4D Flow CMR in the assessment of residual mitral regurgitation after TEER: correlation with left ventricular reverse remodelling using multiple CMR quantification methods

Abstract Background Transcatheter edge-to-edge repair (TEER) is a validated treatment for severe mitral regurgitation (MR) in high-risk patients. Accurate quantification of residual MR post-procedure remains challenging with echocardiography. Cardiac magnetic resonance (CMR) provides reproducible chambers and valves regurgitation quantification. However, the comparative performance of classical and 4D flow-based MR quantification methods in predicting reverse cardiac remodelling after TEER is not fully established. Purpose To evaluate the relationship between MR quantification by classical and 4D flow CMR methods and left ventricular (LV) reverse remodelling after TEER in a prospective cohort of 50 patients. Methods Fifty consecutive patients undergoing mitral TEER were enrolled in a prospective single-center study and completed 6-month CMR follow-up. MR severity was quantified using classical indirect, 4D flow indirect, and 4D flow direct methods. Reverse LV remodeling was defined as a reduction in LV end-diastolic volume index (LVEDVi) >15%. Associations between MR quantification and remodelling were tested using logistic regression and ROC analysis. Study flow-chart is showed in figure 1. Results Reverse remodelling was observed in 56% of patients. Baseline mitral MR volumes were significantly higher in patients who experienced reverse remodelling, across all quantification methods (p < 0.05). MR quantification using 4D flow showed strong correlation with the classical indirect method for both the 4D flow indirect (r = 0.82) and direct (r = 0.83) approaches. Among all techniques, baseline MR quantified by the classical indirect method demonstrated the highest predictive accuracy for reverse remodelling (AUC = 0.80), followed by 4D flow indirect and direct methods (AUC = 0.74 for both), figure 2. At follow-up, the degree of MR reduction was significantly associated with reverse remodelling when assessed using the classical indirect method (OR = 1.08, 95% CI: 1.01–1.15, p = 0.039) and the 4D flow indirect method (OR = 1.10, 95% CI: 1.03–1.18, p = 0.028). Although the 4D flow direct method proved technically feasible, its performance was limited by post-TEER artifacts and showed only a weak, non-significant association with reverse remodelling (OR ≈ 1.03, 95% CI: 0.99–1.08, p = 0.105). Conclusions CMR-based quantification of MR is associated with reverse LV remodelling after TEER. The classical indirect method offers the best diagnostic performance, with 4D flow indirect analysis representing a robust alternative. Although technically feasible, the 4D flow direct approach is currently less reliable in the post-TEER setting. Integrating multiparametric CMR and 4D flow techniques into routine evaluation may enhance patient selection and outcome prediction in mitral TEER.Figure 1.Study flow-chart Figure 2.Reverse remodelling