Carotid-femoral pulse wave velocity assessment using novel cuff-based techniques: comparison with tonometric measurement.

BACKGROUND Carotid-femoral pulse wave velocity, a predictor of cardiovascular outcome, is conventionally measured using a tonometer sequentially placed upon the carotid and femoral arteries, gated using an electrocardiogram. Leg cuff detection of the femoral pulse removes the need for signal gating, reduces the time required for a single measurement, but gives different pulse wave velocity values to tonometric analysis. A novel algorithm to correct for the transit time and distance related to the additional femoral segment was applied to the cuff-based approach in this study. METHOD Eighty-eight individuals were recruited across four centres and carotid-femoral pulse wave velocity measured in triplicate using two operators with both a tonometer-based device and a device using an inflated thigh cuff with and without the use of the novel algorithm. Comparison was made by Bland-Altman and regression analysis. RESULTS The unadjusted cuff-based approach gave lower pulse wave velocity values than the tonometer-based approach (6.11 ± 1.27 and 7.02 ± 1.88 m/s, P < 0.001). With application of the algorithm, the cuff-based device gave similar pulse wave velocity values (7.04 ± 1.72 m/s) as the tonometer-based approach (P = 0.86). Analysis of covariance with age showed a difference between the tonometer and cuff-based methods (P < 0.001), with a dependence upon age (P = 0.004). The adjusted cuff-based method gave similar results to the tonometer-based method (P = 0.94), with no dependence upon age (P = 0.46). CONCLUSION This study provided validation of a cuff-based assessment of carotid-femoral pulse wave velocity against the universally accepted tonometric method. Adjusting the cuff-based method for the additional femoral segment measured gives results comparable to the tonometer-based method, for which the majority of population data exist to date.