Sealing Zone Failure Decreases the Long Term Durability of Endovascular Aneurysm Repair.

OBJECTIVE Endovascular aneurysm repair (EVAR) has higher long term aneurysm related mortality compared with open surgery, mainly due to aneurysm rupture. Loss of stent graft-vessel apposition at the EVAR sealing zones is a potential cause of post-EVAR rupture. This study aimed to investigate sealing zone failure and its relation to post-EVAR rupture. METHODS This was a retrospective structured review of pre-operative and post-operative computed tomography (CT) scans of 399 consecutive patients treated with standard bifurcated EVAR. The primary outcome was total loss of seal at last post-operative CT. Secondary outcomes were partial loss of seal, standard follow up detection, post-EVAR rupture, aneurysm sac development, and endoleaks. RESULTS During a median follow up of 5.3 years, total and partial loss of seal occurred in 85 (21.3%) and 78 (19.5%) patients, respectively. Initial mean sealing zone lengths were within current recommendations but decreased over time, mainly due to vessel dilatation. Mean proximal sealing length at one month CT was 15.5 ± 10.5 mm (95% confidence interval [CI] 12.6 - 18.5 mm) in the group with total loss of seal, 14.3 ± 6.9 mm (95% CI 12.2 - 16.4 mm) with partial loss of seal, and 23.2 ± 7.4 mm (95% CI 22.3 - 24.0 mm) with preserved seal through follow up (p < .001). Mean iliac sealing lengths were 22.4 ± 12.1 mm (95% CI 18.9 - 25.8 mm) if total loss and 21.8 ± 10.0 mm (95% CI 19.6 - 24.0 mm) if partial loss of seal vs. 34.7 ± 12.4 mm (95% CI 33.8 - 35.7 mm) if preserved seal. Larger vessel diameters were associated with loss of seal both in proximal and distal sealing zones. During the study period, 13 post-EVAR ruptures occurred, all preceded by CT findings of total (n = 7) or partial (n = 6) loss of seal. Aneurysm sac expansion was seen in 40% of patients with total loss of seal, 18% with partial loss of seal, and 6.6% with preserved seal. CONCLUSION Loss of seal after EVAR is frequent and associated with post-EVAR rupture. Increased recommended sealing zones lengths and focus on sealing zones in surveillance may reduce post-EVAR ruptures and aneurysm related mortality.