Associations between parameters of flow-mediated vasodilatation obtained by continuous measurement approaches and the presence of coronary artery disease and the severity of coronary atherosclerosis

A new peripheral endothelial function measurement improves prediction of symptomatic coronary artery disease

Objective

This study aimed to determine whether a peripheral artery volume (PAV) test can improve the predictive value of the age-adjusted Framingham risk score (AFRS) for coronary artery disease (CAD) in symptomatic patients.

Methods

A total of 317 consecutive patients who were referred for coronary angiography were prospectively enrolled. Before cardiac catheterization, a PAV test was performed to measure changes in pulsatile blood flow volume following reactive hyperemia.

Results

PAV was significantly lower in patients with CAD than in those without CAD (1.21 ± 0.32 vs. 1.50 ± 0.45). Multivariate logistic regression analysis showed that PAV and the AFRS were independent predictors of CAD. Pairwise comparison of receiver operating characteristic curves showed that the predictive power for CAD increased when PAV was incorporated into the AFRS (area under the curve: from 0.76 to 0.80). The net reclassification index was also improved when PAV was added to the AFRS (0.65, 95% confidence interval: 0.44–0.85).

Conclusions

Digital endothelial function measurement is an independent predictor of CAD. PAV is potentially useful for identifying patients at high risk for CAD.

Associations between microalbuminuria and parameters of flow-mediated vasodilatation obtained by continuous measurement approaches

The associations between microalbuminuria and various parameters of flow-mediated vasodilatation (FMD) are not completely understood. We retrospectively analyzed 265 consecutive patients who underwent coronary angiography and in whom we could measure FMD and the urine albumin-creatinine ratio (UACR). Using 15 continuous measurement approaches, we measured FMD as the magnitude of the percentage change in the brachial artery diameter from baseline to peak (bFMD), the maximum FMD rate calculated as the maximal slope of dilation (FMD-MDR), and the integrated FMD response calculated as the area under the dilation curve during the 60- and 120-s dilation periods (FMD-AUC60 and FMD-AUC120). We divided the patients into two groups according to UACR: normoalbuminuria (NOR, n = 211) and microalbuminuria (MIC, n = 54). The MIC group showed a significantly higher percentage of coronary artery disease than the NOR group. FMD-AUC60 and FMD-AUC120, but not FMD-MDR, in the MIC group were significantly lower than those in the NOR group. On the other hand, bFMD in the MIC group tended to be lower than that in the NOR group, but this difference was not significant. A multiple regression analysis indicated that FMD-AUC120 and diabetes mellitus were predictors of MIC. Finally, we defined the cut-off value of FMD-AUC₁₂₀ for the presence of MIC in all patients as 8.4 mm x second (sensitivity 0.640, specificity 0.588) by a receiver-operating characteristic curve analysis. In conclusion, this study provides more definitive evidence for the association of microalbuminuria with endothelial dysfunction. FMD-AUC120 may be a superior marker for MIC.