Rambaran, Curtis, Benyu Jiang, Ritter, James M., Shah, Ajay, Kalra, Lalit, and Chowienczyk, Philip J.
British Journal of Clinical Pharmacology; Feb2008, Vol. 65 Issue 2, p238-243, 6p, 2 Charts, 3 Graphs
ENDOTHELIUM, ADRENERGIC receptors, NITROGLYCERIN, BRACHIAL artery, and CLINICAL pharmacology
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 (ΔRISALB) and endothelium-independent (ΔRINTG) pressure wave reflection. ΔRISALB 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 ΔRISALB between two visits was −0.2%, with SD of the difference 4.9%. Both ΔRISALB 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 ΔRISALB and FMD, respectively), whereas ΔRINTG and NTGD were similar in the two groups. ΔRISALB 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. [ABSTRACT FROM AUTHOR]