Sebastian Szabo

Thrombolytic therapy in acute myocardial infarction : Comparison of procoagulant effects of streptokinase and alteplase regimens with focus on the Kallikrein system and plasmin

BACKGROUND Thrombolytic therapy in patients with acute myocardial infarction (AMI) is hampered by procoagulant effects. In vitro studies have indicated that plasmin stimulation activates the kallikrein-contact-phase system, resulting in thrombin activation. This prospective comparative study was designed to examine the procoagulant effects of streptokinase or alteplase in AMI. METHODS AND RESULTS Sixty-one patients with AMI received 1.5 million U of streptokinase or front-loaded alteplase (up to 100 mg) and systemic heparin. Twenty-four patients with AMI and no thrombolytic therapy and 30 control subjects were examined for comparison. Molecular markers of thrombin, plasmin activation, and coagulation activities were determined before therapy and serially for up to 10 days. Moderate thrombin (initial thrombin-antithrombin [TAT] complex 18+/-5 versus 4+/-0.3 microg/L, P<0.05) and kallikrein (up to 45+/-4 versus 30+/-1 U/L at 3 hours, P<0.01) activation occurs in patients with AMI. D-Dimers are increased (P<0.01), and plasmin is stimulated (P<0.01). Streptokinase and alteplase increase TAT to 50+/-17 and 51+/-18 microg/L at 3 hours and to 50+/-17 and 33+/-14 microg/L at 6 hours, respectively (P<0.01). Kallikrein activity is elevated (P<0. 01) to 76+/-5 and 71+/-7 U/L at 3 hours and 64+/-6 and 47+/-5 U/L by streptokinase and alteplase, respectively, at 6 hours. Reductions in fibrinogen and increases in D-dimers and plasmin-antiplasmin complexes are more marked (P<0.05 and 0.01) after streptokinase versus alteplase. Correlations were found among TAT, kallikrein activity, and plasmin activation (P<0.01). CONCLUSIONS The data indicate a more marked procoagulant action of the streptokinase regimen compared with front-loaded alteplase, thus supporting the hypothesis of a plasmin-mediated kallikrein activation with consecutive procoagulant action in vivo.

Comparison of C-reactive protein and terminal complement complex in patients with unstable angina pectoris versus stable angina pectoris

Elevated C-reactive protein (CRP) can identify patients with coronary artery disease who are prone to future acute events. We investigated whether elevated CRP is related to the activation of the terminal complement cascade in 66 patients with unstable angina pectoris (UAP), in 45 patients with stable angina pectoris, and in 42 controls. CRP, additional acute phase reactants, the terminal complement complex (sC5b-9), leukocytes, and troponin T were measured. In 47 patients with UAP the CRP values were regarded as elevated (>0.3 mg/dl). In patients with UAP and elevated CRP, the plasma levels of sC5b-9 were markedly higher than in patients with UAP and lower CRP (245 +/- 14 vs 188 +/- 19 ng/ml, p <0.02) and in patients with stable angina pectoris with slightly (0.4 +/- 0.1 mg/dl) increased CRP (sC5b-9 173 +/- 21 vs 130 +/- 7 ng/ml [controls; p <0.05]). A further acute phase reaction was present only in patients with UAP and elevated CRP already on admission (p <0.01). sC5b-9 was not related to troponin release. Thus, elevated CRP levels are associated with activation of the plaque destabilizating terminal complement system in patients with UAP during the acute phase reaction. This may explain the prognostic value of CRP in acute coronary syndromes (ACS).

Fibrin specificity and procoagulant effect related to the kallikrein-contact phase system and to plasmin generation with double-bolus reteplase and front-loaded alteplase thrombolysis in acute myocardial infarction.

This study was undertaken to compare the effects of reteplase and alteplase regimens on hemostasis and fibrinolysis in acute myocardial infarction (AMI). Thrombolytic treatment in patients with AMI is hampered by paradoxical procoagulant effects that favor early reocclusion. In vivo data comparing this effect and the fibrin specificity of double-bolus reteplase and front-loaded alteplase regimens are not available. In a prospective, randomized study, 50 patients with AMI were either treated with double bolus (10 + 10 U) reteplase or with front-loaded alteplase (up to 100 mg) within 6 hours of symptom onset. Thirty apparently healthy persons served as controls. Molecular markers of coagulation and fibrinolysis were serially examined for up to 5 days. Paradoxical thrombin activation at 3 hours after initiation of therapy was comparable between reteplase and alteplase. Reteplase (65 +/- 5 U/L) and alteplase (72 +/- 8 U/L) caused significantly elevated kallikrein activity at 3 hours after adminstration (p <0.01 vs controls 30 +/- 1 U/L). Fibrin specificity was less for reteplase (p <0.05) with a decrease in fibrinogen at 3 hours to 122 +/- 27 mg/dl versus 224 +/- 28 mg/dl for alteplase (p <0.01 and p <0.05 vs controls). D-Dimer levels at 3 hours were higher (p <0.05) after reteplase (5,459 +/- 611 ng/ml) versus alteplase (3,445 +/- 679 ng/ml) (both p <0.01 vs controls 243 +/- 17 ng/ml). Plasmin generation (plasmin-antiplasmin complexes) was significantly (p <0.01) increased at 3 hours with both regimens to 27,079 +/- 3,964 microg/L (reteplase) and 19,522 +/- 2,381 microg/L (alteplase). The data from 3 hours after start of thrombolytic therapy proved less marked fibrin specificity of the reteplase regimen (in vivo) compared with front-loaded alteplase. Both regimens have a moderate procoagulant effect without differences in activation of the kallikrein system.

Effect of Atorvastatin on Haemostasis, Fibrinolysis and Inflammation in Normocholesterolaemic Patients with Coronary Artery Disease A Post Hoc Analysis of Data from a Prospective, Randomized, Double-Blind Study

AbstractBackground: Treatment with HMG-CoA reductase inhibitors (statins) reduces the morbidity and mortality of coronary artery disease (CAD). In addition to their lipid-lowering actions, pleiotropic effects of statins have been demonstrated. Objective: The aim of the present study was to assess if atorvastatin therapy has an impact on haemostasis, fibrinolysis and inflammation in normocholesterolaemic patients with CAD. Methods: Fifty-four patients with CAD who had received atorvastatin treatment for at least 8 weeks (mean dosage 30 mg/day) and 54 patients with CAD who had not received atorvastatin therapy were selected from a larger prospective, randomized, double-blind study for inclusion in this post hoc analysis. Patients were matched by their total cholesterol levels. All patients were normocholesterolaemic. Results: In the atorvastatin-treated patients significantly lower plasma levels of thrombin-antithrombin complexes (p<0.05), plasminogen activator inhibitor-1 activity (PAI-1) [p<0.05], soluble vascular cell adhesion molecule-1 (p<0.05), soluble platelet selectin (p < 0.05) and high-sensitivity C-reactive protein (p < 0.05) were measured compared with patients not on atorvastatin therapy. Additionally, a strong trend towards lower soluble intercellular adhesion molecule-1 plasma levels was detected in patients treated with atorvastatin. No differences were found in tissue-type plasminogen activator antigen, plasmin-plasmin inhibitor complexes, fibrinogen, D-dimer and activated factor XII values. Conclusion: Atorvastatin appears to have an effect on coagulation activation, fibrinolysis and inflammation in patients with CAD. Reduction in PAI-1 and reduced thrombin formation may have an impact on cardiovascular morbidity and mortality in patients with CAD.

Absence of paradoxical thrombin activation by fibrin-specific thrombolytics in acute myocardial infarction: comparison of single-bolus tenecteplase and front-loaded alteplase.

OBJECTIVES Thrombolytic therapy in patients with acute myocardial infarction is hampered by bleeding complications and procoagulant effects favoring early reocclusion. TNK-tPA was shown in vitro to have considerable fibrin specificity. We investigated the effects of tenecteplase (TNK-tPA) and alteplase (rt-PA) on the haemostasis and fibrinolytic system. METHODS AND RESULTS We enrolled 30 patients with AMI into the study. Twenty patients received front-loaded rt-PA up to 100 mg; 10 patients were given TNK-tPA in a single bolus up to 50 mg. All patients received aspirin and intravenous heparin. During the first 2 days, the following parameters were repetitively determined: thrombin-antithrombin III complexes (TAT), antithrombin III (ATIII), prothrombin fragment F 1 + 2 (F 1 + 2), kallikrein-like activity (KK), activated factor XII (FXIIa), plasmin alpha 2-antiplasmin complexes (PAP), fibrinogen, D-dimers (DD), tissue-type plasminogen activator (t-PA). A total of 75 healthy persons served as control group. TAT increased significantly after rt-PA but not after TNK-tPA (3 h: 38.1 +/- 29.4 versus 10.5 +/- 4.2 microg/l; p < 0.01), indicating paradoxical thrombin activation. F 1 + 2 increased transiently after rt-PA but not after TNK-tPA. Fibrinogen was significantly lower after rt-PA versus TNK-tPA (3 h: 163 +/- 27 versus 380 +/- 54 mg/dl; p < 0.05). KK activities in the rt-PA group were significantly (p < 0.01) increased over 48 h versus TNK-tPA. PAP and D-dimers were lower over the time course of 48 h in the tenecteplase group versus rt-PA. CONCLUSIONS This study indicates that tenecteplase has higher fibrin specificity not only in vitro but also in vivo versus alteplase. TNK-tPA consecutively has no paradoxical systemic procoagulant effect due to the lower extent of activation of the kallikrein-factor XII system than alteplase.

Relationship Between Minor Myocardial Damage and Inflammatory Acute-Phase Reaction in Acute Coronary Syndromes

AbstractBackground: In severe acute coronary syndromes (ACS) elevation of markers of inflammation and acute phase reaction (APR) like C-reactive protein (CRP) as well as a release of troponin have been reported.Using a high sensitivity troponin T (TnT) test we investigated whether an APR occurs in ACS only in the presence of ischemic myocardial damage. Methods: In 85 patients with ACS C-reactive protein (CRP), serum amyloid A (SAA), fibrinogen, thrombin antithrombin III complexes (TAT) and kallikrein were determined vs. high sensitive TnT (≥0.02 ng/ml) initially and 2 d later vs. 45 patients with stable angina pectoris and 42 controls. Results: In stable angina pectoris, markers of inflammation and coagulation were slightly elevated (p < 0.05). Initially in ACS elevations of CRP to 1.2 ± 0.3 mg/dl, SAA to 4.8 ± 2.6 mg/dl and fibrinogen to 448 ± 21 mg/dl (all p < 0.01 vs. controls) were found followed by a significant APR (p < 0.01).In the subgroup of TnT positive ACS patients, an APR with increased CRP (4.1 ± 1.3 mg/dl), SAA (20.4 ± 8.3 mg/dl), and fibrinogen (641 ± 45 mg/dl) was detectable (all p < 0.05 vs. TnT negative patients). In contrast, patients without TnT release showed APR markers comparable to patients with stable angina pectoris. Conclusion: Our findings demonstrate an association between myocardial injury in ACS and acute phase reaction as evidenced by several molecular markers. A highly sensitive TnT-test identified myocardial inury in about all patients with APR while a standard TnT cut-off (0.1 ng/ml) missed 32% of these patients. Thus, the APR in patients with ACS is strongly associated with at least minor ischemic myocardial damage and prior findings of an APR independent from myocardial injury are probably based on less sensitive troponin tests.

Benefit of onsite reperfusion therapy or transfer to primary PCI in STEMI patients admitted to hospitals without catheterization laboratory. Results of the MITRA PLUS Registry

The optimal reperfusion strategy in elderly patients with ST‐segment elevation myocardial infarction (STEMI) remains a topic of debate. Therefore, we investigated in the MITRA PLUS registry clinical outcome variables in 5455 patients aged>70 years and STEMI on admission at hospitals without the facilities of coronary catheterization and PCI. Outcome was compared after thrombolysis, transfer to PCI and after no reperfusion therapy. Data of this registry in STEMI patients older than 70 years, who were transferred to another hospital for PCI, showed a strong trend for lower in‐hospital mortality rates compared with a strategy with sole fibrinolysis and significantly lower in hospital death rates compared with a conservative treatment without (medical or mechanical) reperfusion. Additionally, the PCI group also had a reduced incidence of the combined events: death, myocardial reinfarction, stroke in comparison with both other infarct groups. Data of the presented MITRA PLUS registry in STEMI patients older than 70 years support data of several other studies, that patients with STEMI benefit from a transfer to primary PCI even after a time delay of symptom onset to hospital admission of more than 2 h compared with a strategy using sole fibrinolytic therapy.

Combined thrombolysis with abciximab favourably influences platelet-leukocyte interactions and platelet activation in acute myocardial infarction.

Background: In patients with acute myocardial infarction (AMI), activated platelets and altered haemostatic/fibrinolytic systems with and without thrombolytic therapy are known. Platelets thereby interact with neutrophils, stimulated endothelial cells and with monocytes leading to adverse effects on further myocardial damage. Thrombolysis in these patients is still hampered by procoagulant effects favoring early reocclusion. The additional treatment with a GPIIb/IIIa antagonist aimed to minimize early reocclusion thus improving the present therapeutic regimen.Methods: In 38 patients with AMI, we investigated the effects of a thrombolytic regimen with half reteplase (r-PA) dose plus abciximab vs. full dose r-PA on membrane-bound adhesion molecules (CD41, CD42b, CD40, CD40L) expressed on platelets, neutrophils and monocytes as well as on soluble platelet-selectin as interaction and activation markers of these cells.Results: The combination group had significantly (p < 0.05) lower sP-selectin levels over 48 h vs. the group treated with full dose r-PA. After 3 h, the percentage of CD41 and CD42b positive monocytes and granulocytes as well as the percentage of CD40 positive granulocytes and the percentage of CD40L positive monocytes markedly (p < 0.01, p < 0.05) decreased in the combination group vs. data at admission compared with the r-PA group indicating less leukocyte-patelet adhesion.Conclusions: The thrombolytic regimen with half dose r-PA and abciximab had a benefical influence on platelet activation and induced a more marked decrease of platelet-monocyte, and in part, platelet-granulocyte aggregates compared with the r-PA regimen. This could contribute to a probably lesser monocyte activation state with favourable effects on monocyte-endothelial adhesion and a consecutively possible influence of myocardial damage, a reduction of the additionally acute local inflammatory processes and a reduction of adherence of platelet-granulocyte aggregates to subendothelium.

Correlation between ST-T-Segment Changes with Markers of Hemostasis in Patients with Acute Coronary Syndromes

Background: Disturbance of the hemostatic and the inflammatory system plays an important role in the pathophysiology of acute coronary syndromes (ACS). Their markers have been shown to predict further coronary events in patients with ACS. The prognostic value of the admission electrocardiogram (ECG), which is commonly used to evaluate ischemia, was studied previously. We investigated the correlation between serum markers of the hemostatic/inflammatory system and ECG changes in ACS. Methods: A standard 12-lead ECG was obtained from 85 patients with ACS on admission (0d). Markers of the hemostatic and inflammatory system were measured on admission and after 2 days (2d). Results: Patients with ST-T-changes had higher fibrinogen and thrombin-antithrombin III complex (TAT) levels than patients without ECG alterations at both times (fibrinogen: 0d: 492 ± 38 vs. 357 ± 36 mg/dl, p < 0.01; 2d: 633 ± 55 vs. 440 ± 50 mg/dl, p < 0.02; TAT: 0d: 7.2 ± 1.3 vs. 3.6 ± 0.7 µg/l, p < 0.05; 2d: 5.3 ± 0.9 vs. 3.2 ± 0.5 µg/l, p < 0.05). Tissue-type plasminogen activator (TPA) was elevated in patients with ECG changes initially (10.1 ± 0.6 vs. 7.2 ± 0.7 ng/ml, p < 0.02). D-dimers, the acute-phase proteins C-reactive protein, serum amyloid A and the soluble adhesion molecules showed no significance. Conclusions: The data reveal a correlation between electrocardiographic changes and hemostasis in patients with ACS. The association of myocardial damage and a disturbed hemostatic system might stratify patients who are at high risk of suffering further coronary events.

Effect of Clopidogrel on Adhesion Molecules, Hemostasis, and Fibrinolysis in Coronary Heart Disease

Background: The interaction among inflammation, Hemostasis, and fibrinolysis plays a major role in the genesis of coronary artery disease (CAD). The aim of the study was to compare the effect of clopidogrel plus aspirin versus aspirin alone on cellular adhesion molecules on leukocytes, soluble adhesion molecules, and molecular markers of coagulation and fibrinolysis in patients with CAD. Methods: In this randomized, placebo-controlled, and double-blind study, 42 patients with chronic angina pectoris were included. All patients were treated with aspirin (ASA). Twenty-three patients received clopidogrel additionally (75 mg/day with a 300-mg loading dose) for 14 days. Nineteen patients received placebo additionally. Soluble adhesion molecules (sICAM-1, sVCAM-1, sP-selectin), surface expression of CD54, CD11a, CD11b, CD40, CD40L, CD41, CD42b, and CD62L on lymphocytes, monocytes, and neutrophils, and markers of hemostasis and fibrinolysis (TAT, PAP, D-dimers) were measured. Results: In the ASA + clopidogrel group, no change in surface expression of cellular adhesion molecules on leukocytes and on plasma levels of sICAM-1, sVCAM-1, sP-selectin, TAT, PAP, and D-dimers was detectable. Conclusions: Clopidogrel plus aspirin for 2 weeks did not result in a detectable benefit versus sole aspirin therapy regarding cellular adhesion molecules on leukocytes, plasma markers of coagulation, fibrinolysis, and soluble adhesion molecules in patients with CAD.