Reproducibility of arterial stiffness indices in different vascular territories and between different observers.

Background: Increased arterial stiffness (AS) corresponds to an increase in cardiovascular risk. According to recent guidelines AS parameters can be measured on all superficial arteries.

Objective: Proceeding from the assumption that viscoelastic properties differ along the arterial tree we set ourselves the task to study the reproducibility of AS indices measured at the common carotid, brachial and femoral arteries.

Methods: The initial study population included 75 patients (40 ± 14.5 years, 45% males) with a variable distribution of cardiovascular risk factors and without clinical evidence of coronary artery disease. AS parameters were measured at the common carotid, brachial and femoral arteries in all patients using echo-tracking (ET) technique. In a subgroup of 36 patients we tested the interobserver variability in the three vascular territories.

Results: We found that there was a significant correlation between AS indices measured at the common carotid and femoral artery (with the only exception for augmentation index) and that AS parameters measured at the brachial artery did correlate neither with common carotid nor with femoral artery indices. The interobserver variability of ET derived AS parameters was good when they were measured at the carotid or femoral artery. The values of AS indices at the brachial artery however showed considerably lower interobserver agreement.

Conclusion: The reproducibility of ET derived AS parameters was good when AS was measured at the common carotid or femoral arteries. On the basis of our results brachial artery is probably not a reliable site for AS measurement.