New therapies for stroke
L. R. Caplan
Department of Neurology, New England Medical Center, Boston, Mass., USA.
The treatment of patients with stroke and cerebrovascular disease has
entered a new era. During the 1990s there has been a revolution in
technology able to define quickly, safely, and accurately stroke
pathophysiological characteristics and the cardiovascular lesions that
cause stroke in individual patients. Advanced brain imaging with computed
tomography, magnetic resonance imaging, and newer magnetic resonance
modalities, including fluid attenuating inversion recovery imaging,
diffusion, perfusion, functional magnetic resonance imaging, and magnetic
resonance spectroscopy, show clinicians the localization, severity, and
potential reversibility of ischemia. Vascular lesions can be defined using
spiral computed tomographic angiography, magnetic resonance angiography,
and extracranial and transcranial ultrasonography. Cardiac and aortic
sources of stroke are now better studied using transesophageal
echocardiography. More sophisticated hematologic testing gives new insights
into the role of altered coagulability in causing or contributing to
thromboembolism. Clinicians can now recognize the key data elements needed
to logically treat brain ischemia, including the following: The nature,
location, and severity of cardiac and cerebrovascular lesions. The
mechanism by which these lesions cause ischemia--hypoperfusion? embolism?
functional changes such as vasoconstriction? The cellular and serologic
components of the blood that relate to coagulability, viscosity, and blood
flow. The state of the brain--normal, reversibly ichemic ("stunned"), or
infarcted. With these diagnostic advances have come new treatments, new
ideas about treatment, and more and new information about conventional
treatments.
