One of the most common cardiovascular problems that prematurely born infants experience early in life is patent ductus arteriosus (PDA).
The ductus arteriosus is a blood vessel that connects the two major arteries, namely the aorta and the pulmonary artery, and is essential in maintaining circulation in fetal life. After the baby is born and the fetal circulation changes to adult circulation, the ductus arteriosus functionally closes between 18 and 24 hours of life (1 ).
The arterial duct is a fetal blood vessel that is programmed to close shortly after birth. If the vessel remains patent beyond 3 months of life (a persistently patent arterial duct) it can result in volume loading of the left heart and should be closed either surgically or by a catheter-based procedure. A patent arterial duct is common in the newborn, particularly premature infants, and can contribute to persistent respiratory problems. (2) Historical estimates have placed the incidence of isolated PDA at approximately 0.05% of all live births. Isolated PDA accounts for 5% to 10% of congenital heart defects (3) number most likely represents the prevalence of a "symptomatic" PDA-that is, one that results in evidence of increased pulmonary blood flow, left heart volume overload, elevated PA pressure, murmur, etc. With the advent of color Doppler echocardiography, the incidental recognition of asymptomatic "silent" ductus has become more common. Some have estimated the prevalence of silent PDA among children and adults to be up to 0.5%, far more common than the "symptomatic" PDA (4).
However, in babies born prematurely, the ductus arteriosus often fails to close spontaneously and leads to a number of morbidities. it has been shown that in infants born with a birth weight of \<1000 g, the ductus arteriosus remains open in 66% of infants beyond the first week of life. In the extreme premature population born at 24 weeks of gestation, only 13% of infants are found to have their ductus closed by the end of the first week (5).This makes PDA an important issue from the clinical management perspective in the first few days of life in preterm infants.
It is associated with a number of comorbidities such as necrotising enterocolitis (NEC), bronchopulmonary dysplasia and intraventricular haemorrhage (IVH) (6-7).
The management controversy has mainly focused on when to treat and with what to treat. To increase the complexity of m atters, these two aspects of PDA management are not mutually exclusive, with the modality of treatment often being dictated by the timing of treatment. There have been a large number of published studies, meta-analyses and editorials focusing on different aspects of management.(8-9)Regarding the timing of treatment, prophylactic therapy has gradually fallen out of favor and neonatal units have shifted towards a more conservative approach by treating only the clinically and echocardiographically (ECHO) significant PDA (10).However, the big dilemma that still persists among neonatologists is what to use as the primary modality of treatment.
