血流向量成像技术评价梗阻性与非梗阻性肥厚型心肌病左心室内血流流场特征

Evaluation on the left ventricular flow field characteristics in patients with obstructive and non-obstructive hypertrophic cardiomyopathy using vector flow mapping

目的 应用超声血流向量成像（VFM）技术评价梗阻性与非梗阻性肥厚型心肌病（HCM）患者左心室血流流场特点,比较二者的血流动力学状态.方法 随机选取HCM患者40例为病例组,根据有无梗阻将其分为梗阻组（Ⅰ组）和非梗阻组（Ⅱ组）;健康志愿者40例为对照组.测量常规超声心动图参数及VFM参数收缩期总负向流量（SQ-）、收缩期峰值流速（Vs）、峰值流量（Fs）等,比较三组间各参数的差异,并将Ⅰ、Ⅱ组间差异有统计学意义的VFM参数与左室流出道（LVOT）中间段梗阻处的压差做相关性分析.结果 与对照组比较,病例组室间隔厚度、LVOT中间段流速及压差均明显增加（P＜0.05）,三组间左室射血分数差异无统计学意义（P＞0.05）;与对照组比较,病例组基底段SQ-绝对值降低,中间段和心尖段SQ-绝对值增加,基底段、中间段及心尖段Vs及Fs绝对值增加,涡流圈数与强度明显增加,涡流直径明显增大,差异均有统计学意义（P＜0.05）.与Ⅱ组比较,Ⅰ组基底段和心尖段SQ-绝对值减小,中间段SQ-及各节段Vs和Fs绝对值增加,涡流圈数和涡流直径增加,差异有统计学意义（P＜0.05）.Ⅰ组中心尖段Fs、涡流圈数与梗阻处的压差有一定的相关性（r分别为0.60、0.65）.结论 VFM技术能直观显示梗阻性及非梗阻性HCM左室内血流流场的分布特征,且梗阻性HCM心尖段Fs、涡流圈数与梗阻程度有一定相关性,能够量化评估HCM的梗阻程度.

Objective To evaluate the left ventricular flow field characteristics in patients with obstructive and non-obstructive hypertrophic cardiomyopathy （HCM） using vector flow mapping （VFM）,then assess the left ventricular hemodynamics.Methods 40 patients with HCM were randomly selected as case group,among which 20 patients with left ventricular outflow tract（LVOT） obstruction （group Ⅰ） and 20 patients without LVOT obstruction（group Ⅱ）,40 healthy adult volunteers served as control group.The conventional parameters：left ventricular ejection fraction（LVEF）,interventricular septal thickness and radial and pressure gradient of left ventricular outflow tract and VFM parameters：left ventricular peak systolic velocity （Vs）,systolic flow （Fs）,total negative systolic flow （SQ-） and vortex parameters were measured and compared.The correlation between LVOT pressure gradient and VFM parameters were assessed.Results There was no significant difference of LVEF in three groups.Compared with control group,interventricular septal thickness in group Ⅰ and group Ⅱ was much higher（P 〈0.05）.Radius in group Ⅰ was much lower than that of group Ⅱ and pressure gradient of LVOT in group Ⅰ was significantly higher compared with group Ⅱ （P 〈0.05）.Comparison of VFM parameters：①Compared with control group,SQ-of basal segments in case groups were lower （P 〈0.05）,while SQ-of mid and apical segments were higher（P 〈 0.05）,Vs and Fs of all segments increased （P 〈0.05）,and number of vortex,vortex diameter and vorticity of obstruction and non-obstruction groups were higher（P 〈0.05）.②Compared with group Ⅱ,SQ-of basal segments decreased and SQ-of mid and apical segments increased in group Ⅰ,Vs and Fs of all segments were higher.The number of vortex,vortex diameter were higher in group Ⅰ （P 〈 0.05）.③ Correlation analysis：Fs in apex,the number of vortex relatively correlated with press gradient of LVOT（r =0.60,0.65,respectively）.Conclusions VFM can effectively evaluate the flow field characteristics of left ventricle in patients with obstructive and non-obstructive HCM,and Fs in apex,number of vortex were correlated with the degree of obstruction,then further assess the left ventricular hemodynamics quantitively.