RELATIONSHIP BETWEEN BRACHIAL ARTERY FLOW- MEDIATED DILATION AND CAROTID ARTERY INTIMA - MEDIA THICKNESS IN THE MIDDLE-AGED SUBJECTS WITH LOW CARDIOVASCULAR RISK

Endothelial vasodilator dysfunction, assessed by brachial artery flow-mediated dilatation (FMD) and carotid intima-media thickening (IMT), is an indicator of subclinical atherosclerotic disease. We examined their correlation and interaction with traditionally cardiovascular risk factors, in a group of middle-aged subjects with a low total cardiovascular risk ( 50 mm Hg above systolic blood pressure (SBP), for 5 minutes. After the cuff was deflated ischemia-induced distal hyperemia produced a transient increase of artery diameter. The relative change in mean arterial diameter was calculated as: % Dilation = (Maximum diameter - Baseline diameter) × 100 / Baseline diameter, where maximum diameter was the maximum mean diameter observed at 45 - 60 seconds after cuff release. For carotid ultrasound study, the image was focused on the posterior (far) of the left carotid artery. A minimum of 4 measurements of the common carotid far wall were taken 10 mm proximal to the bifurcation to derive mean carotid IMT. Continuous variables are expressed as means ± SD. Means were compared using analysis of variance or the Stude nt t-test. Our study shows that in a relatively healthy middle-aged subject, there is no significant correlation between carotid IMT and brachial artery FMD. This finding may be related to a temporal dissociation between functional and structural vascular abnormalities in a low risk population.