title: Dynamic Cerebral Autoregulation in Asymptomatic Patients With Unilateral Middle Cerebral Artery Stenosis.
abstract: The aim of the study was to assess the capacity of dynamic cerebral autoregulation (dCA) in asymptomatic patients with unilateral middle cerebral artery (MCA) stenosis.Fifty-seven patients with asymptomatic mild, moderate, and severe unilateral MCA stenosis and 8 patients with symptomatic severe unilateral MCA stenosis diagnosed by transcranial Doppler were enrolled. Twenty-four healthy volunteers served as controls. The noninvasive continuous cerebral blood flow velocity and arterial blood pressure were recorded simultaneously from each subject in the supine position. Transfer function analysis was applied to determine the autoregulatory parameters (phase difference [PD] and gain).The PD values in the severe stenosis groups were significantly lower than those of the control group (60.71 ± 18.63°), the asymptomatic severe stenosis group was impaired ipsilaterally (28.94 ± 27.43°, P < 0.001), and the symptomatic severe stenosis group was impaired bilaterally (13.74 ± 19.21°, P < 0.001; 19.68 ± 14.50°, P = 0.006, respectively). The PD values in the mild and moderate stenosis groups were not significantly different than the controls (44.49 ± 27.93°; 48.65 ± 25.49°, respectively). The gain values in the mild and moderate groups were higher than in the controls (1.00 ± 0.58 cm/s/mm Hg vs 0.86 ± 0.34 cm/s/mm Hg, and 1.20 ± 0.59 cm/s/mm Hg vs 0.86 ± 0.34 cm/s/mm Hg, respectively). The gain values in the severe stenosis groups were significantly lower than that in the control group: the asymptomatic severe stenosis group was lower bilaterally (0.56 ± 0.32 cm/s/mm Hg, P = 0.003; 0.60 ± 0.32 cm/s/mm Hg, P < 0.05, respectively), whereas the symptomatic severe group was lower unilaterally (on the contralateral side) (0.53 ± 0.43 cm/s/mm Hg, P < 0.05).In asymptomatic patients with unilateral MCA stenosis, only the dCA of the severe stenosis was ipsilaterally impaired. Acute stroke may aggravate the impaired dCA and even spread contralaterally.
authors.affiliation: From the Stroke Center, Department of Neurology (SW, HM, HJ, YY); Neuroscience Center, Department of Neurology (Z-NG); Center for Neurovascular ultrasound (Y X), the First Hospital of Jilin Universit, Changchun, China and Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Xueyuan Avenue, Shenzhen University Town, Shenzhen, China (JL).
authors.forename: Shuang
authors.initials: S
authors.lastname: Wang
authors.forename: Zhen-Ni
authors.initials: ZN
authors.lastname: Guo
authors.forename: Yingqi
authors.initials: Y
authors.lastname: Xing
authors.forename: Hongyin
authors.initials: H
authors.lastname: Ma
authors.forename: Hang
authors.initials: H
authors.lastname: Jin
authors.forename: Jia
authors.initials: J
authors.lastname: Liu
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
mesh_terms: D000328:Adult; D058070:Asymptomatic Diseases; D002560:Cerebrovascular Circulation; D003251:Constriction, Pathologic / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D005260:Female; D006706:Homeostasis; D006801:Humans; D002537:Intracranial Arteriosclerosis / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D018810:Magnetic Resonance Angiography / Q000379:methods; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000473:pathology / Q000503:physiopathology; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D020521:Stroke / Q000209:etiology; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods