- Email: [email protected]
Comparison of effects of dalteparin and enoxaparin on hemostatic parameters and von Willebrand factor in patients with unstable angina pectoris or non–ST- segment elevation acute myocardial infarction
history in patients undergoing percutaneous coronary interventions. J Am Coll Cardiol 1998;32:936 –941. 16. Harrell L, Schunkert H, Palacios IF. Risk predictors in patients scheduled for percutaneous coronary revascularization. Cathet Cardiovasc Intervent 1999;48: 253–260. 17. O’Connor GT, Malenka DJ, Quinton H, Robb JF, Kellet MA Jr, Shubrooks S, Bradley WA, Hearne MJ, Watkins MW, Wennberg DE, et al. Multivariate prediction of in-hospital mortality after percutaneous coronary interventions in
1994 –1996: Northern New England Cardiovascular Disease Study Group. J Am Coll Cardiol 1999;34:681–691. 18. Saucedo JF, Mehran R, Dangas G, Hong MK, Lansky AJ, Kent KM, Satler LF, Pichard AD, Stone GW, Leon MB. Long-term clinical events following CK-MB elevation after successful coronary stenting. J Am Coll Cardiol 2000; 35:1134 –1141. 19. Abdelmeguid AE, Topol EJ. The myth of the myocardial “infarctlet” during percutaneous coronary revascularization procedures. Circulation 1996;94:3369 –3375.
Comparison of Effects of Dalteparin and Enoxaparin on Hemostatic Parameters and von Willebrand Factor in Patients With Unstable Angina Pectoris or Non–STSegment Elevation Acute Myocardial Infarction Ronald Ho ¨ dl, MD, Kurt Huber, MD, Wilfried Kraxner, MD, Mariam Nikfardjam, Martin Schumacher, MD, Friedrich M. Fruhwald, MD, Gerlinde Zorn, Manfred Wonisch, MD, and Werner Klein, MD compared the effects of dalteparin and enoxW eaparin on the distinct hemostatic parameters of
the thrombin and plasmin activation systems in patients with unstable angina pectoris (UAP) and non– ST-segment elevation acute myocardial infarction (non–ST-AMI). Changes in these parameters have previously been used as surrogate markers for antithrombotic efficacy and to explain differences in clinical outcome during different treatments with low molecular weight heparin (LMWH).1 We also determined circulating plasma levels of von Willebrand factor (vWF), a parameter that has been correlated with impaired clinical outcome2: in patients with UAP, an increase of vWF over the first 48 hours was associated with an adverse outcome at 1-year followup. Release of vWF has been shown to be influenced differently by various anticoagulants.3 •••
The study was approved by the ethics committees of the Universities of Graz and Vienna and performed according to the Declaration of Helsinki. We enrolled 61 consecutive patients. All patients had ischemic chest pain during the 24 hours before enrollment. UAP was defined as new onset angina or increasing intensity and duration of chest pain within the previous 2 months. In addition, 1 of the following electrocardiographic findings had to be present: transient or constant ST-segment depression of ⱖ0.1 mV or transient or constant T-wave inversion of ⱖ0.1 mV in 2 From the Division of Cardiology, Department of Medicine, Karl-Franzens University, Graz; and Department of Cardiology, University of Vienna, School of Medicine, Vienna, Austria. Dr. Ho¨ dl’s address is: Karl-Franzens-University, Department of Medicine, Division of Cardiology, Auenbruggerplatz 15, A-8036 Graz, Austria. E-mail: ronald. [email protected]. Manuscript received July 9, 2001; revised manuscript received and accepted November 2, 2001. ©2002 by Excerpta Medica, Inc. All rights reserved. The American Journal of Cardiology Vol. 89 March 1, 2002
MD,
contiguous leads. Non–ST-AMI was defined as an increase of creatine kinase-MB to twice the normal range and/or positive troponin T values (⬎0.1 ng/ml). All patients gave informed consent for participation in the study. On entry, patients were randomized to subcutaneously receive either dalteparin 120 IU/kg or enoxaparin 1 mg/kg every 12 hours. The last study drug application was at 60 hours. After randomization (random generator, software: PC-Plan, V1.0, GE Dallal, Tufts University, Boston, Massachusetts) and immediately before initiation of treatment, baseline blood samples were drawn into tubes prepared with either 0.129 M sodium citrate or 15% ethylenediaminetriacetic acid (Vacutainer system, Becton Dickinson and Company, Franklin Lakes, New Jersey). Further samples were taken 4, 12 and 66 hours after initiation of LMWH treatment. The 12-hour sample was taken just before the administration of 12-hour subcutaneous injection of LMWH. All blood samples were taken by simple needle puncture of a cubital vein. After inverting the vials twice, they were placed on ice for 20 minutes and then centrifuged at 9°C for 20 minutes at 3,000 g. Plasma was separated and stored at ⫺40°C until use. For the duration of the study no antithrombotic drugs except aspirin were allowed. Patients who required urgent coronary intervention were to be removed from the study. All laboratory evaluations were performed in a blinded fashion. For the evaluation of antifactor IIa, antifactor Xa, and soluble fibrin, Chromogenix AB (Coatest, Mo¨ lndal, Sweden) assays were used. Prothrombin fragment F1⫹2 was evaluated with the immunoassay Enzygnost F1⫹2; micro and thrombin antithrombin complexes were measured by use of the Enzygnost TAT micro assay (Behring, Marburg, Ger0002-9149/02/$–see front matter PII S0002-9149(01)02300-1
589
TABLE 1 Baseline Characteristics of the Study Population Variable
Dalteparin (n ⫽ 31)
Enoxaparin (n ⫽ 30)
Men Women Mean age (yrs) Non–ST-AMI UAP Systemic hypertension Lipid disorder Diabetes mellitus Current smokers Peripheral vascular disease Heart failure BMI ⬎30 kg/m2
21 (68%) 10 (32%) 66 ⫾ 9 3 (10%) 28 (90%) 15 (48%) 12 (39%) 5 (16%) 4 (13%) 2 (6%) 2 (6%) 7 (23%)
13 (43%) (p ⫽ 0.097) 17 (57%) 64 ⫾ 12 4 (13%) 26 (87%) 20 (67%) (p ⫽ 0.23) 9 (30%) 5 (17%) 9 (30%) (p ⫽ 0.19) 1 (3%) 2 (7%) 7 (23%)
There were no significant differences between the study groups regarding the demographic data or concomitant diseases and risk factors. Systemic hypertension is defined as blood pressure ⬎140/90 mm Hg. Lipid disorder is defined as total cholesterol ⬎230 mg/dl and/or triglycerides ⬎180 mg/dl. p Values are provided for the most questionable points.
many). Total plasminogen activator inhibitor-type 1 (PAI-1) antigen was evaluated with the Technoclone PAI-1 enzyme-linked immunosorbent assay (Technoclone, Vienna, Austria). This assay measures complexed, activated, and latent PAI-1. Complexes of tissue-plasminogen activator and PAI-1 were measured with a Technoclone striptest. Tissue plasminogen activator antigen was evaluated using the Technoclone tissue plasminogen activator antigen enzymelinked immunosorbent assay. D-dimer evaluation was performed with the Dimertest gold enzyme immunoassay (Agen, Australia). Measurements of vWF were carried out using the vWF assay from Gradipore (Gradipore, Bristane, Australia). To show a difference of 0.75 ⫻ SD between the groups (␣ ⫽ 0,05 2 sided) to a power of 0.8, 30 patients were required per treatment group. The extra patient in the dalteparin group was the result of a transmission delay in halting randomization. All statistical calculations were performed with Sigmastat statistical software (Jandel Corporation, San Rafael, California). t Tests were performed to compare the 2 treatment arms. If the distribution was not normal, Wilcoxon-Mann-Whitney tests were performed. Friedman’s repeated measures analysis followed by Dunnet’s procedure were used to compare treatment effects with baseline values within 1 treatment arm. Chi-square tests were carried out to compare the 2 treatment populations with regard to demographic data and concomitant diseases. Changes of vWF were calculated as a percent level of vWF at 4 and 66 hours, respectively, minus the percent level of vWF at baseline. A p value ⬍0.05 was considered significant. The baseline characteristics of the patients are listed in Table 1. Of the 61 patients who entered the 590 THE AMERICAN JOURNAL OF CARDIOLOGY姞
VOL. 89
study, 89% (n ⫽ 54) had UAP and 12% (n ⫽ 7) had non–ST-AMI. Mean age was 65 ⫾ 10 years and 58% were men (n ⫽ 34). Thirty-one patients received dalteparin and 30 patients received enoxaparin. No patient from either treatment group died, experienced moderate or severe bleeding, or required urgent coronary intervention within the study period. The results of this study are listed in Tables 2 and 3. For each of the parameters of the thrombin activation system, there was no significant difference between the values at baseline in the treatment groups (Table 2). After the start of treatment, there was a significant increase in antifactor Xa and antifactor IIa activity compared with baseline in both treatment groups. Levels at 12 hours tended to be lower than levels at 4 and 66 hours. There were no significant differences in the antifactor Xa and antifactor IIa values for the different time points of blood collection between the 2 treatment groups. Prothrombin fragment F1⫹2 and thrombin antithrombin complexes decreased significantly with treatment, with the lowest levels recorded at 12 hours (thrombin antithrombin complexes) and 12 and 66 hours (prothrombin fragment F1⫹2). Parameters of plasmin activation showed no significant differences between dalteparin and enoxaparin treatment at any time (Table 3). There were significant changes compared with baseline in each arm, which were most pronounced at 12 and 66 hours: PAI-1 antigen, complexes of tissue plasminogen activator and PAI-1, as well as tissue plasminogen activator antigen, showed a continuous increase in both therapy arms, whereas there were no significant changes in D-dimer levels. Levels of vWF exhibited a nonsignificant increase after 4 and 66 hours, but there were no significant differences between the treatment groups at any time of blood sampling (Figure 1). •••
In the present study, the antifactor Xa/antifactor IIa ratio was (not significantly) higher in patients treated with enoxaparin, which reflects the pharmacokinetic profile of these LMWHs.4 – 6 However, both LMWH preparations resulted in a similar reduction of the thrombin activation and a comparable increase in plasmin activation, thus representing comparable effects for the antithrombotic and fibrinolytic actions of the drugs. Differences in the course of the parameters of the thrombin activation system between 4, 12 and 66 hours can be explained by the time span between administration of LMWHs and blood sampling: the 12-hour blood sample was drawn at the end of the activity curves of the drugs, immediately before reinjection of the maintenance dose. Thus, it exhibited lower levels compared with the blood samples taken at 4 and 66 hours, which were taken during the full therapeutic range. Parameters of the plasmin activation system showed a continuous increase over time. This can be MARCH 1, 2002
TABLE 2 Markers of Thrombin Generation: Median Values (interquartile range) Dalteparin Variable Anti-Xa (anti-Xa U) Anti-IIa (anti-IIa U) Xa/IIa ratio F1 ⫹ 2 (nmol/l) TAT (g/l) SF (U/ml)
0h 0.14 (0.12–0.16) 0
1.2 (0.8–1.2) 2.15 (1.2–3.6) 47 (39.25–61)
Enoxaparin
4h
12 h
66 h
0h
4h
12 h
66 h
0.65* (0.51–0.96) 0.03* (0–0.08) 12.5 (4.01–25) 1.0* (0.7–1.22) 1.6* (0.52–2.5) 47 (35–63.5)
0.53* (0.21–1.3) 0.02* (0–0.06) 19.17 (4.42–50) 0.7* (0.6–1.0) 1.25* (0.7–2.3) 50 (38.7–64.7)
0.79* (0.68–1.4) 0.06* (0.02–0.16) 9.37 (4.66–25.67) 0.8* (0.62–1.17) 1.7* (0.75–2.7) 46.5 (30–67)
0
0.62* (0.46–0.84) 0.02* (0–0.05) 24.75 (4.78–36.25) 0.95* (0.55–1.5) 1.4* (0.65–3.55) 60 (47–72)
0.32* (0.15–0.89) 0.01* (0–0.03) 23.0 (4.56–44.17) 0.7* (0.45–1.25) 1.3* (0.5–4.27) 60 (45–70.75)
0.92* (0.63–1.25) 0.04* (0.01–0.11) 12.75 (6.19–35) 0.65* (0.4–1.0) 2.0* (1.12–3.17) 55 (41.5–75)
0
1.2 (0.8–1.75) 2.7 (1.25–4.12) 50 (46–71.5)
*Significant change compared with baseline (0 hour) value (p ⬍0.05). There were no significant differences between the 2 treatment arms concerning the parameters of thrombin generation at any time. anti-Xa ⫽ anti-factor Xa; anti-IIa ⫽ anti-factor IIa; Xa/IIa ratio ⫽ anti-factor Xa/anti-factor IIa ratio; F1 ⫹ 2 ⫽ prothrombin fragment F1⫹2; SF ⫽ soluble fibrin; TAT ⫽ thrombin antithrombin complex.
TABLE 3 Markers of Plasmin Activation: Median Values (interquartile range) Dalteparin Variable
0h
4h
12 h
Enoxaparin 66 h
0h
4h
12 h
66 h
t-PA ag 14 14.15 20* 27.4* 12.8 15.75 17.7* 26* (ng/ml) (9.05–14.7) (10–19.2) (12.7–26.2) (21–33.6) (9.5–16.8) (10.8–20.8) (12.4–27.2) (17.27–34.5) PAI-1 ag 74.5 54.0 91.8* 115.2* 79.2 61.8 128.4 101.4 (ng/ml) (28–135.3) (28.8–127) (39.8–160.8) (55.22–228) (30.05–24.8) (27–129) (49.8–192.6) (65.8–187.8) t-PA/PAI-1 20.0 20.2 34.0* 47.6* 30.0 29.6 46.4* 56.2* (ng/ml) (15.2–33.1) (18–26.8) (28.4–40.4) (42.1–69.3) (15.2–35.4) (19.4–45.4) (24.2–59.4) (31.8–78.6) DD 24.55 27.3 26.3 20.25 33.4 22.4 30.25 27.9 (ng/ml) (10.5–35.7) (13.2–52.47) (8.4–39.6) (14.9–33.45) (10.85–63.5) (9.65–62.2) (8.55–47.95) (14.15–36.5) *Significant change compared with baseline (0 hour) value (p ⬍0.05). There were no significant differences between the 2 treatment arms concerning the parameters of plasmin activation at any time. DD ⫽ D-dimer; PAI-1 ag ⫽ total plasminogen activator inhibitor-type 1 antigen; t-PA ag ⫽ tissue plasminogen activator antigen; t-PA/PAI-1 ⫽ complexes of tissue plasminogen activator and plasminogen activator inhibitor 1.
FIGURE 1. Change of vWF at 4 and 66 hours after initiation of treatment: both time points (4 hours after first injection and 6 hours after final drug injection) provide the full drug effect. There were no significant differences between treatment groups concerning either the changes or the absolute values (not shown) of vWF.
explained by a reactive increase of tissue plasminogen activator antigen, which is based on an increased endothelial release during the prothrombotic state, especially on elevated PAI-1 antigen plasma levels in acute coronary syndrome.7,8 Concomitant increases of tissue plasminogen activator antigen, PAI-1 antigen, and of their complexes as shown over time can be explained by the relatively unspecific assay systems used, which not only detect free but also complexed tissue plasminogen activator and PAI-1 molecules.9,10 Neither soluble fibrin as a marker of the final stage of the thrombin activation nor D-dimer proved to be useful in the monitoring of LMWH treatment because they showed no distinct alteration over time. As with the course of thrombin activation parameters, vWF also demonstrated a time-dependent progression with respect to the last LMWH application; these changes, however, were not statistically signifBRIEF REPORTS
591
icant. In addition, no significant difference could be demonstrated with respect to the action of enoxaparin or dalteparin on vWF levels as shown in the blood samples taken during the full therapeutic range at 4 and 66 hours (Figure 1). These findings seem to be in conflict with those published by Montalescot et al,3 who indirectly postulated superiority of the action of enoxaparin over dalteparin in limiting acute vWF levels. The post hoc analysis of Montalescot et al3 investigated partially combined data11 of 2 prospective trials with enoxaparin (Efficacy and Safety of Subcutaneous Enoxaprin in Non–Q-wave Coronary Events [ESSENCE],12 Thrombolyis In Myocardial Infarction [TIMI] 11B13) and 1 registry with dalteparin (USIC registry) as opposed to our investigation, which directly compared the action of dalteparin and enoxaparin in a prospective fashion in comparable patient groups. Several potential limitations of our study should be mentioned. The first is the rather wide interquartile range, which appears in the examined parameters. These wide margins decrease the likelihood to prove differences in a small study, despite the given statistical power. Another point is the small number of patients, resulting in statistical underpower of the investigation for any clinical outcome data, such as major adverse cardiac events or bleeding rates. The results of our study indicate that dalteparin and enoxaparin, when compared directly, have similar effects on parameters of thrombin and plasmin activation and vWF. The present study provides the first prospective, comparative results between dalteparin and enoxaparin in patients with UAP or non–ST-AMI.
592 THE AMERICAN JOURNAL OF CARDIOLOGY姞
VOL. 89
1. Ernofsson M, Strekerud F, Toss H, Abildgaard U, Wallentin L, Siegbahn A. Low-molecular weight heparin reduces the generation and activity of thrombin in unstable coronary artery disease. Thromb Haemost 1998;79:491–494. 2. Montalescot G, Collet JP, Choussat R, Ankri A, Thomas D. A rise of troponin and/or von Willebrand factor over the first 48 hours is associated with a poorer 1-year outcome in unstable angina patients. Int J Cardiol 2000;72:293–294. 3. Montalescot G, Collet JP, Lison L, Choussat R, Ankri A, Vicant E, Perlemuter K, Philippe F, Drobinski G, Thomas D. Effects of various anticoagulant treatments on von Willebrand factor release in unstable angina. J Am Coll Cardiol 2000;36:110 –114. 4. Collignon F, Frydman A, Caplain H, Ozoux ML, Le Roux Y, Bouthier J, Thebault JJ. Comparison of the pharmacokinetic profiles of three low molecular mass heparins— dalteparin, enoxaparin and nadroparin—administered subcutaneously in healthy volunteers (doses for prevention of thromboembolism). Thromb Haemost 1995;73:630 –640. 5. Bratt G, To¨ rnbohm E, Widlund L, Lockner D. Low molecular weight heparins (Kabi 2165, Fragmin®): pharmacokinetics after intravenous and subcutaneous administration. Thromb Res 1986;42:613–620. 6. Frydman AM, Bara L, Le Roux Y, Woler M, Chauliac F, Samama MM. The antithrombotic activity and pharmacokinetics of enoxaparin, a low molecular weight heparin, in humans given single subcutaneous doses of 20 to 80 mg. J Clin Pharmac 1988;28:609 –618. 7. Geppert A, Graf S, Beckmann R, Hornykewycz S, Schuster E, Binder BR, Huber K. Concentration of endogenous tPA antigen in coronary artery disease: relation to thrombotic events, aspirin treatment, hyperlipidemia, and multivessel disease. Arterioscler Thromb Vasc Biol 1998;18:1634 –1642. 8. Hoffmeister HM, Jur M, Wendel HP, Heller W, Seipel L. Alterations of coagulation and fibrinolytic and kallikrein-kinin systems in the acute and postacute phases in patients with unstable angina pectoris. Circulation 1995;91:2520 –2527. 9. Korninger C, Speiser W, Wojta J, Binder BR. Sandwich ELISA for t-PA antigen employing a monoclonal antibody. Thromb Res 1986;41:527–535. 10. Wojta J, Holzer M, Hufnagl P, Christ G, Hoover R, Binder BR. Hyperthermia stimulates plasminogen activator inhibitor type-1 expression in human umbilical vein endothelial cells in vitro. Am J Pathol 1991;139:911–919. 11. Ho¨ dl R, Huber K, Kraxner W, Klein W. Limitation of vWf meta-analysis in LMWH comparison. J Am Coll Cardiol 2001;37:2006. 12. Cohen M, Demers C, Gurfinkel EP, Turpie AG, Fromell GJ, Goodman S, Langer A, Califf RM, Fox KA, Premmereur J, Bigonzi F. A comparison of low-molecular-weight heparin with unfractionated heparin for unstable coronary artery disease. Efficacy and Safety of Subcutaneous Enoxaparin in Non-Q-Wave Coronary Events Study Group. N Engl J Med 1997;337:447–452. 13. Antman EM, McCabe CH, Gurfinkel EP, Turpie AG, Bernink PJ, Salein D, Bayes De Luna A, Fox K, Lablanche JM, Radley D, Premmereur J, Braunwald E. Enoxaparin prevents death and cardiac ischaemic events in unstable angina/non-Q-wave myocardial infarction. Results of the Thrombolysis In Myocardial Infarction (TIMI) 11B trial. Circulation 1999;100:1593–1601.
MARCH 1, 2002
1994 –1996: Northern New England Cardiovascular Disease Study Group. J Am Coll Cardiol 1999;34:681–691. 18. Saucedo JF, Mehran R, Dangas G, Hong MK, Lansky AJ, Kent KM, Satler LF, Pichard AD, Stone GW, Leon MB. Long-term clinical events following CK-MB elevation after successful coronary stenting. J Am Coll Cardiol 2000; 35:1134 –1141. 19. Abdelmeguid AE, Topol EJ. The myth of the myocardial “infarctlet” during percutaneous coronary revascularization procedures. Circulation 1996;94:3369 –3375.
Comparison of Effects of Dalteparin and Enoxaparin on Hemostatic Parameters and von Willebrand Factor in Patients With Unstable Angina Pectoris or Non–STSegment Elevation Acute Myocardial Infarction Ronald Ho ¨ dl, MD, Kurt Huber, MD, Wilfried Kraxner, MD, Mariam Nikfardjam, Martin Schumacher, MD, Friedrich M. Fruhwald, MD, Gerlinde Zorn, Manfred Wonisch, MD, and Werner Klein, MD compared the effects of dalteparin and enoxW eaparin on the distinct hemostatic parameters of
the thrombin and plasmin activation systems in patients with unstable angina pectoris (UAP) and non– ST-segment elevation acute myocardial infarction (non–ST-AMI). Changes in these parameters have previously been used as surrogate markers for antithrombotic efficacy and to explain differences in clinical outcome during different treatments with low molecular weight heparin (LMWH).1 We also determined circulating plasma levels of von Willebrand factor (vWF), a parameter that has been correlated with impaired clinical outcome2: in patients with UAP, an increase of vWF over the first 48 hours was associated with an adverse outcome at 1-year followup. Release of vWF has been shown to be influenced differently by various anticoagulants.3 •••
The study was approved by the ethics committees of the Universities of Graz and Vienna and performed according to the Declaration of Helsinki. We enrolled 61 consecutive patients. All patients had ischemic chest pain during the 24 hours before enrollment. UAP was defined as new onset angina or increasing intensity and duration of chest pain within the previous 2 months. In addition, 1 of the following electrocardiographic findings had to be present: transient or constant ST-segment depression of ⱖ0.1 mV or transient or constant T-wave inversion of ⱖ0.1 mV in 2 From the Division of Cardiology, Department of Medicine, Karl-Franzens University, Graz; and Department of Cardiology, University of Vienna, School of Medicine, Vienna, Austria. Dr. Ho¨ dl’s address is: Karl-Franzens-University, Department of Medicine, Division of Cardiology, Auenbruggerplatz 15, A-8036 Graz, Austria. E-mail: ronald. [email protected]. Manuscript received July 9, 2001; revised manuscript received and accepted November 2, 2001. ©2002 by Excerpta Medica, Inc. All rights reserved. The American Journal of Cardiology Vol. 89 March 1, 2002
MD,
contiguous leads. Non–ST-AMI was defined as an increase of creatine kinase-MB to twice the normal range and/or positive troponin T values (⬎0.1 ng/ml). All patients gave informed consent for participation in the study. On entry, patients were randomized to subcutaneously receive either dalteparin 120 IU/kg or enoxaparin 1 mg/kg every 12 hours. The last study drug application was at 60 hours. After randomization (random generator, software: PC-Plan, V1.0, GE Dallal, Tufts University, Boston, Massachusetts) and immediately before initiation of treatment, baseline blood samples were drawn into tubes prepared with either 0.129 M sodium citrate or 15% ethylenediaminetriacetic acid (Vacutainer system, Becton Dickinson and Company, Franklin Lakes, New Jersey). Further samples were taken 4, 12 and 66 hours after initiation of LMWH treatment. The 12-hour sample was taken just before the administration of 12-hour subcutaneous injection of LMWH. All blood samples were taken by simple needle puncture of a cubital vein. After inverting the vials twice, they were placed on ice for 20 minutes and then centrifuged at 9°C for 20 minutes at 3,000 g. Plasma was separated and stored at ⫺40°C until use. For the duration of the study no antithrombotic drugs except aspirin were allowed. Patients who required urgent coronary intervention were to be removed from the study. All laboratory evaluations were performed in a blinded fashion. For the evaluation of antifactor IIa, antifactor Xa, and soluble fibrin, Chromogenix AB (Coatest, Mo¨ lndal, Sweden) assays were used. Prothrombin fragment F1⫹2 was evaluated with the immunoassay Enzygnost F1⫹2; micro and thrombin antithrombin complexes were measured by use of the Enzygnost TAT micro assay (Behring, Marburg, Ger0002-9149/02/$–see front matter PII S0002-9149(01)02300-1
589
TABLE 1 Baseline Characteristics of the Study Population Variable
Dalteparin (n ⫽ 31)
Enoxaparin (n ⫽ 30)
Men Women Mean age (yrs) Non–ST-AMI UAP Systemic hypertension Lipid disorder Diabetes mellitus Current smokers Peripheral vascular disease Heart failure BMI ⬎30 kg/m2
21 (68%) 10 (32%) 66 ⫾ 9 3 (10%) 28 (90%) 15 (48%) 12 (39%) 5 (16%) 4 (13%) 2 (6%) 2 (6%) 7 (23%)
13 (43%) (p ⫽ 0.097) 17 (57%) 64 ⫾ 12 4 (13%) 26 (87%) 20 (67%) (p ⫽ 0.23) 9 (30%) 5 (17%) 9 (30%) (p ⫽ 0.19) 1 (3%) 2 (7%) 7 (23%)
There were no significant differences between the study groups regarding the demographic data or concomitant diseases and risk factors. Systemic hypertension is defined as blood pressure ⬎140/90 mm Hg. Lipid disorder is defined as total cholesterol ⬎230 mg/dl and/or triglycerides ⬎180 mg/dl. p Values are provided for the most questionable points.
many). Total plasminogen activator inhibitor-type 1 (PAI-1) antigen was evaluated with the Technoclone PAI-1 enzyme-linked immunosorbent assay (Technoclone, Vienna, Austria). This assay measures complexed, activated, and latent PAI-1. Complexes of tissue-plasminogen activator and PAI-1 were measured with a Technoclone striptest. Tissue plasminogen activator antigen was evaluated using the Technoclone tissue plasminogen activator antigen enzymelinked immunosorbent assay. D-dimer evaluation was performed with the Dimertest gold enzyme immunoassay (Agen, Australia). Measurements of vWF were carried out using the vWF assay from Gradipore (Gradipore, Bristane, Australia). To show a difference of 0.75 ⫻ SD between the groups (␣ ⫽ 0,05 2 sided) to a power of 0.8, 30 patients were required per treatment group. The extra patient in the dalteparin group was the result of a transmission delay in halting randomization. All statistical calculations were performed with Sigmastat statistical software (Jandel Corporation, San Rafael, California). t Tests were performed to compare the 2 treatment arms. If the distribution was not normal, Wilcoxon-Mann-Whitney tests were performed. Friedman’s repeated measures analysis followed by Dunnet’s procedure were used to compare treatment effects with baseline values within 1 treatment arm. Chi-square tests were carried out to compare the 2 treatment populations with regard to demographic data and concomitant diseases. Changes of vWF were calculated as a percent level of vWF at 4 and 66 hours, respectively, minus the percent level of vWF at baseline. A p value ⬍0.05 was considered significant. The baseline characteristics of the patients are listed in Table 1. Of the 61 patients who entered the 590 THE AMERICAN JOURNAL OF CARDIOLOGY姞
VOL. 89
study, 89% (n ⫽ 54) had UAP and 12% (n ⫽ 7) had non–ST-AMI. Mean age was 65 ⫾ 10 years and 58% were men (n ⫽ 34). Thirty-one patients received dalteparin and 30 patients received enoxaparin. No patient from either treatment group died, experienced moderate or severe bleeding, or required urgent coronary intervention within the study period. The results of this study are listed in Tables 2 and 3. For each of the parameters of the thrombin activation system, there was no significant difference between the values at baseline in the treatment groups (Table 2). After the start of treatment, there was a significant increase in antifactor Xa and antifactor IIa activity compared with baseline in both treatment groups. Levels at 12 hours tended to be lower than levels at 4 and 66 hours. There were no significant differences in the antifactor Xa and antifactor IIa values for the different time points of blood collection between the 2 treatment groups. Prothrombin fragment F1⫹2 and thrombin antithrombin complexes decreased significantly with treatment, with the lowest levels recorded at 12 hours (thrombin antithrombin complexes) and 12 and 66 hours (prothrombin fragment F1⫹2). Parameters of plasmin activation showed no significant differences between dalteparin and enoxaparin treatment at any time (Table 3). There were significant changes compared with baseline in each arm, which were most pronounced at 12 and 66 hours: PAI-1 antigen, complexes of tissue plasminogen activator and PAI-1, as well as tissue plasminogen activator antigen, showed a continuous increase in both therapy arms, whereas there were no significant changes in D-dimer levels. Levels of vWF exhibited a nonsignificant increase after 4 and 66 hours, but there were no significant differences between the treatment groups at any time of blood sampling (Figure 1). •••
In the present study, the antifactor Xa/antifactor IIa ratio was (not significantly) higher in patients treated with enoxaparin, which reflects the pharmacokinetic profile of these LMWHs.4 – 6 However, both LMWH preparations resulted in a similar reduction of the thrombin activation and a comparable increase in plasmin activation, thus representing comparable effects for the antithrombotic and fibrinolytic actions of the drugs. Differences in the course of the parameters of the thrombin activation system between 4, 12 and 66 hours can be explained by the time span between administration of LMWHs and blood sampling: the 12-hour blood sample was drawn at the end of the activity curves of the drugs, immediately before reinjection of the maintenance dose. Thus, it exhibited lower levels compared with the blood samples taken at 4 and 66 hours, which were taken during the full therapeutic range. Parameters of the plasmin activation system showed a continuous increase over time. This can be MARCH 1, 2002
TABLE 2 Markers of Thrombin Generation: Median Values (interquartile range) Dalteparin Variable Anti-Xa (anti-Xa U) Anti-IIa (anti-IIa U) Xa/IIa ratio F1 ⫹ 2 (nmol/l) TAT (g/l) SF (U/ml)
0h 0.14 (0.12–0.16) 0
1.2 (0.8–1.2) 2.15 (1.2–3.6) 47 (39.25–61)
Enoxaparin
4h
12 h
66 h
0h
4h
12 h
66 h
0.65* (0.51–0.96) 0.03* (0–0.08) 12.5 (4.01–25) 1.0* (0.7–1.22) 1.6* (0.52–2.5) 47 (35–63.5)
0.53* (0.21–1.3) 0.02* (0–0.06) 19.17 (4.42–50) 0.7* (0.6–1.0) 1.25* (0.7–2.3) 50 (38.7–64.7)
0.79* (0.68–1.4) 0.06* (0.02–0.16) 9.37 (4.66–25.67) 0.8* (0.62–1.17) 1.7* (0.75–2.7) 46.5 (30–67)
0
0.62* (0.46–0.84) 0.02* (0–0.05) 24.75 (4.78–36.25) 0.95* (0.55–1.5) 1.4* (0.65–3.55) 60 (47–72)
0.32* (0.15–0.89) 0.01* (0–0.03) 23.0 (4.56–44.17) 0.7* (0.45–1.25) 1.3* (0.5–4.27) 60 (45–70.75)
0.92* (0.63–1.25) 0.04* (0.01–0.11) 12.75 (6.19–35) 0.65* (0.4–1.0) 2.0* (1.12–3.17) 55 (41.5–75)
0
1.2 (0.8–1.75) 2.7 (1.25–4.12) 50 (46–71.5)
*Significant change compared with baseline (0 hour) value (p ⬍0.05). There were no significant differences between the 2 treatment arms concerning the parameters of thrombin generation at any time. anti-Xa ⫽ anti-factor Xa; anti-IIa ⫽ anti-factor IIa; Xa/IIa ratio ⫽ anti-factor Xa/anti-factor IIa ratio; F1 ⫹ 2 ⫽ prothrombin fragment F1⫹2; SF ⫽ soluble fibrin; TAT ⫽ thrombin antithrombin complex.
TABLE 3 Markers of Plasmin Activation: Median Values (interquartile range) Dalteparin Variable
0h
4h
12 h
Enoxaparin 66 h
0h
4h
12 h
66 h
t-PA ag 14 14.15 20* 27.4* 12.8 15.75 17.7* 26* (ng/ml) (9.05–14.7) (10–19.2) (12.7–26.2) (21–33.6) (9.5–16.8) (10.8–20.8) (12.4–27.2) (17.27–34.5) PAI-1 ag 74.5 54.0 91.8* 115.2* 79.2 61.8 128.4 101.4 (ng/ml) (28–135.3) (28.8–127) (39.8–160.8) (55.22–228) (30.05–24.8) (27–129) (49.8–192.6) (65.8–187.8) t-PA/PAI-1 20.0 20.2 34.0* 47.6* 30.0 29.6 46.4* 56.2* (ng/ml) (15.2–33.1) (18–26.8) (28.4–40.4) (42.1–69.3) (15.2–35.4) (19.4–45.4) (24.2–59.4) (31.8–78.6) DD 24.55 27.3 26.3 20.25 33.4 22.4 30.25 27.9 (ng/ml) (10.5–35.7) (13.2–52.47) (8.4–39.6) (14.9–33.45) (10.85–63.5) (9.65–62.2) (8.55–47.95) (14.15–36.5) *Significant change compared with baseline (0 hour) value (p ⬍0.05). There were no significant differences between the 2 treatment arms concerning the parameters of plasmin activation at any time. DD ⫽ D-dimer; PAI-1 ag ⫽ total plasminogen activator inhibitor-type 1 antigen; t-PA ag ⫽ tissue plasminogen activator antigen; t-PA/PAI-1 ⫽ complexes of tissue plasminogen activator and plasminogen activator inhibitor 1.
FIGURE 1. Change of vWF at 4 and 66 hours after initiation of treatment: both time points (4 hours after first injection and 6 hours after final drug injection) provide the full drug effect. There were no significant differences between treatment groups concerning either the changes or the absolute values (not shown) of vWF.
explained by a reactive increase of tissue plasminogen activator antigen, which is based on an increased endothelial release during the prothrombotic state, especially on elevated PAI-1 antigen plasma levels in acute coronary syndrome.7,8 Concomitant increases of tissue plasminogen activator antigen, PAI-1 antigen, and of their complexes as shown over time can be explained by the relatively unspecific assay systems used, which not only detect free but also complexed tissue plasminogen activator and PAI-1 molecules.9,10 Neither soluble fibrin as a marker of the final stage of the thrombin activation nor D-dimer proved to be useful in the monitoring of LMWH treatment because they showed no distinct alteration over time. As with the course of thrombin activation parameters, vWF also demonstrated a time-dependent progression with respect to the last LMWH application; these changes, however, were not statistically signifBRIEF REPORTS
591
icant. In addition, no significant difference could be demonstrated with respect to the action of enoxaparin or dalteparin on vWF levels as shown in the blood samples taken during the full therapeutic range at 4 and 66 hours (Figure 1). These findings seem to be in conflict with those published by Montalescot et al,3 who indirectly postulated superiority of the action of enoxaparin over dalteparin in limiting acute vWF levels. The post hoc analysis of Montalescot et al3 investigated partially combined data11 of 2 prospective trials with enoxaparin (Efficacy and Safety of Subcutaneous Enoxaprin in Non–Q-wave Coronary Events [ESSENCE],12 Thrombolyis In Myocardial Infarction [TIMI] 11B13) and 1 registry with dalteparin (USIC registry) as opposed to our investigation, which directly compared the action of dalteparin and enoxaparin in a prospective fashion in comparable patient groups. Several potential limitations of our study should be mentioned. The first is the rather wide interquartile range, which appears in the examined parameters. These wide margins decrease the likelihood to prove differences in a small study, despite the given statistical power. Another point is the small number of patients, resulting in statistical underpower of the investigation for any clinical outcome data, such as major adverse cardiac events or bleeding rates. The results of our study indicate that dalteparin and enoxaparin, when compared directly, have similar effects on parameters of thrombin and plasmin activation and vWF. The present study provides the first prospective, comparative results between dalteparin and enoxaparin in patients with UAP or non–ST-AMI.
592 THE AMERICAN JOURNAL OF CARDIOLOGY姞
VOL. 89
1. Ernofsson M, Strekerud F, Toss H, Abildgaard U, Wallentin L, Siegbahn A. Low-molecular weight heparin reduces the generation and activity of thrombin in unstable coronary artery disease. Thromb Haemost 1998;79:491–494. 2. Montalescot G, Collet JP, Choussat R, Ankri A, Thomas D. A rise of troponin and/or von Willebrand factor over the first 48 hours is associated with a poorer 1-year outcome in unstable angina patients. Int J Cardiol 2000;72:293–294. 3. Montalescot G, Collet JP, Lison L, Choussat R, Ankri A, Vicant E, Perlemuter K, Philippe F, Drobinski G, Thomas D. Effects of various anticoagulant treatments on von Willebrand factor release in unstable angina. J Am Coll Cardiol 2000;36:110 –114. 4. Collignon F, Frydman A, Caplain H, Ozoux ML, Le Roux Y, Bouthier J, Thebault JJ. Comparison of the pharmacokinetic profiles of three low molecular mass heparins— dalteparin, enoxaparin and nadroparin—administered subcutaneously in healthy volunteers (doses for prevention of thromboembolism). Thromb Haemost 1995;73:630 –640. 5. Bratt G, To¨ rnbohm E, Widlund L, Lockner D. Low molecular weight heparins (Kabi 2165, Fragmin®): pharmacokinetics after intravenous and subcutaneous administration. Thromb Res 1986;42:613–620. 6. Frydman AM, Bara L, Le Roux Y, Woler M, Chauliac F, Samama MM. The antithrombotic activity and pharmacokinetics of enoxaparin, a low molecular weight heparin, in humans given single subcutaneous doses of 20 to 80 mg. J Clin Pharmac 1988;28:609 –618. 7. Geppert A, Graf S, Beckmann R, Hornykewycz S, Schuster E, Binder BR, Huber K. Concentration of endogenous tPA antigen in coronary artery disease: relation to thrombotic events, aspirin treatment, hyperlipidemia, and multivessel disease. Arterioscler Thromb Vasc Biol 1998;18:1634 –1642. 8. Hoffmeister HM, Jur M, Wendel HP, Heller W, Seipel L. Alterations of coagulation and fibrinolytic and kallikrein-kinin systems in the acute and postacute phases in patients with unstable angina pectoris. Circulation 1995;91:2520 –2527. 9. Korninger C, Speiser W, Wojta J, Binder BR. Sandwich ELISA for t-PA antigen employing a monoclonal antibody. Thromb Res 1986;41:527–535. 10. Wojta J, Holzer M, Hufnagl P, Christ G, Hoover R, Binder BR. Hyperthermia stimulates plasminogen activator inhibitor type-1 expression in human umbilical vein endothelial cells in vitro. Am J Pathol 1991;139:911–919. 11. Ho¨ dl R, Huber K, Kraxner W, Klein W. Limitation of vWf meta-analysis in LMWH comparison. J Am Coll Cardiol 2001;37:2006. 12. Cohen M, Demers C, Gurfinkel EP, Turpie AG, Fromell GJ, Goodman S, Langer A, Califf RM, Fox KA, Premmereur J, Bigonzi F. A comparison of low-molecular-weight heparin with unfractionated heparin for unstable coronary artery disease. Efficacy and Safety of Subcutaneous Enoxaparin in Non-Q-Wave Coronary Events Study Group. N Engl J Med 1997;337:447–452. 13. Antman EM, McCabe CH, Gurfinkel EP, Turpie AG, Bernink PJ, Salein D, Bayes De Luna A, Fox K, Lablanche JM, Radley D, Premmereur J, Braunwald E. Enoxaparin prevents death and cardiac ischaemic events in unstable angina/non-Q-wave myocardial infarction. Results of the Thrombolysis In Myocardial Infarction (TIMI) 11B trial. Circulation 1999;100:1593–1601.
MARCH 1, 2002