Use of creatine kinase MB isoenzyme for diagnosing myocardial infarction when total creatine kinase activity is high

The usefulness of measuring creatine kinase MB isoenzyme for diagnosing myocardial infarction when activities of total creatine kinase are very high is unclear. We conducted a retrospective study in an urban hospital that serves a largely indigent population. We concentrated on 146 patients whose creatine kinase activity was greater than 1000 U/L (upper limit of normal: 165 U/L for women and 225 U/L for men), with MB isoenzyme greater than 10 U/L and less than 5% of total creatine kinase. The positive predictive value of MB isoenzyme (isoimmune method) values greater than 10 U/L was between 11.6% and 56.8% when the value for total creatine kinase exceeded 1000 U/L. Using different values (MB greater than 4% of total creatine kinase) as positive for myocardial infarction would have resulted in far fewer false-positives, but 10 cases of myocardial infarction would have been missed. The most appropriate cutoff value for MB isoenzyme in this population (total creatine kinase greater than 1000 U/L) was found to be greater than 2% of total creatine kinase.     

Mitochondrial and cytoplasmic isoenzymes of aspartate aminotransferase in sera of patients after myocardial infarction

Mitochondrial and cytoplasmic isoenzymes of aspartate aminotransferase (AST) were studied in the sera of 42 patients following acute myocardial infarction and compared to creatine kinase (CK), lactate dehydrogenase (LDH) and alanine aminotransferase (ALT). Mitochondrial AST( ASTm ) was detected in 93% (39/42) of patients. Maximum recorded ASTm activity was 59.5 +/- 8.8 U/l and was found 39.4 +/- 3.5 hours after the onset of symptoms (chest pain) of myocardial infarction. In contrast the maximum recorded cytoplasmic AST ( ASTc ) activity was greater (327 +/- 23 U/l) and it occurred earlier (33.5 +/- 2.2 hours) after onset of infarction compared to ASTm . ASTm correlated significantly (p less than 0.05) with ASTc , LDH and ALT but not with total CK or CK-MB. ASTc correlated significantly (p less than 0.05) with total CK, CK-MB and LDH but not ALT. Maximum recorded ASTm activity was significantly associated with the clinical assessment of left ventricular failure ( Killip classification) but not with ventricular arrhythmias. In a subset of 15 patients evaluated with invasive hemodynamic measurements of cardiac output and pulmonary capillary wedge pressure. ASTm correlated significantly (p less than 0.05) and better than CK-MB with the hemodynamic assessment of left ventricular dysfunction. Thus ASTSm can be readily identified in sera of patients after acute myocardial infarction and may be of value in the evaluation of patients with acute myocardial infarction.     

心肌肌钙蛋白Ⅰ快速检测在急性心肌梗死诊断中的价值

比较心肌肌钙蛋白Ⅰ(CTnI)与几种常用的急性心肌梗死(AMI)诊断标记物的临床应用价值。方法对36例AMI和70 例非心肌梗死患者同时检测血清CTnI、肌酸激酶(CK)、肌酸激酶同功酶(CK-MB)、乳酸脱氢酶(LDH)、天冬氨酸转氨酶(AST)和α-羟丁 酸脱氢酶(α-HBD)等6项指标,并进行2组间比较,分别对AMI和非心肌梗死组各指标间的差异作对比分析。结果CTnI诊断AMI的敏 感性(91.7％)高于CK(75.0％)、CK-MB(63.9％)、AST(66.3％)、LDH(75.0％)、α-HBD(69.4％),P<0.05～0.01;CTnI诊断AMI的特异 性(95.7％)与CK-MB(92.6％)相近(P>0.05),高于CK(84.3％)、ASr(81.4％)、LDH(72.9％)及α-HBD(80.0％),P<0.05～0.01。结论 CTnI对AMI的诊断具有较高的敏感性和特异性,作为一种心肌损伤的特异标记物,具有较好的临床应用价值。     

Measurement of creatine kinase isoforms by agarose gel electrophoresis in the diagnosis of myocardial infarction.

To evaluate a method to quantitate the isoforms of serum creatine kinase isoenzyme MM (CK-MM) by agarose gel electrophoresis, sera of normal subjects (n = 74) and patients with acute myocardial infarction (n = 21) and other diseases (n = 67) were studied. The within-assay imprecision (CV) for CK-MM1, -MM2, and -MM3 was 1.9%, 0.8%, and 2.2% at the activity of 79, 105, and 64 U/L (30 degrees C, CK-NAC), respectively; while the assay-to-assay imprecision was 4.8%, 3.2% and 3.9%, respectively. The method could detect 5 U/L or more of any CK-MM isoform and was linear with respect to CK activity at values less than 1100 U/L. Sera from healthy subjects (n = 74) contained mainly CK-MM1 (mean = 48.5%), with lesser amounts of CK-MM2 (mean = 30.6%) and CK-MM3 (mean = 20.8%). The central 95-percentile reference range for the ratio of MM3/MM1 was 0.12-1.34 with mean = 0.49. The sensitivity of CK-MM3/MM1 ratio greater than 1.3 in the diagnosis of acute myocardial infarction employing the first available sample was 90% at a specificity of 91%, compared with a sensitivity of 81% and specificity of 87% for the conventional CK-MB assay. At CK-MM3/MM1 ratio of 1.6 or more, the specificity increased to 96% while sensitivity remained unchanged at 90%. This procedure for the quantitation of serum CK-MM isoforms is convenient, practical and suitable for inclusion in the routine panel of cardiac tests.     

Analytical and clinical evaluation of creatine kinase MB mass assay by IMx: comparison with MB isoenzyme activity and serum myoglobin for early diagnosis of myocardial infarction.

We analytically and clinically evaluated Abbott's IMx assay for creatine kinase (CK) isoenzyme MB (CK-MB) in serum. Over a 1-year period, the method was more specific but less precise than catalytic isoenzyme measurements by electrophoresis or immunoinhibition. Sera from different individuals without electrophoretic evidence of CK-MB but containing macro CK type 1 (n = 20), mitochondrial CK (n = 5), or CK-BB (n = 5) were scored as CK-MB negative by the IMx. Likewise, CK-MB-negative by the sera remained so after addition of purified human CK-MM (< or = 7600 U/L) or CK-BB (< or = 8100 U/L). For 39 patients admitted for suspicion of uncomplicated acute myocardial infarction (precordial pain for < or = 4 h), the diagnostic performance of the IMx CK-MB assay on admission and 4 h later was superior to that of total CK activity and compared well with that of CK-MB activity measured by electrophoresis or immunoinhibition. An admission, myoglobin showed a higher diagnostic sensitivity, specificity, and predictive value than did CK-MB and was the most informative test. Diagnostic performance on admission and 4 h later was further improved by considering positivity for myoglobin and for CK-MB by IMx and for the change in each over the first 4 h of hospitalization as criteria. Twelve hours after admission, diagnostic performance was further improved for all CK and CK-MB methods but began to decline for myoglobin.     

Evaluation of a paired creatine kinase test for the diagnosis of acute myocardial infarction in patients with a non-diagnostic electrocardiogram.

OBJECTIVE: The rate of rise of total plasma creatine kinase (CK) activity in the first 12 hours from presentation can be used to diagnose acute myocardial infarction. The aim of this study was to evaluate the performance of an abbreviated form of this test in the diagnosis of acute myocardial infarction in patients in whom the initial electrocardiogram was inconclusive. METHODS: Using a protocol that requires only two CK measurements (separated by four hours) to estimate the rate of rise, the performance of the test was investigated using data accrued from 345 consecutive admissions with suspected acute myocardial infarction. RESULTS: A CK increment (delta CK) of > 20% in the first four hours from presentation had a diagnostic sensitivity of 84.4% (95% confidence interval 75.5 to 93.3), specificity of 85.8% (80.1 to 91.5), positive predictive accuracy of 73.0% (62.9 to 83.1), and negative predictive accuracy of 92.4% (87.9 to 96.9). Using more stringent diagnostic criteria (delta CK > 20% and 4 h CK value > 160 U/litre) resulted in an increase in specificity and positive predictive accuracy to 96.5% and 91.1% respectively, and a small reduction in sensitivity and negative predictive accuracy to 79.7% and 91.3%, respectively, 94% of all infarcts were correctly identified using the ECG as the initial investigation and paired CK measurement as an additional test when this was inconclusive. In the 44 patients who received thrombolysis on the basis of an early biochemical diagnosis of acute myocardial infarction, the median time delay (75th centile) to thrombolysis was 10.75 (SD 15.0) hours. CONCLUSIONS: When the presenting ECG is non-diagnostic, sequential sampling of cardiac enzymes is a feasible alternative in the early diagnosis of patients with suspected myocardial infarction, even in the emergency setting. Further studies are required to define the optimal biochemical assay and timed sampling protocol.     

Clinical effectiveness of the Du Pont aca measurement of creatine kinase MB in serum from patients in a coronary-care unit

We evaluated the clinical effectiveness of measuring creatine kinase (CK; EC 2.7.3.2) isoenzyme MB and lactate dehydrogenase (LD; EC 1.1.1.27) isoenzymes in diagnosis of acute myocardial infarction. We used an agarose electrophoresis method to measure CK and LD isoenzymes and the Du Pont aca column method to measure CK-MB. Serial blood specimens were drawn from 100 patients consecutively admitted to our Coronary Care Unit. Because of the low diagnostic specificity for CK-MB measurements by both agarose electrophoresis and the discrete-analysis method, as compared with reported values, we re-evaluated our isoenzyme data by using Receiver Operating Characteristic curves. Such analysis of the data established optimal decision levels of greater than or equal to 25 U/L and greater than or equal to 18 U/L plus greater than or equal to 6% of total CK for serum CK-MB measured by the agarose electrophoresis and the aca methods, respectively, and an optimal decision level of greater than or equal to 0.92 for the ratio of LD 1/2 measured after agarose electrophoresis. At these decision levels we obtained a sensitivity of 100%, 100%, and 95% and a specificity of 94%, 92%, and 90% for CK-MB (agarose electrophoresis), CK-MB (aca), and the LD 1/2 ratio, respectively.     

Creatine kinase B-subunit activity in serum after immunoinhibition of M-subunit activity.

Creatine kinase (EC 2.7.3.2) B-subunit activity in serum may be routinely measured as residual activity after specific immunoinhibition of the M-subunit. We assessed the inhibition kinetics, specificity, completeness of inhibition, and inhibitory capacity of three different anti-M preparations, with use of isolated human BB, MM, and MB isoenzymes. The Scandinavian-recommended reaction system was used. We suggest a set of tentative quality requirements for anti-M for use in diagnosing acute myocardial infarction. The need to measure and subtract sample residual adenylate kinase activity was demosntrated. We describe a routine photometric method for determining B-subunit activity in serum. With the Scandinavian CK method the upper reference value for total creatine kinase in serum was found to be 150 U/L for women, 270 U/L for men. By bioluminescence, we found the upper reference value for B-subunit activity to be 6 U/L for both sexes. We discuss three different modes for applying B-subunit determinations to the diagnosis of acute myocardial infarction.     

Ratio of creatine kinase 2 mass concentration to total creatine kinase activity not altered by heavy physical exercise.

Serum creatine kinase isoenzyme 2 concentrations (CK 2 mass) were measured in marathon runners during training and 1 and 2 days after a race and compared with values from 36 acute myocardial infarction (AMI) patients whose total CK and (or) CK 2 activities were similar to those of runners in the basal state. During training, runners had CK and CK 2 activities 53% and 43% above reference values, respectively, and 36% had CK 2 activity > 5% of total CK. Nine runners (26%) showed CK 2 mass values > 6 micrograms/L but < or = 10 micrograms/L; 35 of the AMI subjects, despite having CK activities similar to those of runners, had values > 10 micrograms/L. The ratio of CK 2 mass to total CK activity was significantly (P < 0.0002) different between sexes for runners. At 1 and 2 days after racing, 100% of CK and CK 2 activities and 71% and 57% of the percentages of CK 2 activity, respectively, were abnormally high; 57% and 43% of CK 2 mass values were > 10 micrograms/L, being comparable with those observed for the AMI group. Basal CK 2 mass values of the runners appeared only slightly higher than that for sedentary subjects, but after exercise half the subjects presented increased values similar to those observed for AMI subjects. The ratio of CK 2 mass to total CK activity appeared unaltered by exercise in all but one of the samples assayed, indicating its utility in evaluating CK 2 mass increases originating in skeletal muscle.     

Activity of serum aspartate aminotransferase isoenzymes in patients with acute myocardial infarction

Activities of aspartate aminotransferase (AST) isoenzymes were determined in serial serum samples from 40 cases of acute myocardial infarction, and compared with activities of creatine kinase, CK-MB isoenzyme, lactate dehydrogenase, and alpha-hydroxybutyrate dehydrogenase for temporal changes. Cytosolic (soluble) AST (s-AST) and mitochondrial AST (m-AST) respectively increased 6.6 and 9.0 h after onset of chest pain. The median time at which serum m-AST activity peaked (15.8 U/L, range 6.4-53.5 U/L) was 47.8 h after the onset of infarction, 19.8 h later than the peak s-AST activity (171 U/L, range 53-517 U/L) and m-AST also disappeared from the serum more slowly than s-AST (p less than 0.001). Serum m-AST values were above normal for at least six days after the infarct. The ratio of m-AST to total AST in serum increased after myocardial infarction, being greatest (20%, range 11-32%) on the third day after onset. For individuals, peak activities of s-AST correlated well with total CK (r = 0.91) and CK-MB (r = 0.86) peak activities, indicating that s-AST also reflects the infarct size. However, m-AST correlated poorly with the enzymes commonly used in infarct diagnosis; it apparently provides different biological information.     

Diagnosis of perioperative myocardial infarction by considering relationship of postoperative electrocardiogram changes and enzyme increases after coronary bypass operation

We report the results of enzyme determinations in sera from 88 patients, 65 of whom showed inconspicuous reconvalescence, 14 who had myocardial infarction within 24 h (MI 1) after bypass surgery, and nine with myocardial infarction between 24 and 48 h postoperatively (MI 2). We wanted to determine whether the consequent measurement of activities of total creatine kinase (CK), CK isoenzyme MB (CK-MB), lactate dehydrogenase, alpha-hydroxybutyrate dehydrogenase, and aspartate aminotransferase, conducted as a part of routine laboratory diagnostics, provided meaningful information for diagnosing infarcts besides that obtained from the electrocardiogram. The postoperative mean values of the enzyme activities in blood were significantly different among the three groups; however, only a combined evaluation of CK and CK-MB by means of a discriminant analysis allowed the prediction of MI (sensitivity: MI 1 = 98.5%, MI 2 = 95.4%; specificity: MI 1 = 71.4%, MI 2 = 81.8%). CK greater than 600 U/L or CK-MB greater than 45 U/L supports the diagnosis of acute MI.     

Changes in creatine kinase activity in the course of acute myocardial infarction

Peak activity of creatine kinase (CK; EC 2.7.3.2) and its decline were determined in 380 patients with acute myocardial infarction (AMI) whose CK values had peaked after admission to the hospital. During hospitalization, 26 patients either died (14 patients) or experienced nonfatal re-infarction (12 patients). In 22 of these 26 patients CK activity decreased by less than 50% within 48 h after the peak value was measured. In all patients who did not die or develop re-infarction, CK activity decreased by greater than 50% during the 48 h after the peak. Evidently the rate of decline of CK (i.e., whether more than or less than 50%) from its peak value during the 48 h after AMI may be helpful in assessing which patients are at high risk for developing re-infarction or dying.     

应激性心肌病与急性心肌梗死患者肌钙蛋白检查结果差异性

目的分析应激性心肌病与急性心肌梗死患者肌钙蛋白检查结果差异性。方法收集分析本院2018年1月至2020年6月收治的10例应激性心肌病患者(应激性心肌病组)以及100例急性心肌梗死患者(急性心肌梗死组)临床资料,对两组患者肌钙蛋白(肌钙蛋白T、肌钙蛋白I)、心肌酶谱(ALT、AST、CK、CK-MB、LDH)、心电图表现(I导联抬高、aVL导联抬高、V2-V5导联ST段抬高)进行对比,利用Spreaman相关性分析法检验以上指标与应激性心肌病的相关性,绘制受试者工作特征曲线计算应激性心肌病与急性心肌梗死肌钙蛋白的cut-off值。结果两组患者肌钙蛋白检测结果比较,应激性心肌病组CTNT及CTNI值分别为(0.46±0.05)μg/L,(3.67±0.41)μg/L,高于急性心肌梗死组的(1.27±0.11)μg/L,(24.38±1.42)μg/L,差异有统计学意义(P<0.05),心肌酶谱检测结果、心电图表现相比较,差异无统计学意义(P>0.05);Spreaman相关性分析结果显示,肌钙蛋白与应激性心肌病有关,心肌酶谱、心电图表现与与应激性心肌病无关;受试者工作特征曲线显示:应激性心肌病与急性心肌梗死肌钙蛋白T的cut-off值为0.97μg/L、肌钙蛋白I的cut-off值为7.71μg/L。结论肌钙蛋白检查结果可以作为应激性心肌病、急性心肌病梗死的初步诊断。     

罗氏Cobas8000全自动生化分析仪检测心肌酶谱的性能评价

目的对在罗氏公司Cobas8000型全自动生化分析仪上检测的心肌酶谱:天门冬氨酸氨基转移酶(AST)、乳酸脱氢酶(LDH)、肌酸激酶(CK)、肌酸激酶同工酶(CK-MB)的分析性能进行评价。方法参考美国临床和实验室标准化协会性能评价方法和相关报道,并根据临床需求和实际要求,对罗氏公司Cobas8000型全自动生化分析仪测定血清心肌酶谱的准确度、精密度、线性范围、生物参考区间和最大稀释倍数5项分析性能进行验证和评价,并与强生公司Vitro5600型分析仪进行方法学比对。结果罗氏Cobas8000分析仪对心肌酶谱的检测准确度较好,各项指标的相对偏倚均小于允许总误差的1/2,符合美国临床实验室改进修正法案(CLIA′88)的指标要求。精密度验证结果显示批内变异系数和不同批次之间的检测标本变异系数分别小于允许总误差的1/4和1/3。线性回归方程的斜率在0.998~1.017,r 2均≥0.995。AST、LDH、CK、CK-MB的临床可报告范围分别为2~700 U/L、10~1000 U/L、7~2000 U/L、3~2000 U/L。参考范围验证除LDH有一个值超出该参考区间外,其他结果均在参考范围内。高浓度的标本可经稀释后再行测定,测定结果表明4项测定指标的相对偏差在允许误差范围内,具有较高的临床参考价值。实验室内结果比对,4个项目比对结果均符合CLIA′881/2允许偏倚,与Vitro5600型分析仪具有良好的一致性。结论罗氏Cobas8000型全自动生化分析仪检测心肌酶谱的主要分析性能均符合厂商声明的性能和有关的质量要求,检测结果准确性较高、可靠性较好,临床参考价值较高,故可满足临床需求。     

"Flipped" patterns of lactate dehydrogenase isoenzymes in serum of elite college basketball players

We kinetically measured total lactate dehydrogenase (LD, EC 1.1.1.27), total creatine kinase (CK, EC 2.7.3.2), and aspartate aminotransferase (AST, EC 2.6.1.1.) in 16 elite college basketball players, before the competition season and not in close temporal relation to near-maximal exercise, and in 17 healthy non-athlete controls. LD isoenzymes were determined by both electrophoretic and immunoprecipitation methods. CK-MB isoenzyme was measured electrophoretically. We found significantly higher mean LD-1 values and LD-1/LD-2 ratios in the players than the controls: 31.6 (SD 3.7)% vs 25.8 (SD 3.2)% (P less than 0.005) and 1.1 (SD 0.13) vs 0.87 (SD 0.16) (P less than 0.001), respectively. A "flipped" LD pattern (LD-1 greater than LD-2) was found in half the players and in six of the eight black athletes, but in only two of the control group and in none of the black controls. Mean CK activity in serum exceeded normal values in the serum of the athletes and was higher in comparison with the control group [274 (SD 156) vs 103 (SD 82) U/L]. Mean CK was significantly higher in the eight athletes with the flipped LD pattern than in those with LD-1 less than LD-2 [322 (SD 163) vs 180 (SD 98) U/L; P = 0.05], and also in comparison with CK in the two controls with flipped LD pattern. We saw no significant difference in mean CK between the nine players with normal immunochemical LD-1/LD ratios and the seven players with above-normal ratios. CK-MB was not detected in either athletes or controls. None of the players had any clinical or electrocardiographic evidence for myocardial ischemia or infarction. Evidently the flipped LD pattern usually found in patients with acute myocardial infarction and reported in some athletes after extreme exercise such as ultra-marathon running may also be found in athletes who are in their "basal fitness shape" but who are not involved in competitive physical activity.     

Differentiating muscle damage from myocardial injury by means of the serum creatine kinase (CK) isoenzyme MB mass measurement/total CK activity ratio

We immunoenzymometrically measured creatine kinase (CK) isoenzyme MB in extracts of myocardium and in homogenates of five different skeletal muscles. CK-MB concentrations in the former averaged 80.9 micrograms/g wet tissue; in the skeletal muscles it varied widely, being (e.g.) 25-fold greater in diaphragm than in psoas. CK-MB in skeletal muscles ranged from 0.9 to 44 ng/U of total CK; the mean for myocardium was 202 ng/U. In sera from 10 trauma and 36 burn patients without myocardial involvement, maximum ratios for CK-MB mass/total CK activity averaged 7 (SEM 1) ng/U and 18 (SEM 6) ng/U, respectively. Except for an infant (220 ng/U), the highest ratio we found for serum after muscular damage was 38 ng/U. In contrast, the mean maximum ratio determined in 23 cases of acute myocardial infarction exceeded 200 ng/U. Among seven determinations performed 8 to 32 h after onset of symptoms, each infarct patient demonstrated at least one ratio greater than or equal to 110 ng/U. Ratios observed after infarct were unrelated to treatment received during the acute phase. We propose a CK-MB/total CK ratio of 80 ng/U as the cutoff value for differentiating myocardial necrosis from muscular injury.     

Evaluation of the clinical usefulness of a chemiluminometric method for measuring creatine kinase MB

The use of creatine kinase isoenzymes (CK-MB) in the diagnosis of acute myocardial infarction (AMI) is well established. We evaluated the use of a new chemiluminometric method (CK-Ciba) for measuring CK-MB by calculating its sensitivity, specificity, positive and negative predictive values, and diagnostic efficiency for diagnosing AMI. We tested 633 samples from 229 patients within 4 h of receipt. The patients were divided into four groups: (1) patients who had an AMI, (2) patients who had AMI ruled out, (3) patients who had CK-MB measured for reasons other than to rule out AMI, and (4) patients who had only one sample drawn. Only patients in Groups 1 and 2 were used in the study. AMI was diagnosed by a cardiologist. The prevalence of AMI in our population was 0.18. A receiver-operator characteristic curve was used to establish optimal values for identifying AMI with the CK-Ciba results: CK-MB greater than or equal to 10 micrograms/L and a CK-MB index of greater than or equal to 3.0 (micrograms of CK-MB per U of CK x 100). Using these values, we calculated a sensitivity of 1.00, specificity of 0.97, positive predictive value of 0.87, negative predictive value of 1.00, and a diagnostic efficiency of 0.97. We conclude that the CK-Ciba method has high sensitivity, high specificity, and good predictive values for CK-MB and is appropriate to use to rule out AMI.     

Creatine kinase isoenzyme MB assay by electrophoresis

A method for determination of the creatine kinase isoenzyme MB (CK-MB) is reported: separation of the isoenzymes was done by electrophoresis and the activity of the isoenzyme bands quantitated by scanning fluorometry. Total CK activity was used for calculation of CK-MB level. The precision of the method was satisfactory: coefficient of variation 5-10%. Its accuracy good: CK-MB was consistently found in high concentrations in tissue extracts of myocardium, but was virtually absent in skeletal muscle and could not be demonstrated in serum from patients with skeletal muscle damage. The sensitivity of the method fitted its clinical use: CK-MB was undetectable (less than 5 U/l) in normal sera, below 30 U/l in seventy-six out of seventy-seven patients in whom the diagnosis of acute myocardial infarction (AMI) was disproved, and above 30 U/l in all seventy-two patients with AMI according to WHO criteria. The CK-MB concentration in serum rises to a maximum about 20 h after onset of clinical symptoms of AMI and reaches baseline levels 20-30 h later. The electrophoretic CK-MB method is easy, fast and reliable and is considered as an important diagnostic test for AMI.     

Effect of exercise on plasma pyruvate kinase and creatine kinase activity

Plasma pyruvate kinase (PK) and creatine kinase (CK) were measured in healthy subjects engaging in (a) mild exercise, 30 min on an exercise cycle maintaining a pulse rate of 150/min, (b) moderate exercise, squeezing a ball until exhaustion with a sphygmomanometer cuff inflated above systolic pressure around the arm (max. 2 min) and (c) severe exercise, completing a marathon race. Mild exercise resulted in no change in enzyme levels over 24 h. Moderate exercise produced a small increase in PK but no change in CK. PK activity rose from 35.3 +/- 10 U/l pre-exercise to 41.3 +/- 13 U/l 15 min post-exercise (n = 8, p less than 0.025). Severe exercise (completing a marathon race) resulted in a 3-fold increase in PK from 26 (4-87) U/l pre-race to 69 (21-156) U/l immediately post-race, and also, as expected, an increase in CK from 60 (15-164) U/l to 257 (72-1535) U/l (results are means and ranges, n = 69, p less than 0.001 for both enzymes). Runners showed parallel increases in PK and CK (p less than 0.05 by Spearman rank correlation). The mean post-race activity of CK-MB was less than 5% of total CK but 18 runners had values greater than 6% (mean 4.8, range 1-18). We conclude that PK, like CK, is increased following exercise due to liberation of muscle enzyme. However, only severe exercise is likely to lead to a substantial increase in plasma PK activity and therefore prejudice its clinical usefulness as a diagnostic test.     

肝硬化患者血清肌酸激酶、肌酸激酶同工酶-MB水平与Child-Pugh评分的相关性分析

目的探讨肝硬化患者血清肌酸激酶(CK)、肌酸激酶同工酶-MB(CK-MB)水平与Child-Pugh评分的相关性。 方法分析2013年4—7月确诊的肝硬化患者临床资料。入选标准：(1)肝硬化诊断符合全国传染病与寄生虫病防治学术会议诊断标准;(2)既往无冠心病、高血压、心肌病病史;(3)心电图无ST-T动态变化;(4)cTnI正常。排除标准：(1)脾脏切除史;(2)合并肝癌,肝移植者,进行干扰素、免疫抑制剂或抗病毒治疗者;(3)存在血液系统疾病或严重感染性疾病。对患者入院进行Child-Pugh分级测评,记录各组患者临床基线资料,包括年龄、性别、原发肝脏疾病、肝功能、血常规等,分别采用酶动力法和免疫抑制法,检测入选患者的CK和CK-MB水平。比较患者CK、CK-MB水平及CK-MB/CK比值,采用有序Logistic回归分析肝硬化患者CK-MB/CK比值与Child-Pugh评分之间的相关性。 结果总共入选符合标准的肝硬化患者121例,平均年龄(56.67±10.88)岁,其中男性89例,乙肝肝硬化患者72例。Child-Pugh C级患者年龄明显高于Child-Pugh A、B组患者(P＝ 0.021),3组患者γ-谷酰转肽酶、CK[(82.18±23.60)U/L、(98.22±33.13)U/L、(117.05±27.31)U/L,F＝23.248,P<0.01)]、CK-MB[(29.77±12.75)U/L、(63.26±36.35)U/L、(69.76±27.05)U/L、F＝20.588,P<0.05)]、CK-MB/CK比值(0.36±0.08、0.54±0.26、0.75±0.30,F＝31.558,P<0.05)、凝血酶原活动度(PA)[(71.77±14.88)%、(56.82±16.61)%、(41.73±11.43)%,F＝54.483,P<0.05)]、血红蛋白(HGB)[(138.21±8.24)g/L、(108.16±23.60)g/L、(78.52±23.64)g/L,F＝95.752,P<0.05)]以及血小板(PLT)[(153.86±92.59)g/L、(108.38±51.90)g/L、(93.88±54.51)g/L,F＝12.965,P<0.05)]水平差异均有统计学意义。3组患者原发肝脏疾病、谷草转氨酶(ALT)、谷丙转氨酶(AST)以及肌酐水平(SCr)差异均无统计学意义。对资料进行有序Logistic回归分析,发现CK-MB/CK比值对Child-Pugh评分有显著影响,其OR值为e^－0.98＝0.375,提示CK-MB/CK比值>0.30时,Child-Pugh分级C级的可能性为CK-MB/CK<0.30时的2.67倍。 结论肝硬化患者CK-MB/CK比值与Child-Pugh分级严重程度密切相关。