Comprehensive Assessment of Mitral Valve Geometry and Cardiac Remodeling With 3-Dimensional Echocardiography After Percutaneous Mitral Valve Repair

MitraClip is a validated treatment for significant mitral regurgitation (MR) in high risk patients. Aims of the study were to evaluate immediate changes in mitral valve (MV) geometry induced by MitraClip and correlations between baseline geometry and cardiac remodeling. Eighty patients undergoing MitraClip for primary (48%) or secondary (52%) MR were enrolled. Intraoperative transesophageal echocardiographic 3D images were acquired immediately before and after the procedure for MV annulus (MVA) morphology analysis. Transthoracic 3D echocardiography was performed pre-operatively and at 6 months follow-up (6MFU). Patients were classified on the basis of MR reduction (ΔMR) at 6MFU as Optimal (ΔMR≥2) or Suboptimal (ΔMR<2). An optimal result was reached in 60 (75%) patients, whereas 20 subjects showed a ΔMR<2 at 6MFU. The Optimal showed significantly smaller baseline MVA (antero-posterior diameter 4.05±0.59 vs. 4.43±0.68cm; anterolateral-posteromedial diameter 4.38±0.56 vs. 4.70±0.73cm; MVA circumference 14.1±1.7 vs. 15.1±2.3cm and 3D area 14.8±3.9 vs. 17.4±5.3cm2), lower sphericity index and non-planar angle compared to Suboptimal. A value of antero-posterior diameter ≥4.44 cm was identified (ROC curve) as a possible cut-off for pre-operative identification of Suboptimal patients. Post-operatively, MitraClip reduced MVA flattening (non-planar angle), sphericity index and size (as expressed by antero-posterior diameter, MVA circumference and area). At 6MFU the Optimal showed significant decrease in left ventricular volumes and pulmonary artery systolic pressure. In conclusion, MitraClip induces remarkable changes in MVA geometry and favorable LV remodeling is detected in patients with optimal mid-term outcome. A pre-procedural antero-posterior diameter <4.44cm seems to be a potential predictor of mid-term optimal result.

经导管二尖瓣夹合器（MitraClip）是一款经临床验证的、用于高危患者重度二尖瓣反流（MR）的治疗手段。本研究旨在评估经导管二尖瓣夹合器（MitraClip）术中即刻引发的二尖瓣（mitral valve，简称MV）几何形态变化，以及基线几何形态与心脏重构之间的相关性。本研究共纳入80例因原发性（48%）或继发性（52%）二尖瓣反流接受经导管二尖瓣夹合器治疗的患者。于手术即刻前后采集术中经食管三维超声心动图图像，用于二尖瓣环（mitral valve annulus，简称MVA）的形态学分析。分别于术前及术后6个月随访（6MFU）时行经胸三维超声心动图检查。研究人员根据患者术后6个月随访时的二尖瓣反流减少量（ΔMR）将其分为最优组（ΔMR≥2）与亚最优组（ΔMR<2）。共有60例（75%）患者达到最优治疗效果，剩余20例患者术后6个月随访时的ΔMR<2。与亚最优组相比，最优组患者的基线二尖瓣环参数显著更小：前后径为4.05±0.59 cm vs 4.43±0.68 cm；前外侧-后内侧径为4.38±0.56 cm vs 4.70±0.73 cm；二尖瓣环周长为14.1±1.7 cm vs 15.1±2.3 cm；三维面积为14.8±3.9 cm² vs 17.4±5.3 cm²；同时其球形指数与非平面角均更低。通过受试者工作特征曲线（ROC曲线）分析确定，术前前后径≥4.44 cm可作为识别亚最优组患者的潜在截断值。术后，经导管二尖瓣夹合器可改善二尖瓣环扁平化（即降低非平面角）、降低球形指数并缩小二尖瓣环尺寸（以前后径、二尖瓣环周长及面积为表征）。术后6个月随访时，最优组患者的左心室容积与肺动脉收缩压均显著降低。综上，经导管二尖瓣夹合器可显著改变二尖瓣环的几何形态，且在获得最优中期治疗效果的患者中可观察到良好的左心室重构。术前前后径<4.44 cm似乎可作为预测中期最优治疗效果的潜在指标。