A New Simple Method to Estimate Pulmonary Regurgitation by Echocardiography in Operated Fallot: Comparison With Magnetic Resonance Imaging and Performance Test Evaluation

Background

The aim of this study was to assess a novel transthoracic echocardiographic method to estimate the severity of pulmonary regurgitation (PR) in patients with surgically repaired tetralogy of Fallot.

Method

In 63 patients with operated tetralogy of Fallot, PR was evaluated by vena contracta width, jet deceleration, PR index, pressure half-time, and a new index, referred to as Pulmonary Regurgitation Index by M-mode echocardiography (PRIME), which is the systolic-to-diastolic variation in right pulmonary artery diameter. The results were matched to PR fraction (PRF) assessed by cardiovascular magnetic resonance imaging. PRIME cutoff values for selecting patients with mild, moderate, and severe PR were identified by maximizing PRIME sensitivity and specificity. Nonlinear regression by 3-parameter logistic function was used to estimate PRF by PRIME.

Results

The sensitivity and specificity of PRIME were high for all diagnostic targets: PRF ≥15% versus <15%, PRF ≥25% versus <25%, and PRF >40% versus ≤40%. The nonlinear regression model showed a good correlation between PRF and PRIME (R² = 0.95).

Conclusion

PRIME is a simple and accurate method to estimate PR by transthoracic echocardiography in patients with operated tetralogy of Fallot.

Keywords: Transthoracic echocardiography, Pulmonary regurgitation, Operated tetralogy of Fallot, Magnetic resonance imaging

Abbreviations: 2D, Two-dimensional, AUC, Area under the ROC curve, CV, Cardiovascular, MRI, Magnetic resonance imaging, PR, Pulmonary regurgitation, PRF, PR fraction, PRIME, Pulmonary Regurgitation Index by M-mode echocardiography, PVC, Phase velocity contrast, ROC, Receiver operating characteristic, RPA, Right pulmonary artery, RV, Right ventricular, TOF, Tetralogy of Fallot, TTE, Transthoracic echocardiography