Validity, intra‐ and inter‐test reliability of arterial stiffness and wave reflection measured by the new brachial cuff SphygmoCor Xcel

Abstract

Large artery stiffness (AS) and wave reflection are independent predictors of cardiovascular disease. Aortic pulse wave velocity (AoPWV) and augmentation index (AIx) are commonly used as non‐invasive measures of AS and wave reflection, respectively. We sought to examine 1) the validity of the new SphygmoCor Xcel (Xcel; AtCor Medical) compared with the SphygmoCor MM3 (MM3) model in measuring AoPWV and AIx and 2) the intra‐ and inter‐test reliability of Xcel. Twenty‐six adults participated in this study (16 men, 25 to 75 yrs). To assess the validity, AoPWV and AIx were measured using Xcel and MM3. To examine the intra‐test reliability, AoPWV and AIx were measured three times within the same testing session using Xcel. Finally, to assess the inter‐test reliability, AoPWV and AIx measures were repeated on Xcel within 1 week of the first testing session. AoPWV and AIx were not significantly different as measured by Xcel compared to MM3 (mean differences: −0.15±0.16 m/s, P=0.4 and −0.3±2%, P=0.9, respectively) and there were strong correlations between the Xcel and MM3 measures (AoPWV: r=0.84, P<0.001; AIx: r=0.77, P<0.001). Intra‐test (AoPWV: Intra‐class correlation (ICC)=0.996, P<0.0001;AIx: ICC=0.986, P<0.0001) and inter‐test reliability (AoPWV: ICC=0.979, P<0.0001; AIx: ICC=0.936, P<0.0001) were high. In conclusion, assessment of AS with Xcel is valid and highly reliable within and between testing sessions.