Cerebral Autoregulation in Middle Cerebral Artery Territory Precedes That of Posterior Cerebral Artery in Human Cortex

Rosengarten, Bernhard; Kaps, Manfred

doi:10.1159/000047741

Cited by 21 publications

(24 citation statements)

References 21 publications

(48 reference statements)

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“…The MCA was insonated because stable, long-term recordings can be easily obtained and because this artery supplies a substantial portion of cerebral blood flow to the anterior circulation. The dynamic autoregulatory response characteristics of the MCA largely mirror those of arteries of the posterior circulation (21,36,40).…”

Section: Discussionmentioning

confidence: 93%

“…One possibility is that symptoms arise from impaired perfusion of structures (e.g., vestibular nuclei) receiving blood supply from the posterior circulation. As noted above, there is no evidence that the dynamic autoregulatory response characteristics of the posterior circulation differ from that of the anterior circulation (21,36,40). Further studies, however, are required to directly confirm this in patients with POTS.…”

Section: Discussionmentioning

confidence: 97%

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Cerebral autoregulation is preserved in postural tachycardia syndrome

Schondorf¹,

Benoit²,

Stein³

2005

Journal of Applied Physiology

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autoregulation is preserved in postural tachycardia syndrome. J Appl Physiol 99: 828 -835, 2005. First published April 28, 2005 doi:10.1152/japplphysiol.00225.2005.-To test whether cerebral autoregulation is impaired in patients with postural tachycardia syndrome (POTS), we evaluated 17 healthy control subjects and 27 patients with POTS. Blood pressure, heart rate, and cerebral blood velocity (transcranial Doppler) were recorded at rest and during 80°h ead-up tilt (HUT). Static cerebral autoregulation, as assessed from the change in cerebrovascular resistance during HUT, was the same in POTS and in controls. The properties of dynamic cerebral autoregulation were inferred from transfer gain, coherence, and phase of the relationship between blood pressure and cerebral blood velocity estimated from filtered data segments (0.02-0.8 Hz). Dynamic cerebral autoregulation of patients with POTS did not differ from that of controls. The patients' dynamic cerebral autoregulation did not change over the course of HUT, despite increased tachycardia suggestive of worsening orthostatic stress. Inflation of military anti-shock trouser pants substantially reduced the tachycardia of patients with POTS without affecting cerebral autoregulation. Symptoms of orthostatic intolerance were reduced in one-half of the patients following military anti-shock trouser pants inflation. We conclude that cerebral perfusion and autoregulation in many patients with POTS do not differ from that of normal control subjects. cerebrovascular circulation; Fourier analysis; hemodynamics THE POSTURAL ORTHOSTATIC TACHYCARDIA syndrome (POTS) is a form of orthostatic intolerance that is characterized by symptoms of lightheadedness, fatigue, palpitations, diminished concentration, blurred vision, tremulousness, shortness of breath, nausea, and impaired cognition that mainly occur during upright posture (5,24,31,33). To qualify for the diagnosis of POTS, these symptoms must occur in conjunction with an increase in heart rate (HR) of Ͼ30 beats/min or a HR Ͼ 120 beats/min within the first 5 min of standing (23)(24)(25)31). The HR increase should be sustained and not associated with orthostatic hypotension (46). Many patients have evidence of hypovolemia (16,26) or exaggerated venous pooling with central hypovolemia (32,48). Inflation of military anti-shock trousers (MAST pants), which prevent venous pooling in the legs, usually causes reversal of the tachycardia (49). The pathophysiology of POTS is poorly understood. Various abnormalities have been described, including the presence of an attenuated autonomic neuropathy (25, 43), increased cardiac norepinephrine spillover (19), impaired norepinephrine transporter (45), or reduced vagal cardiac baroreflex sensitivity (14). Some patients may have evidence of increased sympathetic activity while supine (17, 18), whereas others do not (5).Regardless of pathophysiology, all patients with POTS are significantly disabled by the constellation of symptoms noted above (2).Lightheadedness and impaired concentration while ...

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Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 97%

Cerebral autoregulation is preserved in postural tachycardia syndrome

Schondorf¹,

Benoit²,

Stein³

2005

Journal of Applied Physiology

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“…Unlike Park's study, we used a static autoregulation testing method, in which the decrease in blood pressure is sustained. In addition, other studies compared the MCA with the posterior cerebral artery but not the BAS (16,17). We examined the BAS primarily because it supplies the posterior fossa contents as opposed to the posterior cerebral artery, which supplies the occipital cortex (18).…”

Section: Figurementioning

confidence: 99%

Gender Differences in Cerebral Blood Flow Velocity and Autoregulation between the Anterior and Posterior Circulations in Healthy Children

et al. 2005

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There is little information on gender differences in cerebral autoregulation. The purpose of this study was to compare autoregulation of the anterior and posterior circulations using the tilt test method in healthy boys and girls who were 10 -16 y of age. Transcranial Doppler was used to measure middle cerebral artery and basilar artery flow velocities (Vmca and Vbas). Cerebral autoregulation (ARI) of the middle cerebral (ARImca) and basilar arteries (ARIbas) was examined using the tilt test method. An ARI Ͻ0.4 indicates impaired autoregulation. Among the 13 boys and 13 girls, Vmca and Vbas were higher in girls. All children demonstrated intact autoregulation, but boys had higher ARImca than girls, whereas girls had higher ARIbas than boys. Girls demonstrated greater autoregulation in the basilar artery, whereas boys demonstrated greater autoregulation in the middle cerebral artery. Girls had higher flow velocities in both vessels. This study provides normative data on cerebral autoregulation of the poste- Autoregulation of cerebral blood flow (CBF) is a physiologic and homeostatic process that maintains nearly constant CBF over a range of mean arterial pressures (MAPs). Disease states, including traumatic brain injury, can impair cerebral autoregulation, rendering the brain susceptible to inadequate (cerebral ischemia) or excessive (cerebral hyperemia) CBF (1). Despite its critical role in maintaining CBF, there is limited information on cerebral autoregulation in healthy children.Little has been published on pediatric cerebral autoregulation in children outside the clinical arena of neurogenic syncope (2-4). In one study that examined dynamic cerebral autoregulation in awake adolescent study participants, the time to return of middle cerebral artery flow velocity (Vmca) to normal after a transient hypotensive stimulus was reported to be more in healthy adolescents compared with their healthy adult counterparts (5). However, in a subsequent evaluation of cerebral autoregulation in children versus adults during general anesthesia using static autoregulation testing, the investigators reported no age-related differences in autoregulatory capacity and no difference in cerebral autoregulation compared with adults (6). Because both of these studies examined cerebral autoregulation of the anterior circulation only, differences in cerebral autoregulation between the anterior and posterior circulation in children could not be evaluated. In addition, to our knowledge, there is no information regarding cerebral autoregulation of the posterior circulation in children, no information on gender differences in cerebral autoregulation in children, and finally no normative data on cerebral autoregulation using the tilt test method. Therefore, the purpose of this study was to 1) provide normative data on cerebral autoregulation using the tilt test method, 2) describe cerebral autoregulation of the posterior cerebral circulation, and 3) examine gender-related differences in autoregulatory capacity in healthy, awake boys and girl...

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“…Radiosurgery reduced the collateralization demand, which shut down recruitment and led to a false-positive MRA diagnosis of CoW vascular hypoplasia. CoW segmental hypoplasia is not only a variable feature, but is also enrolled as part of an autoregulatory mechanism [3,4]. …”

Section: Discussionmentioning

confidence: 99%

“…However, the number of blocked recruiting segments in the CoW was statistically higher than that of ‘hypoplastic’ segment openings in the CoW. The hemodynamic redistribution after carotid artery stenting was predominantly observed in the anterior circulation [3,4]. Given this background, we hypothesized that the plasticity of CoW served as a reservoir for cerebral hypoperfusion stress and collateral demand.…”

Section: Introductionmentioning

confidence: 99%

Appraising the Plasticity of the Circle of Willis: A Model of Hemodynamic Modulation in Cerebral Arteriovenous Malformations

Chuang

Guo²,

Lin³

2010

Eur Neurol

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Objectives: Cerebral arteriovenous malformations (AVMs) harbor a network of abnormal vasculatures, namely the nidus between arterial and venous components. The pressure gradient between these two components results in abnormal high-velocity arteriovenous shunts flowing through the nidus and alternate intracranial hemodynamics. This study hypothesizes that the flow patterns of the circle of Willis (CoW) are modulated by the alternation of intracranial hemodynamics occurring in cerebral AVMs. The flow patterns of the CoW before and after AVMs had been corrected and the arteriovenous shunts closed by radiosurgery were assessed to validate the hypothesis. Patients and Methods: Fifty patients (32 men and 18 women; mean age 35.8 ± 4.2, range 23–52 years) with cerebral AVMs previously treated by radiosurgery were retrospectively investigated. This investigation used magnetic resonance angiography, performed prior to and after AVM surgery, to assess the CoW flow patterns. Results: The CoW flow patterns in nearly half of the subjects (20/50, 40%) altered after the AVMs had been corrected. The alterations included: (1) decreased size or ceased flow patterns in the CoW vascular segment: ipsilateral A1 (n = 1) of the anterior cerebral artery (ACA), ipsilateral posterior communicating artery (PCoA) segment (n = 7), contralateral PCoA collateral (n = 4), bilateral PCoA (n = 2); (2) increased size or opening of the previous ‘hypoplastic’ segment of CoW: ipsilateral A1 of ACA (n = 1), contralateral PCoA (n = 2), bilateral PCoA (n = 1), and (3) biphasic alteration of the CoW: ceased ipsilateral PCoA segment and opening ipsilateral A1 of the ACA (n = 1), ceased ipsilateral PCoA and opening contralateral P1 of the posterior cerebral artery (n = 1). Conclusion: The plasticity of the flow patterns in the CoW are modulated by intracranial hemodynamics as shown by the AVM model. The calibers of CoW arterial segments are not a static feature. Willisian collateralization with recruitment of the CoW segment may cease, or hypoplastic segments may reopen after closing arteriovenous shunts of the AVM.

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Cerebral Autoregulation in Middle Cerebral Artery Territory Precedes That of Posterior Cerebral Artery in Human Cortex

Cited by 21 publications

References 21 publications

Cerebral autoregulation is preserved in postural tachycardia syndrome

Cerebral autoregulation is preserved in postural tachycardia syndrome

Gender Differences in Cerebral Blood Flow Velocity and Autoregulation between the Anterior and Posterior Circulations in Healthy Children

Appraising the Plasticity of the Circle of Willis: A Model of Hemodynamic Modulation in Cerebral Arteriovenous Malformations

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