Source: American Heart Association
Literature search described? No
Evidence rating system used? Yes
Published source: Circulation, October 17, 2006
Available at: http://circ.ahajournals.org/cgi/content/full/114/16/1761
Over the past decade, electron beam computed tomography (CT) and multidetector CT have increasingly been used to identify and measure coronary artery calcification. Calcification levels can be related to the extent and severity of underlying atherosclerosis and can potentially improve cardiovascular risk prediction. However, broad use of these methods for screening is controversial. The American Heart Association (AHA) has released guidelines for the use of cardiac CT when evaluating patients for coronary artery disease (Table 1).
|Recommendations||Level of evidence*|
|Asymptomatic patients should be assessed for cardiovascular risk using tools such as the Framingham Risk Score; those found to be at low risk (10-year risk of less than 10 percent) or high risk (10-year risk of more than 20 percent) do not benefit from coronary calcium assessment||B|
|In clinically selected, intermediate-risk patients (10-year risk of 10 to 20 percent), it may be reasonable to measure the atherosclerosis burden using electron beam CT or multidetector CT to refine clinical risk prediction and to select patients for more aggressive target values for lipid-lowering therapies||B|
|Coronary calcium assessment may be reasonable in symptomatic patients, especially in the setting of equivocal treadmill or functional testing||B|
|Coronary calcium assessment may be considered in symptomatic patients to determine the cause of cardiomyopathy||B|
|Coronary calcium assessment may be considered in patients with chest pain who have equivocal or normal ECG findings and negative cardiac enzyme test results||B|
|CT coronary angiography is reasonable for the assessment of obstructive disease in symptomatic patients||B|
|Electron beam CT and multidetector CT for detecting restenosis after stent placement cannot be recommended||C|
|CT coronary angiography for the assessment of noncalcified plaque or to track atherosclerosis or stenosis over time is not recommended||C|
|CT coronary angiography is not recommended in asymptomatic persons for the assessment of occult CAD||C|
|Serial imaging for the assessment of coronary calcification progression is not indicated||C|
|The use of hybrid scanning to assess cardiovascular risk or the presence of obstructive disease is not recommended||C|
Asymptomatic patients at low or high risk of cardiovascular disease do not benefit from coronary calcium measurements. However, these measurements may benefit asymptomatic, intermediate-risk patients by refining the risk assessment and prompting lifestyle changes and pharmacologic therapy. Coronary calcium measurements may be reasonable in some symptomatic patients, especially to determine the etiology of cardiomyopathy, to assess patients who have equivocal treadmill or functional test results, and to assess patients with chest pain who have equivocal or normal echocardiography findings and negative cardiac enzyme test results.
Research is lacking on the use of serial cardiac CT in assessing subclinical atherosclerosis over time and in detecting noncalcified plaque, although further evidence is emerging. Research is also ongoing to determine the benefit of hybrid scanning in assessing cardiovascular risk and in detecting obstructive disease.