In vitro and in silico study of intracranial stent treatments for cerebral aneurysms: effects on perforating vessel flows.

BACKGROUND Many cerebral aneurysms can be treated effectively with intracranial stents. Unfortunately, stents can occlude perforating vessels near the treatment site which can decrease cerebral perfusion and increase the risk of stroke. METHODS Particle image velocimetry was used to investigate the effects of intracranial stents on flows in perforators near a treated aneurysm. In Phase 1 of the study, different stent configurations were deployed into an idealized physical model of a sidewall aneurysm with perforating vessels. The configurations investigated were the Pipeline embolization device (PED) and one, two and three telescoping Neuroform stents. In Phase 2 of the study a single Neuroform stent was deployed so that the stent struts directly occluded the perforating vessel. RESULTS In Phase 1 of the study it was found that even three telescoping stents affected perforating vessel flow less than a single PED under pulsatile conditions (average reduction 32.7% vs 46.5%). Results from Phase 2 indicated that the location of the occluding strut across the perforating vessel orifice had a greater impact on perforating vessel flow than the percentage occlusion. CONCLUSION The findings of this study show that the use, configuration and positioning of intracranial stents can all have considerable influence on flow in affected perforating vessels near treated cerebral aneurysms.