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patent ductus arteriosus pa·tent ductus ar·te·ri·o·sus (pāt'nt; är-tēr'ē-ō'səs)
A cardiovascular defect that is caused by failure of the arterial canal to close after birth.
congenital heart defect characterized by the persistence of the ductus arteriosus, a channel that shunts blood between the pulmonary artery and the aorta. Normally, after birth the pulmonary artery carries blood depleted of oxygen and laden with carbon dioxide from the right ventricle (lower chamber) of the heart to the lungs, where the excess carbon dioxide is removed from the blood and replaced with oxygen. Before birth the fetus depends upon its mother's circulation for this function and not on its own lungs. Consequently, most of the blood pumped into the pulmonary artery is shunted through the ductus arteriosus into the aorta for distribution into the general circulation. Normally, at birth the ductus arteriosus constricts and closes, becoming a fibromuscular cord.