Which parameter is better for assessment of vascular endothelial function: absolute changes of vascular diameter or percentage index of it?

Abstract

Objective According to the current guideline, mostly is used percentage index of flow-mediated vasodilatation (FMD%), but there are many controversies in literature. Aim of the study was to show whether absolute changes of vascular diameter while reactive hyperemia test (RHtest) or percentage index of it is most valuable parameter for assessment of vascular endothelial function. Methods 57 patients with arterial hypertension (mean age±SD, 51.26±1.94) and 17 healthy controls (mean age±SD, 51±5.41) were included in the study. All the subjects underwent to the investigation of endothelial function via high resolution vascular dopplerechography, ambulatory blood pressure monitoring and investigation of blood rheology. Patients with cardio, peripheral and cerebrovascular diseases, diabetes mellitus, smokers, pregnant, obese as well as those with secondary forms of hypertension, ischemic heart disease and heart failure were excluded from the study. Results Compared with hypertensive population, FMD% as well as the absolute change of vascular diameter after RHtest (ΔD) was higher in healthy subjects (6.49±1.58 vs. 13.73±1.21; P=0.000 and 0.25±0.06 vs. 0.54±0.04; P=0.000; respectively). Correlation analyzes showed, that compared with FMD%, ΔD correlates with blood pressure characteristics, received by ABPM. Correlation between haemorheological parameters and FMD%/ΔD was not practically different in patients with arterial hypertension. Therefore, in contrary to the FMD%, ΔD showed significantly higher correlations with haemorheological characteristics; namely, platelet aggregative activity (r=0.488, P=0.047 vs. r=0.603, P=0.010), platelet adhesive activity (r=0.412, P=NS vs. r=0.537, P=0.026), fibrinogen concentration (r=0.198, P=NS vs. r=0.566, P=0.018), erythrocyte aggregative activity (r=0.049, P=NS vs. r=0.627, P=0.007) and blood viscosity (r=−0.256, P=NS vs. r=0.552, P=0.022). Conclusions In spite of the priority meaning of percentage index of flow-mediated vasodilatation for assessment of endothelial function in the current guideline, our study showed that for the assessment of endothelial function most valuable is to use absolute index of diameter changes, instead of percentage index of it. Objective According to the current guideline, mostly is used percentage index of flow-mediated vasodilatation (FMD%), but there are many controversies in literature. Aim of the study was to show whether absolute changes of vascular diameter while reactive hyperemia test (RHtest) or percentage index of it is most valuable parameter for assessment of vascular endothelial function. Methods 57 patients with arterial hypertension (mean age±SD, 51.26±1.94) and 17 healthy controls (mean age±SD, 51±5.41) were included in the study. All the subjects underwent to the investigation of endothelial function via high resolution vascular dopplerechography, ambulatory blood pressure monitoring and investigation of blood rheology. Patients with cardio, peripheral and cerebrovascular diseases, diabetes mellitus, smokers, pregnant, obese as well as those with secondary forms of hypertension, ischemic heart disease and heart failure were excluded from the study. Results Compared with hypertensive population, FMD% as well as the absolute change of vascular diameter after RHtest (ΔD) was higher in healthy subjects (6.49±1.58 vs. 13.73±1.21; P=0.000 and 0.25±0.06 vs. 0.54±0.04; P=0.000; respectively). Correlation analyzes showed, that compared with FMD%, ΔD correlates with blood pressure characteristics, received by ABPM. Correlation between haemorheological parameters and FMD%/ΔD was not practically different in patients with arterial hypertension. Therefore, in contrary to the FMD%, ΔD showed significantly higher correlations with haemorheological characteristics; namely, platelet aggregative activity (r=0.488, P=0.047 vs. r=0.603, P=0.010), platelet adhesive activity (r=0.412, P=NS vs. r=0.537, P=0.026), fibrinogen concentration (r=0.198, P=NS vs. r=0.566, P=0.018), erythrocyte aggregative activity (r=0.049, P=NS vs. r=0.627, P=0.007) and blood viscosity (r=−0.256, P=NS vs. r=0.552, P=0.022). Conclusions In spite of the priority meaning of percentage index of flow-mediated vasodilatation for assessment of endothelial function in the current guideline, our study showed that for the assessment of endothelial function most valuable is to use absolute index of diameter changes, instead of percentage index of it.