Hemodynamic changes in a middle cerebral artery aneurysm at follow-up times before and after its rupture: a case report and a review of the literature

Abstract

Hemodynamic parameters play a significant role in the development of cerebral aneurysms. Parameters such as wall shear stress (WSS) or velocity could change in time and may contribute to aneurysm growth and rupture. However, the hemodynamic changes at the rupture location remain unclear because it is difficult to obtain data prior to rupture. We analyzed a case of a ruptured middle cerebral artery (MCA) aneurysm for which we acquired imaging data at three time points, including at rupture. A patient with an observed MCA aneurysm was admitted to the emergency department with clinical symptoms of a subarachnoid hemorrhage. During three-dimensional (3D) digital subtraction angiography (DSA), the aneurysm ruptured again. Imaging data from two visits before rupture and this 3D DSA images at the moment of rupture were acquired, and computational fluid dynamic (CFD) simulations were performed. Results were used to describe the time-dependent changes of the hemodynamic variables associated with rupture. Time-dependent hemodynamic changes at the rupture location were characterized by decreased WSS and flow velocity magnitude. The impingement jet in the dome changed its position in time and the impingement area at follow-up moved near the rupture location. The results suggest that the increased WSS on the dome and increased low wall shear stress area (LSA) and decreased WSS on the daughter bleb with slower flow and slow vortex may be associated with rupture. CFD performed during the follow-up period may be part of diagnostic tools used to determine the risk of aneurysm rupture.

High wall shear stress beyond a certain range in the parent artery could predict the risk of anterior communicating artery aneurysm rupture at follow-up

“…More and more published CFD studies seem to suggest that high WSS results in intracranial aneurysm growth and low WSS in rupture. 7,12,14,15,18,19,22,24,25,27 However, these results were inconsistent with those obtained by Liu et al and Yu et al 13,26,30,34 They found high WSS in the ruptured aneurysm group. Moreover, it is important to note that their average WSS in the aneurysm region (1.64 ± 1.16 N/m 2 ) was significantly lower than that observed in the vessel region (p < 0.05), which highly accords with our findings.…”

“…We discovered that high WSS in the parent artery was significantly correlated with ACoA aneurysm rupture when it was higher than 12.3 dyne/cm 2 , which is partially inconsistent with the high-or low-WSS theory. 7,14,15,18,19,22,24,25,27 WSS in the parent artery may be different from that in an ACoA aneurysm itself. Vasospasm caused by subarachnoid hemorrhage (SAH) when aneurysms easily rupture results in a smaller inner diameter and increased blood flow velocity.…”

“…35 Recently, several studies of morphological and hemodynamic parameters have used numeral simulation of computational fluid dynamics (CFD) techniques and found that both high and low aneurysmal wall shear stress (WSS) have separately correlated with intracranial aneurysm growth and rupture. 15,18,24,25 However, specific geometries with different aneurysm locations in each study may result in divergent and controversial findings. 22,35 The results of large-scale and multicenter clinical trials have been insufficient in clinical application.…”

Hemodynamics in Ruptured Intracranial Aneurysms

“…Hemodynamics in Ruptured Intracranial Aneurysms DOI: http://dx.doi.org/10.5772/intechopen.88695 rare [32,40]. Our own study showed that a secondary aneurysm, a frequent rupture site, was observed in the aneurysm that subsequently ruptured (Figure 2A-C) [40]. WSS was reduced and the flow was slow at the rupture point.…”

Relationship between cerebral aneurysms and variations in cerebral basal arterial network: a morphometric cross-sectional study in Computed Tomography Angiograms from a neurointerventional unit

“…14 Fluctuations of peak systolic pressures may contribute to the occurrence and rupture of cerebral aneurysm. 18 In addition, the amount of blood flowing through a MCA had been found to be increased in the presence of the hypoplastic or absent A1 segment or PcomA on that side of the CBAN. 19 Therefore, the eight cases of AcomAC aneurysms that cooccurred with aneurysms elsewhere (ie, AcomAC aneurysms cooccurred with right ICA, right MCA and left MCA regions) might have been associated with the presence of hypoplastic or absent A1 segments or PcomA (online supplemental file 1).…”