Atrial Functional Tricuspid Regurgitation in Patients Undergoing Transcatheter Aortic Valve Replacement

Introduction Recently, a novel entity of tricuspid regurgitation (TR) - atrial functional TR, which is caused by enlargement of the right atrium - has gained in awareness. In comparison, ventricular functional TR occurs in the setting of left heart disease with pulmonary hypertension and subsequent enlargement of the right ventricle. While it could be demonstrated that in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR), an improvement of moderate or severe tricuspid regurgitation (TR) can be observed in many patients, knowledge about the association between entity and improvement of TR is scarce. Purpose The aim of this study was to analyse if atrial functional TR, defined by the enlargement of the right atrium is associated with the persistence of TR after TAVR in patients with severe AS and at least moderate concomitant TR at baseline. Moreover, 3-year all-cause mortality in patients with atrial and ventricular TR was assessed. Methods We retrospectively examined 363 patients with at least moderate tricuspid regurgitation undergoing TAVR from January 2013 to December 2020 due to severe AS. Patients with primary TR, a history of tricuspid valve surgery or with TAVR due to severe aortic regurgitation were excluded. Endsystolic area of the right atrium (RA) and enddiastolic area of the right ventricle (RV) were assessed in transthoracic echocardiography and atrial TR was defined as RA/RV area ratio above the median value of 1.125. Results TR improvement of at least one grade after transcatheter aortic valve replacement was significantly less frequent in patients with atrial compared to patients with ventricular TR (29.2% vs. 60.3%, p < 0.001, Figure 1). Multivariate logistic regression analysis with adjustment for left ventricular ejection fraction, Vena contracta and CT-determined tricuspid annulus diameter confirmed that atrial functional TR was an independent predictor for absence of TR improvement after TAVR (adjusted odds ratio: 3.03, 95% CI 1.65-5.64; p<0.001). Moreover, improvement of TR was associated with a significantly lower 3-year all-cause mortality compared to patients with persistence of TR (log rank test p<0.001, Figure 2A). However, no difference could be observed regarding 3-year all-cause mortality between patients with atrial and ventricular TR (log-rank test p=0.500, Figure 2B). Conclusion In patients undergoing TAVR for severe AS and at least moderate concomitant TR, atrial functional TR is an independent predictor for TR persistence. In addition, TR persistence is associated with increased 3-year all-cause mortality.