Prognostic value of coronary electron-beam computed tomography for coronary heart disease events in asymptomatic populations.

The predictive ability of electron-beam computed tomography (EBCT) for coronary heart disease outcomes, particularly hard coronary outcomes (myocardial infarction or death), has been questioned in asymptomatic populations. Our objective was to synthesize data on the use of EBCT for determining cardiovascular prognosis in asymptomatic populations. Studies were identified using standard systematic review methods. The outcome of interest was relative risk for myocardial infarction or sudden death, and combined events including revascularization. Nine articles met the inclusion criteria, of which 5 were of independent studies. Using meta-analytic techniques to synthesize prognostic data, there was an increased risk (summary risk ratio 8.7, 95% confidence interval 2.7 to 28.1) of a combined outcome of nonfatal myocardial infarction or death or revascularization if the calcium score was above a median score. Similarly, there was an increased risk for hard events: myocardial infarction or death (summary risk ratio 4.2, 95% confidence interval 1.6 to 11.3). However, there was significant heterogeneity in the studies' quality and patient populations. Although EBCT appears to predict combined and hard coronary outcomes similarly in high risk, asymptomatic populations, these results should be interpreted with caution. Further study is needed on the incremental value of EBCT over conventional risk prediction before this test is used in screening asymptomatic populations.