Prognostic significance of coronary artery calcium in asymptomatic subjects with usual cardiovascular risk.

ABSTRACT

BACKGROUND: Coronary calcium detected noninvasively is an attractive way to diagnose atherosclerosis before the development of symptoms. This study examines the prognostic value of coronary calcium in asymptomatic subjects with usual cardiovascular risk. METHODS AND RESULTS: In 425 asymptomatic subjects, 229 men (aged 45.1 +/- 14 years) and 196 women (aged 42.7 +/- 13 years), coronary calcium presence was studied by digital cinefluoroscopy. The majority (76%) had no or at most one risk factor. Subjects were followed up for 58.4 +/- 12.7 months for cardiac events. Coronary calcium was present in 76 of 425 (17.9%) subjects. Cardiac events were observed in 21 subjects: 2 cardiac deaths, 7 acute myocardial infarctions, 3 coronary artery bypass grafts, 3 coronary angioplasty procedures, 3 events of unstable angina, and 10 events of stable angina pectoris. Survival curve analysis showed significant differences in all the studied end points between subjects with and those without calcium. Coronary calcium was an independent predictor of all events (3.6-fold increase, P <.008), cardiac death/myocardial infarction/revascularization (13.9-fold increase, P <.02), and stable angina (7.4-fold increase, P <.007). However, calcium did not independently predict cardiac death/myocardial infarction or acute coronary syndromes. CONCLUSIONS: Coronary calcium in asymptomatic subjects with usual cardiovascular risk adds significant incremental information to risk factors information for the development of symptomatic coronary artery disease.