Book Review

Prevention of Myocardial Infarction

N Engl J Med 1997; 336:383January 30, 1997

Article

Prevention of Myocardial Infarction
Edited by JoAnne Manson, Paul Ridker, J. Michael Gaziano, and Charles H. Hennekens. 564 pp. New York, Oxford University Press, 1996. $65. ISBN: 0-19-508582-5

This comprehensive book covers a wide range of topics relevant to the prevention of myocardial infarction: epidemiology, the pathogenesis of atherosclerosis and thrombosis, genetic determinants of atherosclerosis, smoking cessation, cholesterol reduction, treatment of hypertension, exercise, psychological stress, treatment with aspirin and natural antioxidants, and dietary factors. There are special chapters on risk modification in obese and diabetic patients, sex differences in the risk of coronary events, postmenopausal hormone therapy, preventive pediatric cardiology, and secondary prevention. Where relevant, the chapters start with a discussion of molecular biology and studies in animals. The authors were requested to evaluate the quality of the data on estimated risk reductions and the comparability of effects in men and women. Many chapters have special sections discussing the strength of evidence and cost effectiveness. The book is well written and has a good theoretical discussion of prevention as well as practical advice. Even though many of the chapters explicitly consider North American perspectives, the book can be broadly recommended. However, some chapters contain virtually no references to non-American studies.

The chapter on hemostatic and thrombotic risk factors stresses that only a few infarctions could be predicted on the basis of elevated serum cholesterol levels, tobacco smoking, and elevated blood pressure. This may be true of the studies cited, but other prospective studies found that 90 percent or more of men who had a myocardial infarction had one or all of these risk factors.

The brief overview of the promotion of coronary health discusses population attributable risk and prevention in populations, with the following example: “Thus, while a therapy that improves survival by 20% for hospitalized patients could prevent 10,000 to 20,000 deaths, a similar magnitude of benefit in primary prevention of [myocardial infarction] would save over 100,000 lives in the United States each year.” Even moderate reductions in risk factors in the general population are considerably more important for the population than many sophisticated interventions in people at high risk, such as patients who have had an infarction. Yet these interventions have tremendous importance for the individual. There is a similar problem with regard to elevated blood pressure. All epidemiologic studies indicate that there is a gradually increasing risk of complications with increasing blood pressure, so a nonpharmacologic reduction of blood pressure in the general population would theoretically have a stronger preventive effect than vigorous antihypertensive treatment of patients with hypertension.

The short, well-written chapter on aspirin in primary and secondary prevention includes a good perspective on cost effectiveness. The chapter on natural oxidants is a comprehensive overview of the various antioxidants, the status of ongoing trials, and a well-balanced summary of their use. The chapter on dietary factors is also well balanced.

I very much enjoyed the chapter on sex differences in coronary heart disease. However, one statement in this chapter — that “no primary or secondary prevention trials of cholesterol-lowering with total mortality endpoints have included women” — can now be modified. Both the Scandinavian Simvastatin Survival Study, whose results were published in 1994, and the Cholesterol and Recurrent Events (CARE) trial in the United States, recently reported in the Journal, included women. In the latter, the effect of lowering lipid levels was stronger among women than among men.

The chapter on secondary prevention is largely based on intervention trials. It shows the difficulty of keeping up with new information. For example, it states “It is not clear whether [patients with coronary heart disease] who have average cholesterol levels, for example, <240 mg/dl, will receive benefit from efforts to achieve lower than average levels.” The CARE trial showed that these patients benefit from treatment. This chapter also states that many patients with coronary heart disease have normal or even below-normal total and low-density lipoprotein cholesterol levels. But cholesterol levels decrease rapidly after a myocardial infarction and do not return to the preinfarction levels for three months. What are called “normal” cholesterol levels in many Western countries are most probably too high for susceptible people. This chapter on secondary prevention says nothing about antismoking advice to patients after an infarction, or about hypertension in such patients. Should blood pressure be reduced as much as in healthy people, and which drugs are preferred? A summary of all treatment methods in patients who have had an infarction would have been useful.

Lars Wilhelmsen, M.D.
Östra Hospital, S-416 85 Göteborg, Sweden