Cardiac Remodeling After Transcatheter Tricuspid Valve Replacement: Insights From Multimodality Imaging.

Background
Few studies have evaluated ventricular remodeling following transcatheter tricuspid valve replacement (TTVR) for tricuspid regurgitation.Objectives
The authors sought to describe biventricular structural and functional changes after TTVR.Methods
This single-center, retrospective study included all patients undergoing TTVR. Remodeling was evaluated using transthoracic echocardiographic and cardiac computed tomography (CT). CT measurements included: right ventricular (RV) ejection fraction (RVEF), effective RVEF (forward stroke volume [SV]/right ventricular end-diastolic volume [RVEDV]), RV coupling (SV/right ventricular end-systolic volume [RVESV]), septal curvature analysis and average eccentricity index (aEI) of the mid- and distal left ventricle (LV).Results
Of the 80 TTVR patients included, 87.5% had baseline massive/torrential and 95.9% had ≤mild tricuspid regurgitation post-implantation. Post-TTVR, all transthoracic echocardiographic measures of RV function were reduced (P < 0.001) with an increase in SV and cardiac index (P < 0.001). Paired analysis of 50 patients with pre- and post-CT imaging (performed median of 40 days post-TTVR) showed a 65.3% increase in effective RVEF and 20.3% increase in RV coupling (P < 0.001 for both). RVEDV decreased (138.2 mL/m2 to 59.5 mL/m2; P < 0.001) with increase in LVEDV (49.6 mL/m2 to 57.9 mL/m2; P = 0.001). Septal curvature increased and LV aEI decreased (P < 0.001 for both). Compared with patients with low aEI, patients with baseline greater aEI (≥1.25) showed greater reverse remodeling, lower follow-up NT-proBNP, and greater symptom improvement.Conclusions
Reduction in RVEDV with increase in LVEDV following TTVR is associated with reduction in LV eccentricity with an increase in forward SV. CT measures of RV function (effective RVEF) and RV coupling (SV/RVESV) both improve following TTVR. Patients with baseline higher LV eccentricity may derive more benefits from TTVR.