Abstract 4141135: Right atrial functional reserve and liver stiffness after complete repair of tetralogy of Fallot

BACKGROUND: Right atrial (RA) dysfunction related to right ventricular (RV) function has been reported in patients with repaired TOF. Increased liver stiffness in these patients has also been reported. Whether RA function worsens under exercise stress, and its relationship with worsened liver stiffness is unknown. HYPOTHESIS: In patients after TOF repair, RA functional reserve during exercise stress is reduced and correlated with raised liver stiffness and RV dysfunction. METHODS: 19 patients (8 male) aged 17.92 ± 3.81 at 16.06 ± 3.98 years after repair and 25 controls (16 male, aged 19.99 ± 1.67 years) were studied. RA mechanics was assessed by speckle-tracking echocardiography (STE) at rest and during bicycle exercise, with quantification of positive, negative, and total strain, and strain rates at ventricular systole (aSRs), early diastole (aSRed), and atrial contraction (aSRac). RAFR is calculated as (Change in RA total strain x [1-1/ baseline RA total strain]). Biventricular (RV, LV) function were quantified using Doppler interrogation and STE. Hepatic shear wave velocity (c) and tissue elasticity (E) were measured using shear wave elastography. RESULTS: At rest, patients had lower RA positive, negative and total strain, aSRs and aSRed than control subjects (all p<0.001). RAFR were lower in patients than controls (p<0.05). Hepatic shear wave velocity and tissue elasticity were higher in patients than controls (both p<0.003). Compared with controls, patients had lower RA strains, aSRs, aSRed and aSRac during exercise (all p<0.001). No significant difference in hepatic stiffness indices were found between patients and control subjects at exercise (both p>0.05). RAFR correlated negatively with baseline hepatic shear wave velocity and tissue elasticity (both p<0.001). RAFR tended to correlate with pulmonary regurgitation severity (p=0.06), and correlated with RV function, such as exercise RV strain rate at late diastole (SRa), exercise transtricuspid early (E) and late (A) inflow velocities during exercise, and resting RV systolic strain (all p<0.05). Multivariate analyses revealed that RV and LV systolic strain, and RV strain rate at early diastole (SRe) are predictors of right atrial total strain at exercise and RAFR, whilst RV SRa is also a predictor of exercise RA total strain (all P<0.05). CONCLUSIONS: In young adults after TOF repair, right atrial function reserve is impaired, and is associated with increased liver stiffness and RV dysfunction.