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...