Detection of reverse flow by duplex ultrasonography in orthostatic hypotension.

Yonehara, Toshiro; Ando, Yumiko; Kimura, Keishi; Uchino, Makoto; Ando, Masayuki

doi:10.1161/01.str.25.12.2407

Cited by 18 publications

(10 citation statements)

References 15 publications

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“…In a previous study, end-diastolic reverse flow in CCA at HUT was recognized in all symptomatic OH patients but not in asymptomatic OH patients [17]. In our study, this reverse flow was detected not only in symptomatic OH patients, but also in asymptomatic OH patients, indicating that a reverse flow was not specific to symptomatic OH.…”

Section: Discussioncontrasting

confidence: 65%

“…Therefore, estimation of blood flow velocity (BFV) of the common carotid artery (CCA) by carotid duplex ultrasonography may be a potential method for estimating the change of CBF during HUT. A previous study reported the detection of reverse flow at the end-diastolic phase in the CCA by carotid duplex ultrasonography as a marker for symptomatic OH patients; however, there was no significant difference between patients with symptoms and those without [17]. Here, we report that BFV of the CCA estimated by carotid duplex ultrasonography is significantly different between symptomatic and asymptomatic OH patients, indicating the usefulness of this method.…”

Section: Introductionsupporting

confidence: 47%

“…In our study, this reverse flow was detected not only in symptomatic OH patients, but also in asymptomatic OH patients, indicating that a reverse flow was not specific to symptomatic OH. The decrease in EDV of CCA during HUT was not evaluated in the previous study [17]. …”

Section: Discussionmentioning

confidence: 99%

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Carotid Duplex Ultrasonography during Head-Up Tilt in Patients with Orthostatic Hypotension

Hamaguchi

Iwasa²,

Okino³

et al. 2007

Eur Neurol

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Orthostatic hypotension (OH) is defined by evaluating postural blood pressure (BP) change, but the correlation between postural BP decreases and OH-associated symptoms is poor. We examined carotid duplex ultrasonography during HUT in 27 patients with various neurological disorders. Nine patients were diagnosed to have OH, and 4 of them had symptoms associated with OH. Decreased end-diastolic velocity of common carotid artery in symptomatic OH patients (–24.5 ± 4.2 cm/s) was significantly larger than that in asymptomatic OH patients (–11.0 ± 8.0 cm/s; p = 0.0143), despite no significant differences in values and changes of BP between them. This may be useful for predicting the development of OH symptoms.

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Section: Discussioncontrasting

confidence: 65%

Section: Introductionsupporting

confidence: 47%

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Carotid Duplex Ultrasonography during Head-Up Tilt in Patients with Orthostatic Hypotension

Hamaguchi

Iwasa²,

Okino³

et al. 2007

Eur Neurol

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“…The autonomic nervous system appears to be earlier and more severely involved in Japanese than in Swedish patients [45]. A pronounced ortostatic hypotension with fainting and even a reverse blood flow in the carotic artery has been observed in Japanese patients after tilting [46]. However, such reactions are less common in Swedish cases.…”

Section: Somatic and Autonomic Polyneuropathymentioning

confidence: 99%

Hereditary transthyretin amyloidosis from a Scandinavian perspective

Suhr

Svendsen²,

Andersson³

et al. 2003

Journal of Internal Medicine

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“…1,2 Blood flow to the brain can be influenced through adjustments in systemic hemodynamics (ie, perfusion pressure) or through local vascular modulation (ie, cerebral autoregulation). 3 Thus, impaired adjustment of systemic hemodynamics or disordered regulation of cerebrovascular tone could contribute to cerebral hypoperfusion with standing.…”

mentioning

confidence: 99%

Interaction of Carbon Dioxide and Sympathetic Nervous System Activity in the Regulation of Cerebral Perfusion in Humans

et al. 2000

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Abstract-Recent studies suggest that activation of the sympathetic nervous system either directly or indirectly influences cerebrovascular tone in humans even within the autoregulatory range. In 6 healthy subjects (aged 29Ϯ4 years), we used transcranial Doppler sonography to determine cerebral blood flow velocity during sympathetic activation elicited through head-up tilt (HUT) and sympathetic deactivation through ganglionic blockade. PaCO 2 was manipulated through hyperventilation and CO 2 breathing (5%). With subjects in the supine position and during HUT, mean arterial pressure was not influenced by PaCO 2 . During ganglionic blockade, mean arterial pressure decreased markedly with hyperventilation (Ϫ13Ϯ1.9 mm Hg). Manipulation of sympathetic tone elicited only mild changes in cerebral blood flow (64Ϯ5.8 cm/s supine, 58Ϯ4.9 cm/s upright, and 66Ϯ6.2 cm/s during ganglionic blockade; Pϭ0.07 by ANOVA). The slope of the regression between PaCO 2 and mean velocity was 1.6Ϯ0.18 cm/(s ⅐ mm Hg) supine, 1.3Ϯ0.14 cm/(s ⅐ mm Hg) during HUT, and 2.3Ϯ0.36 cm/(s ⅐ mm Hg) during ganglionic blockade (PϽ0.05). Spontaneous PaCO 2 and ventilatory response to hypercapnia were also modulated by the level of sympathetic activity. Changes in sympathetic tone have a limited effect on cerebral blood flow at normal PaCO 2 levels. However, the sympathetic nervous system seems to attenuate the CO 2 -induced increase in cerebral blood flow. This phenomenon may indicate a moderate direct effect of the sympathetic nervous system on the cerebral vasculature. Furthermore, sympathetic activation tends to increase ventilation and thus can indirectly increase cerebrovascular tone. (Hypertension. 2000;36:383-388.)Key Words: carbon dioxide Ⅲ baroreflex Ⅲ receptors, adrenergic Ⅲ phenylephrine Ⅲ sympathetic nervous system T he ability to assume the upright posture depends crucially on sufficient perfusion of the brain. 1,2 Blood flow to the brain can be influenced through adjustments in systemic hemodynamics (ie, perfusion pressure) or through local vascular modulation (ie, cerebral autoregulation). 3 Thus, impaired adjustment of systemic hemodynamics or disordered regulation of cerebrovascular tone could contribute to cerebral hypoperfusion with standing. An example of the former is the profound orthostatic hypotension seen in autonomic failure patients, which leads to cerebral hypoperfusion as the decrease in blood pressure (BP) exceeds the autoregulatory capacity of the brain. 1,4 On the other hand, the concept that impaired local regulation of cerebrovascular tone can also lead to cerebral hypoperfusion with standing is supported by recent findings in patients with orthostatic intolerance. [5][6][7][8] These patients experience typical symptoms of cerebral hypoperfusion when they stand, and these symptoms are associated with excessive reductions in cerebral blood flow velocity despite maintenance of arterial BP. 6 This cerebral vasoconstriction is attenuated either by interventions that blunt sympathetic activation or by ␣-adrenoreceptor blockad...

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Detection of reverse flow by duplex ultrasonography in orthostatic hypotension.

Cited by 18 publications

References 15 publications

Carotid Duplex Ultrasonography during Head-Up Tilt in Patients with Orthostatic Hypotension

Carotid Duplex Ultrasonography during Head-Up Tilt in Patients with Orthostatic Hypotension

Hereditary transthyretin amyloidosis from a Scandinavian perspective

Interaction of Carbon Dioxide and Sympathetic Nervous System Activity in the Regulation of Cerebral Perfusion in Humans

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