Objective: For a couple of decades, flow-mediated vasodilation in the brachial artery (FMD) and acetylcholine-mediated vasodilation in the forearm (EDV) have been used to assess endothelium-dependent vasodilation. During recent years a third technique, peripheral artery tonometry (PAT) using EndoPat, has been introduced. We now aimed to investigate the relationships between these techniques, and their relation to cardiovascular risk.
Methods: In the population-based Prospective investigation of Obesity, Energy and Metabolism (POEM) study conducted in individuals all aged 50 years (50% women), EDV, FMD and the reactive hyperemia index were measured in the first 222 individuals. Cardiovascular risk was assessed by the Framingham risk score.
Results: No significant relationships were seen between the three different tests to evaluate endothelium-dependent vasodilation. EDV (r = -0.21, P = 0.004) and FMD (r = -0.19, P = 0.004), but not PAT were significantly related to the Framingham score in an inverse way. Also sodium nitroprusside-mediated vasodilation in the forearm, reflecting endothelium-independent vasodilation (EIDV), was related to the Framingham score in an inverse way (r = -0.30, P < 0.0001).
Conclusion: No close relationships were seen between the three tests of endothelium-dependent vasodilation, suggesting that they each contribute with unique information on vasoreactivity. EDV, EIDV and FMD, but not PAT, were related to the Framingham score, suggesting that vasoreactivity in some vascular beds are related to cardiovascular risk in middle-aged individuals.