Impaired Dynamic Cerebral Autoregulation in Carotid Artery Stenosis

White, Richard P.; Markus, Hugh S.

doi:10.1161/01.str.28.7.1340

Cited by 158 publications

(156 citation statements)

References 17 publications

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“…This is in contrast to previous studies that noted moderate correlation between CA impairment, the degree of carotid steno-occlusive lesion and cerebrovascular reactivity to CO2. 4, 9 The fact that we could not reproduce this moderate correlation could be explained by 2 factors: the present sample size was relatively small and, more importantly, we used acetazolamide and not inspired CO2 for assessment of cerebrovascular reactivity. Acetazolamide yields less sensitivity for assessing cerebrovascular reactivity as compared to acetazolamide: an additional increase of cerebral velocities has been observed with CO2 after maximum increase in velocities after acetazolamide injection.…”

Section: Ca and Cvr-acz Impairment Distal To Carotid Stenosis Or Occlmentioning

confidence: 88%

“…CA impairment is usually viewed as a consequence of cerebral vessel dilation secondary to reduced perfusion pressure downstream of the carotid stenosis. 9 Whether baroreflex and CA are two independent or interdependent mechanisms is not known. Recent data in healthy volunteers showed an inverse correlation between CA and BRS, 10 while other data did not confirm this inverse correlation.…”

mentioning

confidence: 99%

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Baroreflex and Cerebral Autoregulation Are Inversely Correlated

Nasr

Czosnyka

Traon

et al. 2014

Circ J

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Section: Ca and Cvr-acz Impairment Distal To Carotid Stenosis Or Occlmentioning

confidence: 88%

mentioning

confidence: 99%

Baroreflex and Cerebral Autoregulation Are Inversely Correlated

Nasr

Czosnyka

Traon

et al. 2014

Circ J

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“…9,[11][12][13]15 In Tiecks' original publication, 9 it is implied that a least-squares method was used to find the best fit in each case. The drawback with this approach is that it depends on another model parameter, namely, the critical closing pressure, that Tiecks et al assumed to be fixed at 12 mm Hg.…”

Section: Years)mentioning

confidence: 99%

“…Clinical applications of the thigh cuff technique have included patients with orthostatic hypotension, 10 carotid artery disease, 11 head injury, [12][13][14] and studies of the effects of anesthetic agents on cerebral autoregulation. 15,16 Despite its increasing use in cerebrovascular research, several aspects of the thigh cuff method have not been described.…”

mentioning

confidence: 99%

Assessment of the Thigh Cuff Technique for Measurement of Dynamic Cerebral Autoregulation

Mahony

Panerai

Deverson

et al. 2000

Stroke

108

113

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Background and Purpose-Dynamic methods of measuring cerebral autoregulation have become an accepted alternative to static evaluation. This article aims to describe a set of data collected from healthy volunteers by a dynamic method, the purpose being to qualify and quantify expected results for those who may be designing a study using this technique. Methods-Cerebral blood flow velocity (CBFV) (measured by transcranial Doppler) and arterial blood pressure (Finapres) were recorded in 16 normal subjects before, during, and after the induction of a blood pressure drop (release of bilateral thigh cuffs). This procedure was repeated 6 times for each subject. A mathematical model was applied to the data to generate an autoregulatory index (ARI) with values between 0 and 9. Results-The ARI values for this sample population follow a normal distribution, with a meanϮSD of 4.98Ϯ1.06 (nϭ15).Analysis of the cumulative mean ARI values of all subjects showed an exponential-type convergence of ARI toward the sample mean as the number of test iterations increased. The population average blood pressure drop on thigh cuff release was 26.4Ϯ7.1 mm Hg (nϭ16), occurring in 4.6Ϯ1.7 seconds. The corresponding population average drop for CBFV was 15.6Ϯ5.8 cm/s, taking 2.5Ϯ1.0 seconds. No significant trend was noted in the measurements as the number of test iterations increased. The correlation between the predicted and actual CBFV, having a mean value of 0.76Ϯ0.19, showed evidence of a nonlinear relationship to ARI values. Significant correlation was also found between ARI and (1) arterial blood pressure before cuff release and (2)

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“…Due to the highly effective control exerted by the mechanism of pressure-autoregulation, CBF is normally maintained within narrow limits for mean blood pressures (MBP) in the range 60-150 mm Hg (Paulson, Strandgaard & Edvinsson 1990). Not surprisingly, it is the CBF autoregulation mechanism itself that has been shown to be impaired in a number of conditions such as ischaemic stroke, severe head injury, carotid artery disease, intracranial hypertension, diabetes and liver failure (Aries et al 2010, Czosnyka et al 1996, Dawson et al 2000, Hauerberg, Juhler 1994, Kim et al 2008, Lagi et al 2002, Panerai 2008, White, Markus 1997, van Beek et al 2008.…”

Section: Introductionmentioning

confidence: 99%

The Leicester cerebral haemodynamics database: normative values and the influence of age and sex

et al. 2016

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Normative values of physiological parameters hold significance in modern day clinical decision-making. Lack of such normative values has been a major hurdle in the translation of research into clinical practice. A large database containing uniform recordings was constructed to allow more robust estimates of normative ranges and also assess the influence of age and sex.Doppler recordings were performed on healthy volunteers in the same laboratory, using similar protocols and equipment. Beat-to-beat blood pressure, heart-rate, electrocardiogram, and end-tidal CO2 were measured continuously. Bilateral insonation of the middle cerebral arteries (MCAs) was performed using TCD following a 15-minute stabilisation, and a 5-minute baseline recording.Good quality Doppler recordings for both MCAs were obtained in 129 participants (57 female) with a median age of 57 years (range 20-82). Age was found to influence baseline haemodynamic and transfer function analysis parameters. Cerebral blood flow velocity and critical closing pressure were the only sex-related differences found, which was significantly higher in females than males.Normative values for cerebral haemodynamic parameters have been defined in a large, healthy population. Such age/sex-defined normal values can be used to reduce the burden of collecting additional control data in future studies, as well as to identify disease-associated changes. Key wordsCerebral haemodynamics, cerebral autoregulation, ageing, sex differences, cerebral blood

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Impaired Dynamic Cerebral Autoregulation in Carotid Artery Stenosis

Cited by 158 publications

References 17 publications

Baroreflex and Cerebral Autoregulation Are Inversely Correlated

Baroreflex and Cerebral Autoregulation Are Inversely Correlated

Assessment of the Thigh Cuff Technique for Measurement of Dynamic Cerebral Autoregulation

The Leicester cerebral haemodynamics database: normative values and the influence of age and sex

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