小剂量多巴酚丁胺试验与肌钙蛋白T预测急性心肌梗死患者左室功能恢复的价值

Prediction of left ventricular function recovery course after successful reperfusion by low dose dobutamine stress echocardiography and cardiac troponin T

目的 分析急性心肌梗死 (AMI)发病后心肌肌钙蛋白T(cTnT)检测和早期小剂量多巴酚丁胺试验 (LDSE)在估计梗死面积、预测左室功能、判断预后方面的价值及两者的相关性。方法 入选AMI患者 46例。男 37例 ,女 9例 ,年龄 33～ 76 (5 5 4± 10 8)岁。其中直接经皮冠状动脉腔内成形术 (PTCA) 35例 ,溶栓治疗 11例。于发病后 12、2 4、48、72h分别采集静脉血 ,以免疫法检测血cTnT的浓度 ,计算cTnT的平均值 (cTnTavg)。发病后 5～ 10d天行小剂量 (5 μg·min-1·kg-1和 10 μg·min-1·kg-1)多巴酚丁胺负荷试验 ,分析给药前后左室功能、室壁运动 ,并计算室壁运动积分 (WMS)和射血分数 (EF) ;每个剂量持续 5min。3个月随访时重复二维超声心动图检查 ,测得EF和WMS。结果 46例患者中 ,LDSE共检出 10 9个心肌运动异常节段 ,其中 6 2个节段为存活心肌 (5 7% ,6 2 / 10 9) ,共有 5 2个节段于 3个月内恢复。cTnTavg≥ 15ng/ml的患者 (B组 ) ,3个月随访时EF值明显小于cTnTavg<15ng/ml的患者 (A组 ) ,而WMS则正好相反 (P <0 .0 1)。接受直接PTCA治疗于发病后 6h内开通梗死相关血管的患者 (2 5例 ) ,cTnTavg及 3个月随访时WMS、EF均明显优于 6h后开通的患者 (10例 )。

Objective To evaluate the role of cardiac troponin T (cTnT) in identifying infarction size, assessing the left ventricular function as well as its correlation with low dose dobutamine stress echocardiography (LDSE) after primary PTCA or thrombolysis. Methods Forty six patients with first acute myocardial infarction were treated by primary PTCA or thrombolysis. Intravenous blood samples were measured sequentially at 12, 24, 48, 72h after the onset of chest pain. LDSE ( 5 μg·min -1 ·kg -1 and 10μg·min -1 ·kg -1 ) was performed 5 to 10 days after acute myocardial infarction. Wall motion abnormality score was measured during the process. Follow up echocardiography was repeated 3 months later. Results There were 109 dyskinetic/akinetic segments. Sixty two segments (57%) were viable by LDSE. Fifty two segments recovered ( or partly recovered ) its function 3 months later. Wall motion abnormality scores of patients with average cTnT <15ng/ml (group A) were lower than that of patients with average cTnT≥15ng/ml (group B) 3 months later ( P <0.01). Furthermore ejection fractions of patients with average cTnT>15ng/ml (group B) were lower than that of patients with average cTnT<15ng/ml (group A) 3 months later ( P <0.01). Patients treated within 6 hours after onset by successful primary PTCA were better compared with those treated after 6 hours (lower wall motion abnormality score, higher ejection fraction and lower average cTnT, P <0.05). Conclusion LDSE and average cTnT are safe and effective methods for detecting myocardial infarction size and predicting left ventricular function recovery course. The two methods are correlated significantly. The earlier the reperfusion of infarction related arteries, the more viable myocardium, and the better recovery of left ventricular function.