Quantitative assessment of effective regurgitant orifice: impact on risk stratification, and cut-off for severe and torrential tricuspid regurgitation grade

Aims: Asses the added value of quantitative evaluation of tricuspid regurgitation (TR), the proper cut-off value for severe TR and 'torrential TR' based on outcome data. The added value of quantitative evaluation of TR, and the cut-off values associated with increased mortality are unknown.

Methods and results: In patients with all-cause TR assessed both qualitatively and quantitatively by proximal iso-velocity surface area method, long-term and 1-year outcome analysis was conducted. Thresholds for excess mortality were assessed using spline curves, receiver-operating characteristic curves, and minimum P-value analysis. The study involved 676 patients with all-cause TR (age 73.9 ± 14 years, male 45%, ejection fraction 52.9 ± 14%). Effective regurgitant orifice (ERO) was strongly associated with decreased survival in unadjusted [hazard ratio (HR) 2.38 (1.79-3.01), P < 0.0001 per 0.1 cm2 increment] and adjusted [2.6 (1.25-5.0), P = 0.01] analyses. Quantitative grading was superior to qualitative grading in prediction of outcome (P < 0.01). The optimal cut-off value for the best separation in survival between groups of patients with severe vs. lesser degree of TR was 0.35 cm2 [P < 0.0001, HR =2.0 (1.5-2.7)]. ERO negatively impacted survival, even when including only the subgroup of patients with severe TR [HR 1.5 (1.01-2.3); P = 0.04]. The optimal threshold corresponding for the best separation for survival between groups of patients with severe vs. 'torrential' TR was 0.7 cm2 [P = 0.005, HR =2.6 (1.2-5.1)].

Conclusion: TR can be severe and even 'torrential' and is associated with excess mortality. Quantitative assessment of TR by ERO measurement is a powerful independent predictor of outcome, superior to standard qualitative assessment. The optimal cut-off above which mortality is increased is 0.35 cm2, similar albeit slightly lower than suggested in recent guidelines. Torrential TR >0.7 cm2 is associated with poorer survival compared to patients with severe TR (ERO > 0.4 cm2 and <0.7 cm2).