In 2004 the U.S. Preventive Services Task Force (USPSTF) issued evidence-based recommendations discouraging the use of resting electrocardiography (ECG), exercise treadmill testing, and electron-beam computed tomography (EBCT) to detect the presence of severe coronary artery stenosis or to predict coronary heart disease events, such as myocardial infarction and coronary death, in adults at low risk for coronary heart disease events. 1 The USPSTF concluded that ECG and the exercise treadmill test (though not EBCT) "can detect severe ACS [acute coronary syndrome] in a small number of asymptomatic adults," but that the potential harm to patients from such screening is not outweighed by potential benefits.

These recommendations differ slightly from those made by the American College of Cardiology and the American Heart Association Task Force on Practice Guidelines, which recommended the use of exercise treadmill testing to evaluate limited groups of individuals who might benefit from risk-reduction therapy. 2 The guidelines gave a class IIa recommendation, meaning that the "weight of evidence/opinion is in favor of usefulness/efficacy," to the use of exercise testing in asymptomatic patients with diabetes mellitus who plan to begin a vigorous exercise regimen. They gave a class IIb recommendation, meaning that "usefulness/efficacy is less well established by evidence/opinion," to its use in patients with multiple risk factors (including hypercholesterolemia, hypertension, smoking, diabetes, and a family history of myocardial infarction or sudden cardiac death in a first-degree relative younger than 60 years) and in asymptomatic men older than 45 and asymptomatic women older than 55 who plan to begin an intense exercise regimen, who work in occupations where sudden incapacitation or death could endanger public safety, or who are otherwise at high risk for coronary artery disease.

The guidelines are similar in many ways, but for the areas in which they differ, how should nurse clinicians interpret these differences and what recommendations should nurses make to patients?

While there are valid reasons for screening for diseases-to modify therapy, to reassure patients who are beginning an intensive exercise program that the exercise will most likely not precipitate a myocardial infarction, or to encourage adherence to a risk-reduction program-screening with exercise treadmill testing or EBCT is not 100% accurate. There are false positives and false negatives, and because of the low prevalence of coronary artery disease in asymptomatic patients, there may be more false positives than true positives. 3 A false positive will lead to coronary angiography, which puts the patients at risk for transfusion, vascular injury, and even death. The diagnosis of coronary artery disease, even if false, may lead to higher health and life insurance premiums or the inability to obtain insurance. Patients with false negative results receive a clean bill of health and may ignore the development of subsequent anginal symptoms, as well as dietary and other recommendations that lower the risk of coronary artery disease.

Neither set of guidelines recommends resting ECG or EBCT as screening tests for coronary artery disease. While resting ECG is relatively inexpensive, EBCT is expensive and usually not covered by insurance. Additionally, although EBCT has high sensitivity for coronary artery disease, its specificity and accuracy may be less than that of thallium scintigraphy and echocardiography. 4 EBCT results in heavy radiation exposure and, if repeated periodically to screen for or to track the progression of coronary artery disease, may increase the patient's risk of cancer. 5 Currently, it is a radiologic tool in search of an indication; additional studies are needed to evaluate its role in screening for coronary artery disease.

Patients should be counseled on risk-factor reduction, which includes smoking cessation, a "heart-healthy" diet (with lipid-lowering agents, if needed), a daily exercise program, weight loss to achieve a normal body-mass index, and tight control of blood glucose and blood pressure levels. By addressing these factors, a patient can decrease the risk of myocardial infarction or another atherosclerotic coronary event by at least 80%. 6 If a patient develops anginal symptoms without reaching these goals or despite achieving them, then the patient should be tested for the development of coronary artery disease. Asymptomatic patients who request exercise treadmill testing or EBCT should be counseled on the risks of false positives and false negatives and the level of accuracy that each test provides; those requesting EBCT should also be counseled on radiation exposure. Patients should also be informed that if coronary artery disease is found, it is unknown whether surgery or angioplasty is life preserving in asymptomatic patients and that, if it is not found, risk-factor reductions are still recommended.

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