Mortality and heart failure in patients with severe tricuspid regurgitation. Impact of RV volumes and function by CMR

Abstract

Background and objectives Right ventricle (RV) dilatation and dysfunction are established criteria for intervention in patients with significant tricuspid regurgitation (TR); however defined thresholds to support intervention are lacking. As a result the optimal timing for surgery in TR remains controversial and surgery is commonly undertaken at a late stage. Purpose To describe predictive cut-off values of RV size and function of poor prognosis in asymptomatic patients with significant TR. Methods Consecutive patients in stable clinical condition evaluated in the Heart Valve Clinic with significant TR (severe, massive or torrential TR) undergoing a Cardiac Magnetic Resonance (CMR) study were included. Conventional parameters of biventricular volume and function were assessed in all patients. A combined endpoint of hospital admission due to right heart failure and cardiovascular mortality was defined. Results 75 patients were included in this study (age 75±8 years, 75% female, 91% functional TR). During a median follow-up of 3 years (IQR: 1.4–3.9 years), 39% of the patients (n=29) experienced the combined endpoint. After adjusting for age and LVEF in a multivariate Cox proportional model, RV-EDV and RVEF were independently associated with cardiovascular mortality and heart failure. Thresholds of RV-EDV ≥100 ml/m2, RV-ESV ≥40 ml/m2 and RVEF ≤58% held the best accuracy to predict outcomes (figure 1). Regression spline model for RVEF and outcomes are presented in the figure 2. They show that RV function negatively impacted event-free survival, with an increase in the HR spline function near the crossing value (red line, RVEF ≤58%). In multivariable analysis, following adjustment for age and LVEF, a value of RVEF ≤58% and RV-EDV ≥100 ml/m2, was associated with 2.29, and 3.91-fold increased risk of heart failure or cardiovascular death respectively (RVEF Hazard Ratio (HR): 2.29 [1.06–4.9], p=0.03, and RV-EDV HR: 3.91 [1.56–9.82], p=0.004). Conclusion RV size and function are crucial for determining optimal timing for TR intervention. For the first time, cut-off values of RV volume and function are defined in a cohort of consecutive patients based on outcome data. Proposed values provide a basis for prospective studies to establish definitive optimal surgical timing for severe TR. FUNDunding Acknowledgement Type of funding sources: None. Figure 1. ROC and Cox regressions analysis Regression spline curve