Role of the endothelial lining in endoleak formation and persistence after endovascular repair of aneurysm.

Abstract

PURPOSE: To evaluate whether ablation of the endothelial lining of an aneurysm can prevent endoleak persistence after endovascular aneurysm repair (EVAR). MATERIALS AND METHODS: Bilateral aneurysms were constructed in common iliac arteries in three different experimental groups. In group 1 (six dogs), 12 aneurysms without collateral outflow were created, the endothelial layer was removed on one side, and stent-grafts were implanted immediately after surgery with endovascular creation of a type I endoleak. In group 2 (six dogs), the same experiment was performed in aneurysms with collateral outflow. In group 3 (three dogs), six aneurysms with collateral outflow were denuded, but stent-grafts were implanted 3 months later. Follow-up imaging was performed with Doppler ultrasonography (US) and angiography until animal sacrifice 3 months after EVAR. Leak persistence and healing were also evaluated with macroscopic and histopathologic examination. RESULTS: Type I endoleaks persisted in all endothelialized group 1 aneurysms (six of six), but in none that were denuded before stent-graft implantation (P = .03). The ratio between the maximum diameter of the aneurysm measured before sacrifice and at baseline was significantly lower in denuded aneurysms than in aneurysms with an intact endothelial layer (74% vs 92%, P = .003). Endoleaks were observed in all aneurysms of groups 2 (denuded and intact endothelium) and 3. All endoleak areas were surrounded by endothelial lining. CONCLUSIONS: In this animal model of EVAR, ablation of the endothelial lining promotes long-term endoleak thrombosis after EVAR. The presence of collateral flow can promote re-endothelialization and endoleak persistence.