A Simple Method of Measuring Thoracic Aortic Pulse Wave Velocity in Children: Methods and Normal Values

Abstract

The objective of this study was to define a simple method of measuring thoracic aortic pulse-wave velocity (PWV) using only an aortic length regression equation based on the subject's height and two pulsed Doppler recordings of the aorta. The thoracic aortas of 80 subjects (age range, 0-20 years) were measured retrospectively by direct echocardiographic visualization. A simple linear regression equation for thoracic aortic length on the basis of height was derived. PWV was defined as the thoracic aortic length, derived from the subject's height, divided by pulse transit time. Pulse transit time was defined as the difference in the time of onset of two pulsed Doppler recordings placed at the level of the aortic valve leaflet tips and the diaphragm. Normative data were retrospectively defined in 206 children. Thoracic aortic length was linearly related to subject height by the equation thoracic aortic length (cm)=1.7 cm+0.1 (height [cm]) (R2=0.98, P<.0001). Thoracic aortic PWV was independent of age (median, 3.04 m/s). Thoracic aortic PWV can be simply calculated from a routine echocardiogram, it is constant throughout childhood, and it may improve the assessment of left ventricular load.