Background: The prognostic value of non-obstructive, CT low-dense plaques (CTLDP) on multislice computed tomography (MSCT) for the prediction of nonfatal acute myocardial infarction (AMI), unstable angina (UA) and cardiac death has not yet been defined.
Methods and results: In the present study 810 patients who underwent MSCT and had non-obstructive coronary artery disease were followed up for the occurrence of AMI, UA and cardiac death. Non-obstructive CTLDP were defined as plaques with a CT density <68 Hounsfield units, accompanied by mild to moderate coronary artery stenosis (25-75%). Patients were followed-up for 1,062+/-544 days for the occurrence of (1) acute coronary syndrome (ACS) including nonfatal AMI and UA, and (2) cardiac death. CTLDP were detected in 189 patients (23.3%). The annual event rate of AMI, UA, ACS and cardiac death was 0.91%, 0.91%, 1.82% and 0.36%, respectively, in patients with CTLDP and 0.10%, 0.55%, 0.66% and 0.21%, respectively, in patients without CTLDP. The event rate of ACS was significantly higher in patients with CTLDP than in those without CTLDP (p<0.001). Multivariate Cox proportional regression analysis revealed that previous MI and the presence of CTLDP were independent predictors of ACS.
Conclusion: Non-obstructive CTLDP detected by MSCT yield prognostic information toward the identification of ACS.