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Zimmermann et al. Vessel Plus 2019;3:31 I http://dx.doi.org/10.20517/2574-1209.2019.010 Page 9 of 18

Figure 5. Echo Atrial septal defects sizing (left) vs. Balloon sizing of defect (right)

Transcatheter closure of ASDs with a maximal native diameter > 30 mm can be quiet challenging,
and alternative techniques for deployment may be required, which will be discussed later. In regard to
classification of surrounding rims, although there are some differences noted among studies, distances
from ASD to aorta, superior vena cava, right upper pulmonary vein, inferior vena cava, coronary sinus,
and atrioventricular valve are evaluated. Adequate tissue rim is defined by at least 5mm from the defect
edge to the surrounding structures so as not to impinge on the vena cava, pulmonary vein, coronary
[28]
sinus, tricuspid or mitral valve . Figure 6 depicts areas of interest in measuring surrounding tissue rim
dimensions.

Figure 7 illustrates the tissue rim measurements as seen via intraoperative TEE. Tissue measurements
are best taken as follows: AV valve and right upper pulmonary vein tissue rim are best viewed in the 4
chamber view, SVC and IVC rims are best measured in the Bi-Caval view, and the Aortic and posterior
rim measurments are best taken in the short axis view. These are recommendations, but individual body
habitus and variations in heart orientation may necessitate obtaining alternate views to accurately measure
[98]
tissue rims. Interestingly, Yan et al. describe generating a custom 3D model to visualize and assess
device closure feasibility based on 3D TEE end systolic dimensions with 29 of 30 patients found to have
deficient posterior-inferior rim size (< 3 mm), providing a proof of concept for simulated in-vivo device
[98]
fitment prior to undergoing transcatheter intervention . Though, caution should be maintained regarding
attempting transcatheter closure with inadequate rim size, as many studies demonstrate increased risk for
device embolization with difficult retrieval or conversion to open surgery [99-102] .

Special issues in the management of elderly patients with ASD
Comparative benefits from ASD closure in the elderly population have historically been underreported
as compared younger populations. The paradigm of non-operative management of previous generations
had, in some ways, stymied broad acceptance and given cause to thwart intervention where there was no
perceived benefit. However, percutaneous management of ASD in elderly patients has gained reluctant
enthusiasm, as evidenced by analyzing trends in hospitalizations captured by the National Inpatient Sample
Database [103-106] . The promise of shorter hospitalization time and reduced complication rates is tempered
with the many difficulties faced perioperatively due to the tendency toward combined comorbidities.
Realistic benefits of ASD closure include symptomatic relief, improvements of functional status as well as
[25]
the overall improvement in the quality of life .