Background: Self-expanding intracranial stent-assisted coiling of bifurcation aneurysms has recently been shown to straighten target cerebral vessels, a phenomenon with unknown hemodynamic effect.
Objective: To investigate the impact of angular remodeling in aneurysms treated with single stent-assisted coiling using computational fluid dynamic (CFD) techniques.
Methods: Fourteen patients (7 women, mean age 55) who underwent stent-coiling of 14 wide-necked bifurcation aneurysms were included based on availability of high-resolution three-dimensional rotational angiography. Pre-treatment datasets underwent virtual aneurysm removal to isolate the effect of stenting. Wall shear stress (WSS) and pressure profiles obtained from constant flow input CFD analysis were analyzed for apical hemodynamic changes.
Results: Stenting increased bifurcation angle with significant straightening immediately after treatment and at follow-up (107.3[degrees] vs. 144.9[degrees], P<.0001). The increased stented angle at follow-up led to decreased pressure drop at the bifurcation apex (12.2 vs. 9.9 Pa, P<.003) and migration of the flow impingement zone (FIZ) towards the contralateral non-stented daughter branch by a mean of 1.48+/-0.2 mm. Stent-induced angular remodeling decreased FIZ width (WFIZ) separating peak apical WSS (3.4 vs. 2.5 mm, P<.004). Analysis of FIZ distance (DFIZ) measured from parent vessel centerline showed it to be linearly (r=.58, P<.002) and WFIZ inversely correlated (r=.46, P<.02) to vessel bifurcation angle.
Conclusion: Stent-induced angular remodeling significantly altered bifurcation apex hemodynamics in a favorable direction by blunting apical pressure, and inducing narrowing and migration of the flow impingement zone, a novel response to intracranial stenting which should be added to intimal hyperplasia and flow diversion.
From: Angular Remodeling In Single Stent-Assisted Coiling Displaces and Attenuates The Flow Impingement Zone At The Neck Of Intracranial Bifurcation Aneurysms by Gao et al.
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