Noninvasive Estimation of Pulmonary Vascular Resistance by ColorM-Mode Chocardiography Assisted with Computer

Background: The estimation of pulmonary vascular resistance (PVR) is of important in the diagnosis, management, and prognosis of cardiac disease; however, Doppler estimation of PVR is still considered unreliable and clumsy. The goal of this study was to seek a new method for noninvasive estimation of PVR by velocity propagation (VP) within the main pulmonary artery from color M-mode Doppler imaging using custom software on a personal computer. Methods: Color M-mode imaging of the pulmonary flow was obtained and then transferred onto a computer. The flow wave front of the first aliasing velocity was identified with the custom software, then regressed to a straight line. The slope representing VP of the pulmonary flow was automatically obtained. Comparative studies between this color M-mode Doppler echocardiography and cardiac catheterization for predicting PVR were performed in 20 children with congenital heart disease and 20 normal children. Results: VP of children with congenital heart disease were significant lower than those of normal children obtained by color M-mode Doppler echocardiography (38.38 plusmn 18.89 vs 80.34 plusmn 15.65; P0.01) and correlated well with invasive PVR measurements (r = -0.69; P0.01). The correlation and repeatability of the VP obtained by the custom software werebetter than the VP obtained by Doppler echocardiography (r = -0.78; P0.01). A VP cutoff value obtained by the custom software of 35.910 had a sensitivity of 92.9% and a specificity of 100% to determine PVR > 16 kPa-s/L. Conclusions: PVR could be accurately estimated by VP within the pulmonary artery obtained by color M-mode echocardiography using custom software on a personal computer.