Cerebral autoregulation in orthostatic hypotension. A transcranial Doppler study.

Lagi, Alfonso; Bacalli, S.; Cencetti, Simone; Paggetti, Cristiano; Colzi, L

doi:10.1161/01.str.25.9.1771

Cited by 49 publications

(28 citation statements)

References 30 publications

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“…31 Thus, cerebrovascular vasomotor reserve seems to be reduced with only a limited capacity to compensate for changes in BP. Previous studies 32,33 using the reactive hyperemia test have also demonstrated that cerebral circulation passively follows the rise and fall in BP in the supine position in patients with multiple system atrophy and autonomic failure. 33 The possibility of a passive vasodilatation has also been raised based on comparisons between MCA flow velocity and 133 Xe washout measurements of cerebral blood flow in patients with multiple system atrophy and autonomic failure during 45°HUT.…”

Section: Discussionmentioning

confidence: 90%

Autoregulation of Cerebral Blood Flow in Orthostatic Hypotension

Novak

Novák

Spies

et al. 1998

Stroke

215

164

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Background and Purpose-We sought to evaluate cerebral autoregulation in patients with orthostatic hypotension (OH). Methods-We studied 21 patients (aged 52 to 78 years) with neurogenic OH during 80°head-up tilt. Blood flow velocities (BFV) from the middle cerebral artery were continuously monitored with transcranial Doppler sonography, as were heart rate, blood pressure (BP), cardiac output, stroke volume, CO 2 , total peripheral resistance, and cerebrovascular resistance. Results-All OH patients had lower BP (PϽ.0001), BFV_diastolic (PϽ.05), CVR (PϽ.007), and TPR (PϽ.02) during head-up tilt than control subjects. In control subjects, no correlations between BFV and BP were found during head-up tilt, suggesting normal autoregulation. OH patients could be separated into those with normal or expanded autoregulation (OH_NA; nϭ16) and those with autoregulatory failure (OH_AF; nϭ5). The OH_NA group showed either no correlation between BFV and BP (nϭ8) or had a positive BFV/BP correlation (R 2 Ͼ.75) but with a flat slope. An expansion of the "autoregulated" range was seen in some patients. The OH_AF group was characterized by a profound fall in BFV in response to a small reduction in BP (mean ⌬BP Ͻ40 mm Hg; R 2 Ͼ.75). Conclusions-The

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Section: Discussionmentioning

confidence: 90%

Autoregulation of Cerebral Blood Flow in Orthostatic Hypotension

Novak

Novák

Spies

et al. 1998

Stroke

215

164

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“…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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“…As it has been shown that OH is found in PD patients, it is then also important to ask whether or not cerebral autoregulation (CA) is impaired in PD. This is because in cases of OH, it has been found that CA is not as effective, and this could prove to be dangerous for patients with PD [4].…”

Section: Introductionmentioning

confidence: 99%

Linear Assessment of Cerebral Autoregulation in Idiopathic Parkinson's Disease

Chiu

Liao

Yeh

2016

Int J Pharm Pharm Sci

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Parkinson's disease cases have been on the rise in the recent years, which promoted several different researches into the disorder. However, there hasn't much research been done in the non-motor aspects of the disease. This study aims to improve the understanding of one of the non-motor symptoms of Parkinson's disease. Specifically, this research aims to further understand cerebral autoregulation in patients with Parkinson's disease. In order to achieve this aim, 25 subjects were recruited, with 11 healthy controls and 14 patients with Parkinson's disease. The continuous blood pressure and continuous cerebral blood flow velocity of all subjects were recorded and processed while the subjects were at rest, tilt-up, and during hyperventilation. Linear signal and system analysis techniques were applied such as the power spectral density analysis and cross-correlation function analysis. Results showed that patients with Parkinson's disease did not show a significant difference from the control group while at rest and after tilt-up. However, there was a significant difference between the groups during hyperventilation. The results obtained in this study suggested that the metabolic regulatory pathway for cerebral autoregulation is impaired in patients with Parkinson's disease.

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Cerebral autoregulation in orthostatic hypotension. A transcranial Doppler study.

Cited by 49 publications

References 30 publications

Autoregulation of Cerebral Blood Flow in Orthostatic Hypotension

Autoregulation of Cerebral Blood Flow in Orthostatic Hypotension

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

Linear Assessment of Cerebral Autoregulation in Idiopathic Parkinson's Disease

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