肥厚型梗阻性心肌病行室间隔心肌切除术后转归的回顾性研究

Prognostic value of left ventricular hypertrophy by magnetic resonance imaging in post-myectomy hypertrophic obstructive cardiomyopathy patients

目的阐明肥厚型梗阻性心肌病(HCM)患者术后左心室质量指数(LVMI)的变化与与室间隔心肌切除术的相关性,进一步确定LVMI预测室间隔心肌切除术后转归的价值。方法回顾性纳入2012年9月至2019年12月中国医学科学院阜外医院完成术前及术后左右1年行心脏核磁检查的HCM患者89例,研究室间隔心肌切除术术前和切除术后的左心室质量(LVM)差与手术切除心肌重量的线性相关性,并进行中远期随访,应用Cox比例风险模型构建术后复合不良心血管事件发生的预测模型,并应用Kaplan-Meier生存分析比较不同LVMI组间的室间隔心肌切除术后中远期转归结果。结果术后LVM较术前显著性下降[(187.9±115.3)g比(153.6.9±99.3)g,P<0.001]。手术前后LVM差值为26.7(3.7,61.5)g,术中切除心肌重量平均为(11.0±5.1)g,两者比较具有统计学差异(P<0.001)。设定术中切除心肌重量为自变量,手术前后LVM差值为因变量,二元线性回归分析统计结果表明,手术前后LVM差值与术中切除心肌重量呈线性相关性(P=0.0112,R=0.268,R2=0.072)。9例(10.1%)患者在平均(43.4.6±20.5)个月的随访期间发生不良复合事件。在Cox比例风险回归模型中,室间隔心肌切除术后最显著的预测因子是CMR测量的LVMI(风险比1.025,95%CI 1.009~1.040,P=0.002)。在接受者操作特征曲线(ROC)分析中,LVMI≥95.1 g/m2可准确预测不良复合事件发生(敏感度77.8%;特异度77.5%;曲线下面积AUC=0.748,P=0.0109)。Kaplan-Meier生存曲线图提示,HCM患者LVMI增高组室间隔心肌切除术后中远期不良复合事件发生率高(P<0.001)。结论心肌切除术后左心室心肌质量消退明显大于术中切除心肌重量,室间隔心肌切除术利于梗阻性HCM患者的左心室逆向重构。术前较高的LVMI是HCM患者心肌切除术后中远期不良事件的独立预测因子。

Objective To establish an extensive retrospective cohort of obstructive hypertrophic cardiomyopathy(HCM)after performing septal myectomy to explore whether septal myectomy treatment could left ventricular mass index(LVMI).Furthermore,to analyze the correlation between the LVMI and the prognosis of patients with obstructive HCM.Methods A total of 89 patients with obstructive HCM who underwent septal myectomy and pre and post-operative cardiac magnetic resonance(CMR)at our center between 2011 and 2016 were restropectivly enrolled at Fuwai Hospital.We reviewed Pre-and postmyectomy left ventricular mass(LVM)were compared.Primary endpoints were all-cause mortality,and composite endpoint included all-cause mortality and adverse cardiovascular events.Survival estimates were calculated by Kaplan-Meier curves with the log-rank test.Results The mean intraoperative resected myocardial weight was(11.0±5.1)g.The difference in LVM before and after surgery was 26.7(3.7,61.5)g,which was statistically different(P<0.001).CMR measurements of septal thickness correlated well with intraoperative resected myocardial weight(P<0.001).Setting the intraoperative resected myocardial weight as the independent variable and the pre-and post-operative LVM difference as the dependent variable,the statistical results of binary linear regression analysis showed that the pre-and postoperative LVM difference(P=0.0112,R2=0.074)was linearly correlated with the intraoperative resected myocardial weight.The regression equation was developed as:pre-and post-operative LVM difference=2.012×intraoperative resected myocardial weight+2.548(R=0.268,R2=0.072).By constructing a Cox proportional risk regression model we found that LVMI were associated with HCM-related mortality after adjusting for multiple variables.Additionally,Kaplan-Meier survival curve plots suggested that patients with obstructive HCM above the LVMI cutoff had lower composite endpoints-free survival(Log-rank:P<0.001).Conclusion An elevated preoperative LVMI suggests adverse ventricular remodeling was an independent predictor of poor composite endpoints-free survival outcomes in patients with obstructive HCM undergoing septal myectomy over a median to long follow-up period.