What are the anatomical structures associated with patent ductus arteriosus (PDA)?

Updated: Nov 20, 2018
  • Author: Luke K Kim, MD; Chief Editor: Stuart Berger, MD  more...
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Answer

During fetal life, the ductus arteriosus is a normal structure that allows most of the blood leaving the right ventricle to bypass the pulmonary circulation and pass into the descending aorta. Typically, only about 10% of the right ventricular output passes through the pulmonary vascular bed.

The ductus arteriosus is a remnant of the distal sixth aortic arch and connects the pulmonary artery at the junction of the main pulmonary artery and the origin of the left pulmonary artery to the proximal descending aorta just after the origin of the left subclavian artery. It passes from the anterior aspect of the pulmonary artery to the posterior aspect of the aorta. Typically, the ductus has a conical shape with a large aortic end tapering into the small pulmonary connection. The ductus may take many shapes and forms, from short and tubular to long and tortuous.

An anatomic marker of the ductus is the recurrent laryngeal nerve, which nerve typically arises from the vagus nerve just anterior and caudal to the ductus and loops posteriorly around the ductus to ascend behind the aorta en route to the larynx. It is the most commonly injured anatomic structure in ductal ligation. Other less commonly injured structures include the phrenic nerve and the thoracic duct.

Most typically, the patent ductus arteriosus (PDA) is a left aortic remnant; however, it can be right-sided or on both the left side and right side. Although a left ductus arteriosus is a normal structure during normal fetal development, the presence of a right ductus arteriosus is usually associated with other congenital abnormalities of the cardiovascular system, most typically involving the aortic arch or conotruncal development.

The Krichenko classification of PDA is based on angiography and includes type A (conical), type B (window), type C (tubular), type D (complex), and type E (elongated) PDA.

In the presence of complex congenital heart defects, the usual anatomy of the ductus may not be present. Anatomic abnormalities can vary widely and are common in conjunction with complex aortic arch anomalies. Structures that have been mistaken for the patent ductus arteriosus (PDA) in surgical procedures include the aorta, the pulmonary artery, and the carotid artery.


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