Patent Ductus Arteriosus or PDA is one of the commonest congenital heart defects that account for almost 5-10% of all congenital heart disease in term infants.(1)
The rate of occurrence of PDA is inversely related to gestational age and weight, with a greater incidence seen in preterm infants.(1)
How Common Is Patent Ductus Arteriosus In Babies Or Is It A Rare Disease?
The reported number of cases of patent ductus arteriosus in term neonates is around 1 in 2000 births that account for 5-10% of all congenital heart disease. However, the incidence of patent ductus arteriosus in preterm neonates is far greater, with reported cases being 20% to 60% depending upon the population and diagnostic criteria. The increased number of cases of PDA in preterm infants is due to the lack of normal closure mechanisms due to immaturity. In preterm neonates, the gestational age and weight are closely linked to patent ductus arteriosus. PDA is present in almost 80% of infants weighing less than 1200 grams at birth as compared to 40% of infants who weigh less than 2000 grams at birth. Furthermore, symptomatic patent ductus arteriosus is seen in 48% of infants with a birth weight of fewer than 1000 grams.(1)
Approximately 80% of the preterm infants who have respiratory distress syndrome (RDS) will also present with PDA, which is mostly a result of increased circulating prostaglandins (PGE2) associated with RDS. Some birth factors that also contribute to increased incidence of patent ductus arteriosus include high altitude at birth, genetic factors, and in utero exposure to rubella. A high preponderance of PDA is also seen in females as compared to males in a ratio of 2:1.(2)
Significant PDAs that are hemodynamically stable have also been associated with high rates of mortality and morbidity, which can be as high as 30%. This condition can result in serious complications in preterm neonates and is an area of concern. It, therefore, becomes essential to understand the basic mechanisms involved along with early identification of PDA and knowledge of therapeutic options for successful outcomes.(2)
Pathophysiology Of Patent Ductus Arteriosus
The DA is derived from the sixth distal dorsal sixth aortic arch and is formed completely by the eighth week of gestation. The role of this ductus arteriosus is to shunt blood from the nonfunctional fetal lungs via its connection between the main pulmonary artery to the proximal descending aorta. This right to left shunt allows the blood with low oxygen concentration to pass from the right ventricle via the descending aorta and eventually to the placenta where gaseous exchange occurs. Before birth, approximately 90% of the right ventricular output flows through the ductus arteriosus, thus regulating the neonatal circulation. Normally the DA closed 24 to 72 hours after full-term birth, but in some cases, when the ductus fails to close, a defect remains that is termed as PDA or patent ductus arteriosus.(2)
In some cases, this patent ductus arteriosus can go undetected in the infants. This defect will later lead to symptoms of heart palpitations, shortness of breath, or difficulty breathing and complications such as increased blood pressure in the lungs, an enlarged heart, or congestive heart failure in adults.(3)
Patent ductus arteriosus is defined as the failure of ductus arteriosus to close within 72 hours after birth. Persistent patent DA after birth can result in potential complications such as heart failure, renal dysfunction, necrotizing enterocolitis (NEC), intraventricular hemorrhage, and altered nutrition and growth. Additionally, patent ductus arteriosus is also a risk factor for the development of chronic lung disease (CLD).(1)
Patent ductus arteriosus in term infants is mostly associated with a functional defect, while in preterm infants, it leads to immaturity. The normal physiological mechanism of closure resulting due to oxygen tension and decreased prostaglandins is altered in prematurity. The clinical presentation of ductal patency includes murmur, tachycardia, bounding peripheral pulses, and congestive heart failure along with other symptoms. In most cases, it has been seen that there are no symptoms present, and hence the diagnostic imaging becomes critical if a PDA is suspected on clinical grounds.(1)
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- Is Patent Ductus Arteriosus A Serious Condition & Can It Be Reversed?
- Is Patent Ductus Arteriosus A Progressive Disease & Alternative Treatments For It?
- How Does Patent Ductus Arteriosus Affect A Child & How Dangerous Is It?
- Life Expectancy Of Someone With Patent Ductus Arteriosus & Is It A Disability?
- Is There A Surgery For Patent Ductus Arteriosus & Can A Baby Die From It?