ACCF/AHA 2007 clinical expert consensus document on coronary artery calcium scoring by computed tomography in global cardiovascular risk assessment and in evaluation of patients with chest pain: A report of the American College of Cardiology Foundation Clinical Expert Consensus Task Force (ACCF/AHA Writing Committee to Update the 2000 Expert Consensus Document on Electron Beam Computed Tomography)
Coronary Artery Disease
Tomography, X-Ray Computed
This document has updated information on CAC measurement with particular emphasis on data that have appeared since 2000 when the previous ACC/AHA Expert Consensus Document was published. In considering the data presented here, the Expert Consensus Committee felt that specific clinical examples should be highlighted and clinical recommendations linked to these examples for use by clinicians. The following clinical scenarios were noted to be relevant to CAC measurement, and the Committee's consensus on these questions is noted. 1. What is the role of coronary calcium measurement by coronary CT scanning in asymptomatic patients with intermediate CHD risk (between 10% and 20% 10-year risk of estimated coronary events)? The Committee judged that it may be reasonable to consider use of CAC measurement in such patients based on available evidence that demonstrates incremental risk prediction information in this selected (intermediate risk) patient group. This conclusion is based on the possibility that such patients might be reclassified to a higher risk status based on high CAC score, and subsequent patient management may be modified. 2. What is the role of coronary calcium measurement by CT scan in patients with low CHD risk (below 10% 10-year risk of estimated CHD events)? The Committee does not recommend use of CAC measurement in this selected patient group. This patient group is similar to the "population screening" scenario, and the Committee does not recommend screening of the general population using CAC measurement. 3. What is the rol e of coronary calcium measurement by fast CT scan in asymptomatic patients with high CHD risk (greater than 20% estimated 10-year risk of estimated CHD events, or established coronary disease, or other high-risk diagnoses)? The Committee does not advise CAC measurement in this selected patient stratum as they are already judged to be candidates for intensive risk reducing therapies based on current NCEP guidelines. 4. Is the evidence strong enough to reduce the treatment intensity in patients with calcium score = 0 in patients who are considered intermediate risk before coronary calcium score? No evidence is available that allows the Committee to make a consensus judgment on this question. Accordingly, the Committee felt that current standard recommendations for treatment of intermediate risk patients should apply in this setting. 5. Is there evidence that coronary calcium measurement is better than other potentially competing tests in intermediate risk patients for modifying cardiovascular disease risk estimate? In general, CAC measurement has not been compared to alternative approaches to risk assessment in headto-head studies. This question cannot be adequately answered from available data. 6. Should there be additional cardiac testing when a patient is found to have high coronary calcium score (e.g., CAC greater than 400)? Current clinical practice guidelines indicate that patients classified as high risk based on high risk factor burden or existence of known high-risk disease states (e.g., diabetes) are regarded as candidates for intensive preventive therapies (medical treatments). There is no clear evidence that additional non-invasive testing in this patient population will result in more appropriate selection of treatments. 7. Is there a role of CAC testing in patients with atypical cardiac symptoms? Evidence indicates that patients considered to be at low risk of coronary disease by virtue of atypical cardiac symptoms may benefit from CAC testing to help in ruling out the presence of obstructive coronary disease. Other competing approaches are available, and most of these competing modalities have not been compared head-to-head with CAC. 8. Can coronary calcium data collected to date be generalized to specific patient populations (women, African American men)? CAC data are strongest for Caucasian, non-Hispanic men. The Committee recommends caution in extrapolating CAC data derived from studies in white men to women and to ethnic minorities. 9. What is the appropriate follow-up when an incidental finding in the lungs or other non-cardiac tissues is found on a fast coronary CT study? Current radiology guidelines should be considered when determining need for follow-up of incidental findings on a fast CT study, such as that which was recently published to guide follow-up of small pulmonary nodules (115).