Proximal seal dilatation following fenestrated endovascular repair for complex abdominal aortic aneurysms

Although proximal neck dilatation following infrarenal endovascular aneurysm repair (EVAR) is common and is associated with proximal graft failure, little is known about sealing zone dilatation and its clinical relevance following fenestrated EVAR (FEVAR). We studied proximal seal dilatation (PSD) dynamics following FEVAR and assessed its clinical significance.

We included all consecutive patients treated for a juxta-/supra-renal aneurysm with fenestrated EVAR using the Zenith Fenestrated Endovascular Graft (Cook Medical, Bloomington, Ind) from 2008 to 2018 in two large teaching hospitals in the Netherlands. The primary outcome was PSD over time and was determined using a linear mixed-effects model. Secondary outcomes included associations for early PSD and difference in aortic dilatation at the level of the covered stent compared with the bare stent. Proximal seal-related adverse events were also obtained.

Our cohort included 84 patients with a median computed tomography angiography follow-up time of 24.5 months (interquartile range [IQR], 17-42 months). Maximum aneurysm diameter was 60.1 mm (IQR, 56.9-67.2 mm). Mean proximal seal diameter at baseline was 26.2 mm (standard deviation [SD], ±2.8 mm), mean stent oversizing was 20.1% (SD, ±9.1%), and mean proximal seal length was 29.5 mm (SD, ±11.7 mm). Proximal seal dilatation of 1.7 mm (95% confidence interval [CI], 1.4-2.1 mm) was found in the first year, decelerating thereafter (second year, 0.9 mm/year; 95% CI, 0.7-1.1 mm/y). Over 10% PSD at 1 year occurred in 22 patients (27%) and was associated with stent graft oversizing (odds ratio, 1.1; 95% CI, 1.03-1.2; P = .008) and a lower number of target vessels (four fenestrations/ref two fenestrations: odds ratio, 0.13; 95% CI, 0.02-0.74; P = .029). At last available imaging, dilatation difference was higher at the level of the covered stent compared with the bare stent (3.0 mm [IQR, 1.3-5.1 mm] vs 1.6 mm [IQR, 0.8-2.5 mm]; P < .001). During the study period, only one patient (1.2%) developed a proximal seal-related adverse event (type IA endoleak).

PSD is present following FEVAR, occurring at a faster rate in the first year and subsequently decelerating thereafter, similarly to neck dilatation after standard infrarenal EVAR. Although its clinical implication seems to remain limited in the first years following implantation, further research is required to assess the effect of PSD on long-term FEVAR outcomes.