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Zimmermann et al. Vessel Plus 2019;3:31 I http://dx.doi.org/10.20517/2574-1209.2019.010 Page 5 of 18

Figure 3. 3D transesophageal echocardiography visualization of atrial septal defects (A); same lesion after deployment of Amplatzer
device (B)

images, which is time-consuming and resource intensive. Nowadays real-time 3D echocardiography with
matrix array transducer is available in TTE as well as TEE. 3D TTE is a promising technology capable of
providing comprehensive en face images of ASD with the added benefits of being noninvasive, lower cost
than TEE, portability, and carries better accessibility than TEE. 3D TTE has a potential to provide accurate
information on ASD morphology such as size, location, and surrounding rims for treatment both in
children and adult populations. Furthermore, real-time 3D TEE has utility in providing accurate real-time
information about complex ASDs, especially those in patients with multiple ASDs, and allowing for real-
time feedback of device deployment positioning [29,30] .

Intrauterine Sonographic Detection of ASD
The International Society of Ultrasound in Obstetrics and Gynecology recently published guidelines on the
detection of fetal cardiac anomalies in 2017 with the goal of improving early detection by obstetricians and
[31]
family practitioners . The feasibility of ASD detection via intrauterine sonogram has been demonstrated
by many isolated case reports, retrospective analysis, and prospective studies [32-34] . Despite this, there
are few reports on the sensitivity of intrauterine ASD detection (30%-74%), and should be relegated to
pregnancies that carry high risk for cardiac abnormalities [34-36] .

Transcranial doppler ultrasonography
Transcranial doppler ultrasonography (TCD) is a viable alternative to TTE or TEE for screening and
follow-up evaluation of ASD. It offers a relative degree of comfort over TEE, and offers sensitivities
equivalent to TTE in terms of identifying right to left shunts, but cannot detect other associated defects that
[37]
echocardiography can .

Intracardiac Echocardiogram
Intracardiac echocardiography (ICE) offers superior visualization of the septal morphology during
[38]
transcatheter device deployment . It is, as the name suggests, invasive and requires additional femoral
vessel access for deployment. Real time 4D ICE also appears to be on the horizon with reports on its
[39]
development and pilot study usage are now emerging .

MANAGEMENT OF ASD
Surgical vs. Medical management of Secundum ASD
ASDs are considered for closure in symptomatic patients where a left to right shunt is present with evidence
of right heart pressure overload (right atrial or ventricular enlargement), and pulmonary to systemic
blood flow ratio (Qp:Qs) is greater than 1.5:1 . In addition to right heart overload and Qp:Qs > 1.5:1, in
[40]