Rupture prediction of intracranial aneurysms: A nationwide matched case-control study of hemodynamics at the time of diagnosis

Abstract

OBJECTIVE Hemodynamic rupture predictors in intracranial aneurysms (IAs) must be investigated in prerupture aneurysms, because rupture might significantly alter aneurysm hemodynamics. Both clinical and aneurysmal factors influence hemodynamics, possibly confounding results in unmatched patient materials. The authors aimed to identify hemodynamic variables at the time of diagnosis that could be associated with IA rupture. METHODS A nationwide matched case-control study of IA hemodynamics at the time of diagnosis was performed. Twelve IAs that later ruptured were matched 1:2 with control aneurysms that remained unruptured during a median follow- up time of 4.5 years (interquartile range 3.7-8.2 years). Cases and controls were matched by aneurysm location and size, and patient sex and age. Hemodynamic parameters were obtained from computational fluid dynamics simulations. RESULTS The low shear area (LSA) was significantly higher in cases than in controls in univariate analysis (p = 0.041). Minimum logarithmic wall shear stress, averaged logarithmic wall shear stress, pressure loss coefficient, and inflow concentration index showed a tendency to be associated with later rupture (p = 0.09, 0.14, 0.15, and 0.18, respectively). The LSA remained statistically significant in multivariable analysis (p = 0.030). CONCLUSIONS Hemodynamics at the time of diagnosis are different in aneurysms that later rupture than in those that remain unruptured. Increased LSA might be an early predictor of rupture.