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a Chapter 33 Doppler Echocardiography for Managing Congenital Cardiac Disease 487
Table 33.4. Survival after surgery in the presence of congenital
heart disease: Boston Children's Hospital
Anomaly
Time of
surgery
Early
mortality
%
AVcanal defect 1976±1987 2.9
Ventricular septal 1984±1990 0 0
defect
Fallot's tetralogy 1985±1990 2.5 0
Ebstein's anomaly 1982±1990 17.0 11
Left heart hypoplasia 1984±1985 24.0 17
syndrome
D-Transposition of 1989±1992 0.5 0
great vessels
Truncus arteriosus 1987±1991 18.0
Compiled from [3].
genital heart disease to the year 2000 in the United
States approached almost 800,000 [8]. An additional
emerging benefit of prenatal diagnosis of congenital
heart disease may be the potential for in utero intervention
for congenital structural cardiac disease,
which has been investigated in animal models [9, 10].
Preliminary anecdotal accounts of human fetal cardiac
interventions have been reported in the medical
press [11]. Although they are still experimental
approaches at present, future advances may transform
these approaches into clinical realities. Obviously fetal
echocardiography including Doppler sonography will
continue to play a critical role in any such development.
This is further discussed below.
Utility of Fetal Doppler
Echocardiographic Assessment
Late
mortality
%
Table 33.5. Prognostic factors for congenital heart disease
n Type and severity of the malformation
n Presence of cardiac failure
n Abnormal cardiac rhythm
n Extracardiac malformations
n Chromosomal abnormalities
n Fetal growth restriction
n Level of expertise
The importance of Doppler echocardiography lies in
the fact that it allows noninvasive assessment of cardiovascular
hemodynamic function. Both modalities
of Doppler ultrasound offer significant advantages in
supplementing the diagnostic information obtained
from the 2D echocardiography. However, the operators
should be appropriately trained to use the device
optimally. The advantages and disadvantages of Doppler
echocardiography are summarized in Table 33.6.
Table 33.6. Advantages and disadvantages of spectral and
color Doppler echocardiography
Advantages
Corroborates anatomic diagnosis
Defines normal and abnormal cardiac hemodynamics
Provides functional definition of a cardiac lesion
Elucidates complex malformations
Potentially reduces imaging time
Disadvantages
More expensive instrumentation although increasingly
less expensive
Requires personnel with advanced skills
Spectral Doppler insonation, used in conjunction
with the other ultrasound modalities, allows the measurement
of peak or mean velocity, which may be utilized
to define the normal and the abnormal blood
flow characteristics. Almost two decades ago, the diagnostic
potential of duplex spectral pulsed Doppler
and color Doppler echocardiography was demonstrated
in recognizing fetal cardiac abnormalities
such as pulmonary arterial aneurysm and tricuspid
regurgitation [12, 13]. As reviewed in this chapter,
numerous extensive investigations subsequently confirmed
the utility of these approaches. Chiba and associates
[14] noted the usefulness of color flow mapping
for identifying congenital cardiac malformations
in 107 high-risk mothers, about a third of whom had
cardiac disease. Fetal cardiac malformations were present
in 19 cases and included complex disorders. Copel
and associates [15] used color Doppler in 45 of
48 fetuses with cardiac anomalies and noted that color
flow mapping was essential for making correct
anatomical diagnoses in almost a third of the cases.
Over time, the technique has proved useful in defining
structural, functional, and hemodynamic anomalies
of the fetal heart. Color Doppler facilitates the
recognition of anomalies, especially when they are
not clearly defined in 2D imaging, and may reduce
the examination time. Furthermore, spectral and color
Doppler modes are essential for identifying abnormal
flow patterns associated with valvular incompetence
or stenotic lesions of the vascular channels.
In Utero Evolution
of Cardiac Malformations
Experience with fetal echocardiographic examination
over the years has revealed the dynamics of in utero
evolution of fetal cardiac disease [16]. In addition to
the structural defects, functional changes in the fetal
heart can also be observed secondary to various disorders
including viral infection and rhythm disturbances.
Allan and associates were one of the first groups [17] to