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Page 2 of 5 Chang et al. Vessel Plus 2020;4:20 I http://dx.doi.org/10.20517/2574-1209.2020.10

II 9.1 ± 4.5. These patients received endovascular therapy using ZENITH TX2 (Cook, Bloomington, Ind),
GORE C-Tag (Gore Ltd., London, United Kingdom), or Relay NBS (Bolton, Barcelona, Spain). The early
results revealed a technical success rate of 91.7%, all with proper aortic remodeling and low complication
rates (1 transient stroke and 1 death due to wire induced perforation). Follow-up CT scans demonstrated
[4]
good aortic remodeling. In 2020, Ghoreishi et al. reported a single-centre experience of 13 patients with
ascending aorta disease and a mean age of 69 ± 9 years (including 7 patients with ATAAD) using Gore TAG
(CTAG) (W. L. Gore & Associates, Flagstaff, Ariz). 100% technical success (2 with location of zone 0a) was
achieved and proper aortic remodeling was found on follow-up CT scans. Both studies revealed excellent
results in the elderly and patients with comorbidities with TAAD.

[3,4]
In general, the procedure of TEVAR consists of the following steps : (1) a temporary pacing wire is
inserted to the right ventricle via venous cut-down; (2) a pigtail catheter to the left ventricle is navigated
using a soft guide wire through the true lumen under imaging guidance to confirm the location; (3) a
soft guide wire is then exchanged to a stiff guide wire, followed by delivery of the endograft device to the
ascending aorta under rapid ventricular pacing to reduce the windsock effect during graft deployment;
(4) the location of stent-graft, the patency of coronary arteries and arch vessel, the presence of endoleaks,
and the occurrence of aortic regurgitation are evaluated by angiogram; and (5) the pigtail catheter and
temporary pacing wire are retracted and access sites closed.

Nonetheless, issues have emerged from the current status of endovascular repair for ATAAD based on
unmet requirements.

TECHNICAL ASPECTS OF THE PROCEDURE: A REVIEW OF THE LITERATURE
One issue identified is the immediate impact upon deployment of the stent. The lack of specially designed
stents for the ascending aorta not only increases difficulties of the procedure and patient selection,
but also raises concerns of the unknown effects that the stent-graft has on the ascending aorta in the
multiply comorbid patient with poor cardiovascular reserve. In previous studies, it has been reported that
endovascular device made of artificial material was of poor compliance and even Dacron polyester fabric
[5,6]
grafts were four times less compliant compared to native arteries .

Additionally, elderly patients with multiple comorbidities are pro-inflammatory, which leads to systemic
microvascular endothelial inflammation with subsequent myocardial inflammation and fibrosis. This
increases oxidative stress and alternation in cardiomyocyte signaling pathways which promotes cardiac
remodeling and dysfunction. Therefore, it is crucial to explore an ideal stent-graft, which alleviates the
[7]
harmful long-term effects and potential pathogenicity to these susceptible patients .

Anatomical complexities are another issue surgeons face. Following ATAAD, ascending aorta dilatation,
arch dilatation and aortic valve insufficiency can occur, and the walls of the aorta become fragile. In order
to achieve proper fixation and seal of the stent graft, adequate length of landing zone in both proximal
and distal site of the stent is essential. Proximally, the serrated edge of the stent may cover the coronary
orifices or interfere with the commissures of the aortic valve, resulting in an entry tear in the proximal
[8]
third of the aorta close to the sinus-tubular junction or even the sinus portion. Roselli et al. proposed a
modified classification of landing zones, dividing the ascending aorta into zones 0A, 0B and 0C to address
[8]
the anatomical complexity and importance . Diseases extending to zone 0A pathology (from the annulus
to the distal margin of the highest coronary) had significantly worse outcomes than others. Distally,
[9]
Sobocinski et al. analyzed the feasibility of endovascular therapy and revealed that it may be acceptable
to expand the margin of the distal landing zone from the additional debranching of the brachiocephalic
trunk to the left common carotid artery. Of note, orifices of the innovate artery, left common carotid artery
and left subclavian artery are in close proximity, which gives us limited choice of commercial stent-grafts