Chronic hypoxia and mediastinal mass: think about a pulmonary artery to left atrial fistula!

A pulmonary artery to left atrium (PA to LA) fistula arises from incomplete degeneration of the pulmonary venous and arterial plexus during development. We present a case of a right PA to LA fistula, where the key to diagnosis was the presence of a mediastinal mass combined with mild chronic hypoxia, evidenced by concomitant polycythemia.

Mild desaturation and polycythemia should always raise suspicion of a right-to-left shunt. When these signs are combined with the presence of a mediastinal mass, they strongly suggest a rare pulmonary artery to left atrium fistula. Two transcatheter closure approaches are available: the veno-venous approach and the antegrade approach. The antegrade approach, which employs devices with balanced discs, helps to avoid occluding the left atrial side with large discs.