Abstract 3987: Short-Term Exposure to Fine Particulate Air Pollution is Associated with the Risk of Ischemic Coronary Events, Especially among Patients with Coronary Disease
Background: Evidence suggests that long-term exposure to particulate matter (PM) air pollution contributes to oxidative stress, inflammation, and risk of ischemic heart disease and death. Short-term exposure may contribute to complications of atherosclerosis, including plaque vulnerability, thrombosis, and acute ischemic events. These findings are inconclusive and controversial, thus requiring further study. We evaluated the effect of short-term PM exposure in triggering acute ischemic events and characterized which patients are at greatest risk.
Methods: A case-crossover study design was used to analyze ischemic events in 12,865 patients living on Utah’s Wasatch Front with monitoring of ambient inhalable (PM10) and fine (PM2.5) air pollution. Participants were patients from the cardiac catheterization registry of the Intermountain Heart Collaborative Study, a large, ongoing longitudinal registry of coronary angiography patients. Study endpoints were incident ischemic heart disease events, including myocardial infarction (MI) and unstable angina.
Results: At a lag of 0 days, exposures of 10 μg/m3 of PM2.5 were associated with average increased risk of presenting with MI or unstable angina equal to 4.8% (95% CI = 1.0%, 8.8%). Effects were larger for patients with angiographically-demonstrated coronary artery disease (CAD), congestive heart failure, and CAD risk factors (males, smokers, hypertension, hyperlipidemia, diabetes, and family history of early CAD). PM2.5 was also positively associated with subsequent MI, but the association was statistically significant only for patients with triple-vessel CAD (≥70% stenosis). The association between PM2.5 and stable (non-urgent) presentation was negative and non- significant. Lags of 1, 2, and 3 days provided similar results. Effect sizes for PM10 were lower and p-values not significant (for lag 0, risk was 1.7%, p=0.11).
Conclusions: Short-term particulate exposures contributed to MI and unstable angina events, especially among patients with underlying CAD and cardiac risk factors. Individuals with stable presentation and those with angiographically-demonstrated normal coronaries are not as susceptible to short-term particulate exposure.