Derivation of Pulse Wave Velocity from Arterial Waveforms in Children

Aortic stiffness can be assessed using aortic pulse wave velocity (PWV), which can be estimated from peripheral arterial waveforms in adults. However, this method has not been validated in children. We sought to determine whether PWV could be feasibly measured by tonometry and accurately derived from arterial waveforms available in critically ill infants and children. Applanation tonometry was used to measure brachio-femoral or carotid-femoral PWV (b/cfPWV) in hospitalized, hemodynamically stable, prepubertal children with an indwelling arterial catheter. Peripheral arterial line waveforms were converted to ascending aortic waveforms using a model-based transfer function. PWV was estimated from the time delays (Δt_f-b) between forward and backward wave forms of the ascending aortic waveforms and effective reflecting distance (EfRD). We found that the effective reflecting distance (EfRD) calculation used in adults overestimated b/cfPWV in children. We derived a new EfRD equation that yielded better agreement between measured and estimated PWV (R² = 0.30, p < 0.05). Estimating PWV from arterial waveform data eliminates the need for tonometry, allowing larger samples of infants and children to be included in future studies of cardiovascular disease and development.