Diagnostic ultrasound ( PDFDrive )

CHAPTER 37 The Fetal Heart 1289
RV
TA
RV
AO
PA
LV
SP
FIG. 37.33 Double-Outlet Right Ventricle. The aorta (AO) and
pulmonary artery (PA) both arise from the right ventricle (RV) in a parallel
fashion.
FIG. 37.32 Truncus Arteriosus. The single truncal artery (TA) overrides
both the right ventricle (RV) and left ventricle (LV). A ventricular
septal defect (arrow) is present. No pulmonary artery was seen, helping
to differentiate from tetralogy of Fallot. SP, Spine.
DORV is associated with other cardiac defects (particularly
VSD), various extracardiac defects, fetal chromosomal anomalies,
maternal diabetes, and maternal alcohol consumption. 5,146,147 With
surgical intervention, 10-year survival as high as 97% has been
reported. 145 A more recent study reported near 94% overall 5-year
survival ater surgical correction. 148 When extracardiac or
chromosomal anomalies are present, prognosis is poor, with
69% mortality when the diagnosis of DORV is made in utero. 147
Sonographically, the aorta and pulmonary artery arise predominantly
from the right ventricle (Fig. 37.33). Diferential diagnosis
includes transposition of the great vessels and TOF.
P
A
Transposition of Great Arteries
Transposition of the great arteries (TGA) is subdivided into two
types: (1) complete or dextrotransposition (D-TGA) in 80%
and (2) congenitally corrected or levotransposition (L-TGA)
in 20% of fetuses with transposition. In both types, ventriculoarterial
discordance is present. (he aorta arises from the right
ventricle, and the pulmonary artery arises from the let ventricle.)
Complete transposition (D-TGA) is deined as atrioventricular
concordance (atria and ventricles are correctly paired) with
ventriculoarterial (V-A) discordance (Fig. 37.34). It comprises
5.5% of heart disease in the fetal population. 47 D-TGA is also
classiied into two types, depending on the absence (70%) or
presence of a VSD. A variety of cardiac anomalies are associated
with D-TGA, including pulmonic stenosis, which rarely occurs
in the absence of a VSD. In 8% of cases, other organ systems
are involved. Chromosomal anomalies are not commonly associated
with TGA.
FIG. 37.34 Complete Transposition of Great Arteries. The aorta
(A) is anterior to the pulmonary artery (P). This abnormal arrangement
results in both vessels running parallel to each other in this short-axis
view.
In D-TGA, the aorta arises from the right ventricle, receives
systemic blood, and returns it to the systemic circulation. he
pulmonary artery arises from the let ventricle, receives pulmonary
venous blood, and returns it to the lungs. In general, the aortic
root lies anterior and slightly to the right of the pulmonary outlow
tract. With closure of the ductus arteriosus and foramen ovale
ater birth, this condition is incompatible with life unless an
associated shunt allows mixing of the separate right and let
circulations.