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Page 2 of 9 Buia et al. Vessel Plus 2022;6:48 https://dx.doi.org/10.20517/2574-1209.2022.04

INTRODUCTION
In 2008, the IRAD group endorsed thoracic endovascular aortic repair (TEVAR) as the gold standard for
[1]
the treatment of complicated acute type B aortic dissection (TBAD) . Subsequently, several studies clearly
confirmed the superiority of TEVAR to surgical or medical therapy in the treatment of this life-threatening
[4]
[5]
[2,3]
circumstance . Moreover, during the last decade, the INSTEAD-XL and ABSORB trials demonstrated
how TEVAR can play an emergent role in the management of uncomplicated acute TBAD in selected
patients with high-risk features, even if many aspects remain to be clarified. Less encouraging results
emerged regarding TEVAR for chronic post-dissection thoracoabdominal aortic aneurysms, with complete
thrombosis of false lumen (FL) in only 30% of cases and a reintervention rate of 60% . In all these
[7]
[6]
situations, the goal of TEVAR is to cover the intimal tears promoting thrombosis of the FL. However, about
20% of patients undergoing TEVAR of aortic dissection require reintervention because of incomplete FL
thrombosis promoting aortic wall degeneration, post-dissection aortic aneurysm, and rupture . Incomplete
[8]
thrombosis of the FL can affect the long-term survival of these patients, increasing late mortality [9-11] . Over
the past decades, endovascular strategies to promote FL thrombosis after TEVAR showed good early results
with minimal invasiveness, offering different alternatives according to the anatomy and the level of urgency.
The most important endovascular techniques described include FL embolization (with coils, vascular plugs,
etc.), candy-plug techniques, branched and fenestrated aortic endoprosthesis, and parallel stent graft
technique. Each of these solutions has advantages and disadvantages. In this focused paper, we provide a
brief description of endovascular options available to induce false lumen thrombosis after TEVAR in TBAD
together with a commentary based on our experience.

FL EMBOLIZATION
Currently, there are no devices specifically designed for FL embolization. In 2018, Yuan et al. described the
FLIRT (false lumen intervention to promote remodeling and thrombosis) concept in aortic dissection, using
a combination of patent foramen ovale or atrial septal defect occluders, glue, and coils . In 4/5 cases of
[12]
persistent flow in FL in patients with TBAD previously treated with TEVAR, complete thrombosis was
obtained with the FLIRT concept. Miletic et al. recently described the use of a combination of different
devices in FL embolization, including iliac plugs, coils, and nitinol plugs in 51 patients, with a favorable
aortic remodeling (FL thrombosis with ≥ 10% decrease in diameter and ≥ 10% increase in true lumen
diameter) achieved in 39.2% of cases . Moreover, a complete obliteration of the entire FL was obtained in
[13]
six patients, with only nine patients requiring a second procedure for incomplete thrombosis of FL and
aortic diameter increase. In all these and other studies, FL embolization proved to be feasible and safe.
Technically, the most important aspect of the intervention is a meticulous study of the pre-procedural CT
scan, in order to plan how to “earn” the FL and choose the right devices, based on the anatomy of the
dissection [Figure 1]. Moreover, to choose the size, type, and number of all devices available for the
embolization of the false lumen, fundamental is the measurement of the diameter of the false lumen above
the celiac trunk and its longitudinal extension and the angiographic check during the procedure to ensure
the effectiveness of the embolization. Usually, during this procedure, we gain the false lumen using first a
0.035 floppy guide wire with a diagnostic peripheral catheter (e.g., cobra, vertebral, multipurpose, or
Simmons, depending on the anatomy of the dissection). Then, once in the false lumen, it can be useful to
place an introducer sheath to give more stability to the system as well as the possibility to use a diagnostic
catheter or a microcatheter for the deployment of coils and embolic liquid, or directly the introducer sheath
for the deployment of other devices such as vascular plugs. If suitable, a combination of all devices should
be considered to stop the backflow in the false lumen.

The prompt availability of the devices and their low costs make the embolization of the false lumen
advantageous, especially in the management of selected urgent and emergency cases.