Hydrodynamical evaluation of microporous covered stent for the treatment of intracranial aneurysms: Comparison of flow reduction property with flow diverter stent by using particle imaging velocimetry and in vitro flow simulator

We have developed a microporous covered stent (MCS) for the treatment of intracranial aneurysms (IAs). MCS promotes intentional thrombosis in the IA by blood stagnation and facilitates IA embolization treatment by clotting of whole blood in the IA. Flow reduction is a key property of such stent-type IA embolization devices. In this study, we evaluated the flow reduction property of MCS, and compered that of a general balloon expandable stent (bare stent, BS) for supporting a stenotic vessel and a typical flow diverter stent (FD) for IA treatment. This was carried out using particle imaging velocimetry (PIV) and an in vitro flow simulator with a saccular IA and straight parent vessel model. The PIV results show that the area mean shear rates in the IA flow were reduced to 34.7% (5.56 s–1) for the BS model, 9.2% (1.48 s–1) for the FD model, and 2.7% (0.43 s–1) for the MCS model with respect to the unstented condition (16.04 s–1) at a Reynolds number of 600. Considering that the flow reduction property of the MCS model is three times higher than that of the FD model, it is clear that the MCS facilitates more reliable IA embolization than FD.