RV function in adult patients with repaired tetralogy of Fallot: assessment by three-dimensional echocardiography, comparison to CMR findings and relationship to pulmonary artery distensibility

Purpose. The purpose of this study was to examine right ventricular (RV) function by three-dimensional speckle-tracking echocardiography (3DSTE) in patients after correction of tetralogy of Fallot (TF), the accuracy of 3DSTE compared to cardiovascular magnetic resonance (CMR) findings and assess pulmonary arterial (PA) distensibility in order to achieve a more comprehensive understanding of the matching between RV performance and PA load. Methods. Twenty-one patients (mean age 39±16 years) with repaired TF and twenty-one age-matched healthy subjects selected as controls were studied. CMR findings were available in 14 patients. RV volumes, RV ejection fraction (RVEF) and RV longitudinal and circumferential strains were calculated by three-dimensional echocardiography and three-dimensional speckle tracking echocardiography. The main pulmonary artery was interrogated by color, pulsed, and continuous-wave Doppler. Pulmonary regurgitation (PR) was assessed by color-flow mapping and graded as none, mild, or greater than mild using the measurement of the regurgitant jet width in relation to the outflow tract diameter. Right pulmonary artery (PA) was visualized from suprasternal view by two-dimensional echocardiography. Tissue Doppler Imaging (TDI) mode was activated in B-mode imaging to examine arterial motion, then mode was changed to color-mode with the beam line aligned perpendicular to the superior and inferior walls of the right PA. PA distensibility and strain were determined. Data analysis was performed offline. Results. Overall, 3D RVEF and RV longitudinal strain were reduced in TF patients compared to the control group. Nine patients had moderate or moderate-to-severe PR. PA strain and distensibility were decreased (p=0.003) compared with controls, both in the presence and absence of PR. PA strain had a positive correlation with RVEF (r=0.79, p<0.005) and RV strain (r=0.82, p<0.001). RV end-diastolic and end-systolic volumes by 3DE correlated with the respective parameters by CMR (r=0.88,p<0.001 and r=0.87,p<0.005 respectively). Patients with moderate-to-severe PR had more prominent PA strain changes (p = 0.02). Conclusions. Three-dimensional right ventricular ejection fraction and RV strain are impaired in patients with repaired TF, in agreement with CMR data. Reduced PA strain is associated with reduced RV 3DSTE parameters and is more pronounced in the presence of pulmonary regurgitation.