ultislice computed tomography (MSCT) enables visualization of not only coronary artery stenoses and occlusions, 1-4 but also coronary artery plaque of various textures. [5][6][7][8][9][10][11][12] Previous studies have repeatedly shown that non-calcified, CT low-dense plaques (CTLDP) on MSCT correspond well to rupture-prone soft plaques on intracoronary ultrasound 5,6,9,10,12 and on coronary angioscopy. 9 We have shown that patients with acute coronary syndrome (ACS) are likely to have CTLDP and that the CT density of the culprit coronary artery lesion is significantly lower in patients with ACS as compared with that in patients with stable angina. 8 Furthermore, we have also shown that patients with evolving ACS consistently have CTLDP in their culprit coronary artery lesions. 7,13 Because ACS is a consequence of coronary artery plaque rupture and subsequent thrombosis, 14,15 it would be reasonable to speculate that patients who have CTLDP are more likely to have coronary events, including ACS and sudden cardiac death, than patients without plaque. In this study of a large population, we evaluated the prognostic value of non-obstructive CTLDP in mild to moderate coronary artery stenosis for future cardiac events.
Methods
Study PopulationWe identified 1,179 consecutive patients who underwent MSCT between August 2002 and July 2006, at Nihon University Hospital. The reasons for MSCT were evaluation of typical and atypical chest pain in 715 patients, evaluation of the post-coronary intervention status in 112 patients, and evaluation of coronary artery disease (CAD) in 182 asymptomatic patients with multiple coronary risk factors. A structured interview and clinical history were obtained, and the following cardiac risk factors were assessed prior to the MSCT study: (1) hypertension (defined as blood pressure ≥140/90 mmHg or the use of antihypertensive agents), (2) hyperlipidemia as defined by low-density lipoprotein-cholesterol >140 mg/dl, (3) diabetes mellitus (defined as fasting glucose level >120 mg/dl or the need for insulin or oral antidiabetic medicines), (4) smoking (defined as current or previous smoking), and (5) previous history of acute myocardial infarction (AMI) and unstable angina (UA), and (4). Exclusion criteria for MSCT scans were known allergy to iodine, arrhythmias, impaired renal function (serum creatinine ≥1.3 mg/dl), bronchial asthma and left ventricular failure (left ventricular ejection fraction <30%).
MSCT ProtocolMSCT was performed using either a SOMATOM Volume 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 ResultsIn 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...
