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Early detection of coronary reperfusion by rapid assessment of plasma myoglobin
33
International Journal of Cardiology, 38 (1993) 33-40 0 1993 Elsevier Scientific Publishers Ireland Ltd. All rights reserved 0167-5273/93/$06.00
CARD10 01583
Early detection of coronary reperfusion by rapid assessment of plasma myoglobin Satoshi Abe a, Shinichi Arima a, Kunihiro Nomoto ‘, Ikuro Maruyama b, Masaaki Miyata a, Hiroshi Yamaguchi a, Hideki Okino a, Tsuminori Yamashita a, Yoshihiko Atsuchi a, Minoru Tahara a, Shoichiro Nakao a and Hiromitsu Tanaka a ’ First Department of Internal Medicine and ’ Third Department of Internal Medicine, Faculty of Medicine, Kagoshima University, Kagoshima, Japan; ’ Department
of Cardiology, Minami Kyushu Chuo National Hospital, Kagoshima, Japan
(Received 7 January 1992; revision accepted 14 April 1992)
We assayed plasma myoglobin and creatine kinase to elucidate the usefulness of rapid assessment of myoglobin for detecting coronary reperfusion in 31 patients with acute myocardial infarction. Reperfusion was achieved in 20 patients by thrombolytic therapy or angioplasty, and it was not in 11 patients. Blood sampling was performed before and 43 f 15 (*SD) min after the start of treatment. In the reperfused group, blood samples were obtained before and 26 + 10 min after reperfusion. Myoglobin was assayed by a new quantitative test based on latex agglutination turbidimetry which required an assay time of 10 min. After treatment, the rate of increase of plasma myoglobin was significantly higher than that of plasma creatine kinase in the reperfused group (9.7 + 9.5 and 2.8 + 1.6-fold), but not in the occluded group (1.8 f 0.6 and 1.5 f 0.3-fold). When a 3.0-fold or greater increase in myoglobin (1.9-fold or greater increase in creatine kinase) was taken as evidence of coronary reperfusion, the sensitivity and specificity were 95% and 100% (70% and 82’% in creatine kinase), respectively. In conclusion, using the rate of increase of myoglobin, as measured by latex agglutination turbidimetry, coronary reperfusion can be diagnosed within 1 h after reperfusion. Key words: Myoglobin; Creatine agglutination turbidimetry
kinase; Coronary
Introduction With the development of thrombolytic agents, intravenous thrombolytic therapy in the acute phase of myocardial infarction has become widely
Correspondence to: H. Tanaka, M.D., First Dept. of Internal Medicine, Faculty of Medicine, Kagoshima University, 8-35-1, Sakuragaoka, Kagoshima, 890, Japan.
reperfusion;
Acute myocardial
infarction;
Latex
used without coronary angiography. Further interventions, such as coronary angioplasty and emergency coronary artery bypass surgery are required in cases without coronary reperfusion. Commonly used clinical markers of coronary reperfusion, including relief of chest pain, resolution of ST-segment elevation and occurrence of reperfusion arrhythmias, are not sensitive or specific indicators of the reperfusion status [1,2]. Therefore, a non-invasive and sensitive marker of
34
reperfusion of the infarct-related artery is required. Myoglobin has been reported to be a reliable biochemical marker of coronary reperfusion [3-61. However, the assay of plasma myoglobin, which has generally been performed by radioimmunoassay, is too time-consuming (assay time of more than l-2 h) to be performed in the emergency laboratory [7,8]. Accordingly, emergency assay of myoglobin has rarely been performed in the acute phase of myocardial infarction despite its high sensitivity. Recently, a quantitative assay of plasma myoglobin using latex agglutination turbidimetry, by which rapid assessment (assay time of 10 min) may be possible in the emergency laboratory, was developed by Kawata et al. [9,101. The aim of the present study was to evaluate the usefulness of quantitative assessment of plasma myoglobin using latex agglutination turbidimetry for detecting coronary reperfusion in patients with acute myocardial infarction. Methods Study population The study population consisted of 31 patients with acute myocardial infarction (19 male and 12 female, mean age 68 yr ranging from 48 to 81 yr) in whom thrombolytic therapy or angioplasty was performed within 6 h from the onset of chest pain. The criteria for the diagnosis of acute myocardial infarction were typical chest pain which lasted for more than 30 min and was not relieved by sublingual nitroglycerin, and a more than 0.1 mV ST-segment elevation in at least 2 adjacent electrocardiographic leads. Patients who developed shock or received direct countershock were excluded from the present study. In all patients, total occlusion of the infarct-related artery was documented by initial coronary angiogram using the Judkins technique. During thrombolytic therapy or coronary angioplasty, the patency of the infarct-related artery was confirmed by coronary angiography every 10 min up to 15 min after the second blood sampling. The degree of coronary reperfusion was determined according to the definitions of the TIM1 trial [ill.
Coronary reperfusion was defined as the advancement of grade 0 (no perfusion) to grade 2 (partial perfusion) or 3 flow (complete perfusion). Assays of plasma myoglobin and plasma creatine kinase Blood sampling was carried out immediately before and 10 to 75 min (mean 43 k 15 min) after the start of treatment through a sheath placed in the femoral artery. Plasma samples were drawn into test tubes containing EDTA-2Na, and immediately centrifuged at 3000 rpm for 5 min. Plasma concentration of myoglobin was assayed with a discrete analyser Hitachi 7050 (Hitachi, Tokyo, Japan) using a new reagent (Denka Seiken, Tokyo, Japan) which was based on latex agglutination turbidimetry [9,10]. In this method, a standard curve showed linearity over a range of 10-1200 ng/ml, and intra-assay and inter-assay coefficients of variation were 0.4-2.1% and 1.3-2.3%, respectively. This assay of myoglobin could be performed about 10 min. Creatine kinase activity was also assayed with a discrete analyzer Hitachi 7050 using enzymatic method (Boehringer Mannheim, Mannheim, Germany). Data analysis The rate of increase of myoglobin (creatine kinase), the sensitivity and specificity were determined as follows. (1) Rate of increase = plasma concentration of myoglobin (creatine kinase) after treatment/ plasma concentration of myoglobin (creatine kinase) before treatment. (2) Sensitivity = number of patients with patent artery and reperfusion criteria present/number of patients with patent artery. (3) Specificity = number of patients with occluded artery and reperfusion criteria absent/ number of patients with occluded artery. Data are presented as the mean f SD and the paired or nonpaired Wilcoxon test was used to assess the significance of differences between mean values. A p value of < 0.05 was considered significant.
35 pco.02
Results I
Clinical characteristics Table 1 shows the clinical characteristics. Twenty patients (Group A) were reperfused (TIM1 grade 2 or 3 flow) by thrombolytic therapy including intracoronary infusion of urokinase in 3, intravenous infusion of tissue plasminogen activator in 6 and pro-urokinase in 5, and by direct coronary angioplasty in 6 patients. Duration from the start of treatment to coronary reperfusion in patients with thrombolytic therapy and coronary angioplasty was 18 f 8 min and 4 f 3 min, respectively. Degree of delay of reperfused artery in all 9 patients with TIM1 grade 2 flow was equivalent to that of stenosis grade 3 in European cooperative study group [12]. In group A, blood sampling was carried out before and 39 f 14 min after the start of treatment (26 f 10 min after the onset of coronary reperfusion). On the other hand, 11
TABLE 1 Clinical characteristics.
Number Age
(yrf SD)
Sex Male Female Infarct-related artery LAD LCX RCA Time from the onset to treatment (h + SD) Time from treatment to blood sampling (min f SD) Treatment ic UK iv tPA iv pro-UK PTCA
Group A
Group B
20 66&9
11 71+10
15 5
7 4
13 1 6 4.1*1.1
7 2 2 4.4~ 1.6
39*14
3 6 5 6
50* 15
6 3 2 0
ic UK = intracoronary infusion of urokinase; iv pro-UK = intravenous infusion of pro-urokinase; iv tPA = intravenous infusion of tissue plasminogen activator; LAD = left anterior descending coronary artery; LCX = left circumflex coronary artery; PTCA = percutaneous transluminal coronary angioplasty; RCA = right coronary artery.
0
BEFORE GROUP
I
AFTER A
r
pco.01
BEFORE GROUP
I 1
AFTER e
Fig. 1. Plasma concentrations of myoglobin before and after treatment.
patients (Group B) were not reperfused (TIM1 grade 0 flow) by thrombolytic therapy including intracoronary infusion of urokinase in 6, and intravenous infusion of tissue plasminogen activator in 3 and pro-urokinase in 2 patients. In group B, blood sampling was carried out before and 50 k-15 min after the start of treatment. For 15 min after the second blood sampling, the degree of reperfusion of infarct-related artery on the coronary angiogram remained unchanged. There were no significant differences between the 2 groups in age, sex, infarct-related artery, time from the onset to treatment, or duration between blood sampling. Detection of coronary reperksion Before treatment (4.2 k 1.3 h after the onset of chest pain), plasma concentration of myoglobin in groups A and B was 300 -t 210 ng/ml and 443 + 352 ng/ml, respectively. There were no significant differences between the 2 groups. At 43 f 15 min after the start of treatment, the plasma concentration of myoglobin was significantly (p < 0.02) higher in group A (2437 k 2239 ng/ml) than in group B (772 + 670 ng/ml) (Fig. 1). Before treatment, the plasma concentration of creatine kinase in groups A and B was 140 + 120 IU/l and 220 f 324 IU/l, respectively, showing no significant difference between the 2 groups before and after treatment (Fig. 2).
36 NS
*
1
I
“1
I
NS’
r-=l
Y
0’ /
i
2’ i
BWONE
QNOUP
ACTER A
d ‘DEfoM
OROUP
ACrsd B
Fig. 2. Plasma concentrations of creatine kinase (CK) before and after treatment.
The rate of increase in the plasma concentrations of myoglobin and creatine kinase (43 f 15 min after the start of treatment/before treatment) was significantly higher in group A (9.7 f 9.5 and 2.8 f 1.6) than in group B (1.8 f 0.6 and 1.5 f 0.31, respectively. The rate of increase in the plasma concentration of myoglobin was significantly (p < 0.01) higher than that of creatine kinase in group A, but not in group B (Fig. 3). When a 3.0-fold or greater increase in the plasma concentration of myoglobin was taken as indicaMS I
‘P
Fig. 4. The time course of plasma myoglobin (Mb) and creatine kinase (CKI in a patient in whom intravenous infusion of tissue plasminogen activator (tPA) was successfully per formed.
tive of coronary reperfusion, the sensitivity and specificity of this index were 95% and lOO%, respectively. On the other hand, when a 1.9-fold or greater increase of plasma creatine kinase was taken as indicative of coronary reperfusion, the sensitivity and specificity were 70% and 82%, respectively. Fig. 4 shows the time course of the plasma concentrations of myoglobin and creatine kinase in a patient who underwent successful reperfusion (group A). The plasma concentration of myoglobin increases rapidly compared with that of creatine kinase after coronary reperfusion by thrombolytic therapy. Thirty minutes after the onset of reperfusion, the rate of increase in the plasma concentrations of myoglobin and creatine
C’
,/
3
,,/
~_~
O-
’ dl
TIME A QROUP b MYOQLOBIN
OROUP A
OROUP A
OROUP B C -K
Fig. 3. The rate of increase of plasma myoglobin and creatine kinase (CK) after treatment.
LR
TN&ANT
40 bho’& PTCA1-Ut..,’
Fig. 5. The time course of plasma myoglobin (Mb) and creatine kinase (CK) in a patient in whom percutaneous transluminal coronary angioplasty (PTCA) and intracoronary infusion of urokinase (UK) were unsuccessful.
31
kinase is 3.9 and 1.5, respectively. Fig. 5 shows the time course in a patient who underwent unsuccessful reperfusion (group B). The plasma concentrations of myoglobin and creatine kinase increase slowly despite both coronary angioplasty and thrombolytic therapy. Thirty and 60 min after the start of treatment, the rate of increase of myoglobin is 1.3 and 1.4, respectively. Discussion Detection of coronary reperhsion Relief of chest pain, resolution of ST-segment elevation and occurrence of reperfusion arrhythmia have been used commonly as indicators of coronary reperfusion. However, these clinical markers are not precise enough to allow the clinician to predict coronary reperfusion. Kircher et al. [l] reported that each criterion considered separately was relatively insensitive and lacked specificity, and using all 3 criteria, the predictive value was 100% but the sensitivity was only 14%. Califf et al. [2] also reported that only when ST-segment elevation had completely resolved, the probability of patency was extremely high, but this finding was uncommon (6% of patients). Myoglobin is a low molecular weight protein which is released from injured myocardium and rapidly excreted to the urine during the acute phase of myocardial infarction [13-N]. Grenadier et al. [17] reported that the time to the upper limit of normal value was 1.5 h from the onset of myocardial infarction for serum myoglobin and was significantly shorter than that of serum creatine kinase and creatine kinase-MB (4.5 h). Cairns et al. [18] also reported that the serum concentrations of myoglobin and creatine kinase were 8.3fold and 1.6-fold of the normal value at 4.4 h from the onset of myocardial infarction, respectively. Thus, the concentration of myoglobin is more sensitive as a diagnostic marker of acute myocardial infarction compared with creatine kinase or creatine kinase-MB. Recently, Ellis et al. [4] reported that myoglobin was rapidly washed out into the blood stream after reperfusion of the occluded artery in an animal study. They also reported that the rate of increase in the plasma
concentration of myoglobin over the first 1 or 2 h after the start of treatment was a sensitive index of coronary reperfusion. When more than a 4.6fold increase in the concentration of myoglobin over the first 2 h was regarded as evidence of coronary reperfusion, the sensitivity and specificity were 85% and lOO%, respectively [5]. Thus, assessment of the plasma concentration of myoglobin may be useful not only for diagnosing acute myocardial infarction but also for detecting successful coronary reperfusion. A rapid increase and early peaking of the plasma concentrations of creatine kinase and creatine kinase-MB have also been reported to be non-invasive indices of coronary reperfusion [19-231. In particular, Lewis et al. [22] reported that the first-hour increase of creatine kinase activity in patients with reperfusion (480 f 345 III/l/h) was significantly higher than that in patients without reperfusion (15 + 9 III/l/h). There have been several previous studies in which the clinical usefulness of the plasma concentration of myoglobin has been compared with that of creatine kinase or creatine kinase-MB as biochemical markers of coronary reperfusion [3,6,24,251. Slany et al. reported that time from the onset of chest pain to peak value of myoglobin in the reperfused group (5.5 f 1.3 h) was significantly shorter than that in the non-reperfused group (10.2 f 3.4 h), and described that when time to peak value of myoglobin 5 7h (16 h in creatine kinase) was taken as criterion of coronary reperfusion, the sensitivity and specificity were 83% (67%) and 89% @3%), respectively. Katus et al. [6] also reported that the time interval between reperfusion and marker protein peaking is significantly shorter for myoglobin than for creatine kinase and creatine kinase-MB, and the optimal discriminatory time limits for reperfusion were 7 h for myoglobin, 16 h for creatine kinase and 14.4 h for creatine kinase-MB with a probability of correct classification of 93%, 89% and 88%. However, long-term frequent blood sampling was necessary in these studies, because they used time from the onset of chest pain to reperfusion as an index of coronary reperfusion [3,6,24,25]. The present study is the first to assess the rate of increase in the plasma concentrations of both
38
myoglobin and creatine kinase in patients with acute myocardial infarction. The rate of increase of plasma myoglobin at 26 f 10 min after the onset of coronary reperfusion was markedly higher in the patients who had undergone successful reperfusion (9.7 f 9.5) than in those who had undergone unsuccessful reperfusion (1.8 f 0.6). The sensitivity and specificity for coronary reperfusion using a cut-off value of a 3.0-fold or greater increase in the plasma concentration of myoglobin were 95% and lOO%, respectively. On the other hand, the sensitivity and specificity for coronary reperfusion using the cut-off value of a 1.9-fold or greater increase in the plasma concentration of creatine kinase were 70% and 82%, respectively. Thus, we were able to obviously identify coronary reperfusion using the rate of increase in the plasma concentration of myoglobin compared with that of creatine kinase about 30 min after the onset of coronary reperfusion. The mechanisms of rapid washout of myoglobin compared with creatine kinase may be considered as follows. Firstly, molecular weight of myoglobin (18,000) is lower than that of creatine kinase (80,000). Secondly, creatine kinase is easily inactivated in situ before reperfusion. Thirdly, myoglobin releases directly to blood stream, however, creatine kinase enters the cardiac lymph in greater quantities [4]. Therefore, we could detect coronary reperfusion earlier using myoglobin (about 30 minutes after reperfusion) compared with previous studies using myoglobin [3,5,6] and those using creatine kinase [ 19-231. Significance of latex agglutination turbidimetry Myoglobin has generally been measured by radioimmunoassay which requires special laboratory facilities and an assay time of more than l-2 hours [7,8]. Since Slany et al., Ellis at al. and Katus et al. [3-61 used radioimmunoassay to measure serum myoglobin, they could not detect coronary reperfusion until several hours after the onset of reperfusion. Therefore, the value of myoglobin measured by radioimmunoassay had no advantage over that of creatine kinase and creatine kinase-MB as a non-invasive marker of
coronary reperfusion in the acute phase of myocardial infarction, because reperfusion was detectable using measurement of creatine kinase or creatine kinase-MB within 2 h from the onset of reperfusion [22,23]. On the other hand, the latex agglutination method can be performed rapidly and is suitable for emergency laboratory use. Recently, a semiquantitative latex agglutination test of myoglobin with an assay time of 5 minutes was used for diagnosing acute myocardial infarction [26-281. However, it was not used for detecting coronary reperfusion because the quantitative assay was difficult. Kawata et al. developed a method of quantitative assessment of myoglobin by latex agglutination turbidimetry and reported a good correlation between serum myoglobin levels measured by radioimmunoassay and latex agglutination turbidimetry (r = 0.995). In addition, the assay time of the new latex agglutination turbidimetry using a discrete analyser was 10 min, and was almost equal to that of creatine kinase [9,10]. Our study is the first to apply rapid and quantitative assay of myoglobin to detection of coronary reperfusion. We could obtain plasma concentrations of myoglobin about 15 min (5 min of centrifugation time + 10 min of assay time) after blood sampling, and thus we could diagnose whether or not coronary reperfusion was achieved within one hour (26 f 10 min + 15 min) after the onset of coronary reperfusion. Limitations and conclusion Detection of coronary reperfusion using the washout phenomenon of myoglobin has several limitations. Firstly, myoglobin does not have myocardial specificity at all. Since plasma concentrations of myoglobin increase in case of skeletal muscle injury, our method using the rate of increase of myoglobin cannot be applied to patients with surgical procedures, direct countershock, trauma and extensive cardiac catheterisation procedures [29]. Secondly, the time course of the plasma concentration of myoglobin is not clear in patients showing incomplete occlusion before the start of treatment, TIM1 grade 1 reperfusion or reocclusion after coronary reperfusion. Thirdly,
39
myoglobin may be washed out from the injured myocardium in patients who have persistently occluded coronary arteries and good collateral circulation. Hirai et al. [30] reported that early peaking of the plasma concentration of creatine kinase did not reliably indicate coronary reperfusion in patients who had marked collateral circulation. However, all patients had totally occluded arteries and no or poor collateral circulation before the start of treatment, and showed TIM1 grade 2 or 3 reperfusion and no reocclusion after coronary reperfusion in this study. For the application of biochemical detection of coronary reperfusion using myoglobin to intravenous thrombolytic therapy in the acute phase of myocardial infarction, further investigations about the relation between degree of coronary reperfusion or collateral circulation and washout phenomenon are necessary. Currently, the rate of increase of plasma myoglobin must be combined with clinical markers such as relief of chest pain, resolution of ST-segment elevation and occurrence of reperfusion arrhythmias in order to increase the accuracy of non-invasive detection of coronary reperfusion. In concZz&n, using the rate of increase in the plasma concentration of myoglobin, as measured by latex agglutination turbidimetry, coronary reperfusion can be diagnosed within one h after the onset of reperfusion in patients with acute myocardial infarction. Acknowledgment We thank Makoto Ueno for expert technical assistance. References Kircher BJ, Top01 EJ, O’Neill WW, Pitt B. Prediction of infarct coronary artery recanalization after intravenous thrombolytic therapy. Am J Cardiol 1987;59:513-515. Califf RM, O’Neil W, Stack RS et al. Failure of simple clinical measurements to predict perfusion status after intravenous thrombolysis. Ann Intern Med 1988;108:658662. Slany J, Kroiss A, Ziegler B, Zajicek P, Vanicek T. Frischer Myokardinfarkt; Beurteilung des Thrombolyse-effektes mit Hilfe wiederholter Myoglobin-Bestimmungen. Diagn Intensivther 1983;16:1-6.
4 Ellis AK, Little T, Masud ARZ, Klocke FJ. Patterns of myoglobin release after reperfusion of injured myocardium. Circulation 1985;72:639-647. 5 Ellis AK, Little T, Masud ARZ, Liberman HA, Morris DC, Klocke FJ. Early noninvasive detection of successful reperfusion in patients with acute myocardial infarction. Circulation 1988;78:1352-1357. 6 Katus HA, Diedich KW, Scheffold T, Uellner M, Schwarz F, Kubler W. Non-invasive assessment of infarct reperfusion: the predictive power of the time to peak value of myoglobin, CKMB, and CK in serum. Eur Heart J 1988:9;619-624. 7 Gilkeson G, Stone MJ, Waterman M et al. Detection of myoglobin by radioimmunoassay in human sera: Its usefulness and limitations as an emergency room screening test for acute myocardial infarction. Am Heart J 1978;95:70-77. 8 Grachev MA, Matveev LE, Pressman EK, Roschke VV. A rapid method for myoglobin radioimmunoanalysis as a diagnostic tool in myocardial infarction. Clin Chim Acta 1982;124:235-238. 9 Kawata Y, Fujita S, Katayama Y, Matsuyama T. Evaluation of the rapid method for the quantitation of serum myoglobin by the latex agglutination turbidimetry and studies on the changes in serum levels with acute myocardial infarction. Jpn J Clin Path01 1989;37:668-672 (in Japanese). 10 Uji Y, Okabe H, Sugiuchi H, Sekine S. Measurement of serum myoglobin by a turbidimetric latex agglutination method. J Clin Lab Anal 1992:8;7-11. 11 The TIM1 Study Group. The thrombolysis in myocardial infarction (TIMI) trial. Phase I findings. N Engl J Med 1985;312:932-936. 12 Verstraete M, Bernard R, Bory M, et al. Randomised trial of intravenous recombinant tissue-type plasminogen activator versus intravenous streptokinase in acute myocardial infarction. Report from the European cooperative study group for recombinant tissue-type plasminogen activator. Lancet 1985;1:842-847. 13 Kagen L, Scheidt S, Roberts L, Porter A, Paul H. Myoglobinemia following acute myocardial infarction. Am J Med 1975;58:177-182. 14 Stone MJ, Willerson JT, Gomez-Sanchez CE, Waterman MR. Radioimmunoassay of myoglobin in human serum. Results in patients with acute myocardial infarction. J Clin Invest 1975;56:1334-1339. 15 Miyoshi K, Saito S, Kawai H, et al. Radioimmunoassay for human myoglobin: methods and results in patients with skeletal muscle or myocardial disorders. J Lab Clin Med 1978;92:341-352. 16 Klocke FJ, Copley DP, Krawczyk JA, Reichlin M. Rapid renal clearance of immunoreactive canine plasma myoglobin. Circulation 1982;65:1522-1528. 17 Grenadier E, Keidar S, Kahana L, Alpan G, Marmur A, Palant A. The roles of serum myoglobin, total CPK, and CK-MB isoenzyme in the acute phase of myocardial infarction. Am Heart J 1983;105:408-416. 18 Cairns JA, Missirlis E, Walker WHC. Usefulness of serial
40
19
20
21
22
23
24
determinations of myoglobin and creatine kinase in serum compared for assessment of acute myocardial infarction. Clin Chem 1983;29:469-473. Shell W, Mickle DK, Swan HJC. Effects of nonsurgical myocardial reperfusion on plasma creatine kinase kinetics in man. Am Heart J 1983;106:665-669. Blanke H, von Hardenberg D, Cohen M et al. Patterns of creatine kinase release during acute myocardial infarction after nonsurgical reperfusion: comparison with conventional treatment and correlation with infarct size. J Am Co11Cardiol 1984;3:675-680. Wei JY, Markis JE, Malagold M, Grossman W. Time course of serum cardiac enzymes after intracoronary thrombolytic therapy. Creatine kinase, creatine kinase MB isozyme, lactate dehydrogenase, and serum glutamicoxaloacetic transaminase. Arch Intern Med 1985;145: 1596-1600. Lewis BS, Ganz W, Laramee P et al. Usefulness of a rapid initial increase in plasma creatine kinase activity as a marker of reperfusion during thrombolytic therapy for acute myocardial infarction. Am J Cardiol 1988;62:20-24. Ong L, Coromilas J, Zimmerman JM et al. A physiologically based model of creatine kinase-MB release in reperfusion of acute myocardial infarction. Am J Cardiol 1989;64:11-15. Kaiser H, Rumpf KW, Spaar U, Kreuzer H. Serum-
25
26
27
28
29
30
Myoglobin: klinisch-diagnostische Relevanz. Laboratoriumsblatter 1984;34:17-25. Golf SW, Temme H, Kempf KD, Bleyl H, Briistle A. Systemic short-term fibrinolysis with high-dose streptokinase in acute myocardial infarction: time course of biochemical parameters. J Clin Chem Clin Biochem 1984;22: 723-729. Norregaard-Hansen K, Hangaard J, Norgaard-Pedersen B. A rapid latex agglutination test for detection of elevated levels of myoglobin in serum and its value in the early diagnosis of acute myocardial infarction. Stand J Clin Lab Invest 1984;44:99-103. Chapelle JP, Heusghem C. Semi-quantitative estimation of serum myoglobin by a rapid latex agglutination method: an emergency screening test for acute myocardial infarction. Clin Chim Acta 1985;145:143-150. Mainard F, Massoubre B, IX Marec H, Madec Y. Study of a myoglobin test in patients hospitalized for suspected myocardial infarction. Clin Chim Acta 1985;153:1-8. Varki AP, Roby DS, Watts H, Zatuchni J. Serum myoglobin in acute myocardial infarction: a clinical study and review of the literature. Am Heart J 1978;96:680-688. Hirai T, Fujita M, Sasayama S et al. Importance of coronary collateral circulation for kinetics of serum creatine kinase in acute myocardial infarction. Am J Cardiol 1987; 60:446-450.
International Journal of Cardiology, 38 (1993) 33-40 0 1993 Elsevier Scientific Publishers Ireland Ltd. All rights reserved 0167-5273/93/$06.00
CARD10 01583
Early detection of coronary reperfusion by rapid assessment of plasma myoglobin Satoshi Abe a, Shinichi Arima a, Kunihiro Nomoto ‘, Ikuro Maruyama b, Masaaki Miyata a, Hiroshi Yamaguchi a, Hideki Okino a, Tsuminori Yamashita a, Yoshihiko Atsuchi a, Minoru Tahara a, Shoichiro Nakao a and Hiromitsu Tanaka a ’ First Department of Internal Medicine and ’ Third Department of Internal Medicine, Faculty of Medicine, Kagoshima University, Kagoshima, Japan; ’ Department
of Cardiology, Minami Kyushu Chuo National Hospital, Kagoshima, Japan
(Received 7 January 1992; revision accepted 14 April 1992)
We assayed plasma myoglobin and creatine kinase to elucidate the usefulness of rapid assessment of myoglobin for detecting coronary reperfusion in 31 patients with acute myocardial infarction. Reperfusion was achieved in 20 patients by thrombolytic therapy or angioplasty, and it was not in 11 patients. Blood sampling was performed before and 43 f 15 (*SD) min after the start of treatment. In the reperfused group, blood samples were obtained before and 26 + 10 min after reperfusion. Myoglobin was assayed by a new quantitative test based on latex agglutination turbidimetry which required an assay time of 10 min. After treatment, the rate of increase of plasma myoglobin was significantly higher than that of plasma creatine kinase in the reperfused group (9.7 + 9.5 and 2.8 + 1.6-fold), but not in the occluded group (1.8 f 0.6 and 1.5 f 0.3-fold). When a 3.0-fold or greater increase in myoglobin (1.9-fold or greater increase in creatine kinase) was taken as evidence of coronary reperfusion, the sensitivity and specificity were 95% and 100% (70% and 82’% in creatine kinase), respectively. In conclusion, using the rate of increase of myoglobin, as measured by latex agglutination turbidimetry, coronary reperfusion can be diagnosed within 1 h after reperfusion. Key words: Myoglobin; Creatine agglutination turbidimetry
kinase; Coronary
Introduction With the development of thrombolytic agents, intravenous thrombolytic therapy in the acute phase of myocardial infarction has become widely
Correspondence to: H. Tanaka, M.D., First Dept. of Internal Medicine, Faculty of Medicine, Kagoshima University, 8-35-1, Sakuragaoka, Kagoshima, 890, Japan.
reperfusion;
Acute myocardial
infarction;
Latex
used without coronary angiography. Further interventions, such as coronary angioplasty and emergency coronary artery bypass surgery are required in cases without coronary reperfusion. Commonly used clinical markers of coronary reperfusion, including relief of chest pain, resolution of ST-segment elevation and occurrence of reperfusion arrhythmias, are not sensitive or specific indicators of the reperfusion status [1,2]. Therefore, a non-invasive and sensitive marker of
34
reperfusion of the infarct-related artery is required. Myoglobin has been reported to be a reliable biochemical marker of coronary reperfusion [3-61. However, the assay of plasma myoglobin, which has generally been performed by radioimmunoassay, is too time-consuming (assay time of more than l-2 h) to be performed in the emergency laboratory [7,8]. Accordingly, emergency assay of myoglobin has rarely been performed in the acute phase of myocardial infarction despite its high sensitivity. Recently, a quantitative assay of plasma myoglobin using latex agglutination turbidimetry, by which rapid assessment (assay time of 10 min) may be possible in the emergency laboratory, was developed by Kawata et al. [9,101. The aim of the present study was to evaluate the usefulness of quantitative assessment of plasma myoglobin using latex agglutination turbidimetry for detecting coronary reperfusion in patients with acute myocardial infarction. Methods Study population The study population consisted of 31 patients with acute myocardial infarction (19 male and 12 female, mean age 68 yr ranging from 48 to 81 yr) in whom thrombolytic therapy or angioplasty was performed within 6 h from the onset of chest pain. The criteria for the diagnosis of acute myocardial infarction were typical chest pain which lasted for more than 30 min and was not relieved by sublingual nitroglycerin, and a more than 0.1 mV ST-segment elevation in at least 2 adjacent electrocardiographic leads. Patients who developed shock or received direct countershock were excluded from the present study. In all patients, total occlusion of the infarct-related artery was documented by initial coronary angiogram using the Judkins technique. During thrombolytic therapy or coronary angioplasty, the patency of the infarct-related artery was confirmed by coronary angiography every 10 min up to 15 min after the second blood sampling. The degree of coronary reperfusion was determined according to the definitions of the TIM1 trial [ill.
Coronary reperfusion was defined as the advancement of grade 0 (no perfusion) to grade 2 (partial perfusion) or 3 flow (complete perfusion). Assays of plasma myoglobin and plasma creatine kinase Blood sampling was carried out immediately before and 10 to 75 min (mean 43 k 15 min) after the start of treatment through a sheath placed in the femoral artery. Plasma samples were drawn into test tubes containing EDTA-2Na, and immediately centrifuged at 3000 rpm for 5 min. Plasma concentration of myoglobin was assayed with a discrete analyser Hitachi 7050 (Hitachi, Tokyo, Japan) using a new reagent (Denka Seiken, Tokyo, Japan) which was based on latex agglutination turbidimetry [9,10]. In this method, a standard curve showed linearity over a range of 10-1200 ng/ml, and intra-assay and inter-assay coefficients of variation were 0.4-2.1% and 1.3-2.3%, respectively. This assay of myoglobin could be performed about 10 min. Creatine kinase activity was also assayed with a discrete analyzer Hitachi 7050 using enzymatic method (Boehringer Mannheim, Mannheim, Germany). Data analysis The rate of increase of myoglobin (creatine kinase), the sensitivity and specificity were determined as follows. (1) Rate of increase = plasma concentration of myoglobin (creatine kinase) after treatment/ plasma concentration of myoglobin (creatine kinase) before treatment. (2) Sensitivity = number of patients with patent artery and reperfusion criteria present/number of patients with patent artery. (3) Specificity = number of patients with occluded artery and reperfusion criteria absent/ number of patients with occluded artery. Data are presented as the mean f SD and the paired or nonpaired Wilcoxon test was used to assess the significance of differences between mean values. A p value of < 0.05 was considered significant.
35 pco.02
Results I
Clinical characteristics Table 1 shows the clinical characteristics. Twenty patients (Group A) were reperfused (TIM1 grade 2 or 3 flow) by thrombolytic therapy including intracoronary infusion of urokinase in 3, intravenous infusion of tissue plasminogen activator in 6 and pro-urokinase in 5, and by direct coronary angioplasty in 6 patients. Duration from the start of treatment to coronary reperfusion in patients with thrombolytic therapy and coronary angioplasty was 18 f 8 min and 4 f 3 min, respectively. Degree of delay of reperfused artery in all 9 patients with TIM1 grade 2 flow was equivalent to that of stenosis grade 3 in European cooperative study group [12]. In group A, blood sampling was carried out before and 39 f 14 min after the start of treatment (26 f 10 min after the onset of coronary reperfusion). On the other hand, 11
TABLE 1 Clinical characteristics.
Number Age
(yrf SD)
Sex Male Female Infarct-related artery LAD LCX RCA Time from the onset to treatment (h + SD) Time from treatment to blood sampling (min f SD) Treatment ic UK iv tPA iv pro-UK PTCA
Group A
Group B
20 66&9
11 71+10
15 5
7 4
13 1 6 4.1*1.1
7 2 2 4.4~ 1.6
39*14
3 6 5 6
50* 15
6 3 2 0
ic UK = intracoronary infusion of urokinase; iv pro-UK = intravenous infusion of pro-urokinase; iv tPA = intravenous infusion of tissue plasminogen activator; LAD = left anterior descending coronary artery; LCX = left circumflex coronary artery; PTCA = percutaneous transluminal coronary angioplasty; RCA = right coronary artery.
0
BEFORE GROUP
I
AFTER A
r
pco.01
BEFORE GROUP
I 1
AFTER e
Fig. 1. Plasma concentrations of myoglobin before and after treatment.
patients (Group B) were not reperfused (TIM1 grade 0 flow) by thrombolytic therapy including intracoronary infusion of urokinase in 6, and intravenous infusion of tissue plasminogen activator in 3 and pro-urokinase in 2 patients. In group B, blood sampling was carried out before and 50 k-15 min after the start of treatment. For 15 min after the second blood sampling, the degree of reperfusion of infarct-related artery on the coronary angiogram remained unchanged. There were no significant differences between the 2 groups in age, sex, infarct-related artery, time from the onset to treatment, or duration between blood sampling. Detection of coronary reperksion Before treatment (4.2 k 1.3 h after the onset of chest pain), plasma concentration of myoglobin in groups A and B was 300 -t 210 ng/ml and 443 + 352 ng/ml, respectively. There were no significant differences between the 2 groups. At 43 f 15 min after the start of treatment, the plasma concentration of myoglobin was significantly (p < 0.02) higher in group A (2437 k 2239 ng/ml) than in group B (772 + 670 ng/ml) (Fig. 1). Before treatment, the plasma concentration of creatine kinase in groups A and B was 140 + 120 IU/l and 220 f 324 IU/l, respectively, showing no significant difference between the 2 groups before and after treatment (Fig. 2).
36 NS
*
1
I
“1
I
NS’
r-=l
Y
0’ /
i
2’ i
BWONE
QNOUP
ACTER A
d ‘DEfoM
OROUP
ACrsd B
Fig. 2. Plasma concentrations of creatine kinase (CK) before and after treatment.
The rate of increase in the plasma concentrations of myoglobin and creatine kinase (43 f 15 min after the start of treatment/before treatment) was significantly higher in group A (9.7 f 9.5 and 2.8 f 1.6) than in group B (1.8 f 0.6 and 1.5 f 0.31, respectively. The rate of increase in the plasma concentration of myoglobin was significantly (p < 0.01) higher than that of creatine kinase in group A, but not in group B (Fig. 3). When a 3.0-fold or greater increase in the plasma concentration of myoglobin was taken as indicaMS I
‘P
Fig. 4. The time course of plasma myoglobin (Mb) and creatine kinase (CKI in a patient in whom intravenous infusion of tissue plasminogen activator (tPA) was successfully per formed.
tive of coronary reperfusion, the sensitivity and specificity of this index were 95% and lOO%, respectively. On the other hand, when a 1.9-fold or greater increase of plasma creatine kinase was taken as indicative of coronary reperfusion, the sensitivity and specificity were 70% and 82%, respectively. Fig. 4 shows the time course of the plasma concentrations of myoglobin and creatine kinase in a patient who underwent successful reperfusion (group A). The plasma concentration of myoglobin increases rapidly compared with that of creatine kinase after coronary reperfusion by thrombolytic therapy. Thirty minutes after the onset of reperfusion, the rate of increase in the plasma concentrations of myoglobin and creatine
C’
,/
3
,,/
~_~
O-
’ dl
TIME A QROUP b MYOQLOBIN
OROUP A
OROUP A
OROUP B C -K
Fig. 3. The rate of increase of plasma myoglobin and creatine kinase (CK) after treatment.
LR
TN&ANT
40 bho’& PTCA1-Ut..,’
Fig. 5. The time course of plasma myoglobin (Mb) and creatine kinase (CK) in a patient in whom percutaneous transluminal coronary angioplasty (PTCA) and intracoronary infusion of urokinase (UK) were unsuccessful.
31
kinase is 3.9 and 1.5, respectively. Fig. 5 shows the time course in a patient who underwent unsuccessful reperfusion (group B). The plasma concentrations of myoglobin and creatine kinase increase slowly despite both coronary angioplasty and thrombolytic therapy. Thirty and 60 min after the start of treatment, the rate of increase of myoglobin is 1.3 and 1.4, respectively. Discussion Detection of coronary reperhsion Relief of chest pain, resolution of ST-segment elevation and occurrence of reperfusion arrhythmia have been used commonly as indicators of coronary reperfusion. However, these clinical markers are not precise enough to allow the clinician to predict coronary reperfusion. Kircher et al. [l] reported that each criterion considered separately was relatively insensitive and lacked specificity, and using all 3 criteria, the predictive value was 100% but the sensitivity was only 14%. Califf et al. [2] also reported that only when ST-segment elevation had completely resolved, the probability of patency was extremely high, but this finding was uncommon (6% of patients). Myoglobin is a low molecular weight protein which is released from injured myocardium and rapidly excreted to the urine during the acute phase of myocardial infarction [13-N]. Grenadier et al. [17] reported that the time to the upper limit of normal value was 1.5 h from the onset of myocardial infarction for serum myoglobin and was significantly shorter than that of serum creatine kinase and creatine kinase-MB (4.5 h). Cairns et al. [18] also reported that the serum concentrations of myoglobin and creatine kinase were 8.3fold and 1.6-fold of the normal value at 4.4 h from the onset of myocardial infarction, respectively. Thus, the concentration of myoglobin is more sensitive as a diagnostic marker of acute myocardial infarction compared with creatine kinase or creatine kinase-MB. Recently, Ellis et al. [4] reported that myoglobin was rapidly washed out into the blood stream after reperfusion of the occluded artery in an animal study. They also reported that the rate of increase in the plasma
concentration of myoglobin over the first 1 or 2 h after the start of treatment was a sensitive index of coronary reperfusion. When more than a 4.6fold increase in the concentration of myoglobin over the first 2 h was regarded as evidence of coronary reperfusion, the sensitivity and specificity were 85% and lOO%, respectively [5]. Thus, assessment of the plasma concentration of myoglobin may be useful not only for diagnosing acute myocardial infarction but also for detecting successful coronary reperfusion. A rapid increase and early peaking of the plasma concentrations of creatine kinase and creatine kinase-MB have also been reported to be non-invasive indices of coronary reperfusion [19-231. In particular, Lewis et al. [22] reported that the first-hour increase of creatine kinase activity in patients with reperfusion (480 f 345 III/l/h) was significantly higher than that in patients without reperfusion (15 + 9 III/l/h). There have been several previous studies in which the clinical usefulness of the plasma concentration of myoglobin has been compared with that of creatine kinase or creatine kinase-MB as biochemical markers of coronary reperfusion [3,6,24,251. Slany et al. reported that time from the onset of chest pain to peak value of myoglobin in the reperfused group (5.5 f 1.3 h) was significantly shorter than that in the non-reperfused group (10.2 f 3.4 h), and described that when time to peak value of myoglobin 5 7h (16 h in creatine kinase) was taken as criterion of coronary reperfusion, the sensitivity and specificity were 83% (67%) and 89% @3%), respectively. Katus et al. [6] also reported that the time interval between reperfusion and marker protein peaking is significantly shorter for myoglobin than for creatine kinase and creatine kinase-MB, and the optimal discriminatory time limits for reperfusion were 7 h for myoglobin, 16 h for creatine kinase and 14.4 h for creatine kinase-MB with a probability of correct classification of 93%, 89% and 88%. However, long-term frequent blood sampling was necessary in these studies, because they used time from the onset of chest pain to reperfusion as an index of coronary reperfusion [3,6,24,25]. The present study is the first to assess the rate of increase in the plasma concentrations of both
38
myoglobin and creatine kinase in patients with acute myocardial infarction. The rate of increase of plasma myoglobin at 26 f 10 min after the onset of coronary reperfusion was markedly higher in the patients who had undergone successful reperfusion (9.7 f 9.5) than in those who had undergone unsuccessful reperfusion (1.8 f 0.6). The sensitivity and specificity for coronary reperfusion using a cut-off value of a 3.0-fold or greater increase in the plasma concentration of myoglobin were 95% and lOO%, respectively. On the other hand, the sensitivity and specificity for coronary reperfusion using the cut-off value of a 1.9-fold or greater increase in the plasma concentration of creatine kinase were 70% and 82%, respectively. Thus, we were able to obviously identify coronary reperfusion using the rate of increase in the plasma concentration of myoglobin compared with that of creatine kinase about 30 min after the onset of coronary reperfusion. The mechanisms of rapid washout of myoglobin compared with creatine kinase may be considered as follows. Firstly, molecular weight of myoglobin (18,000) is lower than that of creatine kinase (80,000). Secondly, creatine kinase is easily inactivated in situ before reperfusion. Thirdly, myoglobin releases directly to blood stream, however, creatine kinase enters the cardiac lymph in greater quantities [4]. Therefore, we could detect coronary reperfusion earlier using myoglobin (about 30 minutes after reperfusion) compared with previous studies using myoglobin [3,5,6] and those using creatine kinase [ 19-231. Significance of latex agglutination turbidimetry Myoglobin has generally been measured by radioimmunoassay which requires special laboratory facilities and an assay time of more than l-2 hours [7,8]. Since Slany et al., Ellis at al. and Katus et al. [3-61 used radioimmunoassay to measure serum myoglobin, they could not detect coronary reperfusion until several hours after the onset of reperfusion. Therefore, the value of myoglobin measured by radioimmunoassay had no advantage over that of creatine kinase and creatine kinase-MB as a non-invasive marker of
coronary reperfusion in the acute phase of myocardial infarction, because reperfusion was detectable using measurement of creatine kinase or creatine kinase-MB within 2 h from the onset of reperfusion [22,23]. On the other hand, the latex agglutination method can be performed rapidly and is suitable for emergency laboratory use. Recently, a semiquantitative latex agglutination test of myoglobin with an assay time of 5 minutes was used for diagnosing acute myocardial infarction [26-281. However, it was not used for detecting coronary reperfusion because the quantitative assay was difficult. Kawata et al. developed a method of quantitative assessment of myoglobin by latex agglutination turbidimetry and reported a good correlation between serum myoglobin levels measured by radioimmunoassay and latex agglutination turbidimetry (r = 0.995). In addition, the assay time of the new latex agglutination turbidimetry using a discrete analyser was 10 min, and was almost equal to that of creatine kinase [9,10]. Our study is the first to apply rapid and quantitative assay of myoglobin to detection of coronary reperfusion. We could obtain plasma concentrations of myoglobin about 15 min (5 min of centrifugation time + 10 min of assay time) after blood sampling, and thus we could diagnose whether or not coronary reperfusion was achieved within one hour (26 f 10 min + 15 min) after the onset of coronary reperfusion. Limitations and conclusion Detection of coronary reperfusion using the washout phenomenon of myoglobin has several limitations. Firstly, myoglobin does not have myocardial specificity at all. Since plasma concentrations of myoglobin increase in case of skeletal muscle injury, our method using the rate of increase of myoglobin cannot be applied to patients with surgical procedures, direct countershock, trauma and extensive cardiac catheterisation procedures [29]. Secondly, the time course of the plasma concentration of myoglobin is not clear in patients showing incomplete occlusion before the start of treatment, TIM1 grade 1 reperfusion or reocclusion after coronary reperfusion. Thirdly,
39
myoglobin may be washed out from the injured myocardium in patients who have persistently occluded coronary arteries and good collateral circulation. Hirai et al. [30] reported that early peaking of the plasma concentration of creatine kinase did not reliably indicate coronary reperfusion in patients who had marked collateral circulation. However, all patients had totally occluded arteries and no or poor collateral circulation before the start of treatment, and showed TIM1 grade 2 or 3 reperfusion and no reocclusion after coronary reperfusion in this study. For the application of biochemical detection of coronary reperfusion using myoglobin to intravenous thrombolytic therapy in the acute phase of myocardial infarction, further investigations about the relation between degree of coronary reperfusion or collateral circulation and washout phenomenon are necessary. Currently, the rate of increase of plasma myoglobin must be combined with clinical markers such as relief of chest pain, resolution of ST-segment elevation and occurrence of reperfusion arrhythmias in order to increase the accuracy of non-invasive detection of coronary reperfusion. In concZz&n, using the rate of increase in the plasma concentration of myoglobin, as measured by latex agglutination turbidimetry, coronary reperfusion can be diagnosed within one h after the onset of reperfusion in patients with acute myocardial infarction. Acknowledgment We thank Makoto Ueno for expert technical assistance. References Kircher BJ, Top01 EJ, O’Neill WW, Pitt B. Prediction of infarct coronary artery recanalization after intravenous thrombolytic therapy. Am J Cardiol 1987;59:513-515. Califf RM, O’Neil W, Stack RS et al. Failure of simple clinical measurements to predict perfusion status after intravenous thrombolysis. Ann Intern Med 1988;108:658662. Slany J, Kroiss A, Ziegler B, Zajicek P, Vanicek T. Frischer Myokardinfarkt; Beurteilung des Thrombolyse-effektes mit Hilfe wiederholter Myoglobin-Bestimmungen. Diagn Intensivther 1983;16:1-6.
4 Ellis AK, Little T, Masud ARZ, Klocke FJ. Patterns of myoglobin release after reperfusion of injured myocardium. Circulation 1985;72:639-647. 5 Ellis AK, Little T, Masud ARZ, Liberman HA, Morris DC, Klocke FJ. Early noninvasive detection of successful reperfusion in patients with acute myocardial infarction. Circulation 1988;78:1352-1357. 6 Katus HA, Diedich KW, Scheffold T, Uellner M, Schwarz F, Kubler W. Non-invasive assessment of infarct reperfusion: the predictive power of the time to peak value of myoglobin, CKMB, and CK in serum. Eur Heart J 1988:9;619-624. 7 Gilkeson G, Stone MJ, Waterman M et al. Detection of myoglobin by radioimmunoassay in human sera: Its usefulness and limitations as an emergency room screening test for acute myocardial infarction. Am Heart J 1978;95:70-77. 8 Grachev MA, Matveev LE, Pressman EK, Roschke VV. A rapid method for myoglobin radioimmunoanalysis as a diagnostic tool in myocardial infarction. Clin Chim Acta 1982;124:235-238. 9 Kawata Y, Fujita S, Katayama Y, Matsuyama T. Evaluation of the rapid method for the quantitation of serum myoglobin by the latex agglutination turbidimetry and studies on the changes in serum levels with acute myocardial infarction. Jpn J Clin Path01 1989;37:668-672 (in Japanese). 10 Uji Y, Okabe H, Sugiuchi H, Sekine S. Measurement of serum myoglobin by a turbidimetric latex agglutination method. J Clin Lab Anal 1992:8;7-11. 11 The TIM1 Study Group. The thrombolysis in myocardial infarction (TIMI) trial. Phase I findings. N Engl J Med 1985;312:932-936. 12 Verstraete M, Bernard R, Bory M, et al. Randomised trial of intravenous recombinant tissue-type plasminogen activator versus intravenous streptokinase in acute myocardial infarction. Report from the European cooperative study group for recombinant tissue-type plasminogen activator. Lancet 1985;1:842-847. 13 Kagen L, Scheidt S, Roberts L, Porter A, Paul H. Myoglobinemia following acute myocardial infarction. Am J Med 1975;58:177-182. 14 Stone MJ, Willerson JT, Gomez-Sanchez CE, Waterman MR. Radioimmunoassay of myoglobin in human serum. Results in patients with acute myocardial infarction. J Clin Invest 1975;56:1334-1339. 15 Miyoshi K, Saito S, Kawai H, et al. Radioimmunoassay for human myoglobin: methods and results in patients with skeletal muscle or myocardial disorders. J Lab Clin Med 1978;92:341-352. 16 Klocke FJ, Copley DP, Krawczyk JA, Reichlin M. Rapid renal clearance of immunoreactive canine plasma myoglobin. Circulation 1982;65:1522-1528. 17 Grenadier E, Keidar S, Kahana L, Alpan G, Marmur A, Palant A. The roles of serum myoglobin, total CPK, and CK-MB isoenzyme in the acute phase of myocardial infarction. Am Heart J 1983;105:408-416. 18 Cairns JA, Missirlis E, Walker WHC. Usefulness of serial
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19
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21
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24
determinations of myoglobin and creatine kinase in serum compared for assessment of acute myocardial infarction. Clin Chem 1983;29:469-473. Shell W, Mickle DK, Swan HJC. Effects of nonsurgical myocardial reperfusion on plasma creatine kinase kinetics in man. Am Heart J 1983;106:665-669. Blanke H, von Hardenberg D, Cohen M et al. Patterns of creatine kinase release during acute myocardial infarction after nonsurgical reperfusion: comparison with conventional treatment and correlation with infarct size. J Am Co11Cardiol 1984;3:675-680. Wei JY, Markis JE, Malagold M, Grossman W. Time course of serum cardiac enzymes after intracoronary thrombolytic therapy. Creatine kinase, creatine kinase MB isozyme, lactate dehydrogenase, and serum glutamicoxaloacetic transaminase. Arch Intern Med 1985;145: 1596-1600. Lewis BS, Ganz W, Laramee P et al. Usefulness of a rapid initial increase in plasma creatine kinase activity as a marker of reperfusion during thrombolytic therapy for acute myocardial infarction. Am J Cardiol 1988;62:20-24. Ong L, Coromilas J, Zimmerman JM et al. A physiologically based model of creatine kinase-MB release in reperfusion of acute myocardial infarction. Am J Cardiol 1989;64:11-15. Kaiser H, Rumpf KW, Spaar U, Kreuzer H. Serum-
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Myoglobin: klinisch-diagnostische Relevanz. Laboratoriumsblatter 1984;34:17-25. Golf SW, Temme H, Kempf KD, Bleyl H, Briistle A. Systemic short-term fibrinolysis with high-dose streptokinase in acute myocardial infarction: time course of biochemical parameters. J Clin Chem Clin Biochem 1984;22: 723-729. Norregaard-Hansen K, Hangaard J, Norgaard-Pedersen B. A rapid latex agglutination test for detection of elevated levels of myoglobin in serum and its value in the early diagnosis of acute myocardial infarction. Stand J Clin Lab Invest 1984;44:99-103. Chapelle JP, Heusghem C. Semi-quantitative estimation of serum myoglobin by a rapid latex agglutination method: an emergency screening test for acute myocardial infarction. Clin Chim Acta 1985;145:143-150. Mainard F, Massoubre B, IX Marec H, Madec Y. Study of a myoglobin test in patients hospitalized for suspected myocardial infarction. Clin Chim Acta 1985;153:1-8. Varki AP, Roby DS, Watts H, Zatuchni J. Serum myoglobin in acute myocardial infarction: a clinical study and review of the literature. Am Heart J 1978;96:680-688. Hirai T, Fujita M, Sasayama S et al. Importance of coronary collateral circulation for kinetics of serum creatine kinase in acute myocardial infarction. Am J Cardiol 1987; 60:446-450.