@article {665, title = {Brachial flow-mediated vasodilator responses in population-based research: methods, reproducibility and effects of age, gender and baseline diameter.}, journal = {J Cardiovasc Risk}, volume = {8}, year = {2001}, month = {2001 Oct}, pages = {319-28}, abstract = {

BACKGROUND: Brachial artery ultrasound has been proposed as an inexpensive, accurate way to assess cardiovascular risk in populations. However, analysis and interpretation of these data are not uniform.

METHODS: We analysed the relationship between relative and absolute changes in brachial artery diameter in response to flow-mediated dilation and age, gender and baseline diameter among 4,040 ultrasound examinations from subjects aged 14 to 98 years.

RESULTS: Reproducibility studies demonstrated intra- and interreader and intrasubject correlations from 0.67 to 0.84 for repeated measures of per cent change in diameter. Per cent change in diameter after flow stimulus was 3.58 +/- 0.10\% (mean +/- standard deviation). Corresponding values for baseline diameter and absolute change in diameter were 4.43 +/- 0.87 mm and 0.15 +/- 0.01 mm, respectively. Baseline diameter and its variance were inversely related to per cent change in diameter (P< 0.001). In contrast, absolute change in diameter was more uniform throughout the range of baseline diameters. Baseline diameter was directly related, and per cent change in diameter inversely related, to age (P < 0.001 for all three measures). Time to maximum vasodilator response increased with age (P < 0.001). Women (n=2,315) had significantly larger per cent change in diameter than men (n=1,725) (P < 0.001). However, after adjustment for age and baseline diameter, per cent and absolute change were 5\% smaller in women than men (P < 0.05 for both). In multivariate analysis, age was overwhelmingly the most important determinant of absolute change in diameter (P < 0.001).

CONCLUSIONS: Automated analysis of brachial flow-mediated vasodilator responses is both feasible and reproducible in large-scale clinical and population-based research.

}, keywords = {Adolescent, Adult, Age Factors, Aged, Aged, 80 and over, Blood Circulation, Brachial Artery, Female, Humans, Male, Middle Aged, Observer Variation, Population Surveillance, Reproducibility of Results, Sex Factors, Vasodilation, Vasodilator Agents}, issn = {1350-6277}, doi = {10.1177/174182670100800512}, author = {Herrington, D M and Fan, L and Drum, M and Riley, W A and Pusser, B E and Crouse, J R and Burke, G L and McBurnie, M A and Morgan, T M and Espeland, M A} } @article {670, title = {Estrogen replacement and brachial artery flow-mediated vasodilation in older women.}, journal = {Arterioscler Thromb Vasc Biol}, volume = {21}, year = {2001}, month = {2001 Dec}, pages = {1955-61}, abstract = {

It remains unclear whether estrogen therapy (with or without progestin) improves endothelial function in older postmenopausal women with or at risk for coronary heart disease. To address this issue, we analyzed brachial artery flow-mediated vasodilation in the Cardiovascular Health Study, a longitudinal study of cardiovascular risk factors in subjects over 65 years of age. At the tenth annual Cardiovascular Health Study examination, 1662 women returned for follow-up. Eighteen percent (n=291) were current users of estrogen replacement, most of whom (75.9\%, n=221) took unopposed estrogen. Brachial artery ultrasound examinations measuring vasodilation in response to a flow stimulus (hyperemia) were performed on 1636 women. There were no statistical differences in brachial flow-mediated vasodilator responses between users and nonusers, even after adjustment for potential confounders. Absence of an effect was most notable in women over 80 years old and in those with established cardiovascular disease. However, among women without clinical or subclinical cardiovascular disease or its risk factors, there was a significant association between hormone replacement therapy use and flow-mediated vasodilator responses (P=0.01). Among older postmenopausal women, favorable vascular effects of estrogen may be limited to those who have not yet developed atherosclerotic vascular disease. These data emphasize the importance of ongoing efforts to determine the role of hormone replacement therapy for primary prevention of cardiovascular disease.

}, keywords = {Aged, Aged, 80 and over, Analysis of Variance, Brachial Artery, Cardiovascular Diseases, Drug Therapy, Combination, Estrogen Replacement Therapy, Estrogens, Female, Humans, Longitudinal Studies, Progestins, Risk Factors, Ultrasonography, Vasodilation}, issn = {1524-4636}, doi = {10.1161/hq1201.100241}, author = {Herrington, D M and Espeland, M A and Crouse, J R and Robertson, J and Riley, W A and McBurnie, M A and Burke, G L} }