RESEARCH · November 11, 2014
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- The authors assessed baseline coronary artery calcium (CAC) levels in an asymptomatic multiethnic cohort of 6779 individuals who were then followed for an average of 9.5 ± 2.4 years for diagnosis of stroke or transient ischemic attack (collectively, cerebrovascular events [CVE]). The presence of CAC correlated with lower CVE-related survival compared with the absence of CAC. After adjusting for demographics, smoking, lifestyle, and other factors, the log-transformed CAC values were associated with increased CVE risk, and values above the recommended CAC cutoff significantly correlated with CVE.
- The authors concluded that CAC is an important and reliable predictor of CVE, and is superior to prediction using known risk factors. The total number of CVE was too small in this study to make inferences about relationships with age and ethnicity.
ABSTRACT
OBJECTIVES
This study assessed the predictive value of coronary artery calcium (CAC) score for cerebrovascular events (CVE) in an asymptomatic multiethnic cohort.
BACKGROUND
The CAC score, a measure of atherosclerotic burden, has been shown to improve prediction of coronary heart disease events. However, the predictive value of CAC for CVE is unclear.
METHODS
CAC was measured at baseline examination of participants (N = 6,779) of MESA (Multi-Ethnic Study of Atherosclerosis) and then followed for an average of 9.5 ± 2.4 years for the diagnosis of incident CVE, defined as all strokes or transient ischemic attacks.
RESULTS
During the follow-up, 234 (3.5%) adjudicated CVE occurred. In Kaplan-Meier analysis, the presence of CAC was associated with a lower CVE event-free survival versus the absence of CAC (log-rank chi-square: 59.8, p < 0.0001). Log-transformed CAC was associated with increased risk for CVE after adjusting for age, sex, race/ethnicity, body mass index, systolic and diastolic blood pressure, total cholesterol, high-density lipoprotein cholesterol, cigarette smoking status, blood pressure medication use, statin use, and interim atrial fibrillation (hazard ratio [HR]: 1.13 [95% confidence interval (CI): 1.07 to 1.20], p < 0.0001). The American College of Cardiology/American Heart Association–recommended CAC cutoff was also an independent predictor of CVE and strokes (HR: 1.70 [95% CI: 1.24 to 2.35], p = 0.001, and HR: 1.59 [95% CI: 1.11 to 2.27], p = 0.01, respectively). CAC was an independent predictor of CVE when analysis was stratified by sex or race/ethnicity and improved discrimination for CVE when added to the full model (c-statistic: 0.744 vs. 0.755). CAC also improved the discriminative ability of the Framingham stroke risk score for CVE.
CONCLUSIONS
CAC is an independent predictor of CVE and improves the discrimination afforded by current stroke risk factors or the Framingham stroke risk score for incident CVE in an initially asymptomatic multiethnic adult cohort.
JACC: Cardiovascular Imaging
Coronary Artery Calcium and Incident Cerebrovascular Events in an Asymptomatic Cohort