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Jubouri et al. Vessel Plus 2023;7:5 https://dx.doi.org/10.20517/2574-1209.2022.49 Page 3 of 13

Past to present: an overview of aortic arch surgical repair
Conventional vs. frozen elephant trunk
FET and CET (evaluated in Table 1) are similar in terms of the scope of repair of the ascending aorta and
the aortic arch. In both approaches, the entire transverse aortic arch is completely replaced, with a variable
portion of the ascending aorta replaced, leaving a significant portion of unrepaired thoracoabdominal aorta.
Both approaches also successfully mitigate damage to important anatomical structures (e.g., vagus and
recurrent laryngeal nerves, oesophagus, pulmonary artery, and thoracic duct). The primary difference
between the FET and CET is centred on how the dissected portion of the distal thoracic aorta (DTA) is
managed. In the first stage of CET, the dissected proximal DTA is left unrepaired for an inevitable second-
stage procedure, which introduces higher cumulative surgical risk and interval mortality, and it is likely to
be unsuccessful in sealing the false lumen [6-14] . However, FET combines CET and thoracic endovascular
aortic repair (TEVAR) into a single-step hybrid procedure using a hybrid prosthesis to replace the
[15]
ascending aorta and arch and repair the dissected proximal DTA in the same operation . There is
emerging evidence from multiple studies to support that FET performs stronger than CET, with the
exception of spinal cord injury [16,17] .

Best of both worlds: OSR and TEVAR
The introduction of the FET technique for TAR has revolutionised the field of aortic surgery. Since then, it
has become a vital element in the aortic surgeon’s armamentarium. Importantly, the FET surgical approach
is variable; thus, it is actually flexible rather than frozen, as it can be tailored to individual clinical scenarios
and has the potential to be used in all aortic profiles .
[18]

FET is associated with good survival, both in the short and long terms. Upon searching the literature,
30-day mortality rates ranged from 0%-15%, while long-term mortality was low, with one study reporting
100% survival at 3 years post-discharge [19-21] . Aortic remodelling is well-established in the literature as an
important prognostic factor in AD patients following FET. Two recent reviews by Jubouri et al. and
Kayali et al. showed beyond doubt that FET promotes superior aortic remodelling to CET [22,23] . Remodelling
is also observed distally in the descending thoracic aorta and abdominal aorta due to the extended coverage
of the stent-graft portion of the FET hybrid device. Although FET has proven its high safety and
effectiveness, it still carries a risk of complications, with some even requiring secondary reintervention .
[15]
Another study by Kayali et al., along with the aforementioned Geragotellis et al. and Jubouri et al., all
demonstrated the low incidence of complications post-FET as well as the minimal need for secondary
reintervention [15,22,24] .

Interestingly, TER has shown strong potential for becoming the primary management strategy for
dissections and aneurysms of the thoracic aorta instead of FET. Furthermore, although the continuingly
increasing uptake of FET has meant that several FET hybrid prostheses have become commercially
available, the era of FET device development is being overtaken by the new generation of devices for
endoarch repair using TEVAR, marking a turning point in the management strategy of thoracic aortic
disease.

The future: total endovascular arch repair
Device evolution
Since TEVAR was first introduced in 1994, it has become one of the main strategies for tackling a range of
thoracic aortic pathologies. The first TEVAR device was approved later on in 2005 and was initially used in
the treatment of aortic aneurysmal disease. Thereafter, TEVAR indications expanded to include other aortic
pathologies, including type B dissections and penetrating ulcers [25,26] . TEVAR has also gradually become an
option for endovascularly treating dissections and aneurysms involving the aortic arch and root, offering