2006 Fiscal Year Final Research Report Summary
Autoregulation of cerebral blood flow and postural changes of blood pressure in acute ischemic stroke
| Project/Area Number |
17590876
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Neurology
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| Research Institution | Shimane University |
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Principal Investigator |
IIJIMA Kenichi Shimane University, Faculty of Medicine, assistant professor (70314622)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAGUCHI Shuhei Shimane University, Faculty of Medicine, professor (80135904)
KOBAYASHI Shotai Shimane University, Faculty of Medicine, the director of a hospital (00118811)
KARINO Kenji Shimane University, Faculty of Medicine, medical technologist (20379689)
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| Project Period (FY) |
2005 – 2006
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| Keywords | acute stroke / postural changes of blood pressure / autoregulation / cerebral blood flow / head-up tilting / near infrared spectroscopy |
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| Research Abstract |
Background and Purpose: It is well known that autoregulation of cerebral blood flow (CBF) is impaired in the acute phase of ischemic stroke. However, there are few reports that studied autoregulation of CBF by means of head up tilting in the acute phase of ischemic stroke. We investigated the relationship between autoregulation of CBF and postural changes of systolic blood pressure (SBP) with head up tilt loading in acute ischemic stroke patients.
Methods: Subjects were 72 patients with ischemic stroke (mean aged 71 years). They were studied within seven days from the stroke onset without any medications affecting blood pressure. Postural change of SBP was assessed by comparing SBPs at the spine position and at the tilting position with 45ー head-up. Using a NIRS system, that permits continuous noninvasive monitoring of hemoglobin index (HbI) as an indicator of blood volume, we measured the change in HbI during the head-up tilting. All subjects were divided into 5 groups on the basis of SBP at the spine position; group 1 (SBP <= 120mmHg), group 2 (120<SBP<=140), group 3 (140<SBP<=160), group 4 (161<SBP<=180), and group 5 (SBP>180).
Results: Postural hypotension (SBP reduction of more than 20 mmHg) was observed in 25% of the patients, while dysautoregulation of CBF (HbI reduction of more than 2 standard deviations in normal subjects) was observed in 18 %. There was no correlation between the degree of postural hypotension and HUI reduction. The postural SBP reduction was significantly larger in the high blood pressure group (group 5>group 1 and 2), whereas the HbI was significantly decreased in both the high and low blood pressure groups (group 1 and 5) compared to the medium blood pressure group (group 3).
Conclusion: These results suggest that autoregulation of CBF is impaired in both the patient groups with high (>180mmHg) and low (<120mmHg) blood pressure in the acute phase of stroke.
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