Introduction
Patient history:
The baby had no pre-natal diagnosis of congenital disorders. He had a natural childbirth at full term, with an Apgar Index of 10. About 12 hours after birth the physicians noticed that he presented cyanosis and moderate respiratory distress.
Case Report
Imaging:
A urgent echo was scheduled and, in contrast with the normal anatomy, it showed that:
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The two great vessels were uncoiled and ran parallel one to each other, the more anterior artery being the aorta, while the pulmonary artery was located more posteriorly and slightly to the left (Fig.1);
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The pulmonary artery bifurcated into the right and the left pulmonary artery (Fig.1);
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A parasternal short axis view showing both ventriculo-arterial valves, demonstrated that the aorta was located anteriorly and the pulmonary valve was posterior (Fig.2);
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A reduced curvature ray of the aortic arch could be noticed (Fig.3);
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Patent Botallo before (Fig.4) and after (Fig.5) Prostaglandin E1;
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Mitral and aortic annulus were located on different planes and mitro-aortic continuity had been lost (Fig.6);
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Systemic, dilated, RV caused flattened septum bulging toward the LV (Fig.7) and aneurysmatic interatrial septum (Fig.8). Neither interatrial nor interventricular communication was detected.
The baby was treated with prostaglandin E1 in order to enhance mixing from pulmonary and systemic circulations. Since this patient had neither interatrial nor interventricular communication, he underwent a balloon atrial septostomy, and, after a few days, surgical arterial switch.
Discussion
In babies with DTGA, the pulmonary and systemic circulations are connected in parallel rather than in-series, as in normal subjects.
This situation is incompatible with life, and survival at birth is dependent on mixing of blood from the two circulations via a patent foramen ovale or patent ductus arteriosus. Without surgical treatment, about 30 percent of these infants die within the first week of life, and 90 percent die within the first year. Approximately two thirds of patients with DTGA have no major associated abnormalities (“simple” transposition), and one third have associated congenital abnormalities (“complex” transposition).
The most common associated abnormalities are: ventricular septal defect, pulmonary/subpulmonary stenosis and left ventricular outflow tract obstruction. However, almost all patients have an interatrial shunt, whose amount determines the degree of desaturation.
References
- Skinner J, Hornung T, Rumball E Transposition of the great arteries: from fetus to adult. Heart. 2008 Sep;94(9):1227-35. Review.
- Warnes CA. Transposition of the great arteries. Circulation. 2006 Dec 12;114(24):2699-709. Review.
- Tufekcioglu O, Ozdogan OU, Ozeke O, Maden O, Karabal O. An interesting echocardiographic imaging of d-transposition of the great arteries. Echocardiography. 2005 Oct;22(9):782.