Impact of residual tricuspid regurgitation after transcatheter tricuspid therapies on right and left ventricular mechanics: insights from a case series.

BACKGROUND: Severe tricuspid regurgitation (TR) induces right ventricular (RV) volume overload and disrupts biventricular mechanics. Tricuspid transcatheter edge-to-edge repair (T-TEER) and transcatheter tricuspid valve replacement (TTVR) are effective strategies to reduce or eliminate TR, yet their immediate physiological effects and the impact of residual TR remain incompletely characterized. We used invasive pressure-volume (PV) analysis to assess acute biventricular responses to transcatheter tricuspid valve interventions. CASE SUMMARY: Three patients with severe TR underwent TTVR (n = 1) or T-TEER (n = 2) with invasive RV and left ventricular (LV) PV assessment immediately before and after intervention. In two patients achieving ≤mild residual TR, RV end-diastolic volume decreased (241→205 mL; 81→77 mL), while RV end-systolic pressure increased (32→37 mmHg; 26→32 mmHg). Effective arterial elastance (Ea) increased markedly (0.28→0.50; 0.84→1.33 mmHg/mL), paralleled by increases in end-systolic elastance (Ees) (0.26→0.38; 0.49→0.80 mmHg/mL), consistent with an adaptive contractile response. These changes were accompanied by increased LV end-diastolic volumes (163→176 mL; 68→84 mL) and higher LV/RV volume ratios. In contrast, in the patient with residual moderate-to-severe TR, only modest changes in RV mechanical indices were observed, without an increase in LV preload (102→99 mL). DISCUSSION: Effective TR reduction appears to be a key determinant of acute biventricular adaptation following transcatheter tricuspid valve interventions. Optimal reduction (<moderate TR) is associated with RV volume unloading, increased afterload, and a coupled rise in contractile indices, resulting in improved LV filling. In contrast, suboptimal TR reduction yields limited biventricular benefit.