Prevalence of subclinical atherosclerosis in asymptomatic patients with low-to-intermediate risk by 64-slice computed tomography.

Background: Recent research has shown that cardiovascular risk scoring significantly underestimates or misclassifies risk in key subsets of the population. There is a growing need for a noninvasive imaging to detect a subclinical atherosclerosis. Thus we hypothesized that 64-slice computed tomography (CT) could effectively detect subclinical atherosclerosis in asymptomatic patients with low-to-intermediate risk.

Methods: Four hundred and fifteen asymptomatic patients with coronary risk factors underwent 64-slice CT. When 64-slice CT showed a significant stenosis we recommended that patients receive stress myocardial perfusion imaging (MPI). When MPI showed ischemic findings, we recommended that patients receive a coronary revascularization procedure. We followed our patients for a mean of 2.8 years (2.4-3.3 years).

Results: We detected coronary plaques in 295 patients (71.1%). Of 135 patients with a negative scan for coronary calcification, noncalcified plaques were detected in 15 patients (11.1%). Two hundred and thirty-five patients (79.7%) had multiple plaques and, on average, one patient had 4.6 plaques. Significant coronary stenosis was detected in 91 patients (21.9%) and 85 patients underwent stress MPI. Myocardial ischemia was found in 27 patients (31.8%) and 21 patients underwent percutaneous coronary intervention. For a mean follow-up period of 2.8 years, four patients developed acute coronary syndrome.

Conclusion: Our results showed that the prevalence of subclinical atherosclerosis in asymptomatic patients with low-to-intermediate risk was very high and one-fifth of them had significant stenosis as shown by 64-slice CT. However, myocardial ischemia was detected in only one-third of them.