Pulmonary Arteriovenous Fistula with Pulmonary Hypertension - To Close or Not to Close?

A 37-year-old female presented to our facility suffering from exertional dyspnea for 2-3 months. Her chest x-ray showed a nodular shadow in the right lower lung, and chest CT revealed a pulmonary arteriovenous fistula (PAVF). Subsequent echocardiographic examination detected no intra-cardiac shunt but did indicate pulmonary hypertension as evidenced by a tricuspid regurgitation flow velocity of 4.17 M/sec. Contrast echocardiography with antecubital vein injection of agitated normal saline demonstrated visualization of the left heart chambers compatible with PAVF. At cardiac catheterization, pulmonary arterial pressure was 59/26 mmHg, mean 34 mmHg. Because there was no intra-cardiac communication detected, primary pulmonary hypertension was tentatively diagnosed. Pulmonary angiography demonstrated a PAVF arising from the lower right pulmonary artery, forming a secular structure on its course in draining into the left atrium through a long pulmonary vein. In this particular anomaly, a concurrence of PAVF with pulmonary hypertension, we judged that the PAVF might serve as a safety valve for pulmonary hypertension and should not be closed. We therefore left the PAVF untreated and thereafter provided medical management for this patient. The concomitant presence of PAVF and pulmonary hypertension is a rare clinical condition. The ultimate treatment strategy for this uncommon condition should be carefully considered.