Early-Diastolic Right Ventricle-Pulmonary Artery Pressure Gradient by Doppler Echocardiography to Guide Cardiac Magnetic Resonance Assessment of Pulmonary Regurgitation after Right Ventricular Outflow Tract Reconstruction.

BACKGROUND: Pulmonary regurgitation (PR) after right ventricular outflow tract (RVOT) reconstruction is a major driver of right ventricular (RV) remodeling. Cardiac magnetic resonance (CMR) is the reference standard for quantifying PR but is not routinely feasible in many pediatric follow-up settings. We evaluated whether an echocardiographic early-diastolic RV-pulmonary artery (PA) pressure gradient (Echo-EaDPG), derived from early-diastolic peak PR velocity (ΔP = 4v2), can serve as a practical complementary hemodynamic marker to guide CMR assessment. METHODS: We retrospectively analyzed patients with repaired tetralogy of Fallot or related conditions who underwent echocardiography, CMR, and cardiac catheterization within a 6-month interval of each other after RVOT reconstruction. Echo-EaDPG was compared with CMR-derived PR fraction (CMR-PRF) and catheter-measured early-diastolic RV-PA pressure gradient (Cathe-EaDPG). Clinically significant PR was operationally defined as CMR-PRF ≥ 25%. Correlation, multivariable analyses, receiver operating characteristic (ROC) analysis, and bootstrap internal validation were performed. RESULTS: Forty patients were included. Echo-EaDPG correlated with CMR-PRF (r = 0.65, p < 0.001) and Cathe-EaDPG (r = 0.55, p < 0.001) and was independently associated with CMR-PRF ≥ 25% among tested echocardiographic indices. Echo-EaDPG demonstrated good discrimination for identifying CMR-PRF ≥ 25% on ROC analysis (AUC = 0.90), with bootstrap-supported robustness. Interobserver agreement for Echo-EaDPG was excellent (ICC = 0.96, 95% CI 0.82-0.99, p < 0.001). CONCLUSIONS: Echo-EaDPG is a simple Doppler-derived parameter associated with CMR-quantified PR and invasive early-diastolic RV-PA gradients after RVOT reconstruction. As an adjunct to integrated echocardiographic assessment, Echo-EaDPG may help identify patients who warrant CMR for quantitative PR evaluation, particularly when routine CMR is difficult to obtain.