Quantitative tricuspid regurgitation assessment by cardiac magnetic resonance: novel insights

Quantitative methods for tricuspid regurgitation (TR) severity assessment are insufficiently validated. This study aims to assess cardiac magnetic resonance (CMR) quantitation of TR severity and its association with clinical and physiological consequences.

Patients with prospective comprehensive CMR with TR assessment including regurgitant volume and fraction (TRF) were retrospectively identified. Comprehensive clinical, echocardiographic, and laboratory data were collected to assess other markers of TR severity and of TR-related heart-failure (HF), right-sided volumetric characteristics, and prognostic markers. A total of 335 patients were included presenting with a wide range of TR severity [median TRF 21% (13-33%)]. The number of guideline-based echocardiographic signs of severe TR was strongly associated with TRF (P < 0.001). TRF was significantly associated with subjective/objective signs of right-sided HF, including biomarkers of liver dysfunction and CMR-based liver extracellular volume [L-ECV, 36% (32-39%) for TRF > 40%, 31% (28-34%) for TRF 21-40% and 27% (26-30%) for TRF ≤ 20%, P < 0.001]. TRF was associated with maladaptive right-sided remodelling, including right ventricular end-diastolic volume-indexed [RV-EDVi, 117 mL/m2 (99-135 mL/m2) for T-RF > 40%, 98 mL/m2 (79-118 mL/m2)] for TRF 21-40% and 85 mL/m2 (73-103 mL/m2) for TRF ≤ 20%, P < 0.001]. TRF was also strongly associated with prognostic markers of outcomes in TR including TAPSE/PASP ratio [0.38 (0.32-0.46) for TRF > 40%, 0.53 (0.34-0.68) for TRF 21-40% and 0.69 (0.52-0.87) for TRF ≤ 20%, P < 0.001) and the TRISCORE [5 (3-7) for TRF > 40%, 2 (1-3) for TRF 21-40% and 1 (0-2) for TRF ≤ 20%, P < 0.001).

In this all-comers TR cohort, CMR quantification of TR using TRF associated with guideline-based criteria for echocardiographic diagnosis of severe TR. RV remodelling objective right-sided HF signs/symptoms already occurred at TRF thresholds ≥20%, supporting the physiological consequences.