Blocking
Early Steps in Platelet Aggregation Reduces Stroke Infarct
Size Without Increasing Intracerebral Hemorrhage (ICH)
Ischemic
stroke is the third leading cause of death and permanent
disability in industrialized countries. Currently, the
anticoagulant therapies available to treat ischemic stroke
offer moderate benefit on stroke progression and recurrence,
but this is outweighed by a significant increase in the rate
of ICH. During ischemia, platelets can adhere to hypoxic
endothelial cells by binding of their glycoprotein (GP) Ib
receptor to von Willebrand factor (vWF) on the endothelial
surface. Additionally, subendothelial matrix proteins are
exposed, allowing firm attachment of platelets to the vessel
by binding of collagens to their GPVI receptor. These
processes lead to activation of platelet GPIIb/IIIa and
platelet aggregation. Christoph Kleinschnitz, MD et al from
the University of Würzburg in Würzburg, Germany tested the
hypothesis that blocking platelet aggregation and activation
at various steps in these pathways may reduce infarct size
following ischemic stroke. Their results, published in the
May 1, 2007 issue of Circulation, showed that
targeting platelet GPIb or GPVI receptors protects mice from
ischemic brain injury in an experimental stroke model
without increasing bleeding complications. In contrast,
blockade of the final common pathway of platelet aggregation
with anti-GPIIb/IIIa antibodies had no positive effect on
stroke outcome and dose-dependently raised the incidence of
ICH and mortality.
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High-Dose Atorvastatin Reduces the Overall Incidence of
Stroke or Transient Ischemic Attack
It
has become evident that patients who take statins have a
decreased incidence of stroke and cardiovascular risks. It
has been, however, unknown whether patients with previous
strokes or transient ischemic attacks (TIA) would benefit
from taking statins. A study led by The Stroke Prevention
by Aggressive Reduction in Cholesterol Levels (SPARCL)
Investigators showed that in patients with recent stroke
or TIA and without known coronary heart disease, 80 mg of
atorvastatin per day reduced the overall incidence of
strokes and of cardiovascular events. This study was
published in the August 10, 2006 issue of The New England
Journal of Medicine.
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Blood Pressure Lowering Regimen Delays the
Progression of White Matter Hyperintensities in
Patients With Stroke -
White
matter hyperintensities (WMHs) are observed on brain
MRI’s in elderly people and people with stroke. They
are areas of demyelination and infarct that manifest
in clinical outcomes such as dementia, depression
and gait disturbances. High blood pressure is known
to be a risk factor for WMH and they are said to
increase over time. Carole Dufouil, PhD et al from
the INSERM in France studied whether lowering blood
pressure would reduce the incidence of WHMs. This
study, published in the September 13, 2005 issue of
Circulation journal found that an active blood
pressure-lowering regimen stopped or delayed the
progression of WHMs in patients with cerebrovascular
disease. MORE...
In Large, Primary-Prevention Trial Among Women, Aspirin
Lowered the Risk of Stroke Without Affecting the Risk of
Myocardial Infarction
Use of
Ultrasound Safely Enhances t-PA Thrombolysis for Acute
Ischemic Stroke