April 22, 2002
View Full PaperEvaluation of four different methods to measure endothelium-dependent vasodilation in the human peripheral circulation
Key Result
The reduction in the radial pulse wave inflection point was significantly related to both EDV (r=-0.41) and EIDV (r=-0.42) measured by the invasive forearm technique (P<0.05).
Study Design
Type
Cross-Sectional (n=24)
Structured PICO
How do four different methods for measuring endothelium-dependent vasodilation in the human peripheral circulation correlate with each other in young, healthy subjects?
P
Population
24 young, healthy subjects
I
Intervention
Evaluation of four methods to measure endothelium-dependent vasodilation: invasive forearm technique with local infusion of methacholine and sodium nitroprusside, brachial artery flow-mediated vasodilation (FMD) by ultrasound, FMD with ischaemic hand exercise, and radial pulse wave inflection point reduction following beta(2)-adrenergic receptor stimulation
C
Comparator
Comparison among the four methods
O
Outcome
Relationships (correlations) between the four techniques for measuring endothelium-dependent vasodilationsurrogate
Different methods of measuring endothelium-dependent vasodilation do not correlate well, suggesting that endothelial function differs between conduit and resistance arteries and that the pulse wave technique is not specific to EDV.
Main Result
Effect estimate: r=-0.41 and r=-0.42
p-value: p=<0.05
Abstract
At present, several techniques exist that claim to evaluate endothelium-dependent vasodilation (EDV) in the human peripheral circulation. The present study aims to evaluate the relationships between four of these techniques. A group of 24 young, healthy subjects underwent measurements of EDV and endothelium-independent vasodilation (EIDV) in predominately resistance vessels in the forearm using the invasive forearm technique with local infusion of methacholine and sodium nitroprusside, evaluation of flow-mediated vasodilation (FMD) in the conduit brachial artery measured by ultrasound, with or without the addition of ischaemic hand exercise, and evaluation of the reduction in the relative height of the inflection point of the radial pulse wave following beta(2)-adrenergic receptor stimulation. The reduction in the relative height of the inflection point following beta(2)-adrenergic receptor stimulation was significantly related to both EDV and EIDV in the forearm (r=-0.41 and r=-0.42 respectively; both P<0.05), but not to the EDV/EIDV ratio (r=-0.10). However, FMD, with or without the addition of ischaemic hand exercise, was not significantly related to the results obtained using the other two techniques (r=-0.18 to +0.13). In conclusion, the reduction in the relative height of the inflection point of the pulse wave following beta(2)-adrenergic receptor stimulation was related to both EDV and EIDV measured by the invasive forearm technique, indicating that the pulse wave technique does not measure EDV specifically. FMD in the brachial artery, with or without ischaemic hand exercise, was not significantly related to values obtained using the other two techniques, indicating that endothelial function differs between conduit and resistance arteries, and that both of these measurements should be evaluated in future studies.