Assessment of endothelial function: comparison of the pulse wave response to β₂‐adrenoceptor stimulation with flow mediated dilatation

Aims

To assess the reproducibility of the digital pulse wave response to β₂‐adrenoreceptor stimulation and to determine if an attenuated response to β₂‐adrenoceptor stimulation is associated with impaired flow mediated dilatation (FMD).

Methods

Subjects (n = 20) with endothelial dysfunction (ED), were compared with healthy control subjects (n = 20). Change in reflection index (ΔRI) of the digital volume pulse in response to salbutamol (SALB, 5 µg min⁻¹ i.v) and to nitroglycerin (NTG, 5 µg min⁻¹ i.v) was used to assess endothelium‐dependent (ΔRI_SALB) and endothelium‐independent (ΔRI_NTG) pressure wave reflection. ΔRI_SALB was assessed on two occasions to examine reproducibility. High resolution ultrasound of the brachial artery was used to measure FMD and also dilation to NTG (NTGD).

Results

The mean difference in ΔRI_SALB between two visits was −0.2%, with SD of the difference 4.9%. Both ΔRI_SALB and FMD were impaired in subjects with ED compared with values in control subjects (5.0 ± 0.7 vs. 11.3 ± 1.2%, mean values ± SEM, P < 0.01 and 4.2 ± 0.6 vs. 7.5 ± 0.8%, P < 0.02 for ΔRI_SALB and FMD, respectively), whereas ΔRI_NTG and NTGD were similar in the two groups. ΔRI_SALB was correlated with FMD (r = 0.44, P < 0.01) and had 88% sensitivity and 79% specificity to detect abnormal (FMD < 4%).

Conclusions

The pulse wave response to a β₂‐adrenoceptor agonist correlates with FMD and has high sensitivity and specificity in detecting abnormal endothelial function as defined by FMD. However, FMD is the preferred test to detect effects of interventions on endothelial function.

DOI: 10.1111/j.1365-2125.2007.03006.x

View this article

• Full article (html)
• Enhanced article (html)
• PDF
• References