Hyo Suk Nam1, Fabien Scalzo2, Xinyi Leng3, Hing Lung Ip3, Hye Sun Lee4, Florence Fan3, Xiangyan Chen3, Yannie Soo3, Zhongrong Miao5, Liping Liu5, Edward Feldmann6, Thomas Leung3, Ka Sing Wong3, David S Liebeskind2. 1. Department of Neurology, Yonsei University College of Medicine, Seoul, Korea. 2. Neurovascular Imaging Research Core, University of California, Los Angeles, CA. 3. Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong SAR, China. 4. Department of Biostatistics, Yonsei University College of Medicine, Seoul, Korea. 5. Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China. 6. Baystate Medical Center Springfield, MA.
Abstract
OBJECTIVE: Success in clinical trials of intracranial atherosclerosis (ICAS) is related to accurate identification of high-risk patients. Noninvasive computational fluid dynamics (CFD) of stenotic lesions may enhance therapeutic decision-making. We determined whether physiologic parameters change downstream cerebral hemodynamics in patients with ICAS. METHODS: Consecutive ICAS patients who underwent both CT angiography (CTA) and digital subtraction angiography were enrolled. CFD models were made using CTA source images. Inlet boundary conditions were defined using three ranges of systolic blood pressure (BP) (109.2, 158, and 225 mmHg) and hematocrit (27.3, 40.2, and 48.8). Ratios of pressure, shear strain rates (SSR), and flow velocity across the lesion were calculated using CFD simulations. A linear mixed model was used for the statistical analysis of repeated simulations. RESULTS: Among the 56 patients, 32 had moderate stenosis (50-69%) and 24 had severe stenosis (70-99%). A linear mixed model revealed that the ratio of pressure was predicted by systolic BP and stenosis group interaction (P = .036). These pressure decreases were associated with systolic BP (P < .001) and stenosis group (P < .001), but not with hematocrit (P = .337). Post-hoc analysis revealed that pressure decreases were more profound in the severe stenosis than the moderate stenosis group when comparing high and low systolic BP (P = .0108). Ratios of SSR and velocity were only associated in the stenosis group. CONCLUSIONS: Our study showed that systolic BP along with the degree of stenosis was associated with pressure decreases across stenotic lesions. Physiologic conditions may superimpose further changes in post-stenotic or downstream blood flow.
OBJECTIVE: Success in clinical trials of intracranial atherosclerosis (ICAS) is related to accurate identification of high-risk patients. Noninvasive computational fluid dynamics (CFD) of stenotic lesions may enhance therapeutic decision-making. We determined whether physiologic parameters change downstream cerebral hemodynamics in patients with ICAS. METHODS: Consecutive ICASpatients who underwent both CT angiography (CTA) and digital subtraction angiography were enrolled. CFD models were made using CTA source images. Inlet boundary conditions were defined using three ranges of systolic blood pressure (BP) (109.2, 158, and 225 mmHg) and hematocrit (27.3, 40.2, and 48.8). Ratios of pressure, shear strain rates (SSR), and flow velocity across the lesion were calculated using CFD simulations. A linear mixed model was used for the statistical analysis of repeated simulations. RESULTS: Among the 56 patients, 32 had moderate stenosis (50-69%) and 24 had severe stenosis (70-99%). A linear mixed model revealed that the ratio of pressure was predicted by systolic BP and stenosis group interaction (P = .036). These pressure decreases were associated with systolic BP (P < .001) and stenosis group (P < .001), but not with hematocrit (P = .337). Post-hoc analysis revealed that pressure decreases were more profound in the severe stenosis than the moderate stenosis group when comparing high and low systolic BP (P = .0108). Ratios of SSR and velocity were only associated in the stenosis group. CONCLUSIONS: Our study showed that systolic BP along with the degree of stenosis was associated with pressure decreases across stenotic lesions. Physiologic conditions may superimpose further changes in post-stenotic or downstream blood flow.
Authors: David S Liebeskind; Jason D Hinman; Naoki Kaneko; Hiroaki Kitajima; Tristan Honda; Adam H De Havenon; Edward Feldmann; Raul G Nogueira; Shyam Prabhakaran; Jose G Romano; Peter W Callas; David J Schneider Journal: Front Neurol Date: 2021-02-25 Impact factor: 4.003