PRIMARY AND SECONDARY PREVENTION OF CORONARY-ARTERY DISEASE

A variety of new results from clinical studies point toward improved assessment of and intervention in risk factors for coronary artery disease. Separate analyses of Helsinki Heart Study and Prospective Cardiovascular Muenster (PROCAM) data showed the combination of triglyceride elevation and a high ratio of total cholesterol or low-density lipoprotein cholesterol (LDL-C) to high-density lipoprotein cholesterol (HDL-C) to confer greater risk of coronary artery disease than LDL-C elevation alone. In the Physicians' Health Study (PHS), a change of 1 unit in the total to HDL cholesterol ratio was associated with a 53% change in risk for myocardial infarction after adjustment for other risk factors. Findings from these studies support recommendations by the February 1992 US National Institutes of Health Consensus Development Conference on Triglyceride, High Density Lipoprotein, and Coronary Heart Disease that not only total cholesterol but also HDL-C be measured in healthy individuals to assess coronary artery disease risk and that HDL-C and triglyceride be measured in additional clinical circumstances, eg, in patients with known coronary artery disease or with desirable total cholesterol and two or more risk factors and in such disorders as hypertension and diabetes mellitus, to refine risk assessment. Strong evidence associates much-increased coronary artery disease risk with atherogenic lipoprotein phenotype B, in which presumably atherogenic small, dense LDL particles predominate. A meta-analysis of major cholesterol-lowering trials suggested that targeted secondary intervention could have a major impact on coronary artery disease events in the entire population, because there were 27 fewer myocardial infarctions than expected per 1000 patients treated across eight secondary-intervention trials, compared with six per 1000 across four primary-prevention trials, and because half of all myocardial infarctions occur in men with a history of coronary artery disease. Noteworthy new results have also been published on nonlipid variables in relation to coronary artery disease risk, including aspirin use, propranolol use, tissue plasminogen activator antigen level, family history of myocardial infarction, and adipose distribution. There are promising new findings that directing educational programs on lifestyle risk factors toward families or communities can be effective. The approval in 1991 of two additional reductase inhibitors (pravastatin and simvastatin) for use in the United States provides options in a class of drugs with excellent efficacy and safety records, recently bolstered by publication of the findings of the Expanded Clinical Evaluation of Lovastatin (EXCEL) study.