Autoregulation after ischaemic stroke

William J. Powers, Tom O. Videen, Michael N. Diringer, Venkatesh Aiyagari, Allyson R. Zazulia

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

Objectives Absent outcome data from randomized clinical trials, management of hypertension in acute ischaemic stroke remains controversial. Data from human participants have failed to resolve the question whether cerebral blood flow (CBF) in the peri-infarct region will decrease due to impaired autoregulation when systemic mean arterial pressure (MAP) is rapidly reduced. Methods Nine participants, 1-11 days after hemispheric ischaemic stroke, with systolic blood pressure more than 145 mmHg, underwent baseline PET measurements of regional CBF. Intravenous nicardipine infusion was then used to rapidly reduce mean arterial pressure 16 ± 7 mmHg and CBF measurement was repeated. Results Compared with the contralateral hemisphere, there were no significant differences in the percent change in CBF in the infarct (P= 0.43), peri-infarct region (P= 1.00) or remainder of the ipsilateral hemisphere (P= 0.50). Two participants showed CBF reductions of greater than 19% in both hemispheres. Conclusion In this study, selective regional impairment of CBF autoregulation in the infarcted hemisohere to reduced systemic blood pressure was not a characteristic of acute cerebral infarction. Reductions in CBF did occur in some individuals, but it was bihemispheric phenomenon that likely was due to an upward shift of the autoregulatory curve as a consequence of chronic hypertension. These results indicate individual monitoring of changes in global CBF, such as with bedside transcranial Doppler, may be useful to determine individual safe limits when MAP is lowered in the setting of acute ischaemic stroke. The benefit of such an approach can only be demonstrated by clinical trials demonstrating improved patient outcome.

Original languageEnglish (US)
Pages (from-to)2218-2222
Number of pages5
JournalJournal of Hypertension
Volume27
Issue number11
DOIs
StatePublished - Nov 2009

Fingerprint

Cerebrovascular Circulation
Homeostasis
Stroke
Arterial Pressure
Blood Pressure
Hypertension
Nicardipine
Cerebral Infarction
Regional Blood Flow
Intravenous Infusions
Randomized Controlled Trials
Clinical Trials

Keywords

  • Autoregulation
  • Blood pressure
  • Cerebral infarction
  • Cerebrovascular circulation

ASJC Scopus subject areas

  • Internal Medicine
  • Physiology
  • Cardiology and Cardiovascular Medicine

Cite this

Powers, W. J., Videen, T. O., Diringer, M. N., Aiyagari, V., & Zazulia, A. R. (2009). Autoregulation after ischaemic stroke. Journal of Hypertension, 27(11), 2218-2222. https://doi.org/10.1097/HJH.0b013e328330a9a7

Autoregulation after ischaemic stroke. / Powers, William J.; Videen, Tom O.; Diringer, Michael N.; Aiyagari, Venkatesh; Zazulia, Allyson R.

In: Journal of Hypertension, Vol. 27, No. 11, 11.2009, p. 2218-2222.

Research output: Contribution to journalArticle

Powers, WJ, Videen, TO, Diringer, MN, Aiyagari, V & Zazulia, AR 2009, 'Autoregulation after ischaemic stroke', Journal of Hypertension, vol. 27, no. 11, pp. 2218-2222. https://doi.org/10.1097/HJH.0b013e328330a9a7
Powers WJ, Videen TO, Diringer MN, Aiyagari V, Zazulia AR. Autoregulation after ischaemic stroke. Journal of Hypertension. 2009 Nov;27(11):2218-2222. https://doi.org/10.1097/HJH.0b013e328330a9a7
Powers, William J. ; Videen, Tom O. ; Diringer, Michael N. ; Aiyagari, Venkatesh ; Zazulia, Allyson R. / Autoregulation after ischaemic stroke. In: Journal of Hypertension. 2009 ; Vol. 27, No. 11. pp. 2218-2222.
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N2 - Objectives Absent outcome data from randomized clinical trials, management of hypertension in acute ischaemic stroke remains controversial. Data from human participants have failed to resolve the question whether cerebral blood flow (CBF) in the peri-infarct region will decrease due to impaired autoregulation when systemic mean arterial pressure (MAP) is rapidly reduced. Methods Nine participants, 1-11 days after hemispheric ischaemic stroke, with systolic blood pressure more than 145 mmHg, underwent baseline PET measurements of regional CBF. Intravenous nicardipine infusion was then used to rapidly reduce mean arterial pressure 16 ± 7 mmHg and CBF measurement was repeated. Results Compared with the contralateral hemisphere, there were no significant differences in the percent change in CBF in the infarct (P= 0.43), peri-infarct region (P= 1.00) or remainder of the ipsilateral hemisphere (P= 0.50). Two participants showed CBF reductions of greater than 19% in both hemispheres. Conclusion In this study, selective regional impairment of CBF autoregulation in the infarcted hemisohere to reduced systemic blood pressure was not a characteristic of acute cerebral infarction. Reductions in CBF did occur in some individuals, but it was bihemispheric phenomenon that likely was due to an upward shift of the autoregulatory curve as a consequence of chronic hypertension. These results indicate individual monitoring of changes in global CBF, such as with bedside transcranial Doppler, may be useful to determine individual safe limits when MAP is lowered in the setting of acute ischaemic stroke. The benefit of such an approach can only be demonstrated by clinical trials demonstrating improved patient outcome.

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