P1.38 Conversion Between Definitions of Pulse Wave Velocity

Background Different methodologies for determination of carotid-femoral pulse wave velocity (PWV) exist. Distance (L) can be measured from carotid-femoral measurement sites (L direct ) or obtained by subtracting carotid-sternum from sternum-femoral distances (L subtracted ). Transit times are usually obtained either by detection of the maximal upstroke (Δt maximal upstroke ) or the foot (Δt intersecting tangent ) of the waveform at the measurement sites. This study investigates conversion factors between PWV methodologies. Methods 3043 subjects in which both distance measurements were available were divided into model and validation groups (1502/1541 subjects, respectively). In the model population the main determinants of the ratio distance = L subtracted /L direct were determined and a multivariate model was constructed. Estimated ratio distance,est was used to convert from PWV direct to PWV subtracted,est in the validation population. PWV subtracted,est was compared to measured PWV subtracted . Ninety three subjects in which both transit times were available were divided into model and validation groups (46/47 subjects, respectively). In the model population a model for estimation of Δt maximal upstroke,est from Δt intersecting tangent was constructed and used to estimate Δt maximal upstroke,est in the validation population. Δt maximal upstroke,est was compared to measured Δt maximal upstroke . Data are presented as mean(stdev). Results The main determinants of ratio distance were age (R 2 = 0.17) and BMI (R 2 = 0.15) (combined: R 2 = 0.27, all P