The intra- and inter-operator variability of Echo-Doppler measurements for noninvasive pulmonary arterial pressure determination in congenital heart disease

Abstract

Objective: This prospective study determines reproducibility of measurements derived from the pulmonary arterial (PA) blood flow velocity waveform in infants and children with congenital heart disease by performance of the Doppler echocardiographic examination by different echocardiographers. Additionally, the effect of respiration on reproductibility is investigation. Methods: In group I consisting of 44 consecutive patients (aged 0.1–16.2 years) admitted for echocardiography, the PA blood flow velocity waveform was independently determined by two equally experienced echocardiographers. To obtain intra-operator variability, one performed the examination again. In 38 mechanical ventilated patients (aged 0.2–15.6 years), PA blood flow velocity was examined twice by the same echocardiographer to investigate the effects of respiration on reproducibility (group II). Results: In both groups, no systematic difference between examinations could be shown for all Doppler measurements. In group I, the percentage of absolute difference between echocardiographers ranged from 6.0% to 26.4%. Maximal acceleration and deceleration were least reproducible. In group II, the percentage of absolute difference between successive PA bloodflow velocity waveform determinations ranged from 9.2% to 28.6%. No significant difference in reproducibility between respiratory phases was present for all Doppler measurements. Reproducibility was best in end-expiratory beats. Conclusions: reproducibility of measurements derived from the PA blood flow velocity waveform is low and might explain the conflicting results in non-invasive PA pressure determination. To overcome effects of respiration, selection of end-expiratory beats is reccommended.