Systematic Review of Guidelines on Imaging of Asymptomatic Coronary Artery Disease

Study Questions:

Is there agreement between various guidelines on imaging of asymptomatic coronary artery disease (CAD), and what is the nature of data on which guidelines are based?

Methods:

Guidelines in English published between January 1, 2003, and February 26, 2010, were retrieved using MEDLINE, Cumulative Index to Nursing and Allied Health Literature, the National Guideline Clearinghouse, the National Library for Health, the Canadian Medication Association Infobase, and the Guidelines International Network International Guideline Library. Guidelines developed by national and international medical societies from Western countries containing recommendations on imaging of asymptomatic CAD were included. Rigor of development was scored by two independent reviewers using the Appraisal of Guidelines Research and Evaluation (AGREE) instrument. One reviewer performed full extraction of recommendations, which was checked by a second reviewer.

Results:

Of 2,415 titles identified, 14 guidelines met inclusion criteria. Of 14 guidelines, 11 reported relationships with industry. The AGREE scores varied across guidelines from 21% to 93%. Two guidelines considered cost-effectiveness. Eight guidelines recommended against or found insufficient evidence for testing of asymptomatic CAD. The other six guidelines recommended imaging patients at intermediate or high CAD risk based on the Framingham risk score, and five considered computed tomography calcium scoring useful for this purpose.

Conclusions:

Guidelines on risk assessment by imaging of asymptomatic CAD contain conflicting recommendations. More research, including randomized controlled trials evaluating the impact of imaging on clinical outcomes and costs, is needed.

Perspective:

Approximately 50% of myocardial infarctions occur in people without a pre-existing history of symptomatic CAD. However, it is not known whether early detection of CAD in apparently healthy persons is an effective substitute for, or supplement to, risk assessment based on traditional risk factors. This study found that current and recent guideline recommendations typically are based on few data. If prospective randomized controlled trials are performed or reported in the future, measured outcomes will be of importance: To be of benefit, screening tests should show incremental value in the prevention of myocardial infarction or cardiac death, and should be associated with reasonably low costs and reasonably low added morbidity (including costs and morbidity associated with additional tests and procedures performed as a result of both cardiac and noncardiac findings).

Clinical Topics: Atherosclerotic Disease (CAD/PAD)

Keywords: Coronary Artery Disease, Myocardial Infarction, Canada, Risk Factors, Risk Assessment


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