Multi-Segment Indexes of Arterial Stiffness Show Lower Repeatability Than Carotid–Femoral Pulse Wave Velocity or Systolic Blood Pressure

BACKGROUND: We investigated the inter-day repeatability of newly proposed indexes of cardiovascular health based on the absolute (PWVABS) or relative (PWVRATIO) difference in pulse wave velocity (PWV) between the carotid-femoral (PWVCF) and carotid-radial (PWVCR) segments compared with PWVCF alone and with systolic blood pressure (BPSYST) over multiple days. METHODS: All variables were measured in triplicates in a group of 16 young, healthy individuals (8 men/8 women, body mass 66 ± 14 kg, height 1.7 ± 0.1 m, age 27 ± 3 years old, all mean ± SD) on 6 different occasions, always at the same time of the day (± 1 hour) and with at least 48 hours between assessments. RESULTS: Values did not differ significantly over the 6 different visits for any of the parameters (all Ps > 0.08). Intraclass coefficients (ICCs) ranged from 0.52 (PWVRATIO) to 0.8 (PWVCF). The ICC 95% confidence interval of PWVRATIO (0.30-0.77) and PWVABS (0.33-0.78) did not overlap with that of PWVCF (0.79-0.95), indicating lower repeatability. The coefficient of variation (CV) of PWVABS was over 5-fold larger than the next largest one (46.7 vs. 8.1% for PWVABS and PWVRATIO, respectively), whereas PWVCF and BPSYST showed the lowest CVs (4.6 and 4.0%, respectively). CONCLUSION: Between PWVABS and PWVRATIO, the relative method showed better repeatability and might be more sensitive to longitudinal changes in patients. Nonetheless, indexes of arterial stiffness-based PWV gradients between different segments show lower inter-day repeatability compared with PWVCF or BPSYST, suggesting that the latter are still preferable in clinical practice.