pa·tent ductus arteriosus 'pāt-ənt- n an abnormal condition in which the ductus arteriosus fails to close after birth
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(PDA) abnormal persistence of an open lumen in the ductus arteriosus after birth, the direction of flow being from the aorta to the pulmonary artery, resulting in recirculation of arterial blood through the lungs.Medical dictionary. 2011.