Hemodynamic Changes in the Treatment of Multiple Intracranial Aneurysms: A Computational Fluid Dynamics Study

Background Intracranial aneurysm rupture is associated with a high mortality and disability despite modern medical care. Multiple aneurysms occur in nearly 16% of patients, and imaging studies of naturally occurring multiple aneurysms are valuable for computational fluid dynamics studies. In this study, we describe and analyze the hemodynamic changes produced in a distal aneurysm after the treatment of a proximal aneurysm. Methods Between January 2008 and December 2017, 24 cases of multiple intracranial aneurysms of the same vascular tree were treated in our center. Full carotid segmentations from digital subtraction angiography, computed tomography angiography, or magnetic resonance angiography were obtained, and transient pulsatile simulations were performed using computational fluid dynamics software. Output variables included maximum peak systole wall shear stress (WSS), minimum mid-diastolic WSS, maximum systolic pressure, low shear area, and high shear area both before and after treatment of the proximal aneurysm. Results The mean size of ruptured and unruptured aneurysms was 7.05 and 5.23 mm, respectively ( P  = 0.035), with respective aspect ratios of 1.22 and 2.04 ( P  = 0.001). Maximum peak systole WSS was lower and minimum mid-diastolic WSS was higher in unruptured aneurysms ( P  = 0.04 and 0.034, respectively). After treatment of the proximal aneurysm, low shear area in the distal aneurysm increased from 54.15% to 56.93% ( P  = 0.02). The opposite effect is noted in aneurysms with an interaneurysmal distance P  = 0.03). Conclusions The hemodynamic changes in a distal aneurysm after treatment of a proximal aneurysm showed an unfavorable profile associated with an increased theoretical risk of bleeding.