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. 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). 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. 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.

中文翻译：

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原发性二尖瓣反流中的心脏逆重塑：二尖瓣置换与二尖瓣修复

在可行的情况下，指南建议根据历史结果研究和经胸超声心动图 (TTE) 逆向重构研究，采用二尖瓣修复 (MVr) 而非二尖瓣置换 (MVR) 来治疗原发性二尖瓣反流 (MR)。与 TTE 相比，心血管磁共振 (CMR) 提供了参考标准双心室评估，其 MR 量化更出色。在原发性 MR 患者中使用系列 CMR，我们旨在研究 MVr 后的心脏逆转重塑和残留 MR 与保留腱索的 MVR。前瞻性招募了 83 名 TTE ≥中重度 MR 的患者。在基线和二尖瓣手术后 6 个月或观察等待时进行 6 分钟步行测试 (6MWT) 和 CMR 成像，包括电影成像、主动脉/肺平面相差成像、T1 图和晚期钆增强 (LGE) 成像（控制组）。72 名患者完成了随访（对照 = 20、MVr = 30 和 MVR = 22）。手术组表现出可比较的基线心脏指数和合并症。6 个月时，MVr 和 MVR 组在 6MWT 距离（分别为 + 57 ± 54 m 与 + 64 ± 76 m，p = 1）、指数左心室舒张末期容积（LVEDVi；− 29 ± 21 ml）方面表现出相当的改善/m2 分别 vs − 37 ± 22 ml/m2，p = 0.584）和左心房容积（分别为 − 23 ± 30 ml/m2 和 − 39 ± 26 ml/m2，p = 0.545）。6 个月时，与对照组相比，MVR 后右心室射血分数（分别为 47 ± 6.1% 与 53 ± 8.0%，p = 0.01）相比 MVR 后（分别为 50 ± 5.7% 与 53 ± 8.0%）较差，p = 0.698）。MVR 导致残余 MR 反流分数 (RF) 低于 MVr（分别为 12 ± 8.0% 和 21 ± 11%，p = 0.022）。弥漫性和局灶性心肌纤维化的基线和随访指数（分别为天然 T1 弛豫时间、细胞外体积和定量 LGE）在组间具有可比性。手术组中指数变量的逐步多元线性回归表明，基线指数二尖瓣反流量是左心室 (LV) 舒张末期逆重塑的唯一多变量预测因子，基线 LVEDVi 是随访 LVEDVi、基线的最显着的独立多变量预测因子将 LV 收缩末期容积指数作为后续 LV 射血分数的唯一多变量预测因子，并将接受 MVR（vs MVr）作为较低残余 MR 的最显着（p < 0.001）基线多变量预测因子。在原发性 MR 中，与 MVr 相比，保留腱索的 MVR 在 6 个月时可提供相当的心脏逆重塑和功能益处。需要进行更大规模的多中心 CMR 研究，如果研究结果得到证实，可能会影响未来的手术实践。