Comparison of Flow Reduction Efficacy of Nominal and Oversized Flow Diverters Using aNovel Measurement-assisted in Silico Method.

Abstract

The high efficacy of flow diverters (FD) in the case of wide-neck aneurysms is well demonstrated, yet new challenges have arisen because of reported posttreatment failures and the growing number of new generation of devices. Our aim is to present ameasurement-supported in silico workflow that automates the virtual deployment and subsequent hemodynamic analysis of FDs. In this work, the objective is to analyze the effects of FD deployment variability of two manufacturers on posttreatment flow reduction. The virtual deployment procedure is based on detailed mechanical calibration of the flow diverters, while the flow representation is based on hydrodynamic resistance (HR) measurements. Computational fluid dynamic simulations resulted in 5 untreated and 80virtually treated scenarios, including 2 FD designs in nominal and oversized deployment states. The simulated aneurysmal velocity reduction (AMVR) is correlated with the HR values and deployment scenarios. The linear HR coefficient and AMVR revealed apower-law relationship considering all 80 deployments. In nominal deployment scenarios, asignificantly larger average AMVR was obtained (60.3%) for the 64-wire FDs than for 48-wire FDs (51.9%). In oversized deployments, the average AMVR was almost the same for 64-wire and 48-wire device types, 27.5% and 25.7%, respectively. The applicability of our numerical workflow was demonstrated, also in large-scale hemodynamic investigations. The study revealed arobust power-law relationship between aHR coefficient and AMVR. Furthermore, the 64wire configurations in nominal sizing produced asignificantly higher posttreatment flow reduction, replicating the results of other in vitro studies.