Reliability and accuracy of echocardiographic right heart evaluation in the U.S. Melody Valve Investigational Trial

Background: Appropriate patient selection for transcatheter pulmonary valve (TPV) replacement requires accurate evaluation of right ventricular (RV) performance. The aim of this study was to evaluate the reliability and accuracy of echocardiography for evaluating RV parameters in patients in the five-center Melody TPV trial. Methods: Echocardiographic data were compared with cardiac magnetic resonance (CMR) and catheterization; interobserver comparisons were made using site and core laboratory data. Results: Doppler echocardiographic assessments of RV outflow tract obstruction and RV pressure showed excellent interobserver agreement; mean Doppler gradients were correlated most closely with gradients at catheterization (R = 0.66), and Doppler RV pressure estimates were correlated well with catheterization data (R = 0.58). Assessment of pulmonary regurgitation (PR) using a three-point severity scale showed good agreement with CMR-derived PR fraction (86%). The tricuspid annular Z score was highly reproducible but correlated weakly with CMR RV end-diastolic volume (R = 0.21). However, RV apical diastolic area was highly reproducible (R = 0.87) and had an excellent correlation with CMR RV end-diastolic volume (R = 0.78); all patients with indexed RV apical diastolic areas ≥30 cm²/m ² had CMR RV end-diastolic volumes ≥160 mL/m². RV function using the fractional area change method showed a fair correlation with CMR RV ejection fraction (R = 0.48). Conclusions: In patients with dysfunctional RV outflow tract conduits, echocardiography provided reproducible, accurate estimates of pressure overload and RV size. Echocardiographic assessment of PR correlated less closely with CMR PR fraction but showed good categorical agreement; assessment of RV function by these methods was suboptimal. Echocardiography alone may be a suitable screening test for some TPV replacement candidates; CMR may be indicated for TPV replacement decisions hinging on assessment of RV function.