Comparison of electron beam computed tomography scanning and conventional risk factor assessment for the prediction of angiographic coronary artery disease.

OBJECTIVE: To determine whether electron beam computed tomography (CT) adds to conventional risk factor assessment in the prediction of angiographic coronary artery disease. BACKGROUND: Electron beam CT scanning can be used to predict the severity of coronary atherosclerosis, but whether it does so independently of conventional risk factors is unclear. METHODS: Electron beam CT scans were performed and conventional risk factors were measured in 290 men and women undergoing coronary arteriography for clinical indications. The association of the electron beam CT-derived coronary artery calcium score and conventional risk factors with the presence and severity of angiographically defined coronary atherosclerosis was analyzed by logistic regression and receiver-operator characteristics analysis. RESULTS: Age, the ratio of total cholesterol to high-density lipoprotein (HDL) cholesterol and the coronary calcium score were significantly and independently associated with the presence of any coronary disease and obstructive coronary disease. In association with any coronary disease, odds ratios for age, the ratio of total cholesterol to HDL cholesterol and calcium score, highest quartile vs. lowest quartile, were 6.01 (95% confidence interval 2.87 to 12.56), 3.14 (1.56 to 6.31) and 94.08 (21.06 to 420.12), respectively. For obstructive coronary disease, highest quartile vs. lowest quartile, the respective odds ratios for age, the ratio of total cholesterol to HDL and calcium score were 3.86 (1.86 to 8.00), 4.11 (1.98 to 8.52) and 34.12 (12.67 to 91.86). Male gender was also significantly associated with any coronary disease (odds ratio 2.19, p=0.04) and obstructive coronary disease (odds ratio 2.07, p=0.04). Cigarette smoking was significantly associated with any coronary disease (odds ratio=2.74, p=0.004), and diabetes was significantly associated with obstructive disease (odds ratio 3.16, p=0.01). After adjustment for the coronary calcium score and other risk factors, it was determined that triglycerides, family history and hypertension were not significantly associated with any disease state. A coronary calcium score >80 (Agatston method) was associated with an increased likelihood of any coronary disease regardless of the number of risk factors, and a coronary calcium score > or = 170 was associated with an increased likelihood of obstructive coronary disease regardless of the number of risk factors (p < 0.001). CONCLUSIONS: Electron beam CT scanning offers improved discrimination over conventional risk factors in the identification of persons with any angiographic coronary disease or angiographic obstructive coronary disease.

Predictive value of electron beam computed tomography of the coronary arteries. 19-month follow-up of 1173 asymptomatic subjects.

BACKGROUND: Coronary electron beam computed tomography (EBCT) detects atherosclerotic coronary artery disease by measuring calcium deposition in the walls of coronary arteries. EBCT-derived coronary artery calcium (CAC) scores correlate with the severity of underlying coronary artery disease. METHODS AND RESULTS: We followed 1173 asymptomatic patients who underwent EBCT between September 1993 and March 1994. During average follow-up of 19 months, 18 subjects had 26 cardiovascular events: 1 death, 7 myocardial infarctions, 8 coronary artery bypass graft procedures, 9 coronary angioplasties, and 1 nonhemorrhagic stroke. For CAC score thresholds of 100, 160, and 680, EBCT had sensitivities of 89%, 89%, and 50% and specificities of 77%, 82%, and 95%, respectively. Odds ratios ranged from 20.0 to 35.4 (P < .0001 for all). CONCLUSIONS: Coronary EBCT predicts future atherosclerotic cardiovascular disease events in asymptomatic subjects.