1. Introduction
The management of complex pathologies of the thoracic aorta have always
presented a challenge to surgeons due to the high associated risk of
morbidity and mortality. The introduction of frozen elephant trunk (FET)
technique facilitated total arch replacement (TAR) procedures by
shortening the aortic occlusion time for proximal anastomosis, providing
the opportunity of treating complex aorta pathologies in a single-step
procedure, or by offering a more optimal landing zone for secondary
endovascular intervention if needed [1]. Due to its hybrid approach,
FET has gained great popularity in the field of aortovascular surgery,
and since its introduction, it has become the mainstay technique for TAR
in a wide spectrum of complex thoracic aortic diseases.
The indications for the FET procedure include chronic aortic aneurysms,
acute and chronic type B dissections in cases where endovascular
treatment is contraindicated, and furthermore, acute or chronic type A
aortic dissections (TAAD) [2]. Despite the highly favorable results
associated with FET, particularly aortic remodeling in terms of true
lumen (TL) flow maintenance and false lumen (FL) obliteration, the rates
of reinterventions following the procedure are minor but present
[3-6].
Stent graft-induced new entry (SINE) is one of the major complications
of FET defined as a new tear occurring either at the distal or proximal
end of the stent-graft portion of the FET device that is caused by the
stent-graft itself [7]. This complication was first identified and
documented by Ninomiya et al. [8] in 2002, but was named “SINE”
later on by Dong et al. [7] in 2010. The incidence of distal SINE
(dSINE) post-FET has been associated with the stent-graft size and
length, aortic pathology type and location, and the distal landing zone
of the FET hybrid prosthesis (HP). Other complications of the FET
procedure are, but not limited to, endoleak, spinal cord injury (SCI),
renal complications, cerebrovascular events and graft kinking. Yet, it
is important to note that the incidence of the above postoperative
events is lower with FET compared to conventional arch replacement
techniques [9, 10, 11].
Several commercial FET HPs exist on the global market, these include
Thoraflex Hybrid (Terumo Aortic, Inchinnan, Scotland, UK), E-Vita (JOTEC
GmbH, Hechingen, Germany), J Graft Frozenix (Lifeline Co, Ltd, Tokyo,
Japan) and Cronus (MicroPort Medical Co, Ltd, Shanghai, China). However,
overall evidence in the literature seem to suggest that the Thoraflex
Hybrid (or THP) is the superior FET devices on the arch prosthesis
market [9, 10]. Nevertheless, the literature also describes
controversial evidence on the association between the aforementioned
commercially-available FET devices and clinical outcomes. This
meta-analysis aimed to provide a wide and comprehensive perspective on
the relationship between FET device type and results, including aortic
remodeling and other complications such as dSINE and endoleak.