Noninvasive vascular function measurement in the community: cross-sectional relations and comparison of methods.

BACKGROUND Several methods of noninvasive vascular function testing have been suggested for cardiovascular risk screening in the community. A direct comparison of the different methods and their relation to classical cardiovascular risk factors in a large cohort is missing. METHODS AND RESULTS In 5000 individuals (mean age, 55.5 ± 10.9 years; age range, 35 to 74 years; women, 49.2%) of the population-based Gutenberg Heart Study, we performed simultaneous measurement of flow-mediated dilation (FMD) and peripheral arterial volume pulse determined by infrared photo (reflection index) and pneumatic plethysmography (PAT) and explored their associations. All function measures were recorded at baseline and after reactive hyperemia induced by 5-minute brachial artery occlusion. Correlations between different measures of vascular function were statistically significant but moderate. The strongest association for hyperemic response variables was observed for PAT ratio and FMD (Spearman r = 0.17; age- and sex-adjusted partial correlation, 0.068). Classical risk factors explained between 15.8% (baseline reflection index) and 58.4% (brachial artery diameter) of the baseline values but only accounted for 3.2% (reflection index), 15.4% (FMD), and 13.9% (PAT ratio) of the variability of reflective hyperemic response. Regression models varied in their relations to classical risk factors for the individual vascular function measures. Consistently associated with different vascular function methods were age, sex, body mass index, and indicators of hypertension. Peripheral tonometry also showed a relation to fasting glucose concentrations. CONCLUSIONS Noninvasive measures of conduit artery and peripheral arterial function are modestly correlated, differ in their relation to classical cardiovascular risk factors, and may thus reflect different pathologies.