RESUMO
Objective To determine the biomechanical parameters of left ventricular by using velocity vector imaging (VVI),and to indirectly assess the coronary 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;2 1 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 wall 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 the LV myocardial segment with the coronary stenosis rate ≥ 75%,and GLS had the most sensitivity.The GLS 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.