Quantification of volume changes in the descending aorta after frozen elephant trunk procedure using the Thoraflex hybrid prosthesis for type A aortic dissection

Abstract

Background: Frozen elephant trunk (FET) is an established approach to reduce late complications of type A aortic dissection (AADA) by diminishing false lumen perfusion. Currently, surface size of aortic lumina are evaluated using Computed tomography (CT). However, this 2D method is prone to error as it evaluates dissection progression slice by slice. Volume measurement on the other hand can overcome this limitation and deliver better insights in aortic remodeling. Therefore, the aim was to quantify volume changes of the descending and abdominal aorta at short-and mid-term follow-up after FET. Methods: Between April 2015 and March 2018, 20 patients who underwent surgical repair of AADA using the Thoraflex™ Hybrid Plexus (Vascutek, Terumo Aortic, Scotland) were included in this study. We measured volumetric change before surgical treatment, at discharge, at 12 and at 24 months based on CTAs (Computed tomography angiography). Surfaces and volumes have been analyzed using Aquarius iNtuition (TeraRecon Inc., Foster City, CA, USA). Results: One hundred fifty-eight volumetric measures were obtained. The findings show a significant increase of volume of the true lumen (TL) while surface measurement of the TL did not show any significant change at other levels besides level C (diaphragm, P=0.00193). Variance analysis showed significant increase of volume, whereas no significant change was seen in false lumen. Post-hoc analysis revealed a significance at 24 months (P=0.047). Conclusions: Although previous studies outline the clinical benefit of Thoraflex hybrid prosthesis on short-term follow up, this study provides a more precise understanding of aortic remodeling based on volumetric measurement. Thus, quantification of volume changes should be included for the assessment of optimal follow-up timing and consecutive procedure planning.

Incidence of Distal Stent Graft Induced New Entry vs. Aortic Remodeling Associated With Frozen Elephant Trunk

“…These long-term outcomes seem to be congruent a previous 2018 study, where chronic dissection patients showed significant TL expansion (15 ± 17 mm to 28 ± 2 mm) (p = 0.001) and FL diameter drop (40 ± 11 mm to 32 ± 17 mm) (p = 0.026) 2 years following the procedure (15). Additionally, Usai et al (14) confirmed that in their study almost all Thoraflex Hybrid TM patients had significant TL expansion and reported only 1 patient required reintervention, due to a FL aneurysm. Furthermore, the authors also noted that the most significant growth in the surface TL measurement was at the level of the diaphragm (p = 0.00193) (14).…”

Aortic remodelling and false lumen changes after the frozen elephant trunk technique using the thoraflex hybrid stented graft for aortic dissection

“…Our results, however, contradict those of Weiss et al which did not find, significant change in both diameters [ 1 ]. With regards to true lumen expansion, our results are in agreement of Marco et al [ 7 ] who studied the lumens at the level of celiac axis and pulmonary bifurcation, however, in our study, at the level of the pulmonary bifurcation the distal part of the stent was almost always present and not the actual unstented part of the true lumen. Similarly, Song et al [ 8 ] showed true lumen expansion at the level of the diaphragm and the celiac axis.…”

Post-implantation syndrome after frozen elephant trunk is associated with the volume of new-onset aortic thrombus

“…This could be related to remodelling of the aorta after the Thoraflex hybrid prosthesis implantation in the acute dissection group. This is supported by recently published data demonstrating significant volume changes in true lumen in the descending aorta after FET procedure using the Thoraflex hybrid prosthesis (11). We were able to show that use of the FET procedure for acute aortic dissection leads to a statistically measurable increase in the true lumen volume from the left subclavian artery to the celiac trunk at the short-term follow-up examination (upon discharge) (11).…”

“…The FET technique has been described early (11). A prophylactic antibiotic (Cefazolin, 2 g) was routinely administered to all patients before and after the procedure (for 24 hours).…”

“…Preoperative chronic mural thrombus and the postoperative total volume of thrombus were measured in the venous phase. The new-onset thrombus volume was obtained by subtracting the preoperative chronic mural thrombus measured volume from the postoperative total thrombus measured volume (11). Previous volume rendering methods are shown in Figure 2.…”