Association With Outcome of the Regurgitant-Volume Adjusted Right Ventricular Ejection Fraction in Secondary Tricuspid Regurgitation

Background: In patients with secondary tricuspid regurgitation (STR), right ventricular ejection fraction (RVEF) may not accurately reflect the actual RV systolic performance since a considerable amount of the RV stroke volume (SV) is regurgitated back into the right atrium. To overcome this limitation, we explored the association with the outcome of the effective RVEF (eRVEF), which accounts for the tricuspid regurgitant volume (RegVol). Methods: Five hundred thirteen patients with STR (mean age 75 ± 13 years, 39% atrial STR, 58% severe) underwent complete two-, three-dimensional, and Doppler echocardiography. The eRVEF was computed as RV forward SV/RV end-diastolic volume, where forward SV was obtained by subtracting the tricuspid RegVol from the total RVSV. The end point was a composite of all-cause death and heart failure hospitalization. Results: After a mean follow-up of 18 ± 15 months, 195 patients (38%) reached the composite end point. At time-dependent receiver operating characteristic analysis, eRVEF (area under the curve [AUC] = 0.72; 95% CI, 0.68-0.77) showed a stronger association with outcome than RVEF (AUC = 0.65; 95% CI, 0.59-0.70; P = .006), tricuspid annular plane systolic excursion (AUC = 0.64; 95% CI, 0.59-0.69; P = .01), RV free-wall longitudinal strain (AUC = 0.63; 95% CI, 0.58-0.68; P = .003), and RV fractional area change (AUC = 0.55; 95% CI, 0.50-0.60; P < .001). The eRVEF cutoff associated with an excess event rate was 20% on spline curve modeling. Patients with eRVEF <20% demonstrated a higher rate of events at 2 years (65% ± 6%) than those having an eRVEF ≥20% (22% ± 7%, log-rank <0.0001). An eRVEF <20% was associated with a 3-fold increased risk of experiencing the composite end point (hazard ratio = 3.54 [2.61-4.79], P < .001). On different models of multivariable analysis, eRVEF as a continuous variable remained independently associated with the combined end point (hazard ratio = 0.96; 95% CI, 0.94-0.98; P < .001). Conclusions: In patients with STR, eRVEF was more closely associated with all-cause mortality and heart failure hospitalizations than RVEF and other conventional echocardiographic indices of RV function.