超声评估左室流出道梗阻在肥厚型心肌病的临床意义

The value of left ventricular outflow tract obstruction in the diagnosis of hypertrophic cardiomyopathy by echocardiography

目的确定左室流出道梗阻(left ventricular outflow tract obstruction,LVOTO)在肥厚型心肌病(hypertrophic cardiomyopathy,HCM)的临床意义。方法用超声检查了52例HCM患者的压力阶差,以30 mmHg为界限值分为有梗阻组和无梗阻组,在平均随访(5.9±5.7)年后,用生存分析比较了两组患者的死亡率和发病率并确定了压力阶差与临床终末事件的关系。结果与无梗阻的患者相比,有梗阻组的患者猝死的风险是4.6倍(相对危险度4.6;P=0.047),发展为心力衰竭和中风的风险是3.2倍(相对危险度3.2;P=0.049)。校正年龄后的多变量Cox比例风险回归模型显示LVOTO是进入模型的唯一危险因素(猝死,相对危险度4.1,P=0.084;发展为心力衰竭和中风,相对危险度5.2,P=0.040)。结论 LVOTO是HCM患者猝死及发展为心力衰竭与中风的一个唯一的、独立的、较强的危险因素。压力阶差≥30 mmHg在HCM临床治疗决策中有重要意义。

Objective To define the clinical value of subaortic gradient（30mmHg） in the diagnosis of hypertrophic cardiomyopathy（HCM）. Methods Left ventricular outflow tract obstruction, measured as subaortic gradient, among 52 pa-tients with HCM was initially assessed by Echocardiography. Patients were divided into two groups （without obstruction and with obstruction）based on the gradient threshold value of at least 30mmHg. The morbidity and mortality in the two group were followed up for a mean of 5.9＆#177;5.7 years. Their outcome was assessed by survival analysis and the relation between the outflow tract gradient and the clinical end events was also assessed. Results Patients with obstruction had a 4.6 times higher risk of sudden death compared with patients without obstruction （relative risk,：4.1;P=0.047）. The risk of progres-sion to heart failure and stroke was 3.2 times （relative risk, 3.2;P=0.049）higher when compared to those without obstruc-tion. Age-adjusted multivariate Cox analysis showed that LVOTO was an independent risk factor （relative risk for sudden death was 4.1, P=0.084;relative risk for progression to heart failure and stroke, was 5.2, P= 0.040） for unfavourable out-come. Conclusion In patients with HCM, LVOTO is an independent and strong predictor for sudden death and progres-sion to heart failure and stroke. The subaortic gradient of higher than 30 mmHg has important implications in clinical therapeutic decision makings among patients with HCM.