Coronary Calcium Score as a Predictor for Coronary Artery Disease and Cardiac Events in Japanese High-Risk Patients

BACKGROUND: Although the coronary artery calcium (CAC) score as measured with computed tomography (CT) is associated with cardiovascular mortality and morbidity in Western countries, little is known in Asian populations. METHODS AND RESULTS: Three hundred and seventeen Japanese patients (205 men and 112 women) were followed in the study and they underwent both coronary angiography and CT for CAC measurements. The frequencies of angiographic coronary artery disease (CAD) were 5%, 36%, 76%, 80%, and 94% (P<0.001) and the needs for revascularization were 5%, 26%, 53%, 59%, and 69% (P<0.001) in patients with CAC scores of 0 (n=64), 1-100 (n=58), 101-400 (n=76), 401-1,000 (n=70), and >1,000 (n=49), respectively. In the average of 6.0 (range, 1-10) years follow-up period, 34 patients died including 13 from reasons of cardiac disease. In a Cox proportional hazard model after adjustment for age and sex, traditional coronary risk factors, previous myocardial infarction, and the need for revascularization, the hazard ratio for cardiac mortality in patients with a CAC score >1,000 was 2.98 (95% confidence interval: 1.15-9.40) compared with those with a CAC score=0-100. CONCLUSIONS: The CAC score has a predictive value for angiographical CAD and long-term mortality from cardiac disease in Japanese high-risk patients who undergo coronary angiography.