Predictors of right atrial dilatation and long-term function after right ventricular outflow tract surgical repair: Quantification of restrictive physiology matters

Right ventricular (RV) diastolic dysfunction in patients with a surgically-repaired RV outflow tract (RVOT) obstruction merits further studies. Right atrial (RA) dilation and function may be related to (RV) diastolic dysfunction in this setting. The end-diastolic forward flow (EDFF) in the pulmonary artery (PA) has been suggested as a non-invasive marker of poor RV compliance, however, there is controversy regarding its true significance; EDFF quantification may help elucidate this controversy. Objective: to study predictors of RA enlargement and dysfunction in patients with a surgically-repaired RVOT obstruction and its relationship with quantitative EDFF. Methods: In 81 consecutive patients (mean age: 37.5 (+/- 7) years), transthoracic echocardiography (Echo) and cardiac magnetic resonance (CMR) were performed. Echo parameters: RA size (indexed RA area (iRAA)), RA function (RA global strain (RAGS)) and maximum EDFF velocity-time integral (VTI-EDFF) obtained during a whole respiratory cycle. CMR-indexed RA area (imRAA) was also obtained. Patients were divided into three groups according to iRAA, imRAA and RAGS; bivariate analysis was performed. A multivariate model was then applied using variables that were found to be statistically significant in the bivariate analysis. Results: Upon multivariate analysis, higher VTI-EDFF values and the presence of significant tricuspid regurgitation proved to be independent factors associated with increased iRAA and imRAA and lower RAGS, whereas RV volumes, function and pulmonary regurgitant fraction were not. Conclusion: VTI-EDFF linearly correlated with the degree of RA dilation and deformation; EDFF quantification as against qualitative assessment may be considered a non-invasive tool for diastolic RV dysfunction.