Magnetic Endothelialization of Flow Diverters to Promote Rapid Healing of Cerebral Aneurysms
Abstract
Cerebral aneurysms are dilations of normal vasculature in the brain. When patients are diagnosed with a cerebral aneurysm there are many different treatment options, but one of the newest treatments is flow diversion. Flow diverters create a barrier over the neck of the aneurysm that restores flow to the parent vessel and away from the aneurysm. While these devices have high success rates thus far, they are still associated with some clinical issues such as in-stent thrombosis, delayed aneurysmal occlusion, and side brand occlusion. To mitigate this the current standard of treatment includes a dual anti-platelet therapy regimen which poses a problem for patients that cannot endure antiplatelet therapies and increases the chances of adverse bleeding events. One way to inhibit in-stent thrombosis and promote aneurysm occlusion naturally is through the endothelialization of the luminal surface of flow diverters which subsequently leads to the development of a natural tissue layer over the device. Therefore, the purpose of this investigation is to evaluate the efficacy of magnetic cell capture for the endothelialization of flow diverters to more rapidly endothelialize the luminal surface of the devices. To evaluate this 2205 duplex stainless steel flow diverters and cobalt chromium flow diverters underwent magnetic characterization, were evaluated for magnetic cell capture capabilities, and were evaluated for magnetic cell retention capabilities. Magnetic characterization was performed by magnetizing flow diverters with a neodymium magnet, and then the magnetic field strength was measured both inside and outside of an external magnetic field. Cell capture was evaluated after completing a cell seeding protocol and measuring the average cell density using CellTiter-Glo 3D (Promega Corporation, Madison, WI). Cell retention built off of cell capture and exposed the seeded flow diverters to physiologic levels of wall shear stress before measuring the average cell density. The results of these experiments showed that the 2205 duplex stainless steel flow diverters capture and retain a significantly higher density of cells than the non-magnetic cobalt chromium flow diverters. Therefore, this method of endothelialization can potentially help in more rapidly endothelializing the luminal surface of flow diverters to prevent in-device thrombosis and promote aneurysm occlusion.