Introduction: Understanding the hemodynamic characteristics of residual intracranial aneurysms after surgical clipping or endovascular coiling may aid in assessing individual rupture risk. This study compares low wall shear stress areas (LSA) and high wall shear stress areas (HSA) in residual aneurysms treated with clipping or coiling, using computational fluid dynamics simulations.
Methods: We retrospectively analyzed 22 patients with residual aneurysms following clipping (n=11) or coiling (n=11) between January 2015 and January 2024. Aneurysm locations included the PComA (10 cases), ICA (5), MCA (3), AComA (2), and BA (2). Three-dimensional reconstructions from DSA images were used for hemodynamic simulations with ANSYS® software. Statistical tests (Fisher's Exact Test for sex; Mann-Whitney U test for LSA; t-test for HSA and mean age) compared the clipping and coiling groups.
Results: The patients had no significant differences in age or sex distribution between groups (mean age 57 years; 68.2% female; p>0.05). The median LSA was 1.1% (IQR=41.45%) in the clipping group versus 7.82% (IQR=33.27%) in the coiling group. Although not statistically significant (p=0.071), coiled aneurysms tended to have larger LSAs, suggesting increased inflammatory activity, endothelial dysfunction, and extracellular matrix remodeling that could weaken the aneurysm wall and elevate rupture risk. The mean HSA was 50.1% (SD=29.05%) for clipped aneurysms and 30.4% (SD=21.61%) for coiled aneurysms. While this difference was also not statistically significant (p=0.086), higher HSAs in clipped aneurysms may indicate stronger local hemodynamic forces associated with endothelial damage, wall thinning, and potential for growth in smaller aneurysms. These distinct hemodynamic profiles reflect differential remodeling effects associated with each treatment modality.
Conclusion : Residual aneurysms exhibit distinct hemodynamic patterns, with coiled aneurysms showing higher LSAs and clipped aneurysms demonstrating higher HSAs. These differences may influence aneurysm remodeling and rupture risk. Larger studies are needed to confirm these trends and enhance predictive models of aneurysm behavior post-treatment.
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