Repeatability of the measurement of aortic pulse wave velocity (aPWV) in the clinical assessment of arterial stiffness in community-dwelling older patients using the Vicorder® device

Background. Pulse wave velocity measured using the Vicorder (R) apparatus is a non-invasive indicator of arterial stiffness. The objective of this study was to assess its repeatability in older patients when used by medical professionals with limited experience of the technique. Methods. Aortic pulse wave velocity (aPWV) was measured using the Vicorder (R) system four times using the conventional pathway and twice by adapted pathway in 25 consecutive ambulant patients (15 male) after they rested supine for 15 min. A nurse and a doctor independently and alternately measured PWV using the same equipment and were blinded to their colleague's PWV readings. 'Within' and 'between' observer differences were assessed using intra-class correlation coefficients (rI) and 95% limits of agreement (95% LoA) derived from Bland-Altman plots. Results. Mean age was 79.8 (mean blood pressure [BP] = 133/69, Mean heart rate [HR]: 70.9). Mean PWV was 11.73 (Standard Deviation [SD] 2.6-3.6). 'Between' and 'within' observer repeatability was high, with rIs ranging from 0.8-0.93. The repeatability index for 'between' nurse and doctor measures was slightly lower (rI = 0.88) when an adapted cuff measure was used in assessing PWV compared to conventional cuff measures (rI = 0.93). Mean PWV readings 'between' observers differed by only 0.094 (95% CI 0.24 to 1.59). Conclusion. When undertaken by operators with limited previous technical experience, both 'within' and 'between' observer repeatability of PWV measurement was high. This method has the potential to be included in the clinical assessment of arterial stiffness in older ambulant patients.