Book Review

Drug Therapy for Stroke Prevention

N Engl J Med 2001; 345:1919December 27, 2001

Article

Drug Therapy for Stroke Prevention
Edited by Julien Bogousslavsky. 303 pp. London, Taylor and Francis, 2001. $95. ISBN: 0-7484-0934-3

Two decades ago, it would have been unthinkable that the devastating effects of ischemic stroke would ever be completely reversible, but with thrombolysis this is now a reality. Unfortunately, the therapeutic window remains impracticably narrow (the three-hour barrier has not yet been effectively overcome), and the treatment is very expensive, so that even in the developed world successful thrombolysis is only possible in a tiny minority of patients.

Stroke is now the second most common cause of death globally, with most cases occurring in the developing world, according to statistics from the World Health Organization. Unlike the impracticality of treating the acute condition, prevention of stroke is much more feasible in view of the high prevalence, the low cost, and the effectiveness of simple preventive measures. Thus, stroke prevention is applicable throughout the world, even in areas where acute-stroke units and facilities for thrombolysis will not be available for decades. At the most basic level, education of the public is critical — especially in the developing world, where the vegetarian diet and the bicycle are rapidly being replaced by ample red meat, motor vehicles, and unlimited cigarettes.

As the various risk factors were unmasked, strategies including adjustments of lifestyle and diet, the use of antithrombotic drugs, and especially the treatment of hypertension contributed to a reduction by 40 percent in the incidence of stroke between 1970 and 1990. Today, this decline is no longer evident, mainly because with the aging population the numbers at risk for stroke are increasing, making prevention a global therapeutic target for humanitarian as well as economic reasons.

Three books on the prevention of stroke have already been published over the past year, so duplication of topics and ideas is inevitable. The editor of Drug Therapy for Stroke Prevention enlisted a variety of authors, some of whom are well known in the field, and there is an inevitable overlap among various chapters, though this sometimes makes for interesting reading. Newer emerging concepts that are dealt with include the role of vitamins and antioxidants (how many physicians advise their patients with stroke about diet?) and the still uncertain role of estrogens in cardiovascular and cerebrovascular disease. Surprisingly, there is no mention of the potential role of infectious agents such as chlamydia in the vascular wall contributing to plaque inflammation and stability.

Particularly interesting is the chapter dealing with the paradoxical relation between stroke and blood lipids. Unlike coronary artery disease, high cholesterol levels have never shown a consistent relation to cerebrovascular disease, and primary-prevention strategies to lower blood cholesterol affect only ischemic heart disease, not stroke. Yet statin therapy reduces the risk of stroke, at least in those with ischemic heart disease, which suggests there are other as-yet-uncertain preventive effects of this group of drugs that are unrelated to circulating blood lipids.

The book was published this year, but too late to include current concepts concerning the high rate of recurrence in the first few weeks after threatened or completed cerebral infarction. This finding will have a major effect on future prevention trials, since most planners of epidemiologic studies and drug trials allow entry “windows” of months, unaware that half of the recurrences in the first few months occur in the first two days after the ischemic event. Stroke prevention should start within hours after the transient ischemic attack or stroke, not days and certainly not months later. Since the cause of stroke is heterogeneous, prevention strategies should incorporate an algorithm that includes different types of antithrombotic agents (or even surgical strategies), depending on the probable cause. The only previous studies to attempt this were the International and Chinese Acute Stroke Trials (IST and CAST), but these were partly prevention and partly treatment trials.

In general, the layout of chapters is clear, although the addition of more illustrations (lacking in many chapters) would have made the book easier to read. The insertion of references by name and date clutters the text (as compared with simple numbering) and is also a major obstruction to reading, especially when citations occupy half a paragraph and disconnect the sentences.

These are the early days of the prevention of stroke. Even in the most sophisticated areas of the developed world, knowledge of the most basic signs, symptoms, and risk factors for stroke is abysmal. Most of the public cannot distinguish a stroke from a heart attack, patients with stroke are rarely cared for by physicians specializing in this area, and basic measures such as acute-stroke units still remain a scarce commodity. After extensive investigation, the cause of stroke in most patients remains unknown, so the search for additional risk factors is far from over, and only a minority have yet been identified. There is scope for many more books on stroke prevention in the future.

John W. Norris, M.D.
University of Toronto, Toronto, ON M4N 3M5, Canada