A new screening device for automatic measurements of arterial stiffness and ankle-brachial index

Two of the emerging risk factors that have not been included in the standard office-based tools but have great promise as means to improve office-based risk assessment are arterial stiffness and ankle-brachial index. Despite the well-established clinical significance associated with these risk factors, presently these tests are not yet available outside of vascular laboratories. Recently, a new clinical testing device was developed to simultaneously measure central arterial stiffness, ankle-brachial index, and brachial blood pressure. In the present study, we evaluated the validity and reliability of arterial stiffness and ankle-brachial index obtained with a newly-developed automatic device (Colin VP-2000) by comparing with the manual methods (i.e., gold standards). Fifty two normotensive and hypertensive subjects varying in age were studied. The automatic device simultaneously measured bilateral brachial and ankle blood pressures as well as carotid and femoral arterial pulse waves with a multi-sensor tonometer to facilitate proper positioning at the pulse sites. The device required a total time of ∼5 min, which included set-up, measurement, and analysis. Carotid augmentation index (an index of arterial stiffness) obtained with the manual and automatic methods demonstrated a strong linear association (r=0.98; P<0.0001) with a mean difference of 0.2±4.6%. Similarly, carotid-femoral pulse wave velocity (a measure of arterial stiffness) using these two methodologies demonstrated a strong association (r=0.97; P<0.0001) with the mean difference of 34±68 cm/sec. Ankle systolic blood pressure obtained with the automatic device (via modified oscillometric sensor) exhibited an excellent agreement with the Doppler-derived values (r=0.95; P<0.0001). Each variable examined in the present study demonstrated excellent reliability as evidenced by high correlation coefficients (r=0.93−0.97) and by small coefficients of variation (3–13%) between the two trials. This automatic noninvasive device, which is accurate and requires minimal technical skill and time, has great potential as a screening device for assessments of subclinical vascular pathology.