o_1977r8vv9vk1ts2ms0kd8pksa.pdf

438 A.A. Baschat
agement [67±69]. While coronary perfusion may be
well maintained in utero, the situation may change
after birth. Right ventricular dependent coronary circulation
may occur and result in acute or chronic
global myocardial ischemia or infarction due to coronary
steal and segmental vascular obstruction. Because
of these potential impacts, prenatally detected
outflow tract obstructive lesions with relatively preserved
ventricular architecture should prompt the
search for ventriculocoronary fistula.
Prenatal diagnosis of ventriculocoronary fistula is
achieved by demonstration of high-velocity bi-directional
flow in the coronary artery by color Doppler
flow mapping and verified by pulsed-wave Doppler
examination. A severely dilated coronary artery may
also be imaged by two-dimensional echocardiography.
In cases of right ventricular outflow tract obstruction,
diastolic flow from the aortic sinus is directed
toward the hypoplastic right ventricle. Pressures
are reversed during ventricular systole and
blood flows from the right ventricle to the aorta (Fig.
29.13) [66, 70, 71].
Fig. 29.13. The fetal heart is imaged in a lateral ªfivechamberº
view including the left ventricular outflow tract.
A large tortuous vessel is seen originating from the aorta
connecting into the right ventricular cavity, which is of
moderate size (a). Pulsed-wave Doppler with the gate in
the ventriculocoronary fistula shows the characteristic bidirectional
flow pattern with systolic flow towards the aorta
(below the baseline) and diastolic flow towards the right
ventricle (above the baseline; b). (From [16])
Coronary Arteriovenous Fistula
in the Human Fetus
Congenital coronary fistulae may occur occasionally
if cardiac anatomy is otherwise normal; the majority
of these involve a single coronary artery, less often
multiple branches. Connections may involve the coronary
arterial tree, right atrium, coronary sinus, caval
veins, right ventricle, and the pulmonary trunk.
Drainage into a low-pressure system can result in a
large left-to-right shunt already causing symptoms in
childhood such as congestive heart failure, myocardial
ischemia from coronary artery steal, right-chamber
enlargement, arrhythmia, thrombosis with consecutive
embolization, and bacterial endocarditis
[72]. In the majority of cases symptoms appear in the
second and third decade of life. In a 20-week fetus
prenatal detection of an isolated coronary fistula connecting
to the right ventricle has been reported with
demonstration of a progressive increase in size as
well as tortuosity of the fistula during gestation [73].
A similar case with a fistula between the LCA and the
right atrium has also been recently described [74].
The shunting blood caused a high-velocity flow in
the dilated coronary sinus. In addition to the prenatal
findings a persistent left superior vena cava and a
small ventricle septum defect were also identified
postnatally. Following coil embolization of the coronary
fistula further clinical course was reported as
uneventful.
Idiopathic Arterial Calcification
in the Human Fetus
The idiopathic arterial calcification has an unknown
etiology and is characterized by generalized arterial
calcification and stenoses especially of the walls in
the arterial trunk of the pulmonary artery and aorta
[75, 76]. Most commonly the coronary arteries are
also affected, but peripheral arteries of gastrointestinal
tract, liver, kidneys, brain, extremities, and placenta
may also be involved. Severe myocardial dysfunction
may cause severe fetal hydrops, tissue ischemia,
and fetal death in the late second or third trimester
[77]. In less severe cases, especially in the absence
of hydrops, palliative treatment post-partum
may be started with steroids and bisphosphonates in
order to stop or delay the progression of the disease
[78]; however, most infants with idiopathic arterial