Hemodynamics in Ruptured Intracranial Aneurysms with Known Rupture Points.

BACKGROUND: Hemodynamics plays an important role in aneurysm rupture. Microsurgical clipping provides the best chance to confirm the rupture point. The aim of this study was to explore the associations between the rupture point and hemodynamics.

METHODS: Computational fluid dynamic simulations were performed on 16 intracranial aneurysms. The rupture point was detected at the time of clipping by 3 independent neurosurgeons. Hemodynamic parameters, including wall shear stress (WSS) and oscillatory shear index (OSI), were calculated at the rupture point and the whole aneurysm sac. Intra-aneurysmal flow patterns and flow impingement were also studied.

RESULTS: The time-averaged WSS was 3.4855 ± 3.8881 Pa at the aneurysm sac, which was significantly larger than that at the rupture point (1.5403 ± 2.3688 Pa, P = 0.002). The OSI at the rupture point (0.0354 ± 0.0459) was larger than at the sac (0.0220 ± 0.0232) without difference. Thirteen aneurysms (81.3%) showed a complex flow pattern in the aneurysm sac; however, more than two thirds of the cases (68.7%) did not show a flow impact at the rupture point. Of these cases with daughter blebs, the rupture points were confirmed at the blebs in 6 cases. Two cases did not show association between blebs and rupture point.

CONCLUSIONS: The hemodynamic characteristics at the rupture point were different from the aneurysm sac, and the WSS was significantly lower at the rupture point. Further study on the rupture risk assessment is still needed with more data and detailed information.