Am Fam Physician. 2010 Nov 15;82(10):1167-1173.
Original Article: Secondary Prevention of Coronary Artery Disease
Issue Date: February 1, 2010
Available at: http://www.aafp.org/afp/2010/0201/p289.html
to the editor: When reading the cover article on coronary artery disease (CAD) in the February 1, 2010, issue of American Family Physician, I first felt appreciation, then frustration. Throughout the article, the authors wrongly characterize CAD prevention following myocardial infarction (MI) or revascularization as secondary prevention, whereas it should be tertiary prevention. Imprecision in terminology may be contributed by the article's cited literature1,2 that likewise gets it wrong. The error is worth correcting.
Prevention can and should be divided into three stages: primary, secondary, and tertiary.3 Primary prevention represents the earliest possible interventions to foil disease before it begins. For CAD, this includes measures that prevent atherosclerotic plaques from ever developing. Secondary prevention includes early detection and halting the progression of established but asymptomatic disease. For CAD, this includes taking measures to prevent cardiovascular symptoms (e.g., dyspnea), damage (e.g., ventricular dysfunction), and events (e.g., acute coronary syndromes). However, once such symptoms, damage, or events occur, it is too late for secondary prevention. At this point, the only option is to try to rein in further disease progression with tertiary prevention. Tertiary prevention involves slowing, arresting, or reversing disease to prevent recurrent symptoms, further deterioration, and subsequent events. It is this type of prevention that the authors discuss primarily in their article.
Examples of tertiary prevention include percutaneous coronary intervention and coronary artery bypass grafting. These interventions are only for patients with established symptoms, objective dysfunction, or a history of events. Percutaneous coronary intervention and coronary artery bypass grafting are not examples of secondary prevention. Other interventions described by the authors could represent prevention that is either tertiary or secondary— or even primary (e.g., physical activity, weight and dietary management, tobacco cessation). Overlap in the appropriateness of different interventions at different stages of disease contributes to the muddled distinctions among the stages of prevention. Indeed, the authors, like the statements from the American Heart Association they cite,1,2 seem to combine secondary and tertiary stages of prevention under the imprecise umbrella term, “secondary prevention.” Such imprecision is dangerous.
To illustrate the danger, consider the case of beta blockers. The authors duly note that, “Multiple clinical trials have shown that beta-blocker therapy can reduce recurrent MI, sudden cardiac death, and mortality in patients after MI,” (i.e., beta blockers for tertiary prevention). However, at least two meta-analyses of clinical trials have suggested that beta blockers may lead to an increased risk of cardiovascular events and death in patients with hypertension who have not already had an MI (i.e., beta blockers for secondary prevention).4,5 Thus, recommending beta blockers for “secondary prevention” might do harm if it is unclear whether secondary or tertiary prevention is actually meant. For family physicians, distinguishing between secondary and tertiary prevention should be a primary concern.
1. Leon AS, Franklin BA, Costa F, et al. Cardiac rehabilitation and secondary prevention of coronary heart disease: an American Heart Association scientific statement from the Council on Clinical Cardiology (Subcommittee on Exercise, Cardiac Rehabilitation, and Prevention) and the Council on Nutrition, Physical Activity, and Metabolism (Subcommittee on Physical Activity), in collaboration with the American Association of Cardiovascular and Pulmonary Rehabilitation [published correction appears in Circulation. 2005;111(13):1717]. Circulation. 2005;111(3):369–376.
2. Smith SC Jr, Allen J, Blair SN, et al. AHA/ACC guidelines for secondary prevention for patients with coronary and other atherosclerotic vascular disease: 2006 update: endorsed by the National Heart, Lung, and Blood Institute [published correction appears in Circulation. 2006;113(22):e847]. Circulation. 2006;113(19):2363–2372.
3. Jekel JF, Katz DL, Elmore JG, Wild DMG. Epidemiology, Biostatistics, and Preventive Medicine. 3rd ed Philadelphia, Pa: Saunders/Elsevier 2007.
4. Bangalore S, Sawhney S, Messerli FH. Relation of beta-blocker-induced heart rate lowering and cardioprotection in hypertension. J Am Coll Cardiol. 2008;52(18):1482–1489.
5. Carlberg B, Samuelsson O, Lindholm LH. Atenolol in hypertension: is it a wise choice [published correction appears in Lancet. 2005;365(9460):656]? Lancet. 2004;364(9446):1684–1689.
EDITOR’S NOTE: Although Dr. Lucan’s definitions of secondary and tertiary prevention are consistent with primary care usage, including that of the U.S. Preventive Services Task Force,1 other physicians often use “secondary prevention” to refer to reducing the risk of recurrences of disease-related events, such as myocardial infarction,2 stroke,3 and osteoporotic fracture.4 Dr. Lucan’s observation that failing to precisely define what is meant by secondary prevention may occasionally lead to unnecessary, and potentially harmful, confusion is well taken. Toward this end, we will aim in future articles of this type to be clearer about what is being prevented and the population to whom the interventions apply.
1. U.S. Preventive Services Task Force. Procedure Manual. Rockville, Md.: Agency for Healthcare Research and Quality; July 2008. AHRQ publication no. 08-05118-EF. http://www.uspreventiveservicestaskforce.org/uspstf08/methods/procmanual.htm. Accessed December 13, 2011.
2. Skinner JS, Cooper A, Feder GS; Guideline Development Group. Secondary prevention for patients following a myocardial infarction: summary of NICE guidance. Heart. 2007;93(7):862-864.
3. Rashid P, Leonardi-Bee J, Bath P. Blood pressure reduction and secondary prevention of stroke and other vascular events: a systematic review. Stroke. 2003;34(11):2741-2748.
4. Wells GA, Cranney A, Peterson J, et al. Alendronate for the primary and secondary prevention of osteoporotic fractures in postmenopausal women. Cochrane Database Syst Rev. 2008;(1):CD001155.
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