Can β-blockers prevent intracranial aneurysm rupture?: insights from Computational Fluid Dynamics analysis.

Abstract

Aims: Hypertension is a risk factor for intracranial aneurysm rupture. We analysed whether the intake of drugs from specific classes of anti-hypertensive medications affects haemodynamic parameters of intracranial aneurysm dome.

Methods and results: We recorded medical history including medications and the in-hospital blood pressure values. We then obtained 3D reconstruction of each patients' aneurysm dome and the feeding artery. Using OpenFOAM software, we performed Computational Fluid Dynamics analysis of blood flow through the modelled structures. Blood was modelled as Newtonian fluid, using the incompressible transient solver. As the inlet boundary condition, we used the patient-specific Internal Carotid Artery blood velocity waves obtained with Doppler ultrasound. We calculated haemodynamic parameters of the aneurysm dome. All presented analyses are cross-sectional. We included 72 patients with a total of 91 unruptured intracranial aneurysms. The history of β-blocker intake significantly influenced haemodynamic parameters of aneurysm dome. The patients on β-blockers had significantly smaller aneurysm domes (5.09 ± 2.11 mm vs. 7.41 ± 5.89 mm; P = 0.03) and did not have aneurysms larger than 10 mm (0% vs. 17.0%; P = 0.01). In the Computational Fluid Dynamics analysis, walls of aneurysms in patients who took β-blockers were characterized by lower Wall Shear Stress Gradient (1.67 ± 1.85 Pa vs. 4.3 ± 6.06 Pa; P = 0.03), Oscillatory Shear Index (0.03 ± 0.02 vs. 0.07 ± 0.10; P = 0.04), and Surface Vortex Fraction (16.2% ± 5.2% vs. 20.0% ± 6.8%; P < 0.01). After controlling for covariates, we demonstrated difference of Surface Vortex Fraction (F[1, 48] = 4.36; P = 0.04) and Oscillatory Shear Index (F[1, 48] = 6.51; P = 0.01) between patients taking and not taking β-blockers, respectively.

Conclusion: Intake of β-blockers might contribute to more favourable haemodynamics inside aneurysmal sac. Other anti-hypertensive medication classes were not associated with differences in intracranial aneurysm parameters.