从二尖瓣解剖结构探索容量负荷相关性二尖瓣反流机制

The mechanism of volume-related mitral regurgitation from anatomy of mitral valve

目的从二尖瓣解剖结构探索容量相关性二尖瓣反流的发生机制。方法纳入2018年9月至2019年11月符合标准的室间隔缺损(VSD)伴二尖瓣反流(VSD-MR)患者共32例。相对于心脏轴线的方向:二尖瓣反流束偏离轴线沿左房壁走向为偏心型,反之为中心型。其中,VSD伴偏心型二尖瓣反流(VSD-EMR组)23例,其中男10例、女13例,年龄21(10,56)个月;VSD伴中心型二尖瓣反流(VSD-CMR组)9例,其中男4例、女5例,年龄26(12,87)个月;招募健康儿童9例做为对照组,其中男4例、女5例,年龄49(15,72)个月。分别于术前2周及术后6个月行经胸心脏超声(TTE)检查,评估MR程度,测量各组舒张末期容积(EDV)、收缩末期容积(ESV)、每搏量(SV)、射血分数(EF)、二尖瓣前后交界直径(AP)、瓣环周径(AC)、瓣叶对合处直径(CD)。结果术前VSD-EMR、VSD-CMR组EDV、ESV、SV、AP、AC、CD均较对照组增大,组间比较差异有统计学意义(P<0.05);术后,上述指标均较术前减小。其中,AC与对照组差异有统计学意义(P<0.05),余指标组内比较差异有统计学意义(P<0.05),与对照组相比差异无统计学意义(P>0.05)。术前及术后EF组间、组内差异均无统计学意义(P>0.05)。术后VSD-EMR组二尖瓣反流改善率为78.9%(15/19),VSD-CMR组改善率为100.0%(9/9)。结论容量相关性二尖瓣反流去负荷后,瓣膜结构除瓣环周径外基本恢复正常。VSD-EMR术后二尖瓣反流改善率较VSD-CMR组低,可能提示VSD-EMR反流机制更复杂。

Objective To explore the mechanism of volume-related mitral regurgitation(MR)from the anatomy of mitral valve.Methods A total of 32 patients with ventricular septal defect(VSD)combined MR meeting inclusion criteria in West China Hospital from September 2018 to November 2019 were enrolled in this study.The direction relative to the cardiac axis:the deviation of the MR bundle along the left atrial wall was eccentric,otherwises it was central.There were 23 patients of VSD and eccentric MR(EMR,a VSD-EMR group),including 10 males and 13 females aged 21(10,56)months,and 9 patients of VSD and central MR(CMR,a VSD-CMR group),including 4 males and 5 females aged 26(12,87)months.Besides,9 healthy children were enrolled in a control group,including 4 males and 5 females aged 49(15,72)months.All patients underwent transthoracic echocardiography(TTE)examination at 2 weeks before surgery and 6 months after surgery,respectively,The MR degree,end-diastolic volume(EDV),end-systolic volume(ESV),stroke volume(SV),ejection fraction(EF),antero-posterior diameter(AP),annulus circumference(AC),commissural diameter(CD)were assessed.Results Before operation,EDV,ESV,SV,AP,AC and CD in the VSD-EMR and VSD-CMR groups were significantly larger or longer than those in the control group(P<0.05);after operation,EDV,ESV,SV,AP and CD decreased compared with those before operation(P<0.05),but there was no significant difference compared with the control group(P>0.05).Compared with the control group,AC was slightly decreased(P<0.05).There was no significant difference in EF between and within groups before and after operation(P>0.05).The improvement rate of MR was 78.9%(15/19)in the VSD-EMR group and 100.0%(9/9)in the VSD-CMR group.Conclusion After unloading of volume,the valve structure is back to normal except AC.The improvement rate of MR in the VSD-EMR group is lower than that in the VSD-CMR group,which may indicate that the mechanism of VSD-EMR is more complicated.