The prognostic value of the Dandel´s index in patients undergoing transcatheter tricuspid edge-to-edge repair

Introduction: Conventional parameters of right ventricular (RV) function are load- dependent and therefore do not accurately reflect contractility in patients with relevant tricuspid regurgitation (TR). RV adaptability to load has been characterized using the Dandel´s index in patients with heart failure, but its prognostic value in patients undergoing tricuspid transcatheter edge-to-edge repair (T-TEER) has not been investigated so far.

Methods: From the Euro-TR registry (2019 to 2022), patients with complete datasets and a minimum of 2-years follow-up were included. RV functional parameters (i.e. tricuspid annular plane systolic excursion (TAPSE), fractional area change (FAC), TAPSE/systolic pulmonary arterial pressure (SPAP), as well as a echocardiographic RV load adaption index (“Dandel´s index”) were assessed and their predictive value in terms of all-cause mortality evaluated using logistic multivariate logistic regression.

Results: The majority of the 364 patients had secondary TR (96%) and were severely symptomatic (NYHA class ≥3; 92%). At 2-year follow-up, 36% of patients had died. Functional RV parameters (TAPSE: HR 0.65 [0.52; 0.81]; FAC: HR 0.73 [0.59;0.91]), coupling index (TAPSE/SPAP: HR 0.8 [0.65;0.99]) and Dandel´s index (HR 0.67 [0.53;0.85]) were all associated with mortality at 2 years in univariable analyses. In a multivariate logistic regression model, the Dandel's index maintained its predictive value (p < 0.001), along with TAPSE and absence of signs of right heart failure (RHF), with an optimal threshold of 20.5 determined by ROC analysis. This threshold also successfully predicted cardiac hospital readmission. A multivariate analysis was conducted to identify parameters linked to RV function and predicting clinical outcomes.

Conclusion: Assessment of the RV capacity to adjust for changes in loading conditions predicted mortality in patients with severe symptomatic TR undergoing T-TEER. The use of a multi-parametric approach including the Dandel’s index to assess RV function had an incremental value for the stratification of patients into subgroups with different prognosis.