cereberovascular disease1

Among all the neurologic diseases of adult life, the cerebrovascular
ones clearly rank first in frequency and importance. At least 50
percent of the neurologic disorders in a general hospital are of this
type. At some time or other, every physician will be required to
examine patients with cerebrovascular disease and should at least
know something of the common types—particularly those in
which there is a reasonable prospect of successful medical or surgical
intervention or the prevention of recurrence. There is another
advantage to be gained from the study of this group of diseases—
namely, that they have traditionally provided one of the most instructive
approaches to neurology. As our colleague C. M. Fisher has aptly
remarked, house officers and students learn neurology literally “stroke
by stroke.” Moreover, the focal ischemic lesion has divulged some of
our most important ideas about the function of the human brain.
It must also be noted that, in the last two decades, new and
extraordinary types of imaging technology have been introduced
that allow the physician to make physiologic distinctions between
normal, ischemic, and infarcted brain tissue. This biopathologic
approach to stroke will likely guide the next generation of treatments
and has already had a pronounced impact on the direction
of research in the field. Salvageable brain tissue to be protected in
the acute phase of stroke can be delineated by these methods. To
identify this ischemic but not yet infarcted tissue virtually defines
the goal of modern stroke treatment. Which of the sophisticated
imaging techniques will contribute to improved clinical outcome
is still to be determined, but certain ones, such as diffusionweighted
imaging, have already proved invaluable in stroke work.
Despite these valuable advances in stroke neurology, three
points should be made. First, all physicians have a role to play in
the prevention of stroke by encouraging the reduction in risk factors
such as hypertension and the identification of signs of potential
stroke, such as transient ischemic attacks, atrial fibrillation, and
carotid artery stenosis. Second, careful bedside clinical evaluation
integrated with the newer testing methods mentioned above still
provide the most promising approach to this category of disease.
Finally, the last decade or two have witnessed a departure from the
methodical clinicopathologic studies that have been the foundation
of our understanding of cerebrovascular disease. Increasingly, randomized
studies involving several hundred and even thousands of
patients and conducted simultaneously in dozens of institutions have
come to dominate investigative activity in this field. These multicenter
trials have yielded highly valuable information about the natural
history of a variety of cerebrovascular disorders, both symptomatic
and asymptomatic. However, this approach suffers from a
number of inherent weaknesses, the most important of which is
that the homogenized data derived from an aggregate of patients
may not be applicable to a specific case at hand. Moreover, many
large studies show only marginal differences between treated and
control groups. Each of these multicenter studies will therefore be
critically appraised at appropriate points in the ensuing discussion.