The time course of flow-mediated vasodilation and endothelial dysfunction in patients with a cardiovascular risk factor.

The relationship between having a cardiovascular risk factor and endothelial dysfunction observed on a time-course analysis of brachial artery flow-mediated vasodilation (FMD) remains unclear. We enrolled 257 patients who had at least one cardiovascular risk factor. We measured FMD magnitude of the percentage change in peak diameter (ΔFMD), maximum FMD rate calculated as the maximum slope of dilation (FMD-MDR), and integrated FMD response calculated as the area under the dilation curve during the 60- and 120-second dilation periods (FMD-AUC60 and FMD-AUC120) using a semiautomatic edge-detection algorithm. FMD-AUC60 and FMD-AUC120 were negatively correlated with the Framingham risk score (FMD-AUC60: r = -0.15, P = .023; FMD-AUC120: r = -0.17, P = .007), whereas this association was not found in the case of either the ΔFMD or the FMR-MDR. The Framingham risk score was significantly higher in patients in the lowest tertile for FMD-AUC120 (FMD-AUC120 <5.0 mm × second) than in those in the highest tertile for FMD-AUC120 (FMD-AUC120 ≥11.0 mm × second) (12.9 ± 8.7 vs. 8.6 ± 7.8%, P = .002). The lowest tertile for FMD-AUC120 was independently associated with the Framingham risk score (β = 0.10, P = .011), after adjustments were made for age, gender, and smoking and drinking status. FMD-AUC120 was associated with cardiovascular risk.