RESUMO
BACKGROUND: Pulmonary vascular resistance (PVR) is a crucial parameter in the management of patients with left-to-right shunt lesions. Cardiac catheterization (Cath) is the gold standard test to assess PVR (PVRcath ), but it is invasive and hence, risky in children with pulmonary arterial hypertension (PAH). A noninvasive tool to assess PVR is desirable. Ratio of tricuspid regurgitation velocity (TRV) and time-velocity integral of right ventricular outflow tract (TVIRVOT ) by Doppler was previously shown to be a reliable noninvasive method for estimation of PVR in acquired PAH. METHODS: Peak TR velocity and TVIRVOT were recorded from 63 prospective patients with various congenital shunt lesions. Subsequently, the patients were subjected to cath in less than 2 hours. The patients were subdivided into four subsets based on age and pulmonary arterial mean pressure (PAMP). A regression equation was developed for calculation of PVR from TRV/TVIRVOT (PVREcho ) which was indexed for BSA (PVRIEcho ). Bland-Altman analysis was done for agreement between PVRIcath and PVRIEcho . Receiver operating characteristic (ROC) curves were plotted to test the identity of the two methods and also the applicability of PVRIEcho across a wide range of Wood units. RESULTS: Receiver operating characteristic curve plotted between the two methods showed good identity. Bland-Altman analysis showed excellent agreement between the two methods with negligible bias. ROC curves showed that PVRIEcho was accurate in distinguishing different cutoff values of PVR in each of the 4 groups. CONCLUSION: Noninvasive Doppler estimation of PVR is reliable in patients with shunt lesions over a wide range of PVR.
