Abstract P043: Does The Severity of Coronary Artery Disease Explain The Increased Risk of Death and Myocardial Infarction From Ambient Air Pollution Exposure?

BACKGROUND: Ambient air pollution from traffic increases cardiovascular morbidity and mortality and is associated with coronary artery calcification. Whether this increased risk is mediated by severity of coronary artery disease (CAD) remains unknown. METHODS: In this pilot study, the relationship between living near a major roadway and multivessel CAD confirmed by invasive coronary angiographic was explored. Subjects undergoing coronary angiography in the Los Angeles metropolitan area in 2009-10 were randomly selected. Investigators blinded to the exposure status reviewed coronary angiograms. Subjects were categorized as having: absence of or non-obstructive CAD, 1-vessel, 2-vessel, or 3-vessel CAD based upon the number of major epicardial vessels with > 70% stenoses. The distance from each subject's residence to the nearest major road was calculated in meters. Multivariate logistic regression was used to explore the relationship between severity of CAD and distance to major roadway. RESULTS: There were 642 subjects undergoing coronary angiography. The mean age (SD) was 64 years (12) and 36% were female. In multivariate analysis log-road distance was a predictor of multivessel CAD, odds ratio (OR) = 0.85 (95%CI, 0.75-0.98; p=0. 02) after adjusting for age, gender, hypertension, and diabetes, and smoking status. Other predictors of multivessel CAD included from the multivariate logist model were: male gender (OR, 3.00, 95% CI, 2.06-4.39; p<0.001), diabetes (OR, 2.49; 95% CI, 1.75-3.54; p<0.001), and hypertension 2.58; 95%CI, 1.28-5.21; p=0.008). The most severe form of CAD, >50% stenosis of the left main artery, was observed in 6.6% of the cohort. In a multivariate model, age (P = 0.002) and diabetes (P = 0.002) were significant predictors of severe left main disease; there was a trend for log-road distance (OR, 0.83; 95% CI, 0.67-1.02; P = 0.079) with left main disease. CONCLUSIONS: Multivessel CAD was strongly associated with traditional risk factors. After adjusting for these factors, living near a major roadway was also a predictor. This study demonstrates the feasibility of exploring the association between angiographic CAD and traffic pollution. Additional studies are needed to better understand the mechanisms underlying the increase in adverse cardiovascular events from air pollution.