• Neurosurgery · Jul 2004

    Comparative Study Clinical Trial

    Pressure autoregulation and positron emission tomography-derived cerebral blood flow acetazolamide reactivity in patients with carotid artery stenosis.

    • Pawan S Minhas, Piotr Smielewski, Peter J Kirkpatrick, John D Pickard, and Marek Czosnyka.
    • Wolfson Brain Imaging Centre and Academic Department of Neurosurgery, Addenbrooke's Hospital, Cambridge, England. pawanminhas@hotmail.com
    • Neurosurgery. 2004 Jul 1; 55 (1): 63-7; discussion 67-8.

    ObjectiveTesting autoregulation is of importance in predicting risk of stroke and managing patients with occlusive carotid arterial disease. The use of small spontaneous changes in arterial blood pressure and transcranial Doppler (TCD) flow velocity can be used to assess autoregulation noninvasively without the need for a cerebrovascular challenge. We have previously described an index (called "Mx") that achieves this. Negative or low positive values (<0.4) indicate intact pressure autoregulation, whereas an Mx greater than 0.4 indicates diminished autoregulation. The objective of this study was to compare acetazolamide reactivity of positron emission tomography (PET)-derived cerebral blood flow (CBF) with Mx in patients with carotid arterial disease.MethodsIn 40 patients with carotid arterial disease, we used bilateral TCD recordings of the middle cerebral artery to derive Mx and compared this with PET-derived CBF measurements of acetazolamide reactivity.ResultsMx correlated inversely with baseline PET CBF (P = 0.042, R = -0.349) but not with postacetazolamide CBF or cerebrovascular reactivity to acetazolamide. This may reflect discordance between pressure autoregulation and acetazolamide reactivity. Mx correlated significantly with degree of internal carotid artery stenosis (P = 0.022, R = 0.38), whereas CBF reactivity to acetazolamide did not correlate with Mx (P = 0.22). After the administration of acetazolamide, slow-wave activity in blood pressure and TCD flow velocity recordings was seen to diminish, rendering the calculation of Mx unreliable after acetazolamide.ConclusionThe measurement of Mx offers a noninvasive, safe technique for assessing abnormalities of pressure autoregulation in patients with carotid arterial disease.

      Pubmed     Full text   Copy Citation     Plaintext  

      Add institutional full text...

    Notes

     
    Knowledge, pearl, summary or comment to share?
    300 characters remaining
    help        
    You can also include formatting, links, images and footnotes in your notes
    • Simple formatting can be added to notes, such as *italics*, _underline_ or **bold**.
    • Superscript can be denoted by <sup>text</sup> and subscript <sub>text</sub>.
    • Numbered or bulleted lists can be created using either numbered lines 1. 2. 3., hyphens - or asterisks *.
    • Links can be included with: [my link to pubmed](http://pubmed.com)
    • Images can be included with: ![alt text](https://bestmedicaljournal.com/study_graph.jpg "Image Title Text")
    • For footnotes use [^1](This is a footnote.) inline.
    • Or use an inline reference [^1] to refer to a longer footnote elseweher in the document [^1]: This is a long footnote..

    hide…