Severe stenosis of a long tracheal segment, with agenesis of the right lung and left pulmonary arterial sling.

A baby presented at term with respiratory distress was managed with extracorporeal membrane oxygenation. Bronchoscopy revealed tracheal hypoplasia, complete tracheal rings, and agenesis of the right main bronchus. Echocardiography showed a left pulmonary arterial sling arising from the proximal part of the right pulmonary artery. Cardiac catheterization demonstrated abnormal pulmonary vasculature in the left lung which would have prevented survival, even after surgical repair. Diagnostic catheterization was important in delineating the anatomy, and aided in the decision not to proceed with surgical repair.