THROMBOSIS RESEARCH 67; 191-200,1992 0049-3848/92 $5.00 + .OO Printed in the USA. Copyright (c) 1992 Pergamon Press Ltd. All rights reserved.

FIBRINOLYTIC EFFECTS OF PRO-UROKINASE COMBINED WITH LOW-DOSE UROKINASE COMPARED TO HIGH-DOSE UROKINASE IN PATIENTS WITH ACUTE MYOCARDIAL INFARCTION G. Pindur, M. Koehler, S. Sen‘, E. Wenzel, H. Schieffer'

R. Hermes,

C. Miyashita,

gepartment of Clinical Haemostaseology and Transfusion Department of Internal Medicine III, University Saarland, D-6650 Homburg, FRG (Received

24.4.1992;

accepted

in revised form 3.6.1992

Medicine, of the

by Editor H.A. Vinazzer)

ABSTRACT 20 patients (6 females, 14 males) aged between 47 and and 75 years (mean: 62.6 yrs.) with acute myocardial 6 hours) were infarction (onset of symptoms within treated intravenously with either 200,000 U urokinase U pro-urokinase (pro-UK) within (UK) and 4.5 million 60 min (group I,N=lO),or 2.5 million U UK within 5 min (group 11,N = 10). Blood samples for haemostatic and function tests were taken prior to and fibrinolytic repeatedly during the 24 hours following treatment. activity measured by fibrin plates Peak fibrinolytic Average decreases, was equivalent in both regimens. following with lowest levels within 60 to 120 min thrombolytic therapy, were observed of 27% and 70% for of 71% and 91% for alpha-2-antiplasmin, plasminogen, in group I and and of 20% and 74% for fibrinogen The reptilase time reached maximum II, respectively. within 60 to 180 min. values of 1.5- and 4.5-fold III Peak levels of D-dimers and thrombin-antithrombin complexes in group II were 2.6 and 3.2 times those of group I. After 24 hours, in contrast to group I, all still remained significantly differthese parameters ent from pretreatment values in group II. These data to high-dose UK, pro-UK in indicate that, contrary low-dose UK causes minor systemic combination with fibrinolytic effects and is, therefore, assumed to be clot-specific, although the fibrinolytic largely potential is equivalent for both regimens. Key words: single-chain urokinase-type two-chain urokinase-type plasminogen infarction, fibrinolysis

191

plasminogen activator,

activator, myocardial

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INTRODUCTION Thrombolytic therapy is commonly used in the early stage of myocardial infarction to achieve coronary recanalization and a reduction of left ventricular in infarct size, preservation function and an increased survival (8,20,22,25). Clot-selective agents tissue-type plasminogen activator such as recombinant (rt-PA) were also shown to be effective in coronary thrombolysis and they have been thought to be advantageous, because of fewer systemic effects on haemostatic function, compared with standard thrombolytic agents such as streptokinase and urokinase (two-chain urokinase-type plasminogen activator, UK)(17,20,25). More recently, single-chain urokinase-type plasminogen activator (pro-urokinase, pro-UK) showing also improved fibrin specifity has been introduced into the treatment of myocardial infarction (2,4,9,11,16,21,24,25). However, compared to rt-PA, experience with pro-UK in clinical its influence on use concerning haemostasis is limited. Therefore, in this trial the attempt was made to study the extent of systemic effects of a regimen including pro-UK on haemostasis and fibrinolysis in patients with acute myocardial infarction (AMI). Special emphasis was laid on the investigation of differences compared to standard treatment with UK. Parts of this study including pharmacokinetics of UK have already been published (13).

PATIENTS. MATERIALS Patients

AND METHODS

and study srotocol

20 patients with AM1 diagnosed by ECG and symptoms of less than 6 hours' duration were included in the study after giving informed received intravenous, consent. All patients Pro-UK adjusted-dose heparin which was startetd with 1000 U/h. plasminogen activator single-chain urokinase-type (natural (two-chain provided by Sandoz AG, Nurnberg, FRG) and UK activator: Alphakinase, Alpha urokinase-type plasminogen Therapeutics, Langen, FRG) were used as thrombolytic agents. Group I: 10 patients aged between 47 and 75 years (mean: 60.5) were given 200,000 U UK intravenously within 5 min, thereafter a bolus injection of 500,000 U pro-UK followed by a continous infusion of 4.0 million U pro-UK (equivalent to 33 mg) during 40 Blood samples were taken prior to treatment and 5, 60 min, min. 3, 6, 9, 12 and 24 hours after the beginning of thrombolysis. 48 and 75 years (mean: 64.1) Group II: 10 patients aged between Blood U UK intravenously within 5 min. were given 2.5 million. samples were taken prior to treatment and 5, 60 min, 2, 4, 8, 12 and 24 hours following the injection. concerning Further details previously reported (13).

patients and

protocol

have

been

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Laboratory methods Platelet poor plasma obtained from titrated venous blood (1 part 0.109 M sodium citrate, 9 oparts blood) by immediate centrifugation (3000 g, 15 min, 4 C) was used to determine the parameters of coagulation and fibrinolysis. Fibrinogen was measured immediately after centrifugation by the method of Clauss using fibrinogen reagent (Boehringer, Mannheim, FRG). Prior to the determination of the following parameters, plasma samples shock-frozen immediately after were centrifugation and stored at -70° C for a maximum of 2 weeks. Reptilase time was assessed using reptilase reagent (Boehringer, Mannheim, FRG). Plasmatic fibrinolytic activity was determined by fibrin plate assay as previously described (13). Plasminogen and alpha-2-antiplasmin activities were measured by amidolytic using assays Chromozym PL (Boehringer, Mannheim, FRG). Plasminogen and concentrations alpha-2-antiplasmin were determined by radial immunodiffusion M-Partigen using (Behringwerke, Thrombin-antithrombin III Marburg, FRG). complexes (TAT) and D-dimers were measured by ELISA using TAT-Enzygnost (Behringwerke, Marburg, FRG) and ELISA-D-Dimer (Boehringer, Mannheim, FRG). Statistical

analysis

The results of the laboratory data are expressed as medians and interguartile ranges. The Mann-Whitney test was used to estimate differences between group I and II, a p-value less than 0.05 was regarded as significant.

RESULTS The peak fibrinolytic activities in the plasma of both groups did not differ significantly (table 1). Concerning the time course activities the different duration of of fibrinolytic thrombolytic treatment (45 min vs. 5 min) has to be taken into account. There was a rapid decrease in fibrinogen (fig. 1) in group II reaching its lowest level, which was considerably below normal range, 60 min after injection (mean decrease compared to pretreatment values: - 74.2%). This was significantly different from group I. Thereafter a moderate increase could be observed, however, although initial values were not yet reached 24 hours after treatment. In contrast, in group I the decrease was only moderate (lowest level: - 19.6% compared to initial values) and did not exceed normal range. In group II there was a rapid prolongation of reptilase time (statistically different compared to group I) up to 4.5-fold of

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initial values remaining the observation period (fig. 1). In observed which not did was pretreatment values.

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entire elevated over the group I only a minor increase from significantly differ

TABLE 1 Plasmatic fibrinolytic activity (expressed as U/ml calibrated preparation for against the 1st international reference urokinase) measured by the fibrin plate method: medians and in each interguartile ranges (in parenthesis) of 10 patients group >3 h 2h 3h before 5 min 15 min Ih treatafter starting the treatment ment ---__________-______~~~~~~~~~~~~~~~~~~~~~~~-~~~~~~~~~~~~~~~~ I 0.06 7.5 7.0 (1.25 (3.0 (O-15.0) 0.25) -15.0) -_________-_---_-__-_~~~~~~~~~~~~~~~~~~~_~~~~~~~~-~~~~~~~~~~ II 5.0 6.0 0.11 2.0 (1.25 (0.8 (0.8 (0.03 -10.0) -8.0) -2.6) -0.26) -----__--____________________________~~~_________~~~~~~~----

Group

already Data on plasminogen activity (fig. 2) have been reported (13). The differences between group I and II were -27.3 versus statistically significant (mean maximal decrease of the -70.0% relative to baseline 60 min after the beginning treatment). Major alterations of alpha-2-antiplasmin were observed (fig. decrease (- 90.8% compared to initial values) 2) * The maximum was reached after 1 hour for group II, this was significantly less accentuated (- 71.4%) in group I. concentrations Changes in plasminogen and alpha-2-antiplasmin less pronounced. were determined by immunologic methods However, there was a moderate correlation between functional and for plasminogen r = 0.46 (p