纵向应变及峰值应变离散度评价原发性高血压患者左心室收缩功能及同步性

Evaluation of left ventricular systolic function and synchrony in patients with essential hypertension by longitudinal strain and peak strain dispersion

目的探讨纵向峰值应变(longitudinal peak strain,LPS)及应变达峰时间离散度(peak strain dispersion,PSD)评价左室射血分数(left ventricular ejection fraction,LVEF)≥50%的原发性高血压患者左室收缩功能及同步性的临床应用价值。方法选取LVEF≥50%的原发性高血压患者55例,根据左室肥厚标准分为两组:非左室肥厚(non-left ventricular hypertrophy,NLVH)组30例,左室肥厚(left ventricular hypertrophy,LVH)组25例,同期选取30例健康志愿者作为对照组。三组均行经胸二维超声心动图检查,采集连续3个心动周期的左室心尖四腔、三腔、两腔长轴切面二维动态图像。应用分层应变技术测定左室心内膜下、中层、心外膜下、全层心肌收缩期LPS及PSD并进行三组间应变值比较、相关性分析及ROC曲线分析。结果对照组、NLVH组及LVH组各层LPS的绝对值逐渐减低。与对照组比较,NLVH组心内膜下、中层及全层心肌LPS绝对值均减低,差异有统计学意义(P<0.05);心外膜下心肌LPS绝对值略低于对照组,差异无统计学意义(P>0.05);LVH组心内膜下、中层、心外膜下及全层心肌LPS绝对值均减低(P<0.05);与NLVH组比较,LVH组心内膜下及中层心肌LPS绝对值明显减低(P<0.05);两组心外膜下及全层心肌LPS绝对值差异无统计学意义(P>0.05);与对照组比较,NLVH组和LVH组PSD均增加(P<0.05);与NLVH组比较,LVH组PSD增加(P<0.05)。室间隔厚度(inter-ventricular septum thickness,IVSd)与心内膜下、中层、心外膜下、全层心肌LPS均呈负相关(r=-0.537,-0.518,-0.266,-0.471;均P<0.05),左心室后壁厚度(left ventricle posterior wall thickness,LVPWd)与心内膜下、中层、心外膜下、全层心肌LPS均呈负相关(r=-0.539,-0.524,-0.283,-0.478;均P<0.05)。心内膜下、中层、心外膜下、全层心肌LPS及PSD诊断不同左室构型高血压的ROC曲线下面积(AUC)分别为0.685、0.652、0.510、0.623、0.995,最佳分界值分别为-21.70%、-18.90%、-16.95%、-19.45%、46.50 ms,相对应的敏感性分别为94.4%、83.3%、77.8%、94.4%、100%,特异性分别为47.8%、52.2%、39.1%、39.1%、95.7%。结论分层应变技术可定量评价原发性高血压患者心肌纵向应变,为诊断高血压心脏病变、评估左室心肌分层受累程度提供了一种无创检查方法。PSD评价原发性高血压患者左室心肌收缩同步性改变具有一定的优势。

Objective To investigate the clinical application value of longitudinal peak strain(LPS) and peak strain dispersion(PSD) in evaluating left ventricular systolic function and synchrony in patients with essential hypertension. Methods Fifty-five patients with essential hypertension were enrolled, including 30 patients with non-left ventricular hypertrophy (NLVH), 25 patients with left ventricular hypertrophy (LVH), at the same time, 30 healthy volunteers were selected as the control group. Echocardiography was performed in all three groups, and two-dimensional dynamic images of the left ventricular apical four-chamber, three-chamber, and two-chamber′s long-axis views were collected for three consecutive cardiac cycles. The myocardial layer-specific strain was used to measure the LPS of the left ventricular myocardium of subendocardium, the middle layer, the subepicardium, and the myocardial strain and the PSD of the whole myocardial layers. Correlation analysis and ROC curve analysis were performed. Results The LPS in the control group, NLVH group and LVH group were decreased in turn from inner to out myocardial layers.Compared with the control group, the LPS in the subendocardial, middle, subepicardial, and whole myocardial layer of NLVH group were decreased (P<0.05), and the subepicardial myocardial LPS was slightly lower than that in the control group, the difference was not statistically significant (P>0.05). The LPS in the subendocardial, middle, subepicardial, and whole myocardial layer of LVH group were all reduced (P<0.05). Between the NLVH group and LVH group, the declines of the LPS in the subendocardial and middle layer in the LVH group were statistically significant (P<0.05), the LPS in the subepicardial layer and the whole myocardial layer had no significant difference (P>0.05). Compared with the control group, the PSD of the NLVH group and the LVH group increased (P<0.05). Compared with the NLVH group, the PSD of the LVH group increased (P<0.05). Inter-ventricular septum thickness (IVSd) and the LPS in the subendocardial, middle, subepicardial, and whole myocardial layer were negatively correlated (r=-0.537,-0.518,-0.266,-0.471;all P<0.05), left ventricle posterior wall thickness (LVPWd) and the LPS in the subendocardial, middle, subepicardial, and whole myocardial layer were negatively correlated (r=-0.539,-0.524,-0.283,-0.478;all P<0.05). The area under the ROC curve (AUC) of the LPS in the subendocardial, middle, subepicardial, and whole myocardial layer and PSD for the diagnosis of hypertension were 0.685, 0.652, 0.510, 0.623, 0.995, respectively. The cut-off values were -21.70%,-18.90%,-16.95%,-19.45%, 46.50 ms, and the sensitivities were 94.4%, 83.3%, 77.8%, 94.4%, 100%, respectively, and the specificities were 47.8%, 52.2%, 39.1%, 39.1%, 95.7%, respectively. Conclusions The layer-specific strain can quantitatively evaluate myocardial longitudinal strain in patients with essential hypertension, provide a non-invasive test for early diagnosis of hypertensive heart disease, and the evaluation of left ventricular myocardial stratification. PSD for evaluating primary synchronous changes in left ventricular myocardial contraction in patients with hypertension has certain advantages.