Added value of dedicated, outcome-based partition values to stratify right ventricular dysfunction in patients with secondary tricuspid regurgitation

Abstract Background In patients with secondary tricuspid regurgitation (STR) right ventricular (RV) function has a well-known prognostic significance. Assessing the conventional and advanced echocardiographic RV function parameters in patients with STR might be particularly challenging given the sensitivity of the RV to loading conditions. Several cutoffs for tricuspid annular plane systolic excursion (TAPSE), right ventricular free-wall strain (RVFWS), RV fractional area change (FAC), and RV ejection fraction (RVEF) have been proposed in an attempt to stratify RV systolic dysfunction 1-2. Nonetheless, there is ongoing debate regarding the applicability of established cutoff values for RV systolic function in patients with STR. Purpose We therefore sought to: i. to identify prognostically significant partition values of RV function parameters to stratify RV systolic dysfunction in mildly, moderately, or severely reduced; ii. to assess the association of the identified partition values with clinical outcomes in patients with STR in comparison with previously proposed cutoff values. Methods We included 495 consecutive patients (76±13 years, 54% women) with at least moderate STR (50% moderate, 29% severe, 11% massive, 10% torrential) who underwent comprehensive two-, three-dimensional, and speckle-tracking echocardiography. The primary endpoint was a composite of heart failure hospitalization and all-cause mortality. We used K-Adaptive partitioning for survival data algorithm to identify four groups of patients with significantly different rate of composite endpoint according to each one of the RV function parameters (TAPSE, FAC, RVFWS, and RVEF) (Table). Results Over a median follow-up of 43 months, we recorded 107 deaths and 123 hospitalizations for heart failure. Using a multiway partitioning algorithm to divide the STR cohort into four subgroups based on composite endpoint incidence, we found the following partition values: 57%, 45%, and 31% for RVEF; - 25%, 18%, and 9% for RVFWS; 41%, 32%, and 22% for FAC; and 22 mm, 18 mm, and 13 mm for TAPSE. When previously proposed cutoffs for RV dysfunction were applied to our cohort, Kaplan-Meier survival analysis demonstrated that the use of the newly identified partition thresholds provided superior risk stratification for the composite endpoint, particularly in distinguishing significantly between patients with mild and moderate RV dysfunction (Figure). Conclusions Our findings underscore the need to use dedicated, outcome-based threshold values to grade the extent of RV dysfunction in patients with STR. They better capture the variations in clinical risk compared to currently recommended stratification and may facilitate more individualized therapeutic decision-making or closer follow-up.Table Figure