应用血流向量成像技术对高血压患者左心室力学变化的研究

Evaluation of left ventricular hemodynamic changes of patients with hypertension by vector flow mapping

目的应用血流向量成像（VFM）技术评价高血压患者左心室血流动力学变化，探讨血流改变与左心室功能的关系。方法选取高血压组28例和正常对照组26例，分析速度向量图、流线图、涡量图的变化特征，定量测量各时相各节段涡量的演变规律及组间差异。利用双功能多普勒技术获取二尖瓣舒张早期峰值速度（E）、舒张晚期峰值速度（A）、E波减速时间（EDT）、二尖瓣环侧壁舒张早期峰值速度（e’），计算E／A、E／e’，与涡量进行相关性分析。结果①与对照组比较，高血压组左心室收缩及舒张末容积增加（P〈0．05），速度向量图、流线图、涡量图均欠规则。③正常对照组舒张中期呈现中间段〉基底段〉心尖段的趋势（P〈0．05），高血压组舒张中期心尖段涡量最小（P〈0．05），但基底段与中间段差异无统计学意义（P〉0．05），两组其余时相由基底段到心尖段均逐渐降低（P〈0．01）。④与正常对照组比较，高血压组心尖段舒张早期及舒张晚期、中间段收缩晚期涡量增大（P=O．045，P=0．004，P=0．015）。⑤舒张晚期心尖段、中间段及基底段的涡量与E／A负相关（r=-0．310，-0．334，-0．333；P=0．028，0．020，0．021），等容收缩期心尖段涡量与E／e’正相关（r=0．348，P=0．016）。结论VFM技术可直观反映高血压病患者左室血流动力学变化，涡量与心脏舒张功能的评价指标相关。

Objective To investigate the left ventricular hemodynamic changes of patients with hypertension by echocardiography using vector flow mapping （VFM）. Methods Twenty-eight patients with hypertension （hypertension group） and 26 normal subjects （control group） were involved. All the subjects underwent conventional transthoracic echocardiographic examination and VFM on apical 3 chambers view. The evolution of velocity distribution, stream line and vorticity line in left ventricle were observed. Left ventricle was divided into basal, mid and apical segments, in which vorticity parameter （Vmax） were quantitatively measured and analyzed. Its relations to conventional left ventricular parameters （E, A, E/A, EDT, E/e＇） were then analyzed. Results （1）Compared with the control group, LV end-diastolic,end-systolic volumes and E/e＇ significantly increased. The evolution of velocity distribution, stream line and vorticity in the hypertension group was slightly irregular. （2） In mid-diastole phase, vorticity of the control group showed the trend （middle〉 base 〉 apex）（ P 〈0.05）, which wasn＇t shown in hypertension group.In other phases,vorticity of both groups decreased from base to apex （P 〈 0.05）. （3）There were statistically differences in vorticity between the two groups in early diastolic phase,late diastolic phase of apex and late systolic phase of middle （P = 0.045, 0.004, 0.015, respectively）. （4） There were negative correlations between Vmax in late diastolic phase of every segment and E/A （from basal segment to apex： r = -0.310, - 0.334, - 0.333; P = 0.028,0.020,0.021 ）. There was positive correlation between Vm,x in isovolumic contraction time and E/e＇ （ r = 0.348, P = 0.016）. Conclusions VFM can be utilized to analyze left ventricular hemodynamics quantitatively and it may be a good supplement for assessing cardiac diastolic function.