Reference equations for pulse wave velocity, augmentation index, amplitude of forward and backward wave in a European general adult population

Pulsatile hemodynamics have been shown to be independent predictors of cardiovascular events. The aim of the current study was to describe four pulsatile hemodynamic markers in a large, well-established, population-based cohort and to provide reference equations for sex- and age-based standardization of these measurements. 6828 adult participants from the Austrian LEAD (Lung, hEart, sociAl, boDy) cohort study, who were free from overt cardiovascular disease, non-diabetic based on blood test results, and had no history of pharmacological treatment for hypertension, dyslipidemia, and diabetes, comprised the "reference population". Carotid-femoral pulse wave velocity (cfPWV), augmentation index (AIx), amplitude of forward wave (Pf), and backward wave (Pb) were described in different age categories for both sexes. Sex-specific reference equations for cfPWV, AIx, Pf, and Pb with age as the predictive variable were created using the Lambda-Mu-Sigma (LMS) method. All four parameters increased with age. CfPWV and Pf were higher in males than females, especially in young and middle-age groups (P < 0.001). AIx was higher in females than males in all age categories (P < 0.001). Pb was also higher in females than males in age groups older than 40 years (P < 0.01). Reference equations for the skewness (Lambda), median (Mu), and coefficient of variation (Sigma) values were determined, enabling the calculation of sex- and age-standardized values (z-scores) for each individual's pulsatile hemodynamic measurement, and an online application was developed. Reference equations derived from a large population-based dataset constitute a suitable tool for the standardization of pulsatile hemodynamics and for the accurate interpretation of vascular aging.