Abstract
PurposeWe sought to investigate the capacity of cerebral autoregulation and cerebrovascular reactivity (CVR) in patients with middle cerebral artery (MCA) stenosis.MethodsTwenty-one patients with MCA stenosis diagnosed by magnetic resonance angiography and 15 healthy controls were enrolled. Cerebral autoregulation was assessed by autoregulatory parameters (rate of recovery/phase/gain) derived from transfer function from spontaneous oscillations of cerebral blood flow velocity and blood pressure. CVR was tested by a rebreathing maneuver.ResultsRate of recovery, phase and CVR estimated from moderate MCA stenosis (rate of recovery = 17.76±8.21%/s, phase = 26.93±15.67°, and CVR = 1.53±0.84%/mmHg, respectively) were significantly different (p<0.05) from controls (rate of recovery = 39.62±27.99%/s, phase = 55.66±22.10°, and CVR = 2.18±0.80%/mmHg, respectively). Rate of recovery (r = −0.698, p<0.001), phase (r = −0.738, p<0.001)) and CVR (r = −0.690, p<0.001) were all significantly correlated with the degree of stenosis.ConclusionCerebral autoregulation and CVR were impaired in patients with ≥ 50% MCA stenosis. The measures of both hemodynamic properties were inversely correlated with the stenotic degree.
Highlights
Intracranial artery occlusive diseases, especially middle cerebral artery (MCA) stenosis, are major causes of ischemic stroke in Asian, Black, and Hispanic populations [1]
A number of studies reported that stenosis in internal carotid artery (ICA) may impair cerebral hemodynamics, including cerebral autoregulation and cerebrovascular reactivity (CVR), which increases the risk of cerebral ischemic events [2,3,4,5,6,7,8]
Patients were excluded from the study, if they had coexistent $50% ipsilateral ICA stenosis, stroke or transient ischemic attack (TIA) onset within 3 months, or severe white matter disease (WMD) ($3 grades for either periventricular hyperintensity or deep white matter hyperintensity based on the Fazekas visual scale) [20]
Summary
Intracranial artery occlusive diseases, especially middle cerebral artery (MCA) stenosis, are major causes of ischemic stroke in Asian, Black, and Hispanic populations [1]. A number of studies reported that stenosis in internal carotid artery (ICA) may impair cerebral hemodynamics, including cerebral autoregulation and cerebrovascular reactivity (CVR), which increases the risk of cerebral ischemic events [2,3,4,5,6,7,8] It is unknown how these cerebral hemodynamic parameters alter with respect to the stenotic degree in MCA. According to the previous studies on ICA stenosis, autoregulation is much vulnerable to the stenotic changes yet with almost immediate restoration after carotid endarterectomy or stenting, whereas the status of CVR varies in patients and the response to carotid recanalization is not as sensitive as autoregulation [9] This is sensible as they are intrinsically controlled by different mechanisms. It necessary to investigate these two mechanisms in patients with MCA stenosis
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