What is patent ductus arteriosus? Patent ductus arteriosus is an acyanotic congenital heart defect caused by the failure of the ductus arteriosus to close after birth, resulting in a persistent communication between the aorta and pulmonary artery. Find our full video library only on Osmosis: http://osms.it/find-more. Join millions of current and future clinicians who learn by Osmosis, along with