Endothelialization following Flow Diversion for Intracranial Aneurysms: A Systematic Review

BACKGROUND:

The underlying mechanism of action of flow diverters is believed to be the induction of aneurysm thrombosis and simultaneous endothelial cell growth along the device struts, thereby facilitating aneurysm exclusion from the circulation. Although extensive attention has been paid to the role of altered cerebrovascular hemodynamics using computational fluid dynamics analyses, relatively less emphasis has been placed on the role of the vascular endothelium in promoting aneurysm healing.

PURPOSE:

Our aim was to systematically review all available literature investigating the mechanism of action of flow diverters in both human patients and preclinical models.

DATA SOURCES:

A systematic search of PubMed, Cochrane Central Register of Controlled Trials MEDLINE, EMBASE, and the Web of Science electronic data bases was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

STUDY SELECTION:

We selected articles assessing the role of endothelialization in flow-diverter treatment of cerebral aneurysms, including both preclinical and clinical studies.

DATA ANALYSIS:

Ten articles were eligible for inclusion in this review. Two assessed endothelialization in human patients, while the other 8 used preclinical models (either rabbits or pigs).

DATA SYNTHESIS:

Methods used to assess endothelialization included optical coherence tomography and scanning electron microscopy.

LIMITATIONS:

A limitation was the heterogeneity of studies.

CONCLUSIONS:

Current data regarding the temporal relationship to flow-diverter placement has largely been derived from work in preclinical animal models. Whether these cells along the device struts originate from adjacent endothelial cells or are the result of homing of circulating endothelial progenitor cells is equivocal.