Non-invasive assessment of endothelial function. Intra and inter-observer variability

Area of Science:

• Cardiovascular diagnostics
• Medical imaging
• Vascular biology

Background:

• Non-invasive endothelial function assessment using high-resolution ultrasound is crucial for identifying individuals at high risk for early atherosclerosis.
• Ultrasonographic assessment of brachial artery changes, while seemingly simple, presents technical challenges and a notable learning curve.

Purpose of the Study:

• To evaluate the intra-observer and inter-observer variability in assessing peripheral endothelial function using high-resolution ultrasound.
• To determine the reproducibility of brachial artery ultrasound measurements in a clinical setting.

Main Methods:

• Two physicians assessed endothelial function in 20 healthy volunteers using high-frequency, bidimensional ultrasound with a 10.0-MHz linear-array transducer.
• Each volunteer underwent identical brachial artery diameter measurements by both observers on three separate occasions.

Main Results:

• Excellent correlation (Spearman's correlation coefficient > 0.9, p < 0.0001) was found for all brachial artery measures.
• The study population exhibited a flow-mediated dilation (FMD) of 10.45+/-6.9% and flow-independent dilation (FID) of 24.35+/-7.63%.
• Intra-observer variability was low, recorded as 2.1% for observer A and 1.1% for observer B.

Conclusions:

• Non-invasive assessment of endothelial function via brachial artery ultrasound is a reproducible method.
• The technique demonstrates low intra-observer and inter-observer variability, supporting its clinical utility.