Patent Ductus Arteriosus

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Persistent ductus arteriosus; PDA

Definition and Characteristics

Normal ductal closure after birth consists of physiological contraction followed by irreversible anatomical closure. When this closing process is absent or delayed, we talk about patent ductus arteriosus (PDA). If still present in a full-term infant beyond the age of 3 months, it is referred to as persistent ductus arteriosus. There is no strict use of the terms clinically. The PDA is histologically characterized by the close adherence between the endothelium and a subendothelial elastic lamina. Under pathological circumstances, this is an additional lamina on top of the intimal cushion, whereas in premature infants without cushion formation and delayed closure this is the regular internal elastic lamina [1,2].


PDA occurs in 13.5% of all heart defects at birth. Data on the prevalence of PDA in full-term infants beyond the age of 3 months are not available. PDA ...