Background: The risk of atherosclerosis and its complications differs between male and female subjects. This is probably associated with gender differences in endothelial function as reflected by endothelium-dependent vasodilation. The aim of the study was to compare flow-mediated dilatation (FMD) in males and females with coronary artery disease (CAD), and to determine factors that might potentially influence FMD.
Methods: Ninety-six patients with stable CAD (CCS II-III): 76 males (mean age: 57.7 +/- 10 years) and 20 postmenopausal females (mean age: 60.1 +/- 10 years) were included into the study. Clinical data, pharmacotherapy, concomitant diseases, and FMD were all assessed. FMD was measured with high-resolution ultrasound as the percent change of brachial artery diameter (BAd) after a 3-minute occlusion (%FMD), and following the administration of 0.4 mg sublingual nitroglycerin (%NTG-MD).
Results: The percentage of FMD was significantly decreased (P < 0.05), and BAd was significantly larger (P < 0.001) in males as compared to females. Clinical data, pharmacotherapy, and concomitant diseases were comparable in the study groups. In all subjects examined, %FMD was related to BAd (r =-0.415, P < 0.001) and the percentage of ejection fraction (EF%) (r = 0.325, P < 0.01) in the univariate analysis, and to BAd only (r =-0.343, P < 0.01) in the multivariate analysis. The percentage of nitroglycerine-mediated vasodilatation (NTG-MD) correlated negatively with BAd (r =-0.430, P < 0.001), and positively with EF% (r = 0.334, P < 0.01) in the univariate analysis, and with BAd (r =-0.288, P < 0.05) in the multivariate analysis. Index %FMD x BAd was comparable for male and female subjects.
Conclusions: Males and postmenopausal females with CAD show differences in endothelium-dependent vasodilatation that seem to secondarily result from differences in the BAd. Objective comparison of %FMD is only possible between patients with the same brachial artery size.