心肌肌钙蛋白T对冠状动脉旁路移植术患者围术期心肌梗死的诊断意义

The Significance of Cardiac Troponin T to the Diagnosis of Myocardial Damage in Coronary Artery Bypass Grafting

目的：观察心肌肌钙蛋白T（cTnT）与肌酸激酶同功酶（CK-MB）在冠状动脉旁路移植（CABG）术围术期变化,比较两者对心肌损伤的诊断差异,研究cTnT对CABG术围术期心肌梗死的诊断意义。方法：连续152例患者在心脏停跳体外循环下行CABG术,平均年龄62.5±20.7（39~80）岁,平均每例移植血管2.7（1~5）支,平均心肺转流（CPB）时间113±54min,平均主动脉阻断时间56±31min。围术期9个时间点取静脉血标本,测定cTnT与CK-MB。结果：cTnT与CK-MB均于主动阻断钳开放后明显升高,开放后10h达峰值。CK-MB术后5d恢复至术前水平,而cTnT术后10d才恢复至术前水平。13例围术期心肌梗死（PMI）患者术后各时间点所测cTnT均显著高于无PMI者,术后10h达峰值,为2.97±1.12μg.L-1,且术后10d仍明显高于正常范围,为0.87±0.31μg.L-1,其中有7例术后因PMI而死亡。而无PMI者,无1例因心脏原因死亡。结论：cTnT与CK-MB在CABG术后前期的动态变化相似,但cTnT高于正常值的持续时间长,对心肌缺血损伤诊断时间窗宽于CK-MB。因此,cTnT诊断心肌损伤的晚期敏感性高于CK-MB。围术期cTnT的检测是诊断PMI高度敏感性指标,也是预测CABG术后发生PMI及预后的可靠指标。

Objective：To investigate the perioperative release of cardiac troponin T（cTnT） and creatine kinase-MB isoenzyme（CK-MB） and their efficacy and differences in diagnosing myocardial injury in coronary artery bypass grafting（CABG）.Methods： From Jun.2006 to Oct.2009,in 152 patients,activity of cTnT and CK-MB in serum were analyzed before and after operation at 9 different time intervals.Their mean age was 62.5±20.7（39～80）years old.The average number of graft was 2.7（1～5） per patient,mean CPB time was（113±54） minutes and aortic cross-clamping time was（56±31）minutes.Results： The concentration of cTnT and CK-MB both elevated after aortic cross-clamping release and reached peak（0.49±0.23 μg/L,56.3±28.6 IU/L each other）after 10 hours of cross-clamping release.Five days later of operation,CK-MB resumed to level of preoperation.But cTnT needed 10 days for that.cTnT in 13 patients with perioperative myocardial infarction（PMI） was significantly higher than that of non-PMI during the perioperative period（P0.001） and its peak were 2.97±1.12 μg/L after 10 hours of cross-clamping release.Ten days after operation,it was still higher than the normal level（0.87±0.31 μg/L）.Seven of these 13 patients died of PMI after operation.But in non-PMI patients,no one die of cardiac cause.Conclusions：The change of cTnT and CK-MB is the similar at the preceding stage after coronary artery bypass grafting.But the time which cTnT is higher than the normal level is longer than that of CK-MB.Because of the better sensitivity and specificity than CK-MB,cTnT is the more reliable biochemical marker to diagnose myocardial damage and to predict PMI and the prognosis of coronary artery bypass grafting.