We report the case of a young boy with a history of total occlusion of the superior caval vein, diagnosed early after complex neonatal cardiac surgery, who developed severe protein-losing enteropathy. Protein-losing enteropathy was precipitated by a relatively mild stenosis at the junction of the inferior caval vein with the right atrium. Percutaneous stent dilation of the veno-atrial junction definitively relieved the stenosis, and the protein-losing enteropathy subsequently resolved.