Analysis of the treatment effect of the Contour Neurovascular System in intracranial aneurysms: Larger neck coverage area is associated with longitudinal flow reduction

BACKGROUND: The Contour Neurovascular System (Contour) is a novel device designed for the endovascular treatment of wide-necked bifurcation aneurysms (WNBAs). While clinical reports have shown promising results, some cases have failed to achieve satisfactory angiographic outcomes, and the mechanisms driving these differences remain unclear. Detailed hemodynamic analysis is critical to understanding the device's performance and optimizing treatment strategies. METHODS: Based on in vivo medical images of eight patients from eight pre-, eight post-interventional, six first, and six second follow-up examinations, virtual configurations of the Contour placements were established. Based on a complex workflow, the realistic in vivo Contour deformation was virtually simulated. Subsequently, 28 patient-specific hemodynamic simulations were performed, analyzing the intra-aneurysmal blood flow in detail. Neck- and aneurysm-related hemodynamics and morphological changes in Contour and ostium over time were assessed and correlated. RESULTS: The Contour reduced time-averaged intra-aneurysmal velocity (TAv) and wall shear stress (TAWSS) significantly post-intervention in all cases (mean TAv: pre = 0.1 m/s, post = 0.04 m/s; mean TAWSS: pre = 0.57 Pa, post = 0.16 Pa). Long-term follow-up analysis showed a significant reduction when compared to the pre-interventional state. Due to the limitation of missing thrombus modeling, no longitudinal reduction could be derived. Uncovered ostium area was significantly related to TAv and neck inflow rate over time. CONCLUSIONS: In this study the immediate efficacy of the Contour on reducing flow into WNBAs based on in vivo data was demonstrated through numerical analysis. Sufficient ostium coverage by the Contour was found to be important for flow reduction in WNBAs and proper device positioning a key factor for ensuring the long-term efficacy of the Contour.