二维应变显像评价缺血心肌节段运动达峰时间的改变

目的 采用超声二维应变显像评价不同狭窄程度冠状动脉供血心肌节段在不同方向上运动达峰时间的改变.方法 140例冠心病患者,经胸采集左室心尖四腔、两腔和长轴观及二尖瓣、乳头肌、心尖短轴观二维图像.根据冠脉造影结果将所有心肌节段分为5组:0级组,供血冠状动脉正常;1级组,冠脉狭窄25%～49%;2级组,冠脉狭窄50%～74%;3级组,冠脉狭窄75%～99%;4级组,冠脉完全闭塞.分析各组心肌节段在纵向运动、径向运动、周向运动到达收缩期峰值应变、收缩末期应变、收缩期峰值应变率、舒张早期峰值应变率、舒张晚期峰值应变率的时间值以及各组心肌节段到达收缩峰扭转角度、收缩峰扭转率、舒张早期峰扭转率和舒张晚期峰扭转率的时间值.采用心率对所有的时间值进行校正.结果 纵向运动:3级组到达舒张早期峰值应变率的时间较0级组明显延迟,4级组到达舒张早期峰值应变率和收缩期峰值应变率的时间较0级1级、2级、3级组均明显延迟.径向运动、周向运动:1级组到达收缩峰值应变的时间、收缩期峰值应变率的时间、舒张早期峰值应变率的时间和舒张晚期峰值应变率的时间早于0级组,而2级组、3级组、4级组上述指标的达峰时间较0级组延迟,3级组较2级组好转,4级组较其他各组均延迟.扭转运动:1级组到达收缩峰扭转角度的时间、收缩期峰扭转率的时间和舒张早期峰扭转率的时间较0级组提前;3级组到达收缩峰扭转角度的时间和舒张早期峰扭转率的时间较2级组明显好转.结论 心肌节段在冠状动脉轻度缺血(25%～49%)时出现短轴方向上运动达峰时间的改变;冠状动脉狭窄≥75%心肌节段在各个方向的运动达峰时间均明显延迟.当冠状动脉狭窄75%～99%时,相应供血心肌节段运动达峰时间的延迟较冠状动脉狭窄50%～74%供血的相应心肌节段显著好转.

Alterations of myocardial regional motion time variance caused by different extent of coronary artery stenosis

Objective To access the alterations of ischemic myocardial regional motion time caused by different extent of coronary artery stenosis by 2D-strain technique. Methods Two-dimensional images were acquired of the standard parasternal and apical (4-chamber,2-chamber and long-axis) views and short-axis views (mitral annulus, papillary muscle and apex) in 140 patients with coronary artery disease. All left ventricular segments were divided into 5 groups according to coronary stenosis seen on angiography:normal,25% -49% ,50% -74% ,75% -99% and 100%. The time to segmental systolic peak strain, systolic peak strain rate, end systolic strain, early diastolic peak strain rate and late diastolic peak strain rate in longitudinal, radial, circumferential directions and the systolic peak rotation, systolic peak rotation rate, early diastolic rotation rate,late diastolic rotation rate were analyzed with EchoPAC offline software. Results In longitudinal direction,compared with normal group,the time to early diastolic peak strain rate of segments with 75% - 99% coronary stenosis increased significantly, the time to systolic peak strain rate, early diastolic peak strain rate of segments with occluded artery were significantly delayed compared with the other 4 groups (P ＜0.05). In radial, circumferential directions, the time to systolic peak strain, systolic peak strain rate,late diastolic peak strain rate of segments with 25% - 49% was shorter than that of normal segments. Those indices for segments with 50% - 74% coronary stenosis were delayed compared with segments with 25% - 49% stenosis, however, those for segments with 75% - 99% coronary stenosis showed some improvement in the comparison with segments with 50% - 74% stenosis. All time indices for segments with occluded arteries were delayed ( P ＜0.05). About rotation, the time to the systolic peak rotation,systolic peak rotation rate,early diastolic peak rotation rate with 25% -49% stenosis was shorter than those of normal segments, the time to systolic peak rotation and early diastolic peak rotation rate for segments with 75% - 99% stenosis improved compared with segments with 50% - 74% stenosis.Conclusions 25% -49% coronary stenosis could lead to alterations of peak myocardial systole and diastole motion time in radial,circumferential and rotation directions,and ≥75% coronary stenosis caused the all 4 directions motion delays. Also the time indices for segments with 75% - 99% coronary stenosis showed some improvement in the comparison with segments with 50% -74% coronary stenosis.