Non-invasive assessment of endothelial function - relation between vasodilatory responses in skin microcirculation and brachial artery.

OBJECTIVE

To compare different non-invasive methods for determination of human endothelial function in peripheral circulation.

DESIGN

Observational, cross-sectional study in 39 healthy subjects (21 females, age 17-56 years).

SETTING

Vascular research laboratory at university hospital.

METHODS

Laser Doppler (LD) flowmetry was used to compare skin microvascular perfusion changes during postocclusive reactive hyperaemia with those induced by iontophoretic administration of acetylcholine (ACh), an endothelial-dependent vasodilator. LD measurements were compared with ultrasonographic measurements of postocclusive flow-mediated dilatation (FMD) in the brachial artery (n = 21).

RESULTS

Local ACh induced a larger and more sustained skin perfusion increase than reactive hyperaemia after 4 min of regional arterial occlusion (P<0.001). A significant correlation was found between the magnitude of ACh-induced vasodilatation and peak reactive hyperaemia, both in absolute (r = 0.62, P<0.001) and relative terms (r = 0.58, P<0.001). A correlation was also found between brachial artery FMD and the magnitude of ACh-induced skin perfusion increase (r = 0.43, P<0.05) but not between FMD and reactive hyperaemia.

CONCLUSION

Endothelial function, an early marker of cardiovascular risk, can be non-invasively assessed and graded by LD and FMD-measurements and despite inherent differences, both methods do correlate.