Comparison of effective regurgitant orifice area by the PISA method and tricuspid coaptation gap measurement to identify very severe tricuspid regurgitation and stratify mortality risk

Introduction

Various definitions of very severe (VS) tricuspid regurgitation (TR) have been proposed based on the effective regurgitant orifice area (EROA) or tricuspid coaptation gap (TCG). Because of the inherent limitations associated with the EROA, we hypothesized that the TCG would be more suitable for defining VSTR and predicting outcomes.

Materials and methods

In this French multicentre retrospective study, we included 606 patients with ≥moderate-to-severe isolated functional TR (without structural valve disease or an overt cardiac cause) according to the recommendations of the European Association of Cardiovascular Imaging. Patients were further stratified into VSTR according to the EROA (≥60 mm²) and then according to the TCG (≥10 mm). The primary endpoint was all-cause mortality and the secondary endpoint was cardiovascular mortality.

Results

The relationship between the EROA and TCG was poor (R²=0.22), especially when the size of the defect was large. Four-year survival was comparable between patients with an EROA <60 mm² vs. ≥60 mm² (68 ± 3% vs. 64 ± 5%, p = 0.89). A TCG ≥10 mm was associated with lower four-year survival than a TCG <10 mm (53 ± 7% vs. 69 ± 3%, p < 0.001). After adjustment for covariates, including comorbidity, symptoms, dose of diuretics, and right ventricular dilatation and dysfunction, a TCG ≥10 mm remained independently associated with higher all-cause mortality (adjusted HR[95% CI] = 1.47[1.13-2.21], p = 0.019) and cardiovascular mortality (adjusted HR[95% CI] = 2.12[1.33-3.25], p = 0.001), whereas an EROA ≥60 mm² was not associated with all-cause or cardiovascular mortality (adjusted HR[95% CI]: 1.16[0.81-1.64], p = 0.416, and adjusted HR[95% CI]: 1.07[0.68-1.68], p = 0.784, respectively).

Conclusion

The correlation between the TCG and EROA is weak and decreases with increasing defect size. A TCG ≥10 mm is associated with increased all-cause and cardiovascular mortality and should be used to define VSTR in isolated significant functional TR.

Impact of correcting the 2D PISA method on the quantification of functional tricuspid regurgitation severity

AIMS

In functional tricuspid regurgitation (FTR) patients, tricuspid leaflet tethering and relatively low jet velocity could result in proximal flow geometry distortions that lead to underestimation of TR. Application of correction factors on two-dimensional (2D) proximal isovelocity surface area (PISA) equation may increase its reliability. This study sought to evaluate the impact of the corrected 2D PISA method in quantifying FTR severity.

METHODS AND RESULTS

In 102 patients with FTR, we compared both conventional and corrected 2D PISA measurements of effective regurgitant orifice area [EROA vs. corrected (EROAc)] and regurgitant volume (RegVol vs. RegVolc) with those obtained by volumetric method (VM) using three-dimensional echocardiography (3DE), as reference. Both EROAc and RegVolc were larger than EROA (0.29 ± 0.26 vs. 0.22 ± 0.21 cm2; P < 0.001) and RegVol (24.5 ± 20 vs. 18.5 ± 14.25 mL; P < 0.001), respectively. Compared with VM, both EROAc and RegVolc resulted more accurate than EROA [bias = -0.04 cm2, limits of agreement (LOA) ± 0.02 cm2 vs. bias = -0.15 cm2, LOA ± 0.31 cm2] and RegVol (bias = -3.29 mL, LOA ± 2.19 mL vs. bias = -10.9 mL, LOA ± 13.5 mL). Using EROAc and RegVolc, 37% of patients were reclassified in higher grades of FTR severity. Corrected 2D PISA method led to a higher concordance of TR severity grade with the VM method (ĸ = 0.84 vs. ĸ = 0.33 for uncorrected PISA, P < 0.001).

CONCLUSION

Compared with VM by 3DE, the conventional PISA underestimated FTR severity in about 50% of patients. Correction for TV leaflets tethering angle and lower velocity of FTR jet improved 2D PISA accuracy and reclassified more than one-third of the patients.

Prognostic validation of partition values for quantitative parameters to grade functional tricuspid regurgitation severity by conventional echocardiography

AIMS

Quantitative echocardiography parameters are seldom used to grade tricuspid regurgitation (TR) severity due to relative paucity of validation studies and lack of prognostic data. To assess the relationship between TR severity and the composite endpoint of death and hospitalization for congestive heart failure (CHF); and to identify the threshold values of vena contracta width (VCavg), effective regurgitant orifice area (EROA), regurgitant volume (RegVol), and regurgitant fraction (RegFr) to define low, intermediate, and high-risk TR based on patients' outcome data.

METHODS AND RESULTS

A cohort of 296 patients with at least mild TR underwent 2D, 3D, and Doppler echocardiography. We built statistical models (adjusted for age, NYHA class, left ventricular ejection fraction, and pulmonary artery systolic pressure) for VCavg, EROA, RegVol, and RegFr to study their relationships with the hazard of outcome. The tertiles of the derived hazard values defined the threshold values of the quantitative parameters for TR severity grading. During 47-month follow-up, 32 deaths and 72 CHF occurred. Event-free rate was 14%, 48%, and 93% in patients with severe, moderate, and mild TR, respectively. Severe TR was graded as VCavg > 6 mm, EROA > 0.30 cm2, RegVol > 30 mL, and RegF > 45%.

CONCLUSION

This outcome study demonstrates the prognostic value of quantitative parameters of TR severity and provides prognostically meaningful threshold values to grade TR severity in low, intermediate, and high risk.

A Unifying Concept for the Quantitative Assessment of Secondary Mitral Regurgitation

BACKGROUND

Diverging guideline definitions for the quantitative assessment of severe secondary mitral regurgitation (sMR) reflect the lacking link of the sMR spectrum to mortality and has introduced a source of uncertainty and continuing debate.

OBJECTIVES

The current study aimed to define improved risk-thresholds specifically tailored to the complex nature of sMR that provide a unifying solution to the ongoing guideline-controversy.

METHODS

This study enrolled 423 heart failure patients under guideline-directed medical therapy and assessed sMR by effective regurgitant orifice area (EROA), regurgitant volume (RegVol), and regurgitant fraction (RegFrac).

RESULTS

Measures of sMR severity were consistently associated with 5-year mortality with a hazard ratio of 1.42 for a 1-SD increase (95% confidence interval [CI]: 1.25 to 1.63; p < 0.001) for EROA, 1.37 (95% CI: 1.20 to 1.56; p < 0.001) for RegVol, and 1.50 (95% CI: 1.30 to 1.73; p < 0.001) for RegFrac. Results remained statistically significant after bootstrap- or clinical confounder-based adjustment. Spline-curve analyses showed a linearly increasing risk enabling the ability to stratify into low-risk (EROA <20 mm² and RegVol <30 ml), intermediate-risk (EROA 20 to 29 mm² and RegVol 30 to 44 ml), and high-risk (EROA ≥30 mm² and RegVol ≥45 ml) groups. In the intermediate-risk group, a RegFrac ≥50% as indicator for hemodynamic severe sMR was associated with poor outcome (p = 0.017). A unifying concept based on combined assessment of the EROA, the RegVol, and the RegFrac showed a significantly better discrimination compared with the currently established algorithms.

CONCLUSIONS

Risk-based thresholds tailored to the pathophysiological concept of sMR provide a unifying solution to the ongoing guideline controversy. An algorithm based on the combined assessment of the unifying cutoffs for EROA, RegVol, and RegFrac improves risk prediction compared with currently established grading.