Measurement of pulse wave velocity in children: comparison of volumetric and tonometric sensors, brachial-femoral and carotid-femoral pathways

Background: Pulse wave velocity (PWV), a measure of arterial stiffness strongly predictive of cardiovascular risk in adults, is usually measured by sequential ECG-referenced carotid and femoral tonometry. A simplified technique, more suitable for use in children, employs simultaneous volumetric recording from a sensor applied over the carotid artery and a cuff applied over the femoral artery or arm and thigh pressure cuffs applied over the brachial and femoral arteries. The purpose of this study was to compare PWV computed over the carotid-femoral path (PWVcf) with that over the brachial-femoral path (PWVbf) using a volumetric system (Vicorder) and to compare values of PWVcf obtained by the volumetric and a tonometric method (SphygmoCor) in children. Method: Vicorder PWVcf and PWVbf were compared in 156 children (3-18 years, 110 with chronic kidney disease), and PWVcf by Vicorder was compared to PWVcf by SphygmoCor in a subset of 122 patients. Results: PWVcf by Vicorder was moderately correlated with PWVcf by SphygmoCor (R = 0.50, P< 0.000). PWVbf and PWVcf Vicorder were more closely correlated (R = 0.75, P< 0.0001), but with a significant systematic difference. Applying a correction factor to PWVbf measurements gave results similar to those obtained over the carotid-femoral path. Within-patient coefficients of variation for repeated measures were 5.9, 7.8, and 8.5% for PWVbf (Vicorder), PWVcf (Vicorder) and PWVcf (SphygmoCor), respectively. All PWV values showed a similar relation to age. Conclusion: Volumetric methods appear reproducible and are easy to use in children, but values obtained by Vicorder and SphygmoCor are not interchangeable even when measured over the same pathway.