Estimation of Pulmonary Vascular Resistance: Correlation between Echocardiography and Catheterization Data in Patients with Congenital Heart Disease.

Background: The ratio of peak tricuspid regurgitation velocity (TRV) and right ventricular outflow time-velocity integral (TVI RVOT) has been described as a good correlate of pulmonary vascular resistance (PVR). However, this method has not been well studied in congenital heart disease. Method: Twenty patients with post-tricuspid shunt lesions who were planned to undergo cardiac catheterization were enrolled for the study. The ratio of TRV/TVIRVOT was measured via transthoracic echocardiography and correlated with invasively derived PVR (PVRCATH). PVRCATH was measured by cardiac catheterization. Fick's principle was used to calculate the pulmonary blood flow and oxygen consumption was assumed. Linear regression analysis was done to find the correlation between TRV/TVIRVOT and PVRCATH. Results: There was a significant correlation between the two variables, r = 0.635(P = 0.003). Subgroup analysis revealed that this correlation was better at lower values of PVRCATH (r = 0.817 for PVR < 6 Wood units (WU)) than higher values (r = 0.659 for PVR > 6 WU). TRV/TVIRVOT ratio of greater than 0.145 predicted with 80% sensitivity and specificity a PVR > 6 WU. Conclusions: There is modest correlation between TRV/TVIRVOT ratio and invasively derived PVR in congenital shunt lesions, especially in PVR < 6 WU. TRV/TVIRVOT ratio could be useful in identifying patients with congenital shunts whose PVR is likely to be <6 WU, and hence, do not need cardiac catheterization. (Echocardiography 2012;29:478-483) [ABSTRACT FROM AUTHOR]