Hemodynamics in two tandem aneurysms treated with flow diverters

The purpose of this study was to investigate whether the occlusion time of cerebral aneurysms treated with flow diverters depends on the hemodynamic conditions created immediately after treatment. A case study of a pair of tandem intracranial aneurysms that were treated with flow-diverting devices and occluded at different times was carried out. A patient-specific computational fluid dynamics model was constructed from 3D rotational angiography images. Blood flow simulations were carried out under pulsatile physiologic conditions, and hemodynamic variables before and after deployment of the flow-diverting devices were quantified and compared. The flow-diverting devices reduced aneurysm inflow rates, intra-aneurysmal flow velocities, shear rates, and wall shear stresses. The flow patterns after flow modulation by the flow diverters were smoother and with less swirling. The reductions in hemodynamic quantities depended on the aneurysm and parent artery and were larger in the aneurysm that occluded faster. The results of this case study suggest that the larger the reduction in the hemodynamic variables considered, the shorter the time it takes for the aneurysm to thrombose. This result can help us better define the goal of these interventions.