Pathophysiology of Patent Ductus Arteriosus in the Preterm Infant

The ductus arteriosus is a muscular artery connecting two elastic arteries with different resistances. It is a normal fetal structure that only becomes pathological if it remains patent after birth. A varied clinical impact is observed as some neonates may be asymptomatic, symptoms may be deferred until later in life, or the infant may be overtly symptomatic and present as early as the first days of life. Prematurity increases the likelihood of persistent ductal patency and is seen in about 30% of preterm infants. In premature neonates, patent ductus arteriosus (PDA) is associated with significant morbidity and mortality [1,2]. This discussion explains the pathophysiology behind the pathological events associated with PDA.