Clinical Investigation
Echocardiography in Valvular Heart Diseases
Refining Severe Tricuspid Regurgitation Definition by Echocardiography with a New Outcomes-Based “Massive” Grade

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Highlights

  • Severity of TR frequently exceeds the current definition of severe.

  • Outcomes-based grading approach could identify patients with higher mortality risk.

  • 284 patients with severe functional TR, defined as vena contracta (VC) ≥0.7 cm.

  • VC > 0.92 cm (”massive” TR) associated with adverse RV remodeling + reduced survival.

Background

Current echocardiographic guidelines recommend that tricuspid regurgitation (TR) severity be graded in three categories, following assessment of specific parameters. Findings from recent trials have shown that the severity of TR frequently far exceeds the current definition of severe. We postulated that a grading approach that emphasizes outcomes could be useful to identify patients with severe TR at increased risk of mortality.

Methods

We identified 284 patients with echocardiograms demonstrating severe functional TR, defined as vena contracta (VC) ≥ 0.7 cm. Demographics and mortality data were obtained from the medical records. Patients were divided into study (n = 122 patients with three-dimensional images) and validation (n = 162) cohorts. The VC was measured in both the right ventricular (RV) inflow and apical four-chamber views and averaged. For the study cohort, tricuspid annular, RV end-diastolic (basal, mid, long axis) dimensions, tricuspid leaflet tenting height and area, RV free-wall longitudinal strain, and RV volumes were measured from two- and three-dimensional data sets. A K-partition algorithm was used in the study cohort to derive a mortality-related cutoff VC value, above which TR was termed “massive.” The ability of this VC cutoff to identify patients at greater mortality risk was then tested in the validation cohort using Kaplan-Meier survival analysis.

Results

In the study cohort, VC > 0.92 cm (massive TR) was optimally associated with worse survival. Tricuspid annular and RV size were larger in the massive group (P < .05), while there were no significant differences in demographics between the TR groups. Importantly, in the independent validation cohort, the above VC cutoff also correlated with increased mortality in the massive group (log-rank P < .05).

Conclusions

Among patients traditionally defined as having severe TR, a subset exists with massive TR, resulting in greater adverse RV remodeling and increased mortality. These patients may derive the greatest benefit from emerging percutaneous therapies.

Section snippets

Patient Population and Study Design

This retrospective study was approved by the Institutional Review Board with a waiver of consent. From our database of patients who were referred for a clinically indicated cardiac ultrasound examinations from January 2010 to January 2018, we identified 284 patients diagnosed with severe TR, defined as a VC ≥ 0.7 cm, in either the RV inflow or apical four-chamber views. The presence of severe TR was confirmed by remeasuring VC (K.Y.K., R.M.L.) in both views. The average VC was used, and in

Results

In the study cohort, the median age was 72.5 years (interquartile range, 59.5-84.75); the majority were female (73%), and there was a high prevalence of atrial fibrillation (47%). The K-partition algorithm yielded a partition value of VC ≤ 0.92 cm to define the severe TR group (n = 79; Figure 2A) and >0.92 cm to define the massive TR group (n = 43; Figure 2B) for a survival probability of P = .043 (Figure 3A). There were no significant differences in baseline demographics between these two

Discussion

The goal of this study was to refine the definition of severe TR based on mortality data, so that this definition could be used in device trials in order to select patients who may derive the most benefit from these emerging therapies and to assess improvement postintervention. The additional VC partition value of 0.92 cm was derived in the study cohort and subsequently tested in a separate validation cohort. Our study not only showed worse survival with a higher degree of massive TR but also

Conclusion

Patients with severe TR defined by current guidelines are not a homogenous population in terms of TR severity or potential outcomes. Within the group of patients with VC ≥ 0.7 cm, currently defined as having severe TR, there are varying degrees of severity and coexisting RV remodeling. When these patients are divided by a VC of 0.92 cm, two distinct categories can be appreciated that have divergent outcomes. The ability to distinguish patients with severe TR at particularly high risk may be

Acknowledgments

We thank Nicole Bell for her help with data management.

References (32)

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Philippe Pibarot, DVM, PhD, served as guest editor for this report.

Conflicts of Interest: None.

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