VFM技术在评估扩张性心肌病患者左室腔内血流能量损耗中的应用

The left ventricular cavity blood flow energy loss in patients with dilated cardiomyopathy as detected by vector flow mapping

目的通过血流向量成像(VFM)来研究扩张性心肌病患者左心室(LV)腔内在等容收缩期(IVC)的血流特征。方法对2015年10月至2016年11月本院收治的58例扩张性心肌病患者(观察组)和56例健康志愿者(对照组)的心尖长轴切面进行彩色多普旋涡勒血流显像。在离线VFM工作站上分析IVC期间的血流信号。结果在IVC开始时,对照组漩涡的面积(15±3)cm^2和流量(36±8)cm^2/s均显著小于观察组[(27±8)cm^2,(45±12)cm^2/s,均P=0.000]。在IVC结束时,两组涡旋流量相似[(28±4)cm^2/s vs.(29±11)cm^2/s,P=0.617],对照组旋涡的面积显著小于观察组[(16±3)cm^2vs.(24±9)cm^2,P=0.000]。在IVC期间,对照组旋涡的面积轻微增加并不显著(P=0.073),但流量明显减少[(10±27)%];观察组旋涡的面积和流量均显著下降,其中流量减少了(29±54)%,与对照组相比,差异有统计学意义(P=0.000)。当主动脉瓣开口时,观察组在LV室的中部和基底部的平均血流速度均显著低于对照组(P<0.05)。在多变量模型中,左心室射血分数减少是IVC期间旋涡面积百分比下降的唯一独立预测因子(P=0.000),QRS宽度(P=0.026)和左心室收缩末期长径(P=0.004)是旋涡流量百分比减少的独立预测因子。结论 VFM技术能够通过旋涡显像更好地评估扩张性心肌病患者的IVC期间LV腔内血流能量损耗的病理生理状态。

Objective To study the characteristics of blood flow in isovolumic systole （IVC） of left ventricular （LV） in patients with dilated cardiomyopathy by flow-vector imaging （VFM）. Methods Color flow Doppler imaging was performed from the apical long-axis view in 58 patients with dilated cardiomyopathy who was admitted in our hospital from October 2015 to November 2016 and 56 healthy volunteers as control. Doppler flow data ob- tained during IVC were analyzed offline with vector flow mapping. Results At the beginning of IVC, the swirl area （ 15 ±3） cm2 and flow （36± 8） cm2/s in the control group were significantly less than those in the observation group （27 ± 8） cm2, （45 ±12） cm2/s, all P = 0.000. At the end of IVC, the vortex flow was similar in both groups [ （28 ± 4） cm2/s vs. （29 ± 11 ） cm2/s, P = 0.617） , and the vortex area in the control group was significantly smaller than that in the observation group [ （ 16 ± 3） cm2 vs. （24± 9） cm2, P = 0.000） ]. During the IVC, the area of the vortex in the control group increased slightly but not significantly （P = 0.073） , bat the flow rate decreased significantly （ 10± 27% ）. The area and volume of the vortex in the observation group decreased significantly with the flow de- creased by 29±54% （P = 0.000 vs. the control group）. When the aortic valve was open, the average blood flow veloc- ity in the middle and basal parts of the LV compartment in the observation group was significantly lower than that in the control group （P 〈0.05）. In multivariate models, a decreased LV ejection fraction was the only independent pre- dictor of the percentage decrease in area of the vortex during the IVC （P 〈 0.001）, and a larger QRS width （P = 0.026） and LV end-systolic long diameter （P = 0.004） were independent predictors of the percentage decrease in flow volume of the vortex. Conclusion The VFM technique enables a better assessment of the pathophysiological state of LV lumen energy loss during IVC in patients with dilated cardiomyopathy by vortex imaging.