A matter of proportions: a novel framework to classify functional tricuspid regurgitation

Background

Current approaches for the assessment of tricuspid regurgitation (TR) severity do not correct for right ventricular (RV) size. Similarly to what recently proposed for the left heart, we hypothesized that TR severity can be proportional or disproportional to RV dilation.

Purpose

To characterize the clinical features and the prognosis of patients with disproportionate vs proportionate functional TR (FTR).

Methods

A total of 345 patients (mean age: 70±12 years; 40% male) with significant (≥ moderate) FTR, preserved left ventricular systolic function and who did not undergo tricuspid valvular repair during follow-up were included. Proportional and disproportional FTR were defined according to the ratio between TR severity (vena contracta [VC] width) and RV size (tricuspid annulus [TA] diameter). A prognostic relevant cut-off for VC/TA was identified with spline curve analysis. The primary end-point was all-cause mortality and the event rates were compared between patients with proportionate and disproportionate FTR.

Results

The cut-off for disproportionate FTR associated with an increase in all-cause mortality was identified at 0.24 (Figure 1: left panel). According to this cut-off, 172 (50%) patients showed disproportionate FTR, while the remaining had proportionate FTR. Patients with disproportionate FTR were more frequently symptomatic, had smaller RV basal diameter, higher TR severity, greater left atrial volume, higher prevalence of mitral regurgitation, and higher pulmonary artery pressures compared to those with proportionate FTR. During a median follow-up of 61 (interquartile range, 28–101) months, 135 (39%) patients died. The cumulative 5-year survival rate was significantly worse in patients with disproportionate FTR (57% vs 74%, P=0.001; Figure 1: right panel) and on multivariable Cox regression analysis disproportionate FTR was independently associated with poor outcome (HR 1.56; 95% CI 1.06–2.29; P=0.023) together with age, coronary artery disease, renal impairment, reduced RV systolic function, and increased pulmonary artery pressures. Importantly, this novel framework outperformed the TR grading system recommended by current guidelines, which in this population was not able to effectively stratify the prognosis (HR for severe FTR vs moderate FTR 1.09; 95% CI 0.72–1.64; P=0.694).

Conclusions

In patients with significant FTR, characterization of TR severity in relation to RV size significantly improves risk-stratification since disproportionate FTR if left untreated is associated with worse prognosis compared with proportionate FTR.

Figure 1

Funding Acknowledgement

Type of funding source: None

The truly forgotten chamber: prognostic value of right atrial dilation in patients with sinus rhythm and significant functional tricuspid regurgitation

Background

Functional tricuspid regurgitation (FTR) can be caused by right ventricular (RV) and/or right atrial (RA) dilation, and it leads in turn to further RV and RA remodeling. While it is known that in these patients RV dilation is associated with worse prognosis, there are no data on the prognostic value of RA enlargement.

Purpose

To assess the prognostic impact of RA dilation in patients with significant (≥ moderate) FTR taking into account the presence of atrial fibrillation (AF).

Methods

1382 patients (mean age: 69±13 year; 50% male) with moderate or severe FTR were included. Patients with congenital heart disease were excluded. Significant RA enlargement was identified by the value of RA area associated with excess of mortality according to spline curve analysis in the overall population (30 cm2 – Figure: Left Panel). The prognostic value of RA enlargement was investigated separately in patients with sinus rhythm (SR) and AF. The primary endpoint was all-cause mortality.

Results

A total of 987 (71%) patients were in SR while the remaining 395 (29%) had AF at the time of significant FTR diagnosis. Patients in SR with RA enlargement were more likely to present with RV failure symptoms and to receive diuretics compared with patients in SR with non-enlarged RA, whereas these differences were not detected in patients with AF. During a median follow-up of 53 (interquartile range, 20–89) months, 698 (51%) patients died. The survival rates of patients in SR with RA enlargement were significantly worse compared to the ones of patients in SR with normal RA size (Figure: Right Panel). In contrast, RA enlargement did not affect the prognosis of patients in AF (Log-rank χ2: 0.41; P=0.522). RA enlargement was associated with 33% increase risk of all-cause mortality in patients with SR and this association was retained on a multivariable Cox regression analysis (HR 1.27; 95% CI 1.04–1.56; P=0.022) together with older age, coronary artery disease, diabetes, severe renal impairment, reduced left ventricular or RV systolic function, and increased pulmonary artery pressures.

Conclusion

RA enlargement has an independent prognostic value for all-cause mortality in patients with FTR and SR, and therefore its evaluation might be useful to further improve their risk stratification.

Funding Acknowledgement

Type of funding source: None

A novel quantitative grading system to further characterize the prognosis of patients with functional tricuspid regurgitation

Background

Recent studies have suggested that current grading of tricuspid regurgitation (TR) has significant limitations and specifically cannot identify the various grades of severe TR (such as torrential). New cut-off values for the recommended measures of vena contracta (VC) width and effective regurgitant orifice area (EROA) have been proposed but not yet validated.

Purpose

To test the prognostic utility of new cut-offs for VC width and EROA in a large registry of patients with functional TR (FTR) and to integrate them into a novel comprehensive grading system.

Methods

FTR severity was evaluated in 1148 patients (mean age: 69±13 years, 50% male) with significant FTR (≥ moderate). Patients with congenital heart disease or who underwent tricuspid valve repair during follow-up were excluded. The primary endpoint was all-cause mortality. Based on Kaplan-Meier survival analyses, VC width significantly differentiated the prognosis of patients with moderate FTR vs severe FTR (with a cut-off value of 7 mm), whereas EROA was able to further stratify patients with more than severe (torrential) FTR. Therefore these two parameters were combined into a novel grading system (Figure: Upper Panel) to define: moderate FTR (VC <7 mm), severe FTR (VC ≥7 mm, EROA <80 mm2) and torrential FTR (VC ≥7 mm, EROA ≥80 mm2).

Results

According to our novel grading system a total of 146 patients (13%) showed moderate FTR, 547 patients (48%) had severe FTR and 454 patients (39%) presented with torrential FTR. Patients with torrential FTR had greater right ventricular (RV) dimensions, lower RV systolic function and were more likely to receive diuretics. The cumulative 10-year survival rates were significantly different among the groups: 54% for moderate FTR, 43% for severe FTR and 32% for torrential FTR (P=0.004 Figure – Lower Panel). After adjusting for potential confounders, torrential FTR retained its association with worse prognosis compared with other FTR grades (HR 1.28; 95% CI 1.07–1.54; P=0.007) together with age, coronary artery disease, diabetes, severe renal impairment, lower RV or left ventricular systolic function, higher pulmonary artery pressures, and dilated tricuspid annulus. Differently, severe FTR graded according to current guidelines did not show any association with the primary outcome (HR for severe FTR vs moderate FTR 1.17; 95% CI 0.96–1.42; P=0.128).

Conclusion

The proposed novel grading system combining measures of VC width and EROA is able to further risk stratify patients with FTR and specifically to identify patients with torrential FTR, a new clinical condition associated with even worse mortality than severe FTR.

Figure 1

Funding Acknowledgement

Type of funding source: None