January 12, 2023 Author : José Roquette The ductus arteriosus is a structure that connects the pulmonary artery to the aorta. It has important functions in the fetal circulation, which cease with birth. Therefore, under normal conditions, the ductus arteriosus closes after birth. When it does not close completely, it is said that there is patent ductus arteriosus . The ductus arteriosus in the fetal circulation During pregnancy, oxygenation of the fetus blood does not take place in the lungs, as happens after birth, but in the mother placenta. Since the lungs of the fetus are not functioning, structures intervene in the fetal circulation that divert blood from the lungs and these remain collapsed and filled with liquid until birth; One of these structures is the ductus arteriosus which connects the pulmonary artery to the aorta; The other two structures with important functions in fetal circulation are the foramen ovale , which connects the two heart atria, and the ductus venosus , which connects the umbilical vein to the inferior vena cava. By diverting blood from the pulmonary artery to the aorta, the ductus arteriosus allows: Oxygenated blood reaching quickly the systemic circulation; That there is no overload of the lungs of the fetus during pregnancy, with just enough blood getting there for the maintenance of the organs. After the newborn first breath and the umbilical cord is cut, oxygenation of the blood will carry out in the lungs. The ductus arteriosus is no longer needed and, as a rule, closes within the first few days of life . What is patent ductus arteriosus? Patent ductus arteriosus is a congenital (present at birth) heart disease , in which communication between the pulmonary artery and the aorta persists after birth , because ductus arteriosus has not closed completely. With pulmonary respiration the pressure in the aorta is higher than the pressure in the pulmonary artery, and the blood flow in the ductus arteriosus starts to be done in the opposite direction to what happened in the fetus, causing what is called a left-right shunt with: Oxygenated blood from the aorta returning to the pulmonary artery; Increased blood flow to the lungs; Insufficient blood flow to the systemic circulation. The risk of patent ductus arteriosus is greater in premature newborns and increases with the degree of prematurity . Neonatal respiratory distress syndrome is among other factors that increase the risk. The severity of patent ductus arteriosus is variable: it depends on the size of the communication that remains and the response of the heart, lungs and other organs; It may not cause any symptoms and be accidentally detected on cardiac auscultation; However, it can also cause breathing difficulties, pulmonary hypertension and increases the risk of endocarditis (infection of the endocardium or inner layer of the heart wall). When a patent ductus arteriosus is suspected, other tests are ordered for confirmation, including an echocardiogram. Treatment of patent ductus arteriosus Treatment depends on the particularities of each case, including age at diagnosis. In very small babies, the option may be to wait a few months to confirm whether the ductus arteriosus ends up closing; In other cases, medication that promote the closure of the ductus arteriosus can be used; The ductus arteriosus can also be closed through a procedure in which a catheter is inserted into a vessel in the groin, which is then directed to the heart and to the ductus arteriosus where a device is applied that closes it; Cardiac surgery is another option when none of the above solutions are feasible and significant blood flow is maintained through the ductus arteriosus. Meet the cardiac surgery clinical team from Hospital da Luz network. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
