Role of the endothelial lining in endoleak formation and persistence after endovascular repair of aneurysm.
OBJECTIVE
To evaluate whether ablation of the endothelial lining of an aneurysm can prevent endoleak persistence after endovascular aneurysm repair (EVAR).


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.
Soulez
Gilles
G
Department of Radiology, University of Montreal and CHUM-Notre Dame, 1560 Sherbrooke East, Montreal, Quebec, Canada. gilles.soulez.chum@ssss.gouv.qc.ca
Lerouge
Sophie
S
Darsaut
Tim
T
Salazkin
Igor
I
Oliva
Vincent L
VL
Raymond
Jean
J
D000792:Angiography; D000818:Animals; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000295:instrumentation*; D003097:Collateral Circulation; D004195:Disease Models, Animal; D004285:Dogs; D004730:Endothelium, Vascular / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D017543:Iliac Aneurysm / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D011475:Prosthesis Failure; D012039:Regional Blood Flow; D015607:Stents; D013997:Time Factors; D018608:Ultrasonography, Doppler; D014945:Wound Healing