Table 10.
Literature-based evidence on the importance of hemodynamics in the etiopathogenesis of ICAs. NB: WSS; wall shear stress, MMP-13; matrixmetalloproteneases-13, iNOS; inducible-nitric oxide synthase, NO; nitric oxide, OSI; oscillatory shear index.
| Hemodynamic factors | Intracranial aneurysm | Proposed mechanism(s) | References | ||
|---|---|---|---|---|---|
| Initiation | Growth | Rupture | |||
| Dynamic | |||||
| Wall shear stress (WSS) | High | Low | Low | Increased WSS increases the production of MMP-13 which in turn leads to vessel wall damage. Decreased WSS increases iNOS synthesis—NO induced damage to vessel wall. Low WSS increases endothelial proliferation and apoptosis | Boussel et al. [11], Fukuda et al. [30], Gao et al. [7], Jou et al. [31], Malek et al. [21], Meng et al. [32], Shojima et al. [9], Ujiie et al. [33] |
|
| |||||
| Oscillatory shear index (OSI) | High/Low | High | High | Degenerative changes in endothelium | Glor et al. [35], Goubergrits et al. [34], Mantha et al. [15] |
|
| |||||
| Jet of blood stream | Impingement | Impingement | Impingement | Localized endothelial cell injury | Foutrakis et al. [36], Cebral et al. [14], Cebral et al. [37] |
|
| |||||
| Flow pattern | — | — | Complex | Statistical association | Cebral et al. [14, 37] |
|
| |||||
| Hydrostatic | |||||
| Pressure | High | High | High | Passive yield/water hammer effect | Inci and Spetzler [38], Morimoto et al. [8] Steiger et al. [39] |