Cardiac reverse remodeling in primary mitral regurgitation: mitral valve replacement vs. mitral valve repair

Abstract

Background When feasible, guidelines recommend mitral valve repair (MVr) over mitral valve replacement (MVR) to treat primary mitral regurgitation (MR), based upon historic outcome studies and transthoracic echocardiography (TTE) reverse remodeling studies. Cardiovascular magnetic resonance (CMR) offers reference standard biventricular assessment with superior MR quantification compared to TTE. Using serial CMR in primary MR patients, we aimed to investigate cardiac reverse remodeling and residual MR post-MVr vs MVR with chordal preservation. Methods 83 patients with ≥ moderate-severe MR on TTE were prospectively recruited. 6-min walk tests (6MWT) and CMR imaging including cine imaging, aortic/pulmonary through-plane phase contrast imaging, T1 maps and late-gadolinium-enhanced (LGE) imaging were performed at baseline and 6 months after mitral surgery or watchful waiting (control group). Results 72 patients completed follow-up (Controls = 20, MVr = 30 and MVR = 22). Surgical groups demonstrated comparable baseline cardiac indices and co-morbidities. At 6-months, MVr and MVR groups demonstrated comparable improvements in 6MWT distances (+ 57 ± 54 m vs + 64 ± 76 m respectively, p = 1), reduced indexed left ventricular end-diastolic volumes (LVEDVi; − 29 ± 21 ml/m2 vs − 37 ± 22 ml/m2 respectively, p = 0.584) and left atrial volumes (− 23 ± 30 ml/m2 and − 39 ± 26 ml/m2 respectively, p = 0.545). At 6-months, compared with controls, right ventricular ejection fraction was poorer post-MVr (47 ± 6.1% vs 53 ± 8.0% respectively, p = 0.01) compared to post-MVR (50 ± 5.7% vs 53 ± 8.0% respectively, p = 0.698). MVR resulted in lower residual MR-regurgitant fraction (RF) than MVr (12 ± 8.0% vs 21 ± 11% respectively, p = 0.022). Baseline and follow-up indices of diffuse and focal myocardial fibrosis (Native T1 relaxation times, extra-cellular volume and quantified LGE respectively) were comparable between groups. Stepwise multiple linear regression of indexed variables in the surgical groups demonstrated baseline indexed mitral regurgitant volume as the sole multivariate predictor of left ventricular (LV) end-diastolic reverse remodelling, baseline LVEDVi as the most significant independent multivariate predictor of follow-up LVEDVi, baseline indexed LV end-systolic volume as the sole multivariate predictor of follow-up LV ejection fraction and undergoing MVR (vs MVr) as the most significant (p < 0.001) baseline multivariate predictor of lower residual MR. Conclusion In primary MR, MVR with chordal preservation may offer comparable cardiac reverse remodeling and functional benefits at 6-months when compared to MVr. Larger, multicenter CMR studies are required, which if the findings are confirmed could impact future surgical practice.

Mitral Valve Surgery for Mitral Regurgitation Results in Reduced Left Ventricular Ejection Fraction in Barlow’s Disease as Compared with Fibro-Elastic Deficiency

“…Therefore, disrupting this annulo-ventricular continuity due to the (partial) removal of the subvalvular apparatus during MV replacement is hypothesized to result in less favorable post-operative LV geometry and function compared to MV repair. However, MVR with the preservation of the papillary muscles and/or chordae tendineae is associated with similar post-operative LV reverse remodeling compared to MV repair, as was recently observed by Craven et al [17]. Their findings are in line with our data and subgroup analysis excluding patients without MV subvalvular apparatus preservation, which confirmed that BD was associated with a significantly larger post-operative decrease in LVEF compared to FED.…”

Serial Cardiac Magnetic Resonance Imaging in Patients with Mitral Valve Prolapse—A Single-Center Retrospective Registry

“…However, it cannot be ascertained whether the LGE was directly related to the surgical intervention nor to the ventricular arrhythmias. Two recent prospective studies assessed LV remodeling after mitral valve surgery for primary mitral regurgitation using CMR at the 6-months follow-up [16,17]. Craven et al compared LV remodeling between mitral valve replacement (n = 30) and mitral valve repair (n = 22), but unfortunately the LGE sequences were incomplete or of insufficient quality for direct comparison [17].…”

“…Two recent prospective studies assessed LV remodeling after mitral valve surgery for primary mitral regurgitation using CMR at the 6-months follow-up [16,17]. Craven et al compared LV remodeling between mitral valve replacement (n = 30) and mitral valve repair (n = 22), but unfortunately the LGE sequences were incomplete or of insufficient quality for direct comparison [17]. Liu et al studied 105 patients who underwent mitral valve repair and found no change in LGE before and 8.8 months after mitral valve surgery [16].…”