Aim: This study sought to investigate the effect of tricuspid regurgitation (TR) reduction on right ventricular (RV) function by using cardiac magnetic resonance (CMR) imaging in patients undergoing transcatheter edge-to-edge repair (TEER).

Background: Severe TR is associated with increased risk of heart failure (HF) hospitalizations and mortality. Recently, TEER has emerged as a new treatment option in patients at high surgical risk. Understanding how the RV adapt to different load conditions is crucial to identify patients who could benefit the most from transcatheter treatment strategies.

Methods: We retrospectively enrolled patients with severe isolated TR and high surgical risk who underwent TEER and CMR imaging before and 12 months after intervention. Global RV dysfunction was defined as CMR-derived RVEF <45%. Successful TEER was defined as a reduction of the TR fraction of at least 15% assessed on CMR at follow-up. The primary outcome was a composite of all-cause mortality or first heart failure hospitalization.

Results: Sixty patients (78 years [75-81]; females 54%) were identified. Repeated CMR revealed a marked reduction in TR fraction (41.5% [27.0 - 48.0] vs. 19.5% [10.5 – 34.5]; p < 0.01) and a slight reduction in RV ejection fraction by 4% (51% [47 – 55] vs. 47% [42 – 53]; p < 0.01). RV end diastolic volume and RV stroke volume decreased (222 ml [198 – 264] vs. 205 ml [165 – 268]; p < 0.01 and 116 ml [93 – 129] vs. 98 ml [79 – 116]; p < 0.01, respectively), whereas effective pulmonary forward flow and cardiac index increased numerically without reaching statistical significance. The change in RVEF was correlated with the change in TR fraction (r = 0.34; p= 0.01; Figure 1). Surprisingly, compared with the non-successful group, only patients with successful TEER (31 [52%]) exhibited a significant reduction in RVEF (50% [46 – 55] vs. 44% [36 – 50]; p < 0.01), accompanied by a reduction of circumferential, and radial strain, with a preservation of longitudinal strain. The composite outcome occurred in 14 patients (median follow-up 413 days). Interestingly, patients with global RV dysfunction (n=12, 20%) tended to display a lower reduction in RV ejection fraction after TEER (global RV dysfunction 41% (38 - 42) vs 39% (33 - 47), p = 0.69; normal RV function 53% (50-56) vs 47% (44-53), p < 0.01) and worst outcome at follow-up (p = 0.036).

Conclusions: Acknowledging the complex interplay of the reduction in preload and the increase in afterload on the RV contraction might help us predicting the capability of the RV to favourably respond to therapy. The observed reduction in RVEF might be interpreted as a reduction of the compensatory increased of circumferential function in an overload condition, thus as a shift to a more compensated state of the Frank–Starling curve.

Figure 1

Figure 1: Relationship between change in Tricuspid Regurgitant Fraction and change in Right Ventricular function