Echocardiography in Pediatric and Adult Congenital Heart Disease by Eidem Benjamin W. & O'Leary Patrick W. & Cetta Frank

Author:Eidem, Benjamin W. & O'Leary, Patrick W. & Cetta, Frank
Language: eng
Format: epub, pdf
Publisher: LWW
Published: 2014-09-17T04:00:00+00:00

Figure 19.1. Parasternal short-axis view of the patent ductus arteriosus (PDA) (arrow) connection between the main pulmonary artery (MPA) and descending aorta (DAo). Ao, aorta; LA, left atrium; RV, right ventricle.

Figure 19.2. A high-left parasternal short-axis view (ductal view) of a large patent ductus arteriosus (PDA) between the origin of left pulmonary artery (LPA) and descending aorta (DAo), in a patient with hypoplastic left heart syndrome. In this view, the right pulmonary artery (RPA), left pulmonary artery, and PDA (arrows) are demonstrated from right to left of the image. Notice the small aorta (Ao).

Morphologic Variations in Patent Ductus Arteriosus

A PDA with a left aortic arch connects the aortic isthmus with the proximal left pulmonary artery. A PDA with a right aortic arch can be either right-sided (between the descending aorta and the right pulmonary artery), left-sided (between the innominate artery or left subclavian artery and the left pulmonary artery), or bilateral. To image the PDA arising from the base of innominate artery, the transducer is rotated from the suprasternal or high-parasternal view into a frontal plane such that the aorta is seen in its short axis and the right pulmonary artery is seen in its long axis. From this position, the innominate artery can be visualized by angulating the transducer toward the right or left depending on the side of the aortic arch. The bifurcation of the innominate artery into the subclavian and carotid arteries along with the origin of the PDA at its base can be seen in this view. In the rare instance when there are bilateral PDAs, one ductus is seen in the usual position and the other may arise from the base of either the subclavian artery or the innominate artery on the contralateral side (Video 19.4). The PDA in a normal heart runs in an oblique course, forming an obtuse angle with the descending aorta. This normal course of a PDA is altered in congenital heart diseases associated with right ventricular outflow tract obstruction, such as tetralogy of Fallot and pulmonary atresia. In these cases, the PDA has a nearly vertical orientation between distal aortic arch and the pulmonary artery and therefore is at an acute angle to the descending aorta and is often referred to as a reverse-oriented ductus. Such PDAs are often long and tortuous (Fig. 19.3, Video 19.5) and may be difficult to visualize in a single imaging plane. In hypoplastic left heart syndrome as well as with an interrupted aortic arch, the PDA is almost always large when imaged soon after birth and is at an obtuse angle to the descending aorta (Video 19.6). In the presence of an interrupted aortic arch, one should remember that the true aortic arch is superior to the continuum formed by the pulmonary artery, the PDA, and the descending aorta.

Hemodynamic Consequences of a Patent Ductus Arteriosus

The hemodynamic consequence of a large left-to-right shunt across a PDA is volume overload of the left heart and hence dilatation of the left atrium and left ventricle. Historically, the

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