Giraldi F, Grazi S, Guazzi M D
Istituto di Cardiologia, Universit degli Studi, Centro di Studio per le Ricerche Cardiovascolari del CNR, Centro Centro Cardiologico-Fondzione Monzino, IRCCS, Milano.
Cardiologia. 1998 May;43(5):485-91.
Cardiac troponin-T (Tn-T) and troponin I (Tn-I) isoforms are sensitive and specific tests for the diagnosis of acute myocardial infarction. Information is scanty regarding the ability of these markers to discriminate patients with or without reperfusion early after thrombolytic treatment. To this purpose, 64 patients (mean age 63.7 +/- 7.5 years) with acute myocardial infarction, treated with recombinant tissue-type plasminogen activator within 6 hours from the onset of symptoms, were enrolled in the study. Tn-I was determined by immunofluorescency (Dade, Stratus II) at the beginning of thrombolysis, 30 min after therapy (120 min after starting) and every 6 hours in the first 2 days of acute myocardial infarction. At the same intervals, samples for Tn-T (immunoenzymatic methods ELISA), creatin phosphokinase (CK) and CK-MB (biochemical method) were collected. Normal subjects showed values of Tn-I and Tn-T steadily lower than 0.2 micrograms/l. To evaluate reperfusion, for each parameter the time to peak concentration and the ratio (delta) between the levels of the marker 30 min after thrombolysis vs basal, were considered. Coronary angiography was performed in all patients within 4 days, in 48 patients (Group 1) reperfusion (TIMI grade 2-3) of the involved vessel was reached, in 16 (Group 2) reperfusion was absent (TIMI 0-1). In Group 1, at 30 min after the end of thrombolysis, an increase of cardiac Tn-1 of at least 5.5 times compared to baseline, was observed; In-T, CK and CK-MB reached concentrations at least 7-fold greater than basal ones; in Group 2 patients, no significant variation of concentration of all markers was found. Therefore, in order to discriminate between reperfused and non reperfused patients, cut-off values of the ratio delta of 5.5 for Tn-I and of 7 for Tn-T were chosen. By this method, sensitivity for detection of reperfusion was 95, 80, 54 and 56%; specifically 100, 89, 79 and 82%, respectively. In Group 1 Tn-I peaked earlier than other parameters (9.2 +/- 1.7 vs 12.4 +/- 2.4 hours for Tn-T, p< 0.04 and vs 13 +/- 1.7 hours for CK and CK-MB, p<0.03); the peak of each marker showed the following values of sensitivity and specificity for reperfusion: 86 and 89% for Tn-I, 79 and 82% for Tn-T, 78 and 80% for CK, 83 and 80% for CK-MB. The time to peak of troponins, CK and CK-MB is a sensitive index of reperfusion after thrombolytic therapy in acute myocardial infarction; the delta Tn-I is the earliest marker of reperfusion allowing the assessment of efficacy of treatment within 2 hours after its beginning.
心肌肌钙蛋白T（Tn-T）和肌钙蛋白I（Tn-I）亚型是诊断急性心肌梗死的敏感且特异的检测指标。关于这些标志物在溶栓治疗后早期区分有无再灌注患者能力的信息较少。为此，本研究纳入了64例急性心肌梗死患者（平均年龄63.7±7.5岁），这些患者在症状发作后6小时内接受了重组组织型纤溶酶原激活剂治疗。在溶栓开始时、治疗后30分钟（开始后120分钟）以及急性心肌梗死的头2天每6小时，通过免疫荧光法（达德公司Stratus II）测定Tn-I。在相同时间间隔，采集用于检测Tn-T（免疫酶法ELISA）、肌酸磷酸激酶（CK）和CK-MB（生化法）的样本。正常受试者的Tn-I和Tn-T值稳定低于0.2微克/升。为评估再灌注情况，对于每个参数，考虑达到峰值浓度的时间以及溶栓后30分钟时标志物水平与基线水平的比值（δ）。所有患者在4天内进行冠状动脉造影，48例患者（第1组）受累血管实现了再灌注（TIMI 2-3级），16例患者（第2组）未实现再灌注（TIMI 0-1级）。在第1组，溶栓结束后30分钟时，观察到心肌Tn-1较基线至少增加5.5倍；Tn-I、CK和CK-MB达到的浓度至少比基础浓度高7倍；在第2组患者中，所有标志物的浓度均未发现显著变化。因此，为区分再灌注和未再灌注患者，选择Tn-I的δ比值截断值为5.5，Tn-T的为7。通过这种方法，检测再灌注的敏感性分别为95%、80%、54%和56%；特异性分别为100%、89%、79%和82%。在第1组中，Tn-I比其他参数更早达到峰值（Tn-T为9.2±1.7小时，p<0.04；CK和CK-MB为13±1.7小时，p<0.03）；每个标志物峰值时检测再灌注的敏感性和特异性如下：Tn-I为86%和89%，Tn-T为79%和82%，CK为78%和80%，CK-MB为83%和80%。肌钙蛋白、CK和CK-MB达到峰值的时间是急性心肌梗死溶栓治疗后再灌注的敏感指标；δTn-I是最早的再灌注标志物，可在治疗开始后2小时内评估治疗效果。
