Abstract 12651: Effects of Smoking on Coronary Microcirculatory Function: A Twin Study
Background: In asymptomatic smokers, coronary microcirculatory dysfunction, assessed by coronary flow reserve (CFR) is an early indicator of cardiovascular risk. Inflammation and oxidative stress may be the mechanisms through which smoking affects the microvasculature. The purpose of this study is to determine the relationship between smoking and coronary flow reserve, taking into account potential shared genetic effects.
Methods: We examined 360 male middle aged twins (288 non-smokers and 72 smokers), including 46 twin pairs discordant for current smoking. Coronary flow reserve (CFR) in response to adenosine was measured with positron emission tomography [N13] ammonia and quantitation of coronary blood flow at rest and after adenosine stress. Inflammation was assessed by measuring interleukin-6 and high sensitivity C-reactive protein, and oxidative stress was determined by measuring plasma hydroperoxides, glutathione (GSH), the oxidized form of GSH, GSSG, and the ratio of GSH to GSSG.
Results: CFR was significantly lower in smokers compared to nonsmokers (2.25 vs. 2.75, p<0.01). This relationship persisted after accounting for known cardiovascular disease risk factors, and was marginally affected by adjusting for inflammatory and oxidative stress biomarkers. In addition, in smoking-discordant twin pairs, CFR in the smoking twin was significantly lower than in the non-smoking co-twin (2.25 vs. 2.67, p = 0.03) even after adjustment for cardiovascular factors.
Conclusions: Our results demonstrate the adverse effects of smoking in the early phases of cardiovascular disease. Mechanisms other than peripherally-measured inflammation and oxidative stress are involved.
- © 2010 by American Heart Association, Inc.