Percutaneous closure of patent arterial ducts with the Amplatzer Ductal Occluder has become an effective and widely accepted alternative to surgical management. Although rarely, the occluder can be dislodged after an initially successful deployment, and with catastrophic consequences. We describe such a case in a 12-month-old girl who underwent transcatheter closure of a patent arterial duct. After device deployment, the occluder embolized in the patient's descending thoracic aorta, and severe spinal cord ischemic injury resulted. To our knowledge, ours is the first report of this complication after the deployment of an Amplatzer Ductal Occluder. We discuss pathophysiologic mechanisms that could expose patients to the risk of device dislodgment, and we review the relevant medical literature.