305 Enhancing Endothelialization of Flow Diverting Stents: An In Vitro Study

Abstract

INTRODUCTION: Flow diverting (FD) stents revolutionized the management of broad neck aneurysms. Several FD stents surface modifications have been developed over the last decade to reduce thromboembolic complications or enhance aneurysmal occlusion rates. Promoting FD endothelization through surface coating has emerged as a novel modality to enhance stent coverage, thus improving aneurysmal occlusion, reducing aneurysmal progression and post-treatment failure. Herein, we report our in vitro experience with FD surface modification using gelatin. METHODS: PED Flex stents were incubated overnight with either PBS (unmodified) or gelatin, followed by a three-hour incubation with human microvascular endothelial cells. Endothelial cell attachment and proliferation were assessed at various time points. RESULTS: There was a significant increase(p < 0.05) in endothelial cell attachment on gelatin(6.3 ± 2.1)surface modified stents compared to unmodified control stents. This increase in endothelial cells was maintained 14 days gelatin 6.3 ± 2.7, fold of control)following cell incubation but gradually decreased until it became insignificant by day 21. Next, we analyzed the temporal rate of endothelial stent coverage. Following cell incubation, 20% of surface-modified stents were coated by endothelial cells on day 5 compared to just 2% in unmodified stents. This difference in cell coverage remained significant (p < 0.05), with surface-modified stents being entirely covered by 2 weeks while unmodified stents were only 50% covered. We also observed a significant increase (p < 0.05, fold of unmodified) in endothelial cell migration onto (1.8 ± 0.2) and from (1.5 ± 0.033) gelatin-coated stents compared to unmodified controls. CONCLUSIONS: Our in vitro experience demonstrates that gelatin has the potential to enhance the endothelialization of FD, leading to increased aneurysm occlusion rates, thereby minimizing post-treatment failure. Further investigations are essential to fully evaluate this novel modality and compare it to the commercially available devices.