Natural History of Functional Tricuspid Regurgitation: Implications of Quantitative Doppler Assessment

This study sought to define the relationship between functional tricuspid regurgitation (TR) and mortality in patients with heart failure with reduced ejection fraction (HFrEF); and to establish the prognostic value of quantitative measures of TR severity (i.e., effective regurgitant orifice area [EROA] and regurgitant volume).

The significance of TR in chronic heart failure is controversial. Earlier studies have shown an independent impact of TR on mortality, whereas more recent evidence suggests myocardial impairment to be the driving force of mortality rather than TR itself. Earlier studies have used qualitative measures of TR severity, hence the prognostic value of more quantitative measures of TR severity (i.e., EROA and regurgitant volumes) remains unclear.

We enrolled 382 patients with HFrEF on guideline-directed medical therapy and assessed TR EROA and regurgitant volume by Doppler/2-dimensional echocardiography. All-cause mortality was defined as the primary study endpoint.

TR severity was associated with the HFrEF phenotype with more symptoms (p = 0.004), higher neurohumoral activation (p < 0.001), progressive right-ventricular dilatation (p < 0.001), and impaired function (p < 0.001). Cox regression showed a strong association between quantitative measures of TR with mortality (all p < 0.001). Quantitative metrics of TR severity were consistently associated with mortality with a hazard ratio of 1.009 (95% confidence interval: 1.004 to 1.013; p < 0.001) per 0.01 cm² increase of the EROA and of 1.013 (95% confidence interval: 1.007 to 1.020; p < 0.001) per 1-ml increase in regurgitant volume. Results remained unchanged after bootstrap- or clinical confounder-based adjustment. A spline curve pattern illustrates the association with mortality with thresholds for the EROA ≥0.2 cm², and the regurgitant volume ≥20 ml with sustained excess mortality thereafter.

This large-scale outcome study demonstrates the prognostic value of quantitative Doppler-echocardiographic measures of TR severity in HFrEF. The thresholds for EROA and TR regurgitant volume associated with mortality in our study fall within current ranges defining nonsevere TR. This may potentially impact therapeutic decision making, particularly timing of intervention.