Aortopulmonary artery fistula: ruptured aneurysm of the distal aortic arch into the pulmonary artery.

Aortopulmonary artery fistula is uncommon, but the clinical outcome is often lethal. A 76-year-old man with a history of acute thoracic aortic dissection 6 years previously was admitted with dyspnea. A chest x-ray showed pleural effusion and pulmonary congestion. Transthoracic echocardiography revealed preserved systolic function, but continuous and abnormal flow from the distal aortic arch into the pulmonary artery (PA). Transesophageal echocardiography (TEE) in the Doppler color-flow mode demonstrated a left-to-right shunt between a large distal aortic arch aneurysm and the left PA via an aortopulmonary fistula and a pressure gradient across the shunt of 56 mmHg. Contrast-enhanced computed tomography showed that the aneurysm compressed the PA. Aortography also revealed a large distal aortic arch aneurysm and almost simultaneous contrast enhancement of the aorta and the PA. Right-heart catheterization showed a significant increase in oxygen saturation between the right ventricle and the PA. A left-to-right shunt due to a distal aortic arch aneurysm rupturing into the left PA was diagnosed based on these findings. TEE was very helpful in confirming the presence and precise location of the fistula.