neck veins drained via tortuous venous collaterals to the left upper and right upper pulmonary veins (Figure [B]; …