二维应变显像评价高血压病患者左室收缩应变的跨壁阶差

摘要

目的 应用组织二维应变成像技术检测高血压患者左室心肌内外膜层组织应变特征,评价左心室收缩功能的改变,为早期诊断及治疗高血压心肌病变提供依据.方法 高血压病患者82例(LVN组:左室质量正常,无左室肥厚45例；LVH组:左室肥厚组37例)及健康对照组30例.常规超声心动图检测左心室收缩、舒张功能及左心室心肌质量指数(LVMI).取左心室乳头肌水平将室壁平均分为两层,即心内膜层和心外膜层.获取各节段心肌的纵向应变(SSL)和圆周应变(SSC)的峰值.结果 各组各室壁节段心内膜层心肌收缩期峰值应变均高于心外膜层心肌(P＜0.05).高血压病患者的心内膜层SSL峰值减低,LVH组较LVN组低(P＜0.05).高血压LVN组内膜层SSC较对照组高,LVH组较LVN组和对照组低(P＜0.05).高血压病组患者的心内外膜层应变峰值的比值(跨壁阶差)减低(P＜0.05).结论 二维应变显像技术可早期检测出高血压患者内外膜层心肌应变跨壁阶差的变化,评价心肌局部收缩功能异常具有重要意义.%Objective To explore the characteristics of 2-dimension(2D) strain echocardiography of myocardial strain transmural gradient to assess left ventricle( LV) systolic dysfunction in patients with essential hypertension. Methods 82 hypertension patients were divided into two groups: group LVN(patients with left ventricular normal geometric LVN, n = 45),group LVH (patients with left ventricular hypertrophy LVH, n - 37), as well as 30 age and gender matched healthy volunteers as the control group. M-mode,2-D echocardialgraphy were used to measure the thickness of LV wall, inner diameter of LV, get EF,and calculate LV mass index(LVMI). 2-D strain analysis was carried out by defining the wall as a 2-layer structure with suitable regions of interest, subendocardial(endo) and sub-epicardial(epi) myocardium layers. Systolic longitudinal strain(SSL) and circumferential strain(SSC) were measured from segments at the mid-level LV segments were analyzed offline respectively in the LV long-axis and short-axis views using 2D strain imaging. Results In each group, strain was greater in the subendocardial than that in the sub-epicardial layer. Despite no significant differences in LV ejection fraction (EF) among the three groups, peak SSL of subendocardial layers were significantly decreased in the hypertension groups compared with the control group ( P< 0. 05). The SSC of subendocardial layers in the hypertension LVN groups was higher than that in the control group (P<0. 05) and lower in LVH group compared with group LVN. In hypertension LVH group additional impairment of strain was greater in the endocardial than that in the epicardial layer. The stain transmural gradient in hypertension groups were reduced more than those in control (P<0. 05). Conclusions 2D strain echocardiography is an accurate method to assess the gradient of transmural strain and may be a promising new tool for quantifying hypertension-induced regional myocardial dysfunction.