Benefit of abciximab in patients with refractory unstable angina in relation to serum troponin T levels. c7E3 Fab Antiplatelet Therapy in Unstable Refractory Angina (CAPTURE) Study Investigators.

BACKGROUND: In patients with refractory unstable angina, the platelet glycoprotein IIb/IIIa-receptor antibody abciximab reduces the incidence of cardiac events before and during coronary angioplasty. We investigated whether serum troponin T levels identify patients most likely to benefit from therapy with this drug. METHODS: Among 1265 patients with unstable angina who were enrolled in the c7E3 Fab Antiplatelet Therapy in Unstable Refractory Angina (CAPTURE) trial, serum samples drawn at the time of randomization to abciximab or placebo were available from 890 patients; we used these samples for the determination of troponin T and creatine kinase MB levels. Patients with postinfarction angina were not included. RESULTS: Serum troponin T levels at the time of study entry were elevated (above 0.1 ng per milliliter) in 275 patients (30.9 percent). Among patients receiving placebo, the risk of death or nonfatal myocardial infarction was related to troponin T levels. The six-month cumulative event rate was 23.9 percent among patients with elevated troponin T levels, as compared with 7.5 percent among patients without elevated troponin T levels (P<0.001). Among patients treated with abciximab, the respective six-month event rates were 9.5 percent for patients with elevated troponin T levels and 9.4 percent for those without elevated levels. As compared with placebo, the relative risk of death or nonfatal myocardial infarction associated with treatment with abciximab in patients with elevated troponin T levels was 0.32 (95 percent confidence interval, 0.14 to 0.62; P=0.002). The lower event rates in patients receiving abciximab were attributable to a reduction in the rate of myocardial infarction (odds ratio, 0.23; 95 percent confidence interval, 0.12 to 0.49; P<0.001). In patients without elevated troponin T levels, there was no benefit of treatment with respect to the relative risk of death or myocardial infarction at six months (odds ratio, 1.26; 95 percent confidence interval, 0.74 to 2.31; P=0.47). CONCLUSIONS: The serum troponin T level, which is considered to be a surrogate marker for thrombus formation, identifies a high-risk subgroup of patients with refractory unstable angina suitable for coronary angioplasty who will particularly benefit from antiplatelet treatment with abciximab.     

Pregnancy-associated plasma protein A as a marker of acute coronary syndromes

BACKGROUND: Circulating markers indicating the instability of atherosclerotic plaques could have diagnostic value in unstable angina or acute myocardial infarction. We evaluated pregnancy-associated plasma protein A (PAPP-A), a potentially proatherosclerotic metalloproteinase, as a marker of acute coronary syndromes. METHODS: We examined the level of expression of PAPP-A in eight culprit unstable coronary plaques and four stable plaques from eight patients who had died suddenly of cardiac causes. We also measured circulating levels of PAPP-A, C-reactive protein, and insulin-like growth factor I (IGF-I) in 17 patients with acute myocardial infarction, 20 with unstable angina, 19 with stable angina, and 13 controls without atherosclerosis. RESULTS: PAPP-A was abundantly expressed in plaque cells and extracellular matrix of ruptured and eroded unstable plaques, but not in stable plaques. Circulating PAPP-A levels were significantly higher in patients with unstable angina or acute myocardial infarction than in patients with stable angina and controls (P<0.001). A PAPP-A threshold value of 10 mlU per liter identified patients who had acute coronary syndromes with a sensitivity of 89.2 percent and a specificity of 81.3 percent. PAPP-A levels correlated with levels of C-reactive protein and free IGF-I, but not with markers of myocardial injury (troponin I and the MB isoform of creatine kinase). CONCLUSIONS: PAPP-A is present in unstable plaques, and circulating levels are elevated in acute coronary syndromes; these increased levels may reflect the instability of atherosclerotic plaques. PAPP-A is a new candidate marker of unstable angina and acute myocardial infarction.     

急性心肌梗死患者务清肌钙蛋白T和C反应蛋白变化及其意义

目的：评价血汪肌钙蛋白T（TnT）和C反应蛋白（CRP）在急性心肌梗死（AMI）和不稳定型心绞痛（UAP）的早期诊断及预后评价。方法：分析了AMI48例，UAP45例及健康对照36人血清CRP、TnT、肌酸激酶（CK）和同工酶（CK－MB）水平，并对结果行配对χ^2检验。结果：AMI组入院时血清CRP和TnT阳性率分别为81．3％和97．9％，均明显高于同时间CK和CK－MB的阳性率（p均＜0．01）；UAP组血清CRP、TnT、CK及CK－MB阳性率分别为42．2％、13．3％、11．1％及6．7％。健康对照组36例四项指标均无1例阳性。结论：TnT和CRP在早期辅助诊断AMI和评估UAP患者预后中有应用价值，CK、CK－MB和CRP、TnT联合测定可以提高对AMI诊断的准确性。     

The creatine kinase system in normal and diseased human myocardium

We measured creatine kinase activity, isozyme composition, and total creatine content in biopsy samples of left ventricular myocardium from 34 adults in four groups: subjects with normal left ventricles, patients with left ventricular hypertrophy due to aortic stenosis, patients with coronary artery disease without left ventricular hypertrophy, and patients with coronary artery disease and left ventricular hypertrophy due to aortic stenosis. As compared with specimens of normal left ventricles, those from all patients with left ventricular hypertrophy had lower creatine kinase activity, higher MB creatine kinase isozyme content and activity, and lower creatine content. Specimens from the patients without left ventricular hypertrophy had normal creatine kinase activity, increased MB creatine kinase isozyme content and activity, and decreased total creatine content. The normal ventricles showed almost no MB isozyme content or activity. These data suggest that changes in the creatine kinase system occur in both pressure-overload hypertrophy and coronary artery disease. Patients with myocardial infarction who have mild or no preexisting fixed coronary artery disease or pressure-overload hypertrophy would not be expected to have elevation of serum MB creatine kinase.     

Reliability and significance of increased creatine kinase MB isoenzyme in the serum of uremic patients

The authors quantified creatine kinase MB (CK-MB) isoenzyme activity and mass in the serum of 81 uremic and 20 nonuremic (control) patients who had no clinical or electrocardiographic evidence of acute myocardial infarction. CK-MB was quantified by three methods: electrophoresis, the QuiCK-MB (International Immunoassay Labs), and the Tandem-E CK-MB (Hybritech, Inc.). The authors then followed all uremic patients for subsequent hospitalization for cardiac disease. Median CK-MB was increased in the serum of the uremic patients as compared with the control patients by all methods. Most uremic patients had CK-MB in serum above the median CK-MB of the control group. Seventeen (21%) uremic patients had CK-MB in serum elevated above the reference range by at least one method. All control patients had CK-MB in the serum within the reference range. Twelve of 81 (15%) uremic patients have subsequently developed acute myocardial infarction (six patients; four died) or angina pectoris (six patients; one died). Eleven patients were specifically hospitalized for cardiac symptoms. One patient had acute myocardial infarction three weeks after renal transplant. With the use of the chi-square test and 2 X 2 contingency tables, patients with CK-MB in serum above 5 U/L by electrophoresis (chi 2 = 5.47; P less than 0.05) or at least 2.9 EU/L by the QuiCK-MB (chi 2 = 6.56; P less than 0.01) appeared to be at increased risk of subsequent hospitalization. The authors conclude that a slight increase of CK-MB in serum is found in most uremic patients. However, CK-MB elevated above reference range in the serum of uremic patients without clinical or electrocardiographic evidence of acute myocardial infarction is not common. When found, elevated CK-MB isoenzyme appears to be associated with an increased risk of subsequent cardiac disease. Therefore, quantification of CK-MB in the serum of uremic patients is more reliable than is implied in the literature.     

Positive troponin T without cardiac involvement in inclusion body myositis

Cardiac troponin T (cTnT) is considered as a specific marker for acute myocardial infarction. Here, we present a case with elevated cTnT, determined by a third-generation assay, without signs of a myocardial lesion. Routine investigation of a 66-year-old female patient with indolent B-cell lymphoma revealed increased serum levels of creatine kinase (CK), MB fraction of CK (CK-MB), and cTnT, although she did not complain of cardiac symptoms. Electrocardiographic monitoring, echocardiography, magnetic resonance computed angiography, and percutaneous coronary angiography excluded myocardial damage. However, the close follow-up showed a steady increase of CK-MB and cTnT levels and gradual development of weakness in both thighs. A biopsy of the right quadriceps muscle led to the diagnosis of inclusion body myositis. In contrast to cTnT, cardiac troponin I could not be detected retrospectively in any of her serum samples. These results demonstrate for the first time that cTnT is elevated in patients with inclusion body myositis.     

Strategies for the early diagnosis of acute myocardial infarction using biochemical markers

We evaluated different diagnostic strategies for the early diagnosis of acute myocardial infarction, combining sensitivity and specificity of different markers evaluated singly and using combination testing in parallel and serial modes. Myoglobin, cardiac troponin I (TnI), creatine kinase (CK), and CK-MB mass were tested in blood samples from 26 patients with acute myocardial infarction collected at admission (T0; mean = 3.3 hours from the onset of chest pain) and 3 and 6 hours later. The comparison group was made up of 70 patients with renal failure, skeletal muscle diseases, stable angina, unstable angina, and chest pain of nonischemic origin. Single tests showed different sensitivities in relation to the different release kinetics; myoglobin was the most sensitive (69% at T0) although less specific (46%), and TnI showed the highest specificity (90%) and a sensitivity of 54%. Combination testing in a parallel mode using myoglobin and TnI or CK-MB had the same sensitivity and specificity as myoglobin tested singly. The best combination in a serial mode is myoglobin and TnI (at T0 sensitivity, 54%; specificity, 98%), as confirmed by the analysis of the positive predictive value, the negative predictive value, and the accuracy evaluated as a function of different disease prevalences.     

Circulating CK-MB and CK-BB isoenzyme after gastrointestinal surgery.

The effect of gastrointestinal surgery on serum creatine kinase activity was studied in 30 patients. The MB isoenzyme was demonstrated in sera of 30% of the patients and BB isoenzyme in 23%. MB content varied from 0.8 to 10.3% of the total creatine kinase activity, and the BB content from 0.6 to 18.4%. The CK-BB was probably of gastrointestinal origin, since gastrointestinal tract contains high CK activity with BB isoenzyme predominating. A cardiac origin for the observed serum CK-MB isoenzyme increase would seem the most likely, although no patients showed evidence of electrocardiographic changes. Increased CK-MB activity has been observed in myocardial ischaemia without infarction.     

Protective effects of aspirin against acute myocardial infarction and death in men with unstable angina. Results of a Veterans Administration Cooperative Study

We conducted a multicenter, double-blind, placebo-controlled randomized trial of aspirin treatment (324 mg in buffered solution daily) for 12 weeks in 1266 men with unstable angina (625 taking aspirin and 641 placebo). The principal end points were death and acute myocardial infarction diagnosed by the presence of creatine kinase MB or pathologic Q-wave changes on electrocardiograms. The incidence of death or acute myocardial infarction was 51 per cent lower in the aspirin group than in the placebo group: 31 patients (5.0 per cent) as compared with 65 (10.1 per cent); P = 0.0005. Nonfatal acute myocardial infarction was 51 per cent lower in the aspirin group: 21 patients (3.4 per cent) as compared with 44 (6.9 per cent); P = 0.005. The reduction in mortality in the aspirin group was also 51 per cent--10 patients (1.6 per cent) as compared with 21 (3.3 per cent)--although it was not statistically significant; P = 0.054. There was no difference in gastrointestinal symptoms or evidence of blood loss between the treatment and control groups. Our data show that aspirin has a protective effect against acute myocardial infarction in men with unstable angina, and they suggest a similar effect on mortality.     

新一代肌钙蛋白Ⅰ和T对急性心肌梗死诊断的比较研究

为比较新一代肌钙蛋白I(cTnI)和T(cTnT)水平在急性心肌梗死(AMI)早期的诊断价值, 用Access化学发光仪和Elecsys电化学发光仪, 分别检测126例疑为急性冠状动脉综合征患者入院不同时间血清cTnI和cTnT水平,通过ROC曲线分析比较两者在AMI早期的诊断价值, 并同时检测肌酸激酶同工酶质量.结果显示: 入院即刻、入院后4h和8h, AMI组血清cTnI和cTnT水平显著高于不稳定型心绞痛组和其他疾病组(P＜0.01).cTnI和cTnT对AMI的诊断价值基本相同, 但在入院即刻, 以cutoff值为判定值时, cTnI比cTnT有更高的灵敏度(P＜0.05),表明cTnI和cTnT是诊断AMI高灵敏度和高特异性的血清标志物, cTnI在AMI初期灵敏度更高, 动态观察血清cTnI和cTnT浓度变化对AMI的诊疗具有重要的临床价值.     

Activity of phosphoglycerate mutase and its isoenzymes in serum after acute myocardial infarction

Aims/background—In humans there are three phosphoglycerate mutase (PGM, EC 5.4.12.1) isoenzymes (MM, MB and BB) which have similar distribution and developmental pathways to creatine kinase (CK, EC 2.7.3.2) isoenzymes. Total serum PGM activity increases in acute myocardial infarction with the same time course as creatine kinase activity. The present study was undertaken to determine changes in the activity of PGM and its isoenzymes after acute myocardial infarction.     

心型脂肪酸结合蛋白对急性冠脉综合征患者的诊断价值及预后评估的研究

目的探讨心型脂肪酸结合蛋白（H-FABP）对急性冠脉综合征（ACS）患者诊断及预后评估的价值。方法选择急性心肌梗死（AMI）患者108例;不稳定性心绞痛（UA）患者90例;稳定性心绞痛（SA）患者84例;健康对照组60例。患者各组分别在入院时和入院8h后检测血清H-FABP、cTnI和CK-MB水平。结果入院时,AMI组和UA组H-FABP水平高于SA组和对照组（P〈0.05）,AMI组CK-MB水平高于其他三组（P〈0.05）,H-FABP对AMI和UA的诊断阳性率明显高于cTnI和CK-MB（P〈0.05）;入院8h后,H-FABP水平下降,cTnI和CK-MB水平上升,AMI组H-FABP水平高于其他三组（P〈0.05）,AMI组和UA组cTnI和CK-MB水平明显高于SA组和对照组（P〈0.05）,H-FABP对AMI的诊断阳性率与cTnI和CKMB相比差异无统计学意义（P〉0.05）,而对UA的诊断阳性率低于cTnI和CK-MB（P〈0.05）。发生心脏意外事件的ACS患者H-FABP水平明显高于未发生心脏意外事件的ACS患者（P〈0.01）。结论 H-FABP对ACS患者的早期诊断具有较高的准确性;当发病超过8h后,应联合其他心肌酶学指标共同诊断。临床可结合H-FABP水平对ACS患者预后进行评估。     

Fibrin and fibrinogen-related antigens in patients with stable and unstable coronary artery disease

Coronary-artery thrombosis may be important in the pathogenesis of unstable angina at rest. To study this possibility, we measured the serum concentrations of fibrin-related antigen, D dimer (the principal breakdown fragment of fibrin), and fibrin monomer (an intermediate product of fibrin formation) in the serum of five groups of subjects. These included 10 healthy controls, 10 controls with noncardiac pain, and three groups of 10 patients each with chronic stable angina, unstable angina at rest, or acute myocardial infarction. The concentration of fibrin-related antigen (normal range, 48 to 184 ng per milliliter) was normal in the control patients with noncardiac pain (63 to 202 ng per milliliter) and in patients with chronic stable angina (95 to 186), but it was increased in patients with unstable angina (401 to 2507) or acute myocardial infarction (470 to 1930) (P less than 0.001). D dimer concentrations in patients with unstable angina (178.3 to 310.6 ng per milliliter) or acute myocardial infarction (103.9 to 321.6) were higher than those in patients with chronic stable angina (28.6 to 52.1), in controls with noncardiac pain (44.7 to 53.1), and in healthy controls (40.4 to 50.3) (P less than 0.001). Concentrations of fibrin monomer were highest in patients with acute myocardial infarction (247.5 to 571.3 ng per milliliter) (P less than 0.001), intermediate in those with unstable angina (54.7 to 241.7) (P less than 0.001), and normal (normal range, 14.5 to 19.8 ng per milliliter) in controls with noncardiac pain (12.0 to 18.4). and patients with chronic stable angina (10.7 to 17.6). These findings suggest the presence of an active thrombotic process in patients with unstable angina at rest or acute myocardial infarction. The data do not prove that the coronary arteries were the site of the thrombotic process, but the observations are consistent with the hypothesis that thrombus formation may have an important role in the pathogenesis of these conditions.     

急性冠脉综合症与补体激活

目的： 评价各种类型急性冠脉综合症 (ACS) 病人补体激活的情况和补体激活与心肌损伤的关系。方法： 研究对象分为ACS组110例和正常对照组18人。 ACS组包括ST段抬高型心肌梗死（STEMI）51例，非ST段抬高型心肌梗死（NSTEMI）28例和不稳定性心绞痛（UA）31人。检测病人和正常对照健康人血浆C₃和C₄，CK-MB和肌钙蛋白T (TnT)浓度。结果： STEMI和 NSTEMI病人峰值C₃ 水平［分别为（1 525±302） mg/L和（1 516±289）mg/L］ 和C₄［分别为（423±123） mg/L和（396±68） mg/L］水平高于UA病人和对照组的C₃［分别为（1 275±172） mg/L和（1 072±196） mg/L,P<0.01］ 和C₄［分别为（356±91）mg/L和（182±73） mg/L,P<0.01］。UA病人的 C₃ ［(1 275±172） mg/L］和C₄ ［（356±91） mg/L］均高于对照组（P<0.01）。 ACS病人C₃和C₄水平在住院的前7 d均有明显的变化（P<0.01）。ACS病人峰值C₃和C₄水平与峰值CK-MB（分别为r=0.51和r=0.46，P<0.01）和肌钙蛋白T（分别为r=0.48和r=0.39，P<0.01）呈正相关。结论： ACS病人血浆C₃和C₄均明显升高。C₃和C₄水平与ACS的联系提示补体激活与心肌坏死有关。     

Myocardial infarction during intravenous immunoglobulin infusion in a 65-year-old man with common variable immunodeficiency and subsequent successful repeated administration.

BACKGROUND: Intravenous immunoglobulin (IVIG) may cause thromboembolic events. Although such events are usually associated with large IVIG doses administered to treat neurologic diseases, thromboembolic events may also occur with standard immunodeficiency doses. OBJECTIVE: We describe a 65-year-old man with common variable immunodeficiency (CVID) who experienced angina and myocardial infarction with IVIG infusion. METHODS: The patient's electronic medical record was reviewed. RESULTS: The patient developed substernal chest pain during a scheduled 40-g (400-mg/kg) infusion. The infusion was discontinued, and a cardiac evaluation was initiated. The patient was found to have elevated troponin T and creatine kinase MB levels, signifying cardiac injury. Heart catheterization revealed severe vessel disease, and surgical revascularization was subsequently performed. Three weeks after revascularization, an IVIG dose of 200 mg/kg was cautiously readministered. This dose was increased in 2 weeks to 300 mg/kg, which was tolerated every 3 to 4 weeks without any adverse thrombotic events in the subsequent 12 months. CONCLUSIONS: This case demonstrates not only angina and myocardial infarction associated with IVIG infusion in a patient with CVID but also the successful reinitiation of IVIG infusion after surgical revascularization. This case also underscores the importance of caution with IVIG infusion in patients with CVIDand known coronary artery disease.     

非ST段改变的急性心肌梗死临床分析

目的 探讨非ST段改变的急性心肌梗死患者冠状动脉病变情况,指导进一步治疗。方法 选取我院2013年12月~2018年12月因胸闷、胸痛不适入住苏州高新区人民医院、新疆自治区人民医院的患者76例,入院行心电图未见相关导联ST段改变,动态观察心电图及血清超敏肌钙蛋白T、肌酸激酶同工酶,多次复查未发现心电图有动态改变,但血清超敏肌钙蛋白、肌酸激酶同工酶数小时,甚至更长时间开始升高,急诊行冠状动脉造影术（CAG）,观察有无冠状动脉急性闭塞或次全闭塞,同时观察病变冠脉血管的部位、内径。结果 纳入的76例心电图无ST段改变,但数小时后血清心肌标志物升高的胸闷、胸痛患者行冠状动脉造影术发现:冠状动脉急性闭塞或次全闭塞的患者占94.74%,比例较高,多见于钝缘支,占78.95%,且冠脉血管内径均＞1.5 mm。结论 除了ST段抬高和ST段压低的急性心肌梗死,非ST段改变的急性心肌梗死也常常出现在临床当中,对此类不典型的患者,早期识别很重要,及时有效的处理,预后良好。     

Usefulness of cardiac troponin I in patients with acute myocardial infarction

Cardiac troponin(cTn) is a sensitive marker for acute myocardial infarction(AMI). However, some cases of renal failure have been reported to show false positive results for cardiac troponin T(cTnT). Recently, it has been reported that heart-type fatty acid-binding protein(H-FABP) is a sensitive marker for AMI in the early phase. We evaluated the usefulness of cardiac troponin I(cTNI) using serum samples from patients(age 57-96) confirmed to have AMI with chest pain(n = 48), unstable angina pectoris(n = 11), cardiac failure(n = 5), others with high creatine phosphokinase(CK) activity(n = 81) and renal failure(n = 28), by comparing among cTnT(qualitative and quantitative), H-FABP, CK and creatine phosphokinase isoenzyme MB(CK-MB) activity. The diagnostic validity of cTn was assessed by receiver operating characteristic(ROC) curve analysis. The cut off value for AMI of cTnI was 0.8 ng/ml, cTnT was 0.16 ng/ml and H-FABP was 19.0 ng/ml. The overall diagnostic sensitivity of cTnI was 83.1%, and 84.8% for cTnT (quantitative), 72.3% for cTnT(qualitative), 64.8% for H-FABP, 81.8% for CK and 59.3% for CK-MB. The overall diagnostic specificity of cTnI was 90.9%, and 81.3% for cTnT(quantitative), 60.5% for cTnT (qualitative), 53.2% for H-FABP, 52.9% for CK and 87.7% for CK-MB. The overall diagnostic efficiency of cTnI was 86.5%, and 82.7% for cTnT(quantitative), 63.6% for cTnT(qualitative), 59.8% for H-FABP, 69.0% for CK and 71.9% for CK-MB. False positive results for cTnI were found in a few cases with renal failure. cTnT(qualitative) showed false positive results in 22/28 with serum creatinine over 2.1 mg/dl due to renal failure. In conclusion, cTnI detection is considered a useful and sufficiently sensitive marker for AMI.     

Angioscopic evaluation of coronary-artery thrombi in acute coronary syndromes.

BACKGROUND. Disruption of an atherosclerotic plaque in a coronary artery followed by the formation of a thrombus is believed to be the cause of both unstable angina and acute myocardial infarction. Although thrombolytic therapy is efficacious in patients with acute myocardial infarction, for unknown reasons it is far less effective in patients with unstable angina. We postulated that there might be differences in the composition of the coronary-artery thrombi in unstable angina and acute myocardial infarction. METHODS. To investigate the appearance of coronary-artery thrombi, we performed percutaneous transluminal coronary angioscopy in 15 patients with unstable angina and 16 with acute myocardial infarction. Angioscopy was performed within 48 hours after an episode of pain at rest in the patients with unstable angina and within 8 hours of onset in those with acute myocardial infarction. RESULTS. Angioscopy revealed coronary thrombi in all but two patients (one in each group). Of the 29 patients with thrombi, those with unstable angina were frequently observed to have grayish-white thrombi (10 of 14, 71 percent), but none were seen in the 15 patients with acute myocardial infarction (P less than 0.01). By contrast, reddish thrombi were observed in all 15 patients with acute myocardial infarction who had thrombi, but in only 4 of the 14 patients with unstable angina and thrombi (P less than 0.01). As assessed by coronary angiography, occlusive thrombi occurred frequently in patients with acute myocardial infarction (13 of 16 patients) but were not seen in any of the 15 patients with unstable angina (P less than 0.01). CONCLUSIONS. Coronary-artery thrombi play an important part in the pathogenesis of unstable angina and acute myocardial infarction. However, the appearance of the thrombi is different in the two conditions, possibly reflecting differences in the composition of age of the thrombi or the presence or absence of blood flow in the artery. This difference may account for the contrasting results of thrombolytic therapy.     

Studies on method for electrophoresis of creatine kinase (CK) MB sub-bands and its clinical application

We studied a electrophoretic method for creatine kinase (CK, EC 2.7.3.2) MB sub-bands using a discontinuous buffer system on cellulose acetate membrane. The sub-bands (CK-MB1 and MB2) were clearly separated using a discontinuous buffer consisting of 0.22 mol/1 tris aminomethane-glycine buffer on the anode side and 0.033 mol/l sodium barbital-boric acid buffer on the cathode side at 250 V for 30 minutes. We also examined CK-MB sub-bands in myocardial extracts that showed only a broad MB2. When the extract was incubated with normal serum havings low CK activity at 37 degrees C at MB 1 sub-band appeared within a few hours. We examined the serial changes in these sub-bands in the serum of eight patients with acute myocardial infarction (AMI). The MB2 reached a peak 7-25 hours after onset of chest pain, and MB 1 reached a peak 0-12 hours later. The ratio of MB 2 to MB 1 was high at early phase of AMI. (about 7 hours after onset of chest pain, mean 1.7 S.D. 0.78) These results indicate that a high MB 2/MB 1 ratio is a more sensitive indicator of enzyme release from necrotic myocardium, and is useful for early diagnosis of AMI.     

Role of myeloperoxidase in early diagnosis of acute myocardial infarction in patients admitted with chest pain

Myeloperoxidase (MPO) is an inflammatory marker, elevated in acute coronary syndromes (ACSs), especially in acute myocardial infarction (AMI) cases. This study aimed to evaluate the diagnostic power of MPO in AMI patients. MPO, creatine kinase (CK) MB, and Troponin I (cTn I) were performed for all study patients. Area under the curves (AUCs) and 95% confidence intervals (CI); P values of baseline levels of MPO for discriminating AMI patients from noncoronary chest pain (NCCP) patients, stable angina (SA) patients, and unstable angina (UA) patients were 0.91, 95% CI: 0.82–0.99; P < 0.0001, 0.87, 95% CI: 0.77–0.98; P < 0.0001, and 0.72, 95% CI: 0.58–0.85; P = 0.002, respectively. For diagnosing AMI from ACS patients, MPO was the most efficient marker than others markers with efficiency 82.5% within 0–6 hr after the onset time of chest pain. A predictive score that depends on a combination of baseline levels of three markers (MPO, CK-MB, and TnI) was correctly discriminated 91% of the AMI patients with high specificity 76%. In conclusion, the use of baseline levels of three biomarkers in combination could confer the information that is required for best available early diagnosis of AMI.