Background
Significant tricuspid regurgitation (TR) is related to poor prognosis independently of the etiology. TR severity and right ventricular (RV) size and function are determinant in the evaluation of patients with RT and are independently related to outcomes. While TR severity is commonly evaluated with echocardiography (echo), cardiac magnetic resonance (CMR) is the gold standard to study the RV. The association between CMR and echocardiographic measures of quantitative TR is unknown.
Purpose
Our aim was to evaluate the association between the most commonly used methods in both techniques: biplane vena contracta (VC) and effective regurgitant orifice (ERO) parameters evaluated by echo and TR volume (TRV) and TR regurgitant fraction (TRF) by CMR; secondly we aimed to evaluate the prognostic value of each parameter.
Methods
Consecutive patients in stable clinical status with significant TR evaluated in the Heart Valve Clinic between 2015–2018 with a contemporaneous echo and CMR were included. TR severity was evaluated by VC and ERO method, using EPIQ system and by VRF and TRF using a 1.5 Tesla CMR Philips scanner. End-point included cardiovascular mortality, tricuspid valve surgery or heart failure.
Results
A total of 36 patients were included (mean age was 72±7 years, 72% females, 94% functional TR). Both VC and ERO showed moderate to strong and significant correlations with VRF and TRF (table). During a median follow up of 20 months [IQR: 10–29], 38% of the patients reached the combined end point (n=7 developed right heart failure, n=11 underwent tricuspid valve surgery, and n=2 died). Patients with events showed a larger ERO and higher VRF and TRF (p<0.01 for all) and a tendency to larger VC (p=0.06). PISA, VRF and TRF were prognostic factors of the combined endpoint (PISA per 0.1 cm2, HR: 282 [3.9–20362], p=0.01; VC per 1 mm, HR 1.27 [0.98–1.64] p=0.06; VRF per 1ml: HR: 1.02 [1.005–1.025], p=0.003; FRT per 1%, HR: 219.5 [4.8–9897], p=0.06). A value of PISA of 0.42, of VRF of 46 ml and FRV of 43% reached the best accuracy to predicted poor outcomes (p<0.01 for all).
Table 1. Bivariate correlations ERO VC Regurgitant volume by CMR R=0.57, p=0.004 R=0.55, p=0.003 Regurgitant fraction by CMR R=0.61, p<0.001 R=0.56, p=0.01
Conclusion
Validated echocardiographic parameters of TR are significantly correlated with quantitative measures by CMR. PISA by echo, and VRF and FRV by CMR are predictive of impaired prognosis. Further studies confirming our CMR cut-off values of poor outcomes are needed for clinical implementation.
Background
Right ventricle (RV) dysfunction represent an established criteria for intervention in patients with significant tricuspid regurgitation (TR). RV ejection fraction (RVEF) by Cardiac Magnetic Resonance (CMR) is considered the gold standard of RV function; however it is influenced by changes of preload conditions and may remain unaffected until late stages in severe TR. Novel measures of RV function such as RV longitudinal shortening (RV-LS) and effective RV ejection fraction (eRVEF) may be earlier markers of RV dysfunction.
Purpose
To compare the prognostic impact of conventional and novel parameters of RV systolic function.
Methods
Consecutive patients in stable clinical condition evaluated in the Heart Valve Clinic with significant TR (severe, massive or torrential TR) undergoing a CMR study were included. In addition to conventional parameters of biventricular volume and function, RV-LS and eRVEF were assessed as novel parameters of RV function. RV-LS was assessed in the 4-chamber view by measuring the displacement of the tricuspid annulus during the cardiac cycle. The length between the epicardial border of the LV apex and the middle of a line connecting the origins of the tricuspid valve leaflets was measured in both end-systole and end-diastole. Effective RVEF (eRVEF) is a measure of RV global systolic function but corrected by TR volume. Both formulas are represented in figure 1. A combined endpoint of hospital admission due to right heart failure and cardiovascular mortality was defined
Results
75 patients were included in this study (age 75±8 years, 75% female, 91% functional TR) During a median follow-up of 3 years (IQR: 1.4–3.9 years), 39% of the patients (n=29) experienced the combined endpoint. RV-LS and eRVEF identified higher rates of RV dysfunction than RVEF. RV-LS of ≥−14% and eRVEF of ≤34% were associated with impaired prognosis (figure 2). After adjustment of age and LVEF, both eRVEF (adjusted HR per abnormal value: 5.29 95% CI, [2.25–12.4]) and RV-LS (adjusted HR per abnormal value: 3.46, 95% CI, [1.13–9.17]) were significantly associated with outcomes. Among all parameters of RV function, eRVEF was the strongest predictor of outcomes, incremental to RVEF (Δ C-statistic 0.139 [0.040–0.237], p=0.005).
Conclusion
RV function is crucial for determining optimal timing for TR intervention. RV-LS and eRVEF identify higher rates of RV dysfunction beyond RVEF. Among all measures of RV function, eRVEF held the strongest association with outcome, incremental to RVEF.
FUNDunding Acknowledgement
Type of funding sources: None. Figure 1. RV-LS and eRVEF calculation Figure 2. Kaplan Meier Curves
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