Vascular Contributions to Cognitive Impairment and Dementia

Abstract

Background and Purpose This scientific statement provides an overview of the evidence on vascular contributions to cognitive impairment and dementia. Vascular contributions to cognitive impairment and dementia of later life are common. Definitions of vascular cognitive impairment (VCI), neuropathology, basic science and pathophysiological aspects, role of neuroimaging and vascular and other associated risk factors, and potential opportunities for prevention and treatment are reviewed. This statement serves as an overall guide for practitioners to gain a better understanding of VCI and dementia, prevention, and treatment. Methods Writing group members were nominated by the writing group co-chairs on the basis of their previous work in relevant topic areas and were approved by the American Heart Association Stroke Council Scientific Statement Oversight Committee, the Council on Epidemiology and Prevention, and the Manuscript Oversight Committee. The writing group used systematic literature reviews (primarily covering publications from 1990 to May 1, 2010), previously published guidelines, personal files, and expert opinion to summarize existing evidence, indicate gaps in current knowledge, and, when appropriate, formulate recommendations using standard American Heart Association criteria. All members of the writing group had the opportunity to comment on the recommendations and approved the final version of this document. After peer review by the American Heart Association, as well as review by the Stroke Council leadership, Council on Epidemiology and Prevention Council, and Scientific Statements Oversight Committee, the statement was approved by the American Heart Association Science Advisory and Coordinating Committee. Results The construct of VCI has been introduced to capture the entire spectrum of cognitive disorders associated with all forms of cerebral vascular brain injury—not solely stroke—ranging from mild cognitive impairment through fully developed dementia. Dysfunction of the neurovascular unit and mechanisms regulating cerebral blood flow are likely to be important components of the pathophysiological processes underlying VCI. Cerebral amyloid angiopathy is emerging as an important marker of risk for Alzheimer disease, microinfarction, microhemorrhage and macrohemorrhage of the brain, and VCI. The neuropathology of cognitive impairment in later life is often a mixture of Alzheimer disease and microvascular brain damage, which may overlap and synergize to heighten the risk of cognitive impairment. In this regard, magnetic resonance imaging and other neuroimaging techniques play an important role in the definition and detection of VCI and provide evidence that subcortical forms of VCI with white matter hyperintensities and small deep infarcts are common. In many cases, risk markers for VCI are the same as traditional risk factors for stroke. These risks may include but are not limited to atrial fibrillation, hypertension, diabetes mellitus, and hypercholesterolemia. Furthermore, these same vascul...

Microinfarcts in an older population‐representative brain donor cohort (MRC CFAS): Prevalence, relation to dementia and mobility, and implications for the evaluation of cerebral Small Vessel Disease

“…We demonstrate an association both with a clinical history of stroke and with hypertension. Hypertension is certainly considered to be a major underlying risk factor for cerebral SVD but clinical stroke is diverse both in terms of ischaemic and haemorrhagic pathophysiology and, for ischaemic stroke, in terms of the contributions of intrinsic cerebrovascular disease compared to carotid or cardiac microembolization 1. Within the constellation of pathologies that we have combined into a global concept of SVD the underlying mechanisms that cause microinfarcts, white matter attenuation and lacunes are not precisely defined.…”

“…In neuropathological practice the term ‘microinfarct’ is used to describe CNS lesions of presumed ischaemic origin that are only detected by microscopic examination 1. Such lesions are a common finding at autopsy in older individuals 2.…”

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“…The data tell us that the likelihood of stroke decreases as blood pressure is lowered 2 . And by getting to grips with blood pressure, we can prevent not just the death and physical disability that so often result from stroke, but also age-related cognitive impairment and dementia 3 . Most people who die with a diagnosis of dementia have a mixture of Alzheimer's and vascular disease 4 .…”