A comparative study: right ventricular assessment in post-repaired tetralogy of Fallot patients by echocardiogram with cardiac magnetic resonance imaging.

BACKGROUND: Post-repaired Tetralogy of Fallot (TOF) patients require comprehensive evaluation of the right ventricular (RV) size and function. Currently, cardiac magnetic resonance imaging (CMR) is considered to be the gold standard for RV function assessment. Echocardiogram (ECHO) is the most useful non-invasive tool for RV assessment. However, correlations of ECHO and CMR findings for this particular group of patients require further evaluation. OBJECTIVE: The first objective is to assess the correlation between RV size/function, measured by ECHO and CMR. The second objective is to investigate ECHO parameters that correlate best with RV end diastolic volume index (RVEDVi) of 160 mL/m2 from CMR. MATERIAL AND METHOD: The present study recruited 20 TOF patients (mean age 14 ± 2 years) who underwent right ventricular outflow tract reconstruction and/or pulmonary valve replacement for at least 5 years, from June 2011 to March 2012. The RV was initially evaluated with CMR, followed by ECHO within 3 months. ECHO parameters measured were tricuspid annular plane systolic excursion (TAPSE), fractional area change (FAC), area of right ventricular end diastole index (area RVEDi), RV free wall myocardial performance index (RVMPI), and qualitative assessment of pulmonary valve regurgitation (PR). All ECHO parameters were compared with CMR measurements of right ventricular ejection fraction (RVEF), RVEDVi and quantitative assessment of PR. Comparative analysis were assessed by Pearson's sample correlation coefficient, Kappa, and sensitivity and specificity of RVEDi area from ROC curve analysis. RESULTS: Results showed significant correlations between RVEDVi and area RVEDi (R = 0.768, p < 0.01), RVEF with FAC (R = 0.759, p < 0.01), and RVEF with TAPSE (R = 0.688, p < 0.01). Hundred percent correlation was found in moderate to severe PR assessment by ECHO and CMR (Kappa = 0.912). Abnormal RVMPI was not correlated with NYHA FC, CXR and ECG (Kappa = -0.10, 0.15, -0.04). The area RVEDi ≥ 20.43 cm2/m2 correlated well with RVEDVi ≥ 160 mL/m2 (sensitivity 64%, specificity 83%) from ROC curve analysis. CONCLUSION: ECHO is an effective tool for RV evaluation in post-repaired TOF with PR. FAC, TAPSE and severity of PR from ECHO correlated well with CMR parameters. Measurement of area RVEDi from ECHO is the best parameter to predict RVEDVi from CMR.