Colombian study to assess the use of noninvasive determination of endothelium-mediated vasodilatation (CANDEV). Normal values and factors associated.

Abstract

The endothelium plays a critical role in vascular homeostasis. Recently, a noninvasive method has been developed to assess flow mediated vasodilatation of the brachial artery (FMD). This test is remarkably stable overtime but no clear set of normal values has been developed. The purposes of our study were to evaluate the accuracy and reproducibility and to identify a set of normal values of FMD. We included 253 normotensive healthy volunteers from three Colombian cities (mean age: 38.2 years; 33% were women). All subjects underwent ultrasound evaluation of endothelial and smooth muscle function. Flow mediated vessel diameter change was measured by two independent observers. The interobserver Lin's concordance correlation coefficient was 0.88% (95% CI: 0.82, 0.94) and there was no evidence of systematic difference between the two measurements (mean difference of -0.30% with limits of agreement of -4.48 to 3.87). Mean %FMD was 11.98% (95% CI: 11.36, 12.61), 13.32% (95% CI: 12.39, 14.25) in women and 11.32% (95% CI: 10.52, 12.13) in men. Subjects with no cardiovascular risk factors had a mean %FMD of 13.74% (95% CI: 13.14, 14.35), in contrast to a mean of only 7.40% (95% CI: 4.33, 9.91) in those with at least one risk factor. A %FMD cut point of 10.4 had a sensitivity of 71.2% and an specificity of 77.2% to identify subjects with at least one cardiovascular risk factor. Using this cut point, endothelial dysfunction was 3.13 times more frequent in subjects with than in subjects without cardiovascular risk factors (95% CI: 2.30, 4.25). In addition, obesity, smoking and hypercholesterolemia were the modifiable risk factors with largest independent significant reduction effects on %FMD. FMD measurements can be made with high accuracy and precision, and a cut point of 10.4% is useful to discriminate between subjects with and without cardiovascular risk factors, and can be recommended as a screening test for the detection of patients at risk of CVD.