Distance measurement for pulse wave velocity estimation in pediatric age: Comparison with intra-arterial path length

BACKGROUND AND AIMS: Central pulse wave velocity (PWV) is a marker of arterial stiffness and is calculated by dividing the pulse wave travel distance by the transit time. However, there is no consensus as to the ideal distance measurement in children. The aim of our study was to identify the more reliable method to assess the distance measurement in the pediatric age. METHODS: Carotid-femoral PWV was measured by applanation tonometry in 988 healthy children aged 6.5-19.9 years. Two different surface distances were assessed: the subtraction method, representing the distance from the suprasternal notch to the femoral artery minus the distance from the carotid artery to the suprasternal notch, and the direct method, consisting of 80% of the distance from the carotid artery to the femoral artery. Both these methods were compared with the actual path length determined by magnetic resonance imaging (MRI) in 31 children. RESULTS: Subtraction and direct methods were significantly correlated in patients aged <14 years and the corresponding PWV values showed a good agreement. In children aged ≥14 years, a significant difference between the two methods was found: subtraction - direct distance = -45 ± 28 mm, with a significant difference in the resulting PWV values = -0.57 ± 0.35 m/s (p < 0.0001). This result was confirmed by MRI, showing a 10% overestimation in distance measurement by the direct method in subjects aged ≥14 years, resulting in a significantly higher PWV. CONCLUSIONS: These data suggest a greater reliability of the subtractive method of distance measurement compared to the direct method in children.