Abstract 16175: Coronary Artery Calcium Score is an Independent Predictor of Incident Stroke in Population Based Adults. Multi-Ethnic Study of Atherosclerosis (MESA)
Background: Coronary Artery Calcium (CAC) is an independent predictor of future coronary heart disease (CHD) events and improves the accuracy of many CHD risk prediction tools. The predictive ability of CAC for cerebrovascular events (CVA) and the improvement in discrimination afforded by the addition of CAC to current CVA risk prediction tools remains unclear. We assess the association between CAC and incident CVA in adults free of cardiovascular disease at baseline in the Multi Ethnic Study of Atherosclerosis (MESA).
Methods: 6613 MESA participants age 45-84yrs were included in the study and a Framingham stroke risk score (FSRS) was calculated for each participant. After 10.9 years of follow-up (mean 7.6y), 196 participants experienced an incident CVA defined as a transient ischemic attack or a stroke. Cox proportional hazard, Kaplan Meier and ROC analyses were used to assess the association between CAC and CVA after adjusting for age, gender, race, BMI, LDL, HDL, cigarette smoking status, diabetes, SBP, hypertension medication and statin use. The improvement in c statistics by the addition of CAC to the FSRS was evaluated.
Results: Mean participant age was 62.1 years with 53% of the cohort female, 38% Caucasian, 28% African American, 22% Hispanic, and 11% Chinese. At the baseline exam 12.7% of the cohort was diabetic, 13.1% reported smoking, and mean LDL was 117.2 +/-31.5 mg/dl. In Kaplan Meier analysis, CAC greater than zero was associated with a lower event-free survival compared to a CAC of zero [Log Rank Chi Square = 28.2, p<0.0001]. In univariate Cox proportional hazard analysis, CAC introduced as [ln (CAC+1)], was independently associated with an increased risk of CVA [HR 1.34, 95% CI 1.23-1.46, p<0.0001]. In a multivariate model CAC remained independently associated with incident CVA [HR 1.19, 95% CI 1.07-1.74, p=0.001]. Finally, in a third model containing CAC and FSRS as predictors, CAC remained significantly associated with incident CVA [HR 1.37, 95% CI 1.26-1.49, p=0.001]. In ROC analysis, the addition of CAC to the FSRS improved discrimination for incident CVA (c statistic 0.61 to 0.72, p<0.01).
Conclusion: CAC is an independent predictor of incident CVA and improves risk prediction beyond the FSRS in adults without clinical CHD.
- © 2013 by American Heart Association, Inc.