Prospective Quantification of Tricuspid Regurgitation with Echocardiography vs 4D Flow Cardiac Magnetic Resonance

Introduction Cardiac magnetic resonance (CMR) is a valuable tool in the assessment of valvular disease. However, its utilization in tricuspid regurgitation (TR) evaluation has been limited. We sought to compare TR grading with 4D-CMR and transthoracic echocardiography (TTE). Methods We prospectively recruited patients with ≥moderate TR on TTE to undergo multiparametric CMR with integrated cardiac function and 4D flow assessments using a 1.5-T scanner (Siemens Somatom Aera, Erlangen, Germany). Patients with other severe valvulopathy, end-stage renal disease, or pacemakers were excluded. TR was graded severe on CMR when TR volume ≥45 mL, and/or TR fraction ≥50%. The weighted kappa test was used to assess the agreement in overall TR grading on TTE and MR. Results Fifty-two patients were enrolled (mean age 78.5±7.6 years, 53.8% men). The median interval between CMR and TTE was 2 days (IQR=1-37). The agreement between TTE and CMR-derived TR volume was fair (kappa = 0.28, 95%CI 0.13-0.45), with only 10 of 31 patients (32%) with ≥severe TR on TTE meeting severe TR volume criterion on CMR (TR volume ≥45 ml). There was no agreement between TTE and CMR-derived TR fraction (kappa=0.04, 95%CI 0.13-0.46) with only 3 of 31 patients (13%) with ≥severe TR on TTE meeting severe TR criterion on CMR (TR fraction ≥50%). Conclusion Grading of TR was frequently discordant between TEE and 4D-MRI. Further studies are needed to elucidate the clinical impact of concordant/discordant TR grading on multi-modality imaging.