Page 80 - Read Online

Page 8 of 14 Squizzato et al. Vessel Plus 2023;7:16 https://dx.doi.org/10.20517/2574-1209.2023.05

associated benefits. Alternative options, such as the use of dedicated branched/fenestrated endografts,
physician-modified grafts, or chimney grafts, can also be considered to enable the utilization of more
proximal landing zones. However, it is important to note that physician-modified endografts are considered
off-label and should only be contemplated in highly specific and carefully selected cases where standard off-
the-shelf or custom-made devices are not available.

Custom-made devices are gaining importance in treating challenging anatomies. Nonetheless, it is essential
to recognize that the sealing zone of these devices differs from that of standard TEVAR due to the presence
of fenestrations and branches, thus necessitating a distinct analysis and consideration.

In cases where achieving an optimal sealing length is not feasible, a more rigorous follow-up after TEVAR
may be recommended, particularly for patients with challenging anatomies. (2) During the procedure, the
sealing length within the planned landing zone should be maximized. Therefore, stent graft deployment
accuracy has great value. To increase the precision of deployment, some ancillary techniques may be used.
Different methods to reduce aortic blood wave impulse have been described and the most widely accepted
seems to be rapid pacing, venous inflow occlusion or pharmacological induced hypotension. Rapid pacing
seems to meet the criteria of safety and efficacy together with the shortest duration of induced hypotension
and quick recovery after cessation .
[34]

SPECIFIC PATHOLOGY CONSIDERATIONS
Acute or subacute aortic dissection
Thoracic endovascular aortic repair (TEVAR) has become the standard treatment for complicated type B
aortic dissections (TBADs), and is also gaining importance in the treatment of uncomplicated dissections
during the subacute or early chronic phase. In these cases, the aim of TEVAR is to cover the entry tear,
direct the flow into the true lumen, and promote false lumen thrombosis. As usual, at least 2 cm of proximal
healthy aorta is recommended as proximal sealing length, but the definition of a “healthy” aorta may not be
straightforward in these cases. The false lumen often extends proximally over the intimal tear; therefore,
coverage of one or more SATs may be required [Figure 6].

A clear inverse relationship has been described between the proximal sealing length and associated adverse
outcomes [30,32] ; particularly, it has been demonstrated that landing in non-healthy aorta, where there is
evidence of intramural hematoma, substantially increases the risk of retrograde dissection.

Therefore, in order to avoid dreadful complications such as retrograde dissection, and promote long-term
durability, at least 2 cm of non-dissected aorta should be covered.

Another important point is that a 1:1 oversize is usually sufficient, and an excessive oversize is associated
[35]
with the risk of RTAD. For the same reason, the use of proximal free-flow or barbs should be avoided .

Anatomical factors may contribute to the complexity of TEVAR for acute type B dissections. The arch
anatomy correlates with the risk of aortic dissection, through the creation of fluidodynamic effects that
favor the formation of the intimal tear. In particular, type III arch is associated with a specific, consistent
and abnormal secondary flow pattern, which may account for its high prevalence in patients with type B
aortic dissection .
[36]