Heterogeneous model to evaluate CFD in intracranial bifurcation aneurysms treated with the WEB device to predict angiographic outcome.

INTRODUCTION: The Woven EndoBridge device (WEB) was developed as an alternative to treat Wide-Necked bifurcation aneurysms. It has proven to be effective and safe, however, cases of recanalization have been reported. The purpose of this study was to evaluate and quantify hemodynamic parameters and indexes with CFD of the intracranial aneurysms before and after WEB simulation and to establish their relationship to complete occlusion. MATERIALS AND METHODS: Using the heterogeneous model based on the marching cubes algorithm, we created 3D representations of 27 bifurcated intracranial aneurysms treated with the single-layer WEB device to evaluate hemodynamics parameters with CFD, calculated with and without the WEB. RESULTS: We observed a lower treatment entry concentration indices (ICI) (2.12 ± 1.31 versus 3.14 ± 0.93, p-value: 0.029) previous to placement of WEB and higher pre-treatment FN (7.56 ± 5.92 versus 3.35 ± 1.51, p-value: 0.018) and post-treatment FN (5.34 ± 5.89 versus 1.99 ± 0.83, p-value: 0.021) for cases with successful occlusions. Lower post-treatment SRa (197.81 ± 221.29 versus 80.02 ± 45.25, p-value: 0.044) and higher pre (0.11 ± 0.07 versus 0.25 ± 0.19, p-value: 0.011) and post-treatment MATT (0.69 ± 1.23 versus 1.02 ± 0.46, p-value: 0.006) were observed in non-occluded cases. CONCLUSIONS: In our CFD analysis of the hemodynamic parameters of IA, we found lower ICI before the placement of the WEB device and higher FN pre- and post-treatment for cases with successful occlusions. Non-occluded cases had lower post-treatment SRa and higher pre-treatment and post-treatment MATT.

A single centre retrospective analysis of short- and medium-term outcomes using the Woven EndoBridge (WEB) device and identification of the device-to-aneurysm volume ratio as a potential predictor of aneurysm occlusion status.

BACKGROUND: The Woven EndoBridge (WEB) is a potential treatment option in patients with wide-necked bifurcation aneurysms (WNBAs). We analysed our WEB device outcomes (occlusion rates and complications) and studied factors that may predict aneurysm occlusion status at short- and medium-term follow-up. METHODS: 74 patients with ruptured and unruptured aneurysms underwent treatment with the WEB device over a 5-year period. Simple hypothesis tests assessed differences between treated ruptured and unruptured aneurysms. Univariable binary logistic regression was used to assess the effect of age, gender, and aneurysm location on the likelihood of adequate occlusion at six months. Aneurysm dimentions including device-to-aneurysm volume (DAV) ratios were compared between adequately and inadequately occluded aneurysms. RESULTS: The mean age at the time of the procedure was 58.2 years (SD 12.2; range 34-88) and the male to female ratio was 1:2.7. Middle cerebral artery (MCA) was the most commonly treated aneurysm. There was no significant difference in occlusion rates between ruptured and unruptured aneurysms. The six- and 18-month angiographic follow-up data was available for 61 and 32 patients respectively with adequate occlusion rates of 78.7% (48/61) and 78.1% (25/32). Procedure-related complications occurred in 6 patients (8.1%). Baseline DAV ratio was found to be significantly higher in aneurysms that were adequately occluded at both short- (p-value 0.015) and medium-term (p-value 0.047) follow-up. CONCLUSIONS: WEB devices are a safe and effective endovascular treatment option for WNBAs. WEB device selection incorporating the peri-procedural DAV ratio may help improve the accuracy of device sizing thereby improving the successful occlusion rate.

Simulation of intra-saccular devices for pre-operative device size selection: Method and validation for sizing and porosity simulation.

Intra-saccular devices (ID) are novel braided devices used for complex intracranial aneurysms treatment. Treatment success is associated with correct device size selection. A technique that predicts the ID size within the aneurysm before intervention will provide a powerful computational tool to aid the interventionist during device selection. We present a method to calculate the device's final height, radial expansion and porosity within the patient's anatomy, which allows assessing different device sizes before treatment takes place. The proposed sizing technique was tested in-vitro and in real patient's geometries obtained from 3DRA angiographic images of 8 unruptured aneurysms previously treated with IDs. The obtained simulated height was compared to the real height, with a mean error of less than 0.28 mm (±0.44). The porosity calculation method was tested in-vitro with an error of 0.02 (±0.022). The results of both sizing and porosity experiments resemble well measures from real patients. This methodology could be used before treatment to provide the interventionist with additional information that allows selecting the device that best fits the patient's aneurysm to be treated.

Intra-saccular device modeling for treatment planning of intracranial aneurysms: from morphology to hemodynamics.

MOTIVATION: Intra-saccular devices (ID), developed for the treatment of bifurcation aneurysms, offer new alternatives for treating complex terminal and bifurcation aneurysms. In this work, a complete workflow going from medical images to post-treatment CFD analysis is described and used in the assessment of a concrete clinical problem. MATERIALS AND METHODS: Two different intra-saccular device sizes were virtually implanted in 3D models of the patient vasculature using the ID-Fit method. After deployment, the local porosity at the closed end of the device in contact with the blood flow was computed. This porosity was then used to produce a CFD porous medium model of the device. Velocities and wall shear stress were assessed for each model. RESULTS: Six patients treated with intra-saccular devices were included in this work. For each case, 2 different device sizes were virtually implanted and 3 CFD simulations were performed: after deployment simulation with each size and before deployment simulation (untreated). A visible reduction in velocities was observed after device implantation. Velocity and WSS reduction was statistically significant (K-S statistics, [Formula: see text]). CONCLUSIONS: Placement of different device size can lead to a partial filling of the aneurysm, either at the dome or at the neck, depending on the particular positioning by the interventionist. The methodology used in this work can have a strong clinical impact, since it provides additional information in the process of device selection using preoperative data.