Endothelial denudation combined with embolization in the prevention of endoleaks after endovascular aneurysm repair: an animal study.

Objective: To test whether combining embolization with endothelial denudation could reduce endoleak persistence and recurrence after endovascular aneurysm repair (EVAR) in an animal model.

Methods: Type I endoleaks with collateral outflow were created in bilateral iliac aneurysms in 12 dogs. In 6 animals (group 1), endoleaks were treated by thrombin injection, with or without mechanical denudation of the endothelium. In the other 6 animals (group 2), simultaneous occlusion and endothelial denudation was induced in one side by treatment with a gel containing ethanol, ethylcellulose, and lipiodol, whereas the other side was treated with saline control. Follow-up ultrasonography and angiography were performed before necropsy and histology at 3 months.

Results: Denudation combined with thrombin injection led to higher aneurysm shrinkage than thrombin alone, as shown by the mean relative aneurysm diameter (89% vs. 124% at baseline, p<0.01) and length (61% vs. 82% at baseline, p<0.01). Denudation did not significantly reduce endoleak occurrence (4/6 vs. 6/6); however, endoleaks in denuded aneurysms were significantly smaller and located in areas inaccessible to denudation. Six of the 10 endoleaks seen at 3 months occurred despite complete initial occlusion (recurrent endoleaks). In the gel-treated group, embolized aneurysms did not shrink significantly, and stent-graft thrombosis developed in 3/6 embolized aneurysms; however, the 3 other aneurysms showed no endoleaks, while all 6 saline-treated controls exhibited persistent endoleaks.

Conclusions: This study demonstrates the role of recanalization in endoleak recurrence and indicates that combining embolization and endothelial denudation could be a promising strategy to prevent endoleak persistence or recurrence after EVAR. However, the sclerosing gel tested in this study is not appropriate since it is prone to migration with resultant stent-graft thrombosis.