Introduction: Hemodynamic factors may play a crucial role in the recurrence of intracranial aneurysms after coiling. However, the strongest factor for predicting recurrence remains unclear because each risk factor has been investigated and reported separately.We clarified the strongest predictor of recurrence with computational fluid dynamics (CFD).
Methods: Using pre-treatment patient-specific three-dimensional rotational angiography data of 50 internal carotid artery aneurysms (7 recanalized and 43 stable) treated with endovascular coiling, we created a pre-coiling model and a virtual post-coiling model produced by manually cutting the aneurysm by the flat plane corresponding to the virtual coil surface. We conducted CFD analysis to investigate inflow dynamics in the pre-coiling model and pressure difference and wall shear stress on the virtual coil surface. Pressure difference was calculated by subtracting the average pressure at the proximal ICA from the maximum pressure at the coil surface and dividing by the dynamic pressure at the proximal ICA for normalization. We compared hemodynamic parameters in the two models between recanalized and stable aneurysms.
Results: Compared with stable aneurysms, recanalized aneurysms showed significantly larger inflow area and higher inflow rate in the pre-coiling model (p = 0.016, 0.028) and higher pressure difference at the coil surface in the post-coiling model (p < 0.001). The receiver-operating characteristics analysis showed that the area under the curve value for the pressure difference (0.967) was superior to other evaluated parameters.
Conclusions: The virtual post-coiling model makes it easy to evaluate hemodynamic strength on the virtual coil surface before actual coiling. Pressure difference in the virtual post-coiling model may be a strong predictor of recurrence after coiling.
Patient Care: we hypothesize that pressure elevation at the coil surface is one of the most important factors for recurrence after coiling. The results of this study suggest that a tight packing density should be achieved and careful follow-up is necessary when treating ICA aneurysms with a high pressure difference at the virtual coil surface.
Learning Objectives: Identify the strongest predictor of aneurysm recurrence with computational fluid dynamics.