Causal relation of tricuspid regurgitation for heart failure outcomes: a mediation analysis of echocardiographic predictors

AIMS: Although significant tricuspid regurgitation (TR) is critically associated with heart failure (HF) prognosis, the predictors for large TR impact on HF outcomes remain unknown. This study aimed to identify echocardiographic predictors for a causal relation of TR to HF outcomes. METHODS AND RESULTS: In a retrospective, acute HF cohort of 462 patients, multivariate logistic regression analysis was performed to determine subgroups with strong association of greater-than-moderate TR with HF readmission or cardiovascular death in a year. We then conducted causal mediation analysis according to persistent atrial fibrillation (Af) or mitral regurgitation (MR) to identify the echocardiographic predictors. The association of TR with HF outcomes was prominent in subgroups of females, with Af, the enlarged indexed tricuspid annular diameter (TADi) or right atrial area, or within certain ranges of the left ventricular ejection fraction, indexed right ventricular end-systolic area, or fractional area change (FAC). Causal mediation analysis found that the TR impact was significant in patients with Af. Furthermore, combination of TADi ≥2.1 cm/m(2) and FAC ≥30%, which accounted for half of TR patients, predicted a much larger TR impact irrespective of Af and MR. Its prediction ability was superior to that of the modified Model for End-stage Liver Disease score. CONCLUSION: The causal impact and burden of TR on HF outcomes was significant in patients with Af, and combining TADi ≥2.1 cm/m(2) with FAC ≥30% could provide superior echocardiographic prediction of larger TR impact in HF patients.