摘要

目的：探讨血清心脏肌钙蛋白I(cTnI)在急性心肌梗塞(AMI)中的临床价值。

方法：50例正常人、20例单纯骨骼肌损伤病人、26例慢性肾功能不全透析病人、92例AMI病人［39例直接经皮冠状动脉腔内成形术(PTCA)，26例溶栓，27例未PTCA未溶栓］。AMI病人系列采血测定cTnI和激酸激酶及其同功酶MB(CK-MB)，直接PTCA和溶栓再通的AMI病人于入院后15～30天用核素心肌显像测定心肌梗塞面积指数，超声心动图测定左心室射血分数(LVEF)。

结果：①cTnI诊断AMI敏感性、特异性和准确性均为100%，特异性高于cTnT和CK-MB;AMI时，cTnI升高时间和高峰时间与CK-MB平行，持续时间明显延长；cTnI的释放受血管再通的影响，以峰值时间≤均数±标准差为标准判定AMI溶栓再通，cTnI与CK-MB价值相当。②cTnI峰值与梗塞面积指数呈正相关，与LVEF呈负相关，相关性好于CK-MB峰值。168小时累加∑cTnI与梗塞面积指数相关性比cTnI峰值明显提高。③再灌注治疗2小时后cTnI上升速率，直接PTCA组明显高于溶栓再通组，PTCA组梗塞面积指数明显低于溶栓再通组。

结论：血清cTnI是诊断AMI高度敏感、高度特异的指标，特异性最佳；其峰值时间改变对溶栓疗效判定具有与CK-MB可比的判定价值；cTnI峰值和168小时内累加值可作为判断AMI时梗塞面积、左心室功能和预后的参考指标；直接PTCA与溶栓效果比较，PTCA可及早开通闭塞冠状动脉，及时挽救濒死心肌，缩小梗塞面积，改善预后。

Clinical Value of Serum Cardiac Troponin I in Patients with Acute Myocardial Infarction

The Heart Center, Beijing Red Cross Chaoyang Hospital, The Institute of Cardiovascular Disease,

Capital University of Medical Sciences, Beijing (100020)

Li Jing, Hu Dayi, Xu Zhimin, et al.

Abstract

Objective: To evaluate the diagnostic value of cTnI in acute myocardial infarction (AMI) patients.

Methods: The patient population consisted of 50 healthy persons, 20 patients with simple skeletal muscle injury (SMI), 26 patients treated by hemodialysis for chronic renal failure (CRF), 92 AMI patients (39 receivinjg primary PTCA, 26 receiving venous thrombolysis and 27 neither). Blood samples were collected serially in AMI patients. Within 15～30 days after admission, ^99mTc-MIBI myocardial single photon emission computed tomography (SPECT) was performed to assess the infarct size index and UCG was used to determine left ventricular ejection fraction (LVEF) in AMI patients who received successful primary PTCA or thrombolysis.

Results: ① cTnI elevated in all AMI patients, but normal in SMI and CHF patients. The myocardium-specificity of cTnI was higher than that of cTnI and CK-MB. ② The time-courses of cTnI release were mainly monophasic in form (97.8%). In the reperfusion group after thrombolysis, the time to elevation and time to peak value for cTnI was 4～6 h and 12～16 h after onset of symptom respectively, the plotted line was parallel to what of CK-MB, and cTnI elevation lasted 7～10 days, longer than CK-MB (p＜0.01). In the non-reperfusion and non-thrombolysis group, the time to cTnI peak appeared at abount 24 h and lasted 10～14 days. ③ Using the time to the peak ≤mean±standard deviation as criteria, the sensitivity, specificity and accuracy in predicting resperfusion after thrombolysis were 72.7%, 75% and 73.1% respectively for the time to cTnI peak ≤18 h, while 63.6%, 75% and 65.4% respectively for the time to the peak of CK-MB peak ≤14 h. ④ Serum cTnI peak value showed positive correlation with the infarct size index (r=0.44, p＜0.01) and negative correlation with LVEF (r=-0.39, p＜0.05). The correlation was better than CK-MB peak value (r=0.36, r=-0.16 respectively) (p＜0.05). The correlation between cumulative cTnI concentration in 168 h from onset of symptom (∑cTnI) and MI size index (r=0.72) was significantly higher than cTnI peak value (p＜0.01). ⑤ Increasing rate of cTnI 2 h after primary PTCA was significantly higher than that after throbolysis (p＜0.01). In the PTCA group, infarct size index (0.24±0.07) was significantly lower than that in the thrombolysis group (0.35±0.08), p＜0.01.

Conclusion: ① cTnI is a highly sensitive and specific marker for assessment of myocardial damage, and its specificity is the best particularly. ② The change of the time to the peak of cTnI has comparably predictive value with that of CK-MB in evaluating the efficiency of thrombolysis. ③ Peak and cumulative value of cTnI in 168 h from onset of AMI is a reference index for estimating infarct size, heart function and prognosis. ④ Compared with thrombolysis therapy, primary PTCA reopens the infarct-related artery more timely and saves the dying myocardium more effectively.

Key wordsCardiac troponin I; Acute myocardial infarction; Thrombolysis; Primary Percutaneous transluminal coronary angioplasty; Reperfusion; Diagnosis

肌酸激酶及其同功酶MB(CK-MB)一直是诊断急性心肌梗塞(AMI)的重要指标，诊断敏感性及特异性都比较好。然而，CK-MB并非心脏所特有的酶，正常人骨骼肌中也有少量CK-MB，且CK-MB诊断窗口时间短，这些因素使CK-MB的应用受到限制。血清心脏肌钙蛋白I(cTnI)是心脏结构蛋白，由于它在个体发育的各个阶段均不在骨骼肌中表达，使其成为心脏的特异性抗原。本研究旨在对cTnI诊断AMI的敏感性、特异性、释放动力学、对溶栓疗效的判定价值、与梗塞面积、左心室功能及预后的关系进行探讨，并对溶栓疗法及直接经皮冠状动脉腔内成形术(PTCA)疗法的疗效进行了比较。

1资料与方法

研究对象正常对照组：50例体检正常的健康人，无冠心病，年龄19～86岁(50.1±16.6岁)，男33例，女17例；单纯骨骼肌损伤组：20例无胸部损伤的复合外伤，四肢骨折或骨科手术术后患者，年龄25～69岁(41.8±16.5岁)，男15例，女5例，既往无冠心病史，心电图检查正常。肾功能不全组：慢性肾功能不全肾透析病人26例，男9例，女17例，年龄35～72岁(50.7±12.2岁)，经病史、体征、心电图及超声心动图检查除外冠心病。急性心肌梗塞组(AMI组)：1997年11月～1998年8月连续收入我院CCU并确诊为AMI的病人92例，年龄40～87岁(66.6±10.3岁)，男67例，女25例，其中26例接受静脉溶栓治疗，39例接受直接PTCA治疗，27例因来院已晚未行溶栓或直接PTCA治疗。溶栓再通按中华心血管病杂志编委会于1996年推荐方案中的再通标准判定，22例溶栓后再通，4例未通。

方法生化标志物测定：血清cTnI测定为取静脉血2 ml,离心(2 500 r/min,10分钟)分离血清后，使用Behring公司提供的OPUS自动生化分析仪(免疫荧光分析系统)及其全套试剂盒，以双抗体夹心ELISA法测定。本实验室cTnI测定的批内变异＜5%,批间变异＜5%。血清CK-MB测定，采用免疫抑制酶动力学方法，比色测定CK-MB活性。血清cTnT测定，采用宝灵曼公司的ES 300分析仪及全套试剂盒，以ELISA法测定。

采血方法：正常对照组取血1次，骨骼肌损伤组于外伤后8小时或术后当天内取血1次，肾功能不全组透析病人于透析前取血1次，病例组于入院后即刻(或溶栓前)、发病后第2、4、6、8、12、16、20、24、48、72、96、120、144、168、240、336小时取血。

梗塞面积指数及心功能测定：溶栓再通和接受直接PTCA的AMI患者于入院后15～30天采用^99m锝-甲氧基异丁基异晴(^99mTc-MIBI)心肌核素断层显像后用圆周剖面定量法计算梗塞面积指数。采用二维超声心动图测定左心室功能即左心室射血分数(LVEF)。

统计方法：数值以均数±标准差表示。两组间比较用t检验，率间比较用χ²检验，血清cTnI、CK-MB与梗塞面积指数、LVEF比较采用直线相关回归分析，P＜0.05为具有统计学意义。

2结果

2.1正常对照组,血清cTnI浓度为0.53±0.12 μg/L,按95%可信限，本实验室血清cTnI上限为0.77 μg/L。CK-MB参考值为0～10 IU/L,cTnT上限为0.20 μg/L。单纯骨骼肌损伤病人中有7例CK-MB升高，cTnI和cTnT均在正常范围内。慢性肾功能不全患者，5例cTnT升高，浓度为0.59±0.33 μg/L,cTnT和CK-MB均正常。

2.292例AMI病人，cTnI、cTnT及CK-MB均增高，与单纯骨骼肌损伤组进行比较，计算可得cTnT诊断心肌梗塞特异性、敏感性和准确性均为100%，cTnT与cTnI相同，以上指标亦均为100%，CK-MB特异性为65%、敏感<