Commentary: Mechanism of Action and Biology of Flow Diverters in the Treatment of Intracranial Aneurysms

The authors1 did an excellent job of summarizing where things stand at the present time in terms of our understanding of the mechanism of action of flow diversion and the biology that is occurring at the vessel wall. Flow diversion technology has refused interest from a clinical standpoint and vessel wall healing. The entire biology of endothelial progenitor cells has made great strides as we study the vessel's response to the placement of a tightly woven flow diverter on and into the wall of the vessel. Some of the radiographic images we see in the follow-up of aneurysms treated with flow diversion are truly remarkable. Vessels that were completely tortuous and fusiform at the time of treatment appear normal 1 to 2 yr after the treatment. Flow diversion biology has clearly proven that adult individuals harbor the ability to completely remodel the wall of fully developed mature blood vessels. The implications of this are great in that there is potential further work to be done in modulating the biological response to flow diverter placement. Future flow diversion technology with intraluminal flow diversion can benefit from what we are learning with the intravascular placement of flow diverters. There is some evidence that patients older than 70 have a decreased response in terms of aneurysmal obliteration when using flow diversion. This raises the question as to whether the endothelial response after thrombosis is as robust in older patients. It also opens the possibility to modulating this response with suppressors or enhancers of the endothelial growth process. While aneurysmal thrombosis is clearly a big part of how flow diverters actually work, the re-endothelialization may be the final step in curing an intracranial aneurysm treated with flow diverters. One can only be excited in reading this paper as to the future possibilities of what can be learned in the utilization and modification of the biological response to vessel injury and repair. Disclosures Outside of publication in this supplement, the author has no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article.