Abstract:

Objective To determine  the biomechanical parameters of left ventricular by using  velocity vector imaging(VVI),and  to indirectly assess the  coron
ary artery stenosis  with  VVI in the patients with  coronary artery disease(CAD).Methods 52 patients  who had one coronary artery lesions at least diagnosed
by coronary angiography (CAG)  were divided into coronary artery mild stenosis group and severe stenosis group;21 patients in mild stenosis group had one coronary stenosis <75%;31 patients in  severe stenosis group had one coronary artery stenosis ≥ 75% at least.At the same time,20 cases of normal people without coronary artery stenosis showed by CAG were selected as normal control group.VVI  was used to  detect  the  left ventricular wal
l segments of the overall longitudinal strain (GLS),the overall circumferential strain (GCS) and the overall radial strain (GRS).Results
The absolute values of GLS,GRS,GCS of the patients in  mild and severe coronary artery stenosis groups were significantly decreased  than those in  normal control group(P<0.05),and the strain parameters in severe stenosis group were  decreased more significantly,there  were
significant differences compared  mild stenosis group  (P<0.05).The  distribution of the segments with decreased longitudinal strain  matched  t
he LV myocardial segment with the coronary stenosis rate ≥ 75%,and GLS had  the most sensitivity.TheGLS   in normal control group,mild stenosis group and severe stenosis group were negatively correlated to left ventricular ejection fraction (LVEF) (r=－0.58,P<0.05;r=－0.51,P<0.05;r=－0.43,
P<0.05).GLS-16.14 %  was used to  assess  the  severe coronary artery stenosis with requiring  the implementation of PTCA treatment  as the diagnostic cut-off point with  sensitivity 96.8%,specificity of 70%,the highest Yuedden index  0.668. Conclusion The decreasing of left ventricular strain could be detected by VVI,which  suggests that   severe coronary artery stenosis exists in coronary artery;the distribution of the segments with significantly decreased strains
    can be used to assess the  coronary lesions and stenosis degrees.

Key words: velocity vector , imaging;velocity , strain;left ventricle coronary artery stenosis