Central pulse wave velocity and augmentation index are repeatable and reproducible measures of arterial stiffness

Abstract

Abstract Purpose: Arterial stiffness is an important cardiovascular risk factor. Pulse wave velocity (PWV) and augmentation index (Alx) are established indicators of arterial stiffness. The present study aimed to evaluate the repeatability and reproducibility of PWV and Alx in healthy individuals. Methods: Forty healthy participants (age 33±11 years, 17 females) underwent resting supine PWV and Alx assessments. Measurements were made in triplicate and repeated one week apart. Alx was measured by brachial occlusion and PWV was measured from the carotid artery to the femoral artery by the tonometer - oscillometric method. Repeatability and reproducibility were assessed using intra-class correlation coefficient (ICC). Inter-operator reproducibility was performed on ten participants. Results: The average values for week-to-week visits for PWV and Alx were 6.20±0.91 vs 6.13±0.91 ms-1 and 14.0±11.8 vs 16.3±12.2 %. For same-day measurements, both PWV and Alx showed excellent repeatability (PWV: ICC=0.96, 95% CI 0.92-0.98, p<0.01; and Alx: ICC=0.90 95% CI 0.84-0.94, p<0.01) and inter-operator reproducibility (PWV: ICC=0.98, 95% CI 0.93-1.00, p<0.01; and Alx: ICC=0.93 95% CI 0.69-0.98, p<0.01). Measurements were repeated one week apart and showed good reproducibility (PWV: ICC=0.77, 95% CI 0.61-0.87, p=<0.01; and Alx: ICC=0.73 95% CI 0.73-0.86, p<0.01). Conclusion: PWV and Alx demonstrate excellent repeatability and good reproducibility. Considering these variables are non-invasive and easy-to-measure, arterial stiffness may have a role in routine clinical practice to facilitate risk stratification in cardiovascular diseases.