2015 Volume 56 Issue 1 Pages 29-36
The aim of this study was to investigate the relationship between coronary microvascular function and smoking using the 3 parameters fractional flow reserve (FFR), coronary flow reserve (CFRthermo), and index of microcirculatory resistance (IMR) in patients with coronary artery disease (CAD). A total of 97 CAD patients with 148 intermediate stenotic lesions were divided into two groups: current and former smokers (Smokers: n = 54), and those who had never smoked (Non-smokers: n = 43). Coronary physiology measurements were made following coronary angiography at rest and during hyperemia induced with intravenous adenosine triphosphate. If a patient had several intermediate lesions, the lesion producing the largest IMR value and minimum FFRmyo and CFRthermo value was selected. Averaged over all patients, the FFRmyo, CFRthermo, and IMR values were 0.86 ± 0.10, 2.66 ± 1.50, and 20.8 ± 10.7, respectively. There was no significant correlation between FFRmyoand IMR. There were no significant differences between smokers and non-smokers in FFRmyo value (median: 0.85 [IQR: 0.74-0.90] versus 0.87 [IQR: 0.83-0.90], P = 0.15) and CFRthermo value (median: 1.90 [IQR: 1.56-3.16] versus 2.10 [IQR: 1.50-2.67] U, P = 0.95). The IMR value was significantly greater in smokers (median: 24.2 [IQR: 16.8-32.5] U versus 18.5 [IQR: 15.4-27.0] U, P = 0.04). In multivariate analysis, smoking was an independent predictor of increased IMR. Smoking appears to have a detrimental effect on coronary microvascular function as measured by IMR.