Pathophysiology of post-stroke hyperglycaemia and brain arterial patency

MacDougall, Niall John James (2013) Pathophysiology of post-stroke hyperglycaemia and brain arterial patency. MD thesis, University of Glasgow.

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The pathophysiology of acute post-stroke hyperglycaemia (PSH) is important as hyperglycaemia affects the majority of stroke patients, and is consistently associated with poorer outcome in terms of survival, disability and markers of brain injury such as infarct expansion. There appears to be an interaction between brain arterial patency and hyperglycaemia that has not been fully characterised. This thesis initially reviews the literature on hyperglycaemia and stroke before focusing on animal models of PSH and clinical trials of insulin treatment for PSH in two systematic reviews with meta-analysis. The thesis then looks at the relationship between glucose profiles and clinical outcome in a historical population receiving IV thrombolysis for acute ischaemic stroke, specifically exploring alternative indices of glycaemic state to compare the optimal predictive index for functional outcome as measured by the modified Rankin scale. The main body of the thesis details a prospective observational clinical study which recruited 108 patients within 6 hours of acute ischaemic stroke. These patients had careful monitoring of blood glucose levels over a 48 hour period and detail brain imaging including CT perfusion scanning to examine the ischaemic penumbra, CT angiography on admission and at 24-48 hours to document brain arterial patency with follow-up CT brain imaging to assess outcome infarct volume. The relationship between 48 hour blood glucose profiles, clinical outcome and imaging findings is then explored. The main findings of the thesis are summarized below. · Animal models of PSH have shown that hyperglycaemia exacerbates infarct volume in MCA occlusion models but studies are heterogeneous, and do not address the common clinical problem of PSH because they have used either the streptozotocin model of type I diabetes or extremely high glucose loads. · Animal models show that insulin has a non-significant and significantly heterogeneous effect on infarct growth. 3 · Clinical trials of insulin for post stroke hyperglycaemia have shown no benefit in terms of improved functional outcomes or mortality. Insulin is associated with an increased risk of hypoglycaemia. · In a historical cohort mean capillary blood glucose over 48 hours was more predictive of clinical outcome that admission blood glucose or two consecutive elevated glucose measurements. · A high proportion of acute stroke patients have a blood glucose level above 7mmol/L within 6 hours of onset. Different patterns of blood glucose levels define different populations. · Higher admission and mean glucose levels correlate with larger infarct volumes. Larger core perfusion lesion volumes are associated with a greater risk of mortality. Admission hyperglycaemia is more harmful than hyperglycaemia after 6 hours. · In patients with angiographic evidence of an arterial occlusion infarct volume varies significantly with glycaemic status. In some populations late hyperglycaemia is associated with better imaging outcomes. · Tandem occlusions are associated with bad outcomes after ischaemic stroke.

Item Type: Thesis (MD)
Qualification Level: Doctoral
Keywords: stroke, hyperglycaemia, CT, perfusion CT, animal models, met-analysis, human studies, brain arterial patency, CT angiography, acute stroke.
Subjects: R Medicine > RC Internal medicine > RC0321 Neuroscience. Biological psychiatry. Neuropsychiatry
Colleges/Schools: College of Medical Veterinary and Life Sciences > Institute of Neuroscience and Psychology
Funder's Name: UNSPECIFIED
Supervisor's Name: Muir, Professor Keith W.
Date of Award: 2013
Depositing User: Dr Niall JJ MacDougall
Unique ID: glathesis:2013-4568
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 26 Oct 2013 11:07
Last Modified: 28 Oct 2016 15:14

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