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Rodrigues et al. Vessel Plus 2024;8:10 https://dx.doi.org/10.20517/2574-1209.2023.109 Page 5 of 15

recently by wider adaptation of sheaths with more successful hemostatic valves. Importantly, at 3 years,
patient survival (68% ± 4% vs. 67% ± 8%; P = 0.11), freedom from reintervention (68% ± 4% vs. 68% ± 8%;
P = 0.17), primary (94% ± 2% vs. 92% ± 2%; P = 0.64) and secondary target vessel patency
(98% ± 1% vs. 98% ± 1%; P = 0.89), and freedom from renal function deterioration (75% ± 4% vs. 65% ± 6%;
P = 0.24) were similar for patients treated by PMEGs or PSMDs, respectively .
[32]
An important advantage of a patient-specific stent graft is its versatility of design, allowing it to precisely
address anatomic differences, such as number of vessels to incorporate, its position, direction, and selection
of fenestrations or branches. Single- (10 mm), double- (20 mm), or triple- (30 mm) wide scallops may be
manufactured for artery incorporation (albeit not for TAAA) or for catheterization of the device lumen and
directional branches can be internal, external, downgoing or upgoing. The graft diameter can be planned
with different tapers to better accommodate aortic diameters, and lower profile devices have emerged with
smaller delivery systems, such as 20F or even 18F, thus avoiding the use of iliac conduits and decreasing
[35]
risks of vascular complications .

Currently, the Gore Excluder Thoracoabdominal Multi-Branched Endoprosthesis (TAMBE, W.L. Gore &
Associates Inc, Flagstaff, AZ) and the Cook Zenith t-Branch graft (Cook Medical, Bloomington, IN, USA)
are off-the-shelf alternatives with four downgoing branches; The TAMBE device is currently being
investigated in a pivotal trial at selected US centers and likely will be commercially available in the near
future for anatomically suitable patients with thoracoabdominal pathology [34,36,37] [Table 1]. Experience with
the Cook T-Branch is extensive outside of the USA, with encouraging results including in patients with
[38]
urgent and emergent presentations [Figures 3 and 4].
Selection of branches or fenestrations
To ensure correct diagnosis and planning, accurate imaging of the complete aortic system and its vessels is
mandatory, with computed tomography angiography being the preferred method. Images should be input
into a software capable of reconstruction using the centerline of flow, enabling accurate measurement of
distances, anatomy of target vessels, aortic size, and angulation. The paramount parameter that should be
assessed is the proximal landing zone (PLZ) to certify that attachment sites are free from calcification and
thrombus in a healthy aortic segment with suitable angulation [2,39] . A proximal landing zone of at least
25 mm is necessary for durable endovascular repair. Anatomic contraindications to the procedure, such as
multiple small-diameter target arteries (< 4 mm), excessive angulation, and early bifurcations, should be
[2]
identified prior to the procedure .

In order to incorporate target vessels, the most commonly used methods are fenestrations, directional
branches, or a combination of both configurations. While each approach has its benefits and drawbacks,
fenestrations are typically preferred for smaller aortic diameters or target arteries with cranial or transverse
orientations, while directional branches are favored for wider aortic segments or target arteries that are
caudally oriented and tortuous [40,41] . Target arteries that present with early bifurcations are an important
factor that should be assessed and, depending on the vessel, imposes technical challenges that could be
considered a relative or absolute contraindication to the procedure. Renal arteries and accessory renal
arteries with a minimal diameter of 4 mm should be incorporated as coverage or embolization of accessory
renal vessels represents a potential risk of acute kidney injury (AKI) and compromised long-term renal
function [39,42] .

A large space between the aortic endoprosthesis and a target artery ostium is associated with an increased
risk of target artery endoleak and potential future reinterventions. Chait et al. demonstrated that the