Correlation of baseline plasminogen activator inhibitor activity with patency of the infarct artery after thrombolytic therapy in acute myocardial infarction

Biomarkers of coagulation and fibrinolysis in acute myocardial infarction: a joint position paper of the Association for Acute CardioVascular Care and the European Society of Cardiology Working Group on Thrombosis

The formation of a thrombus in an epicardial artery may result in an acute myocardial infarction (AMI). Despite major advances in acute treatment using network approaches to allocate patients to timely reperfusion and optimal antithrombotic treatment, patients remain at high risk for thrombotic complications. Ongoing activation of the coagulation system as well as thrombin-mediated platelet activation may both play a crucial role in this context. Whether measurement of circulating biomarkers of coagulation and fibrinolysis could be useful for risk stratification in secondary prevention is currently not fully understood. In addition, measurement of such biomarkers could be helpful to identify thrombus formation as the leading mechanism for AMI. The introduction of biomarkers of myocardial injury such as high-sensitivity cardiac troponins made rule-out of AMI even more precise. However, elevated markers of myocardial injury cannot provide proof of a type 1 AMI, let alone thrombus formation. The combined measurement of markers of myocardial injury with biomarkers reflecting ongoing thrombus formation might be helpful for the fast and correct diagnosis of an atherothrombotic type 1 AMI. This position paper gives an overview of the current knowledge and possible role of biomarkers of coagulation and fibrinolysis for the diagnosis of AMI, risk stratification, and individualized treatment strategies in patients with AMI.

The metabolic syndrome: an emerging risk state for cardiovascular disease

The common clustering of glucose intolerance, insulin resistance, abdominal adiposity, elevated blood pressure, and low HDL cholesterol is referred to as metabolic syndrome. Individuals with this syndrome have an increased risk of developing cardiovascular disease (CVD). The World Health Organisation and the National Cholesterol Education Programme’s Adult Treatment Panel III (NCEP-ATP III) have outlined specific diagnostic criteria for the diagnosis of the metabolic syndrome to help in the Identification of this syndrome in clinical practice. While the WHO criteria were specifically developed for use in research, the NCEP criteria are useful in clinical diagnosis of the metabolic syndrome. The metabolic syndrome is amenable to lifestyle modifications such as increased physical activity, weight loss, and possibly intake of low-glycemic foods. Drug therapy may be used to treat individual components of the syndrome such as elevated blood pressure and dyslipidemia. To control elevated glucose levels (when there is failure of lifestyle modification), medications such as metformin, thiazolidinedione derivatives and alpha glucosidase inhibitors may be used.

[Prognosis value of thrombin activatable fibrinolysis inhibitor concentration and C1040T polymorphism in acute myocardial infarction treated with fibrinolysis]

OBJECTIVE

To analyze the prognostic value of thrombin activatable fibrinolysis inhibitor (TAFI) and C1040T polymorphism in acute myocardial infarction treated with fibrinolysis. To analyze C1040T polymorphism influence on its plasma level.

DESIGN

An observational, prospective study performed from November 2003 to November 2005 and with a 3 month follow-up.

SETTING

Intensive Medicine Service from a university-affiliated teaching hospital.

PATIENTS

A total of 53 patients with acute myocardial infarction with persistent ST segment elevation treated with the same fibrinolytic therapy. A control group of 53 biologically similar subjects was included.

INTERVENTIONS

None.

MAIN MEASUREMENTS

Baseline characteristics; frequency of wild-type genotype (Thr325Thr) and of those corresponding to the mutation (Thr325LLe and LLe325lle), TAFI levels at 6 h, 34 h and 3 months post-fibrinolysis; ejection fraction; Killip-Kimball; reperfusion; ischemic recurrence; death.

RESULTS

No relationship was found between biological features and TAFI concentration. The latter was significantly higher in infarct patients (p<0.01) and in the mutation group (p<0.01). The homozygotic mutation (Ile325Ile) was significantly higher in infarct patients (p<0.01). Reperfusion was significantly associated with lower body mass index (p=0.02. OR 0.22. 95% CI), ejection fraction (p=0.004. OR 0.91. 95% CI), triglyceride level (p=0.01. OR 1.02. 95% CI) and cholesterol levels (p=0.001. OR=0.84. 95% CI). Mutation was associated to a significant fall in post-fibrinolysis concentration TAFI antigen and functional TAFI (p=0.01) and (p=0.02), and lower frequency of reperfusion. Reperfusion was associated with a significant post-fibrinolysis reduction in the level of TAFI antigen (p=0.02). Recurrence was associated to a significantly higher post-fibrinolysis level (p=0.05. OR=0.84. 95% CI). This was more frequent in mutation. Post-fibrinolysis TAFI antigen concentration was significantly lower in non-recurrence patients (p=0.028. OR=1.03. 95% CI).

CONCLUSIONS

A higher concentration of TAFI is associated to a worse prognosis in reperfusion and recurrence in acute myocardial infarction treated with fibrinolysis. Homozygotic mutation was more frequent in myocardial infarction patients. Wild genotype is associated to a better prognosis. Mutation is associated to a higher expression of TAFI.

An embolus in the right atrium caught in the Chiari network and resistant to thrombolysis

This case report describes a patient with thromboemboli trapped in the Chiari network within the right side of the heart and resistant to thrombolysis. The right atrial masses were completely removed under cardiopulmonary bypass. Histological evaluation confirmed a mixed thromboemboli, with thrombus structures showing signs of organisation and surrounded by a fibrous capsule. The plasma level of the plasminogen activator inhibitor type-1 (PAI-1) was 50% higher than the normal upper limit. In this presented case, the Chiari network displayed a protective function but the expansion and organisation of the thromboembolus found there made it resistant to lytic treatment. Another important factor that could have influenced the resistance to thrombolysis was the high level of PAI-1.

Prognostic role of plasminogen-activator-inhibitor-1 levels in treatment with streptokinase of patients with acute myocardial infarction

BACKGROUND

The antifibrinolytic effect of plasminogen-activator-inhibitor type 1 (PAI-1) may be responsible for delays in reperfusion and/or reinfarctions after streptokinase (STK) therapy in patients with acute myocardial infarction (AMI).

HYPOTHESIS

This study aimed to demonstrate the prognostic role of pretreatment PAI-1 levels for the outcome of STK therapy in patients with AMI, depending on reperfusion and/ or reinfarction.

METHODS

The mean pretreatment PAI-1 level of 104 patients with AMI, treated with STK, determined by chromogenic method, was 5.8 +/- 8.6 U/ml, range 0.3-66.2 U/ml. Streptokinase therapy was successful when reperfusion was achieved, as assessed noninvasively, without subsequent reinfarction; it failed when reperfusion was delayed and/or reinfarction developed.

RESULTS

Fibrinolysis with STK failed significantly in patients with elevated pretreatment PAI-1 levels (p < 0.05), especially with levels >4.0 U/ml (p< 0.01). The mean pretreatment PAI-1 level was significantly higher in unsuccessfully treated patients. Multivariate statistical testing demonstrated that among pretreatment variables, elevated PAI-1 activity was the most significant independent risk factor of failed fibrinolysis with STK.

CONCLUSIONS

Among pretreatment variables, elevated pretreatment PAI-1 activity in patients with AMI was the most significant independent risk factor of failed fibrinolysis with STK, especially at levels > 4.0 U/ml.

The influence of acute-phase levels of haemostatic factors on reperfusion and mortality in patients with acute myocardial infarction treated with streptokinase

BACKGROUND

The fibrinolytic system and von Willebrand factor (vWF) have been shown to play a role as risk factors for myocardial infarction. We performed this prospective cohort study to determine if components in the fibrinolytic system or vWF before or during treatment of AMI with streptokinase (SK) could predict reperfusion, recurrent ischaemia, reinfarction or mortality at one year, or mortality at five years. Reperfusion and recurrent ischaemia were assessed by continuous vectorcardiography. The setting was Umeå university hospital and Skellefteå county hospital, Sweden.

RESULTS

139 patients were included; successful reperfusion was obtained in 53%. tPA activity, PAI-activity, PAI-mass concentration and vWF were analysed immediately on arrival and after 4 and 10 h. High fibrinolytic activity, measured as tPA activity > 25 U/L after the start of treatment, was associated with reperfusion. No significant associations between pre-treatment levels of the fibrinolytic variables or vWF and reperfusion or recurrent ischaemia were found. Elevated levels of PAI-1 mass concentration and PAI-1 activity after the start of SK treatment were associated with a higher risk for death at one year, but not at five years. High levels of vWF were associated with worse prognosis but not when corrected for age.

CONCLUSION

Pre-treatment levels of PAI-1, vWF and tPA activity showed no association with reperfusion or recurrent ischaemia. Elevated levels of PAI-1 activity after the start of treatment were associated with worse prognosis.

Admission plasma leptin level strongly correlates with the success of thrombolytic therapy in patients with acute myocardial infarction

Obesity-associated alterations in coagulation and fibrinolytic factors in favor of thrombosis are well known. Observations suggest that leptin, a recently discovered obesity gene product, in addition to being a satiety factor, induces platelet aggregation, accelerates formation of firm thrombi, and is associated with abnormal fibrinolysis. The authors studied the influence of plasma leptin concentrations on admission within 6 hours of acute myocardial infarction (MI) on the outcome of thrombolytic therapy (TT). Forty-one patients with acute MI who underwent TT were enrolled into the study. Levels of plasma leptin were determined with radioimmunoassay method in samples obtained just before initiation of TT. Patients were initially classified according to the admission plasma leptin concentrations, and it was observed that failure of reperfusion therapy with streptokinase was significantly higher in patients with admission plasma leptin concentrations > or =14 ng/mL (group 2) as compared to patients with admission plasma leptin concentrations <14 ng/mL (group 1). Final failure of TT, identified both by reinfarction and absence of early reperfusion as assessed noninvasively, was observed in 11 patients (39%) in group 1 and in 10 patients (77%) in group 2 (p=0.025). Left ventricular ejection fraction was slightly but significantly higher in group 1 than in group 2 (p=0.031). High plasma leptin concentrations on admission in patients within 6 hours after the onset of acute MI are associated with less TT efficacy. The authors suggest that admission leptin levels may play a role in the management of patients with acute MI.

Therapeutic Potential of Monteplase in Acute Myocardial Infarction as a Powerful Thrombolytic Agent for Pretreatment of Coronary Intervention

Thrombolysis with conventional thrombolytic agents followed by percutaneous coronary intervention (PCI) had no impact on the treatment of acute myocardial infarction (AMI). However, the development of mutant type plasminogen activator (mt-PA) has prompted us to reassess the combination of thrombolysis and PCI. Monteplase (Eisai, Co. Ltd., Tokyo, Japan) is a newly developed mt-PA that can be administrated as a single intravenous bolus injection. We initiated a clinical trial [Combining Monteplase with Angioplasty (COMA)] to evaluate the effectiveness of monteplase followed by PCI. The AMI patients were randomly assigned to receive PCI following pretreatment with a single bolus intravenous injection of monteplase or direct PCI without monteplase. The initial coronary angiography prior to PCI showed that 36.2% of patients in the monteplase group achieved Thrombolysis in Myocardial Infarction (TIMI) 3 flow in the infarct-related artery, compared with in only 7.9% of patients in the direct PCI group (P < 0.0001). During 24 months following PCI, major cardiac events occurred in 27.7% of patients in the monteplase + PCI group, and in 46.7% of patients in the direct PCI group without monteplase (P < 0.05). Thus, the ideal strategy for the treatment of AMI is the administration of monteplase upon arrival at a community hospital with a prompt transfer to a tertiary center for PCI.

The effect of high plasma levels of angiotensin-converting enzyme (ACE) and plasminogen activator inhibitor (PAI-1) on the reperfusion after thrombolytic therapy in patients presented with acute myocardial infarction

The resistance to thrombolytic agents and delays in reperfusion occur in more than 30% after acute myocardial infarction. This may play an important role in the unsuccessful recanalization after thrombolytic therapy. The aim of this study is to assess the clinical and biochemical markers of reperfusion after different types of thrombolytic therapy and to find out the relationship between PAI-1 and ACE serum levels and the short-term outcome. Pretreatment ACE and PAI-1 plasma levels of 184 patients with acute myocardial infarction, treated with thrombolytic therapy were determined. Failure of thrombolysis was considered when reperfusion was delayed as assessed by noninvasive reperfusion criteria, reinfarction, and impaired left ventricular function. High plasma level of ACE (> 50 U/L), PAI-1 (> 43 ng/ml) and both was found in 57, 108 and 32 patients respectively. Subjects with high ACE plasma levels were characterized by impaired LV systolic function (79.0% vs. 75.0%), new Q-wave (88.4% vs. 74.2%), less reperfusion arrhythmia (19.3% vs. 22.8%) and prolonged hospitalization (70% vs. 66%) but no statistical significance was observed. High enzymes levels of PAI-1 were observed with higher incidence of anterior myocardial infarction (50.0% vs. 41.0%), lesser ST segment resolution (65.6% vs. 58.8%), reinfarction (6.3% vs. 5.9%), and impaired LV systolic function (90.6% vs. 76.0%), and prolonged hospitalization (70.4% vs. 63.4). There was a statistically significant difference between thrombolytic agents in the presence of high ACE regarding hospital overstay (p = 0.02). While the presence of high PAI-1 was significantly affect the degree of ST-segment resolution (p = 0.03).

CONCLUSION

High plasma ACE and/or PAI-1 plays a considerable role in the higher incidence of unsuccessful reperfusion and impaired left ventricular function after thrombolytic therapy. A rapid diagnostic tool that enables physician of detecting those enzymes before giving thrombolytic therapy may change the strategy of treatment to offer another effective revascularization method.

Plasma TAFI and soluble CD40 ligand do not predict reperfusion following thrombolysis for acute myocardial infarction

INTRODUCTION

Thrombolytic therapy fails to achieve reperfusion in almost a third of patients with acute myocardial infarction. Thrombin activatable fibrinolysis inhibitor (TAFI) and soluble CD40 ligand (sCD40L) are novel endogenous fibrinolytic and atherothrombotic factors that determine clot stability. We investigated whether admission plasma thrombin activatable fibrinolysis inhibitor (TAFI) and soluble CD40 ligand (sCD40L) concentrations predicted reperfusion following thrombolytic therapy in patients with acute myocardial infarction.

MATERIALS AND METHODS

Prior to administration of thrombolytic therapy, venous blood was collected from 110 patients presenting with acute ST segment elevation myocardial infarction and plasma assayed for tissue plasminogen activator (t-PA) antigen and activity, plasminogen activator inhibitor type-1 antigen (PAI-1), TAFI antigen and activity, C-reactive protein (CRP) and sCD40L concentrations. Reperfusion was determined using continuous ST segment monitoring.

RESULTS

Reperfusion occurred in 77 (70%) patients with a mean treatment to reperfusion time of 83 +/- 46 min. Peak creatine kinase was significantly lower in patients who reperfused (1578 +/- 1199 versus 2200 +/- 1744 U/L; P < 0.05) and correlated with time to reperfusion (r = 0.44 [95% CI: 0.23 - 0.61], P = 0.0001). There was a modest correlation between plasma TAFI antigen and activity (r = 0.3 [95% CI: 0.04 - 0.53]; P < 0.05). There were no significant associations between coronary reperfusion and plasma concentrations of t-PA, PAI-1, TAFI, CRP or sCD40L.

CONCLUSIONS

Systemic plasma TAFI, sCD40L and CRP concentrations do not predict reperfusion in patients receiving thrombolytic therapy for acute ST elevation myocardial infarction.

Long-term benefits of monteplase before coronary angioplasty in acute myocardial infarction

Patients with acute myocardial infarction were randomly assigned to receive direct percutaneous coronary intervention (PCI) or pretreatment with intravenous monteplase followed by PCI. Although the combination of monteplase and PCI did not alter mortality compared with direct PCI, there was a dramatic reduction in the cardiac event rate over a 2-year follow-up compared with direct PCI.

Failure of peripheral arterial thrombolysis due to elevated plasminogen activator inhibitor type 1

To reduce the risk of intracerebral hemorrhage during thrombolytic therapy, a lower dose of tissue plasminogen activator (t-PA) or urokinase is used for acute peripheral arterial thrombi versus coronary thrombi. We hypothesized that elevated plasminogen activator inhibitor-1 (PAI-1) activity could neutralize infused t-PA or urokinase, resulting in lysis failure. Active PAI-1, active t-PA and total t-PA antigen were measured in 20 patients receiving t-PA, and active PAI-1 was measured in four patients receiving urokinase for acute peripheral arterial thrombosis. The 18 patients that successfully lysed their thrombi all had low active PAI-1 levels (10 +/- 19 pmol/l) during infusion of thrombolytic therapy, while six patients that failed to lyse their thrombi had high active PAI-1 levels (1533 +/- 1384 pmol/l, P = 0.00007) during infusion. Active t-PA levels during t-PA infusion were higher in the group that lysed their thrombi (536 +/- 423 pmol/l versus 42 +/- 45 pmol/l, P = 0.04) even though total t-PA levels were lower (1240 +/- 493 pmol/l versus 1956 +/- 709 pmol/l, P = 0.03). In the patients that failed to lysed their thrombi, > 95% of infused t-PA was neutralized by PAI-1. We conclude that elevated PAI-1 during acute peripheral arterial thrombolysis is associated with an increased risk of lysis failure due to reduced levels of circulating active t-PA or urokinase.

Plasminogen activator inhibitor-1 in patients with atrial arrhythmias during acute myocardial infarction, treated with streptokinase

Atrial arrhythmias (AA), especially atrial fibrillation (AF), during acute myocardial infarction (AMI) are often associated with increased mortality and heart failure. Impaired fibrinolysis with elevated plasminogen activator inhibitor-1 (PAI-1) activity is associated with resistance to fibrinolytic therapy in AMI patients, but it is also found in patients with AF. Our aim was a prospective study of the role of pre-treatment PAI-1 levels for the presence of AA in AMI patients and the influence of AA on in-hospital mortality. In 116 AMI patients, treated with streptokinase, pre-treatment PAI-1 levels were estimated by the chromogenic method (normal levels, 0.3-3.5 U/ml) and in-hospital AA were assessed as atrial fibrillation, flutter and/or tachycardias. Between patients with and without AA, a significant difference was observed in mean pre-treatment PAI-1 levels, in several in-hospital complications and mortality (24 versus 4.4%; P < 0.01; odds ratio, 6.45; 95% confidence interval, 1.66-25.0). The PAI-1 level > 7 U/ml was the most significant independent pre-treatment risk factor for AA (P < 0.05; odds ratio, 3.5; 95% confidence interval, 1.15-10.6). We conclude that AA were a significant risk for in-hospital mortality of AMI patients, treated with streptokinase. A pre-treatment PAI-1 level > 7 U/ml was the most significant pre-treatment risk for AA in these patients.

Plasminogen activator inhibitor type-1 in cardiovascular disease. Status report 2001

Plasminogen activator inhibitor type-1 (PAI-1) is known to contribute to thrombus formation and to the development and the clinical course of acute and chronic cardiovascular disease, as well as of other arterial and venous thromboembolic diseases. Recently, an important role of elevated pretreatment levels of PAI-1 for failure of thrombolytic therapy of acute myocardial infarction has been discussed. PAI-1 plasma levels depend on the one hand on gene regulation but are related on the other hand to known risk factors of atherosclerosis like insulin resistance, diabetes or hypertriglyceridemia, respectively. Furthermore, an activated renin-angiotensin-aldosterone system (RAAS) significantly contributes to the upregulation of PAI-1 concentration via a receptor-mediated mechanism. In accordance to the known mechanisms of regulation of PAI-1 plasma levels, the use of specific agents like antidiabetic drugs, fibrates, statins, ACE inhibitors and angiotensin II type-1 receptor-blockers may contribute to the downregulation of circulating PAI-1 and, therefore, increase the fibrinolytic capacity and consecutively counteract the thrombotic tendency. To further improve the efficacy of thrombolytic therapy, a PAI-1 resistant variant of t-PA, TNK-t-PA, has been developed and is now available for acute myocardial infarction.

Maximal endothelial tissue plasminogen activator release is not impaired in patients with acute coronary syndromes before heparin treatment

Procoagulant and fibrinolytic disturbances are described in patients with acute coronary syndromes (ACS), but whether defective maximal tissue plasminogen activator (t-PA) release from the endothelium is also present is still controversial. Previous studies did not take into consideration the contribution of heparin, which strongly affects fibrinolysis. Accordingly, in this study, we measured maximal t-PA release in patients with ACS before, during, and after heparin treatment. Maximal t-PA release was measured by the venous occlusion test in 38 hospitalized patients with confirmed ACS (18 acute myocardial infarctions and 20 unstable anginas) before starting heparin, during heparin treatment, and 4 and 12 h after discontinuation. Plasma plasminogen activator inhibitor type 1 (PAI-1), D-dimer and prothrombin fragment F1 + 2 were also measured. Eighteen age-matched subjects with no evidence of coronary disease were used as controls. At admission, patients showed significantly higher plasma levels of t-PA, PAI-1, and F1 + 2 than controls. Before heparin, maximal t-PA release was similar in patients and controls. Heparin treatment was associated with a significant increase of plasma t-PA, while it did not affect maximal t-PA release. Coagulative and fibrinolytic disturbances are present in patients with ACS, but these do not include maximal t-PA release. Among our patients, maximal t-PA release appears stable over time and is not affected by heparin treatment.

Plasminogen activator inhibitor type-1 (part two): role for failure of thrombolytic therapy. PAI-1 resistance as a potential benefit for new fibrinolytic agents

Rapid and sustained reperfusion of an occluded coronary artery is the goal of thrombolytic therapy in acute myocardial infarction. However, the clot-dissolving efficacy of fibrinolytic agents such as tissue-type plasminogen activator (t-PA) is limited, in vivo, in part by the action of plasminogen activator inhibitor type-1 (PAI-1). A new generation of fibrinolytic agents has been genetically engineered to have greater resistance to PAI-1 inhibition. This article reviews the pathophysiologic role of PAI-1 in failure of thrombolytic therapy and describes the advantages that PAI-1-resistance may confer upon fibrinolytic agents such as TNK-t-PA, the new fibrinolytic agent with the most powerful PAI-1 resistance.

Plasma and platelet plasminogen activator inhibitor-1 in patients with acute myocardial infarction

Several studies have demonstrated an increased level of plasma plasminogen activator inhibitor-1 (PAI-1) in patients with coronary artery disease (CAD). However, the concentration of PAI-1 in platelets, which accounts for more than 90% of the blood PAI-1, is unknown in these patients. The present study evaluated the concentrations of PAI-1 and several fibrinolytic factors in the plasma and platelets of patients with CAD and the serial changes in patients with acute myocardial infarction (AMI). All 72 subjects had coronary angiography and were divided into 3 groups: CAD(-) group without coronary artery stenosis or myocardial ischemia (n=20), CAD(+) group with either stable angina pectoris (n=18) or old myocardial infarction (n=12) with coronary artery stenosis, and the AMI group admitted within 24h of symptom onset who underwent successful percutaneous transluminal coronary angioplasty (n=22). The concentrations of plasma PAI-1, tissue plasminogen activator (t-PA), and t-PA x PAI-1 complex were similar in the CAD(-) and CAD(+) groups, but were greater on day 1 in the AMI group compared with the 2 CAD groups. There were no significant differences between the 3 groups in the plasma concentrations of thrombin antithrombin III complex (TAT), alpha2-plasmin inhibitor-plasmin complex (PIC), beta-thromboglobulin (beta-TG), and platelet factor 4 (PF-4). The platelet PAI-1 concentrations did not differ between the CAD(-) and CAD(+) groups, but was greater on day 1 in the AMI group compared to the CAD groups. The platelet beta-TG and PF-4 were similar between the 3 groups. In the AMI group, both the plasma and platelet PAI-1 concentrations were greater on day 1, but the plasma PAI-1 rapidly decreased by day 5 and remained low on day 28 compared with day 1. The platelet PAI-1 concentration gradually decreased by day 5 and was further decreased by day 28. The serial changes of the plasma t-PA and t-PA PAI-1 complex during the course of AMI were similar to those of the plasma PAI-1. A positive correlation was found between the plasma and platelet PAI-1 in all 72 patients, but not in the AMI group alone. These results suggest that the PAI-1 that has accumulated in platelets at the onset of AMI might be released in large amounts into the plasma, resulting in an increase in thrombus formation.

Fibrinolysis and thrombosis

The fibrinolytic system generates plasmin, which dissolves fibrin in haemostatic plugs and in thrombi. It is often regarded simply as a secondary phenomenon responsive to the generation of thrombi but it is, rather, in dynamic balance with fibrin formation, such that abnormalities in either can lead to thrombosis. This chapter summarizes the fibrinolytic system and its regulation. It considers the components of the system in blood, both in plasma and in circulating cells, with emphasis on protease-inhibitor balance. It goes on to discuss local fibrinolytic potential in thrombi, both venous and arterial, and in the diseased vessel wall, presenting evidence that increased local inhibition of fibrinolysis by PAI-1, PAI-2 and alpha2-antiplasmin is intimately involved in thrombus stability and in the generation of fibrin-rich vessel wall lesions. Finally, it reviews the evidence that defective plasma fibrinolysis has a causal role in venous and arterial thrombosis.

Comparison of thrombolytic therapies with mutant tPA (lanoteplase/SUN9216) and recombinant tPA (alteplase) for acute myocardial infarction

The fibrinolytic capacity of patients with acute myocardial infarction (AMI) is known to be impaired. The primary regulatory element of the fibrinolytic system is plasminogen activator inhibitor (PAI). It has been previously observed that there are 2 peaks in the plasma PAI level of AMI patients at 4h and 16h after thrombolytic therapy with recombinant tissue plasminogen activator (rtPA). Lanoteplase/SUN9216 is a mutant tPA with a biological half-life longer than that of rtPA. Thrombolytic therapy with mutant tPA or rtPA was carried out consecutively in 21 patients with AMI (8 patients as the mutant tPA group, and 13 patients as the rtPA group). The recanalization time of the mutant tPA group was significantly faster than that of the rtPA group (16.1 +/- 3.9 min vs 39.6 +/- 4.8 min, p<0.01). The PAI activity at 4h after the initiation of thrombolysis was significantly lower in the mutant tPA group than in the rtPA group (8.74 +/- 5.46IU/L vs 26.74 +/- 3.35 IU/L, p<0.01). There was a one mild peak in serial plasma PAI activity levels 24h after the initiation of thrombolysis. The results suggest that thrombolytic therapy with mutant tPA reduced the impairment of fibrinolytic capacity. The mutant tPA gives faster recanalization and lower PAI activity after successful thrombolysis, compared with rtPA.

Concentration of endogenous tPA antigen in coronary artery disease: relation to thrombotic events, aspirin treatment, hyperlipidemia, and multivessel disease

Tissue plasminogen activator (tPA) is the major plasminogen activator responsible for dissolving blood clots found in blood vessels. However, elevated concentrations of tPA antigen were found to be related to adverse events in patients with coronary artery disease (CAD). Considerable controversy about the significance of these results exists. The goal of this cross-sectional study was to identify independent determinants for tPA antigen concentrations in patients with CAD, to possibly clarify the above paradoxical relationship. The baseline tPA antigen concentrations of 366 patients with angiographic evidence of coronary sclerosis were determined. Univariate analysis showed that age (P=0.013), angiographic extent of disease (P<0.001), presence of angina at rest (P<0.001), diabetes mellitus (P=0.004), hypercholesterolemia (P=0. 045), hypertriglyceridemia (P=0.015), and chronic intake of nitrates (P<0.001) were significantly and positively related to tPA antigen concentration, while the chronic intake of aspirin was inversely related to tPA antigen (P<0.001). In addition, plasminogen activator inhibitor type 1 (PAI-1) activity was found to be significantly and positively associated with tPA antigen concentration (P<0.001). A multivariate analysis identified chronic low-dose aspirin therapy (P<0.001), PAI-1 activity (P<0.001), hypertriglyceridemia (P=0.005), the type of angina (P=0.026), multivessel disease (P=0.041), and hypercholesterolemia (P=0.043) as significant and independent determinants of tPA antigen. While hypertriglyceridemia and hypercholesterolemia both are related to the underlying disease, the type of angina and the number of involved vessels are linked to the severity and extent of disease, and all of them are indicators of a prothrombotic state found during the progression of CAD. In contrary, low-dose aspirin rather would decrease the likelihood of thrombotic events. The relation of tPA antigen to PAI-1 activity furthermore underlines the relation between tPA antigen concentration and a prothrombotic state. Therefore, the positive or-in case of aspirin therapy-negative correlation of these parameters with tPA antigen concentration would indicate that thrombus formation and simultaneous endothelial cell activation might be major determinants for tPA antigen concentration in CAD.

Pretreatment plasminogen activator inhibitor-1 (PAI-1) levels and the outcome of thrombolysis with streptokinase in patients with acute myocardial infarction

BACKGROUND

The risk for reinfarctions and delays in reperfusion after streptokinase therapy may be caused by the antifibrinolytic effect of platelet-derived type 1 plasminogen activator inhibitor (PAI-1). This study aims to show the relation of pretreatment PAI-1 levels of patients with acute myocardial infarction treated with streptokinase therapy and the outcome of fibrinolysis, with the emphasis on reperfusion and reinfarction.

METHODS

Pretreatment PAI-1 levels of 60 patients with acute myocardial infarction, treated with streptokinase, were determined by the chromogenic method. Failure of thrombolysis with streptokinase was present when reperfusion was delayed as assessed by noninvasive reperfusion criteria, or reinfarctions developed.

RESULTS

Mean pretreatment PAI-1 level of patients was 6.3+/-1.2 U/ml; span 1.2 U/ml to 34.0 U/ml. Thrombolysis with streptokinse failed significantly in patients with pretreatment PAI-1 levels >4.0 U/ml (p < 0.05), mainly because of significant occurrence of reinfarction (p < 0.05), but less to delayed reperfusion (p > 0.05).

CONCLUSION

Failure of thrombolysis with streptokinase is significantly associated with pretreatment PAI-1 levels of >4.0 U/ml.

Rebound increase of plasminogen activator inhibitor type 1 after cessation of thrombolytic treatment for acute myocardial infarction is independent of type of plasminogen activator used

Plasma concentrations of tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor type 1 (PAI-1), and D-dimer were investigated in 50 patients treated intravenously for acute myocardial infarction with either streptokinase (n = 23), urokinase (n = 17), or recombinant t-PA (rt-PA, n = 10). The fibrinolytic variables were measured by enzyme immunoassay on admission; 1, 2, 4, 6, 8, 12, and 24 h later; and then daily until day 7 after admission. In each subgroup of patients treated with different thrombolytic agents, PAI-1 increased significantly (P &lt;0.01) ∼3 h after cessation of thrombolytic therapy. PAI-1 peak concentrations did not differ significantly (P = 0.82) among these three subgroups. t-PA and D-dimer did not differ significantly (P &gt;0.14) among subgroups except for higher t-PA in the rt-PA group attributable to detection of the therapeutically administered exogenous rt-PA by the t-PA assay. Our findings demonstrate a marked PAI-1 increase after thrombolytic therapy for acute myocardial infarction, which seems to be a common, drug-independent antifibrinolytic rebound phenomenon in response to thrombolytic treatment.

Thrombosis and Hemostasis in Cardiology: Review of Pathophysiology and Clinical Practice (Part I)

The adverse consequences of thrombosis are per haps nowhere more evident than in clinical cardiology. Throm bosis and hemostasis are primary issues in the management of patients with atrial fibrillation, prosthetic heart valves, severe left ventricular dysfunction, and coronary artery disease. Clini cal trials have defined a crucial role for anticoagulation with warfarin in patients with atrial fibrillation to reduce the inci dence of stroke. Anticoagulation with warfarin and aspirin in combination offers significant protection from systemic emboli in patients with mechanical prosthetic valves, without a sub stantial increased risk of hemorrhage. The risk of systemic emboli may also be reduced by anticoagulation in patients with severe left ventricular dysfunction. Disturbance of the normal balance of hemostasis is a major factor in the pathophysiology of coronary artery disease. Antiplatelet therapy, antithrombin agents, anticoagulants, and fibrinolytic agents have been used to prevent and treat acute coronary thrombosis and to prevent reocclusion following thrombolysis and interventional therapy. Guidelines are presented for antithrombotic therapy in the prac tice of clinical cardiology.

Association of hemostatic factors with peripheral vascular disease

Hemostatic risk factors have been well established in coronary artery disease but less well studied in peripheral vascular disease. The relationship of coagulation and fibrinolytic proteins to lower limb arterial occlusive disease and other vascular risk factors remains poorly defined. Fibrinogen, factor VII coagulant activity, von Willebrand factor (vWf) antigen, and plasminogen activator inhibitor-1 (PAI-1) activity were measured in 46 adult participants in the Arterial Disease Multiple Intervention Trial (ADMIT) and in 76 control subjects and related to ankle-brachial systolic pressure index (ABI), a measure of lower limb arterial stenosis. The primary inclusion criterion for the ADMIT study population was an average of two ABIs <0.85. Fibrinogen and PAI-1 in ADMIT subjects were significantly higher than in control subjects (331 +/- 52 mg/dl vs 273 +/- 46 mg/dl, p < 0.0001; 18.7 +/- 10 units/ml vs 13.5 +/- 8.9 units/ml, p < 0.04). There were significant correlations of fibrinogen with ABI, factor VII coagulant activity, and systolic and diastolic blood pressures; PAI-1 with body mass index and age; and factor VII coagulant activity with cholesterol levels. Logistic regression analysis, considering hemostatic variables and several known nonhemostatic risk factors of peripheral arterial disease, showed that fibrinogen and systolic blood pressure were independently associated with ABI status in this population. The results demonstrate a strong independent correlation between fibrinogen levels and the presence of lower limb arterial stenosis. PAI-1 levels were elevated in ADMIT participants, but multivariate analysis did not demonstrate an independent relationship between PAI-1 and ABI.

Angiographic findings and outcome in diabetic patients treated with thrombolytic therapy for acute myocardial infarction: the GUSTO-I experience

OBJECTIVES

This study sought to determine whether diabetes mellitus, in the setting of thrombolysis for acute myocardial infarction, affects 1) early infarct-related artery patency and reocclusion rates; and 2) global and regional ventricular function indexes. We also sought to assess whether angiographic or baseline clinical variables, or both, can account for the known excess mortality after myocardial infarction in the diabetic population.

BACKGROUND

Mortality after acute myocardial infarction in patients with diabetes is approximately twice that of nondiabetic patients. It is uncertain whether this difference in mortality is due to a lower rate of successful thrombolysis, increased reocclusion after successful thrombolysis, greater ventricular injury or a more adverse angiographic or clinical profile in diabetic patients.

METHODS

Patency rates and global and regional left ventricular function were determined in patients enrolled in the GUSTO-I Angiographic Trial. Thirty-day mortality differences between those with and without diabetes were compared.

RESULTS

The diabetic cohort had a significantly higher proportion of female and elderly patients, and they were more often hypertensive, came to the hospital later and had more congestive heart failure and a higher number of previous myocardial infarctions and bypass surgery procedures. Ninety-minute patency (Thrombolysis in Myocardial Infarction [TIMI] flow grade 3) rates in patients with and without diabetes were 40.3% and 37.6%, respectively (p = 0.7). Reocclusion rates were 9.2% vs. 5.3% (p = 0.17). Ejection fraction at 90 min after thrombolysis was similar in diabetic and nondiabetic patients ([mean +/- SEM] 6.10 +/- 1.6% vs. 60.1 +/- 0.7%, p = 0.7), as was regional ventricular function (number of abnormal chords: 19.1 +/- 2.0 vs. 17.5 +/- 0.8, p = 0.3; SD/chord: -2.3 +/- 0.2 vs. -2.4 +/- 0.1, p = 0.6). Diabetic patients had less compensatory hyperkinesia in the noninfarct zone (SD/ chord: 1.3 +/- 0.2 vs. 1.7 +/- 0.1, p < or = 0.01). No significant difference in ventricular function was noted at 5- to 7-day follow-up. The 30-day mortality rate was 11.3% in diabetic versus 5.9% in nondiabetic patients (p < or = 0.0001). After adjustment for clinical and angiographic variables, diabetes remained an independent determinant of 30-day mortality (p = 0.02).

CONCLUSIONS

Early (90-min) infarct-related artery patency as well as regional and global ventricular function do not differ between patients with and without diabetes after thrombolytic therapy, except for reduced compensatory hyperkinesia in the noninfarct zone among patients with diabetes. Diabetes remained an independent determinant of 30-day mortality after correction for clinical and angiographic variables.

Effects of hormone replacement therapy on the circadian pattern of atherothrombotic risk factors

Onset of acute atherothrombotic events (acute myocardial infarction, unstable angina, ischemic stroke) exhibit a circadian pattern that parallels the diurnal pattern of endogenous fibrinolytic activity. Hormone replacement therapy in postmenopausal women has been shown to enhance fibrinolytic capacity by lowering plasminogen activator inhibitor-1 (PAI-1) and tissue plasminogen activator inhibitor (tPA) antigen values. We evaluated the impact of 4 weeks of estrogen alone (Premarin 0.625 mg/day) and 2 weeks of estrogen plus progesterone (Provera 2.5 mg/day) on PAI-1 and tPA in 17 postmenopausal women at multiple time points to assess hormone impact on the diurnal pattern of fibrinolytic potential. At baseline, both PAI-1 and tPA exhibited circadian variability. Estrogen alone selectively lowered 8 A.M. PAI-1 (35.8 +/- 7.1 ng/ml at baseline, 19.8 +/- 3.7 ng/ml on estrogen; p = 0.0002 vs baseline). There was no significant change in the noon or 4 P.M. values, and the diurnal pattern was attenuated. The 8 A.M. PAI-1 remained low at 17.1 +/- 3.6 ng/ml (p = 0.0001 vs baseline) with total loss of the circadian rhythm. Estrogen supplementation reduced tPA antigen at all time points, and the diurnal pattern, although blunted, persisted. Addition of progesterone to estrogen did not reverse effects of the estrogen alone phase of either PAI-1 or tPA values. This hormone-associated reduction of PAI-1 was observed despite increased triglycerides, a known inducer of PAI-1 levels. These observations suggest that hormone replacement therapy may protect postmenopausal women from excess early morning acute ischemic events.

Practical implications of circadian variations in thrombolytic and antithrombotic activities

It recently has been demonstrated that thrombolytic therapy has circadian pattern of efficacy, as assessed by the ability to rapidly provide coronary patency. A study of 692 patients receiving intravenous tPA and undergoing acute coronary arteriography demonstrated a substantial diurnal pattern in patency with a peak at 8:00 pm. The heightened tendency for a coronary artery to be opened in the evening correlates well with the substantial tendency demonstrated in the same study and in multiple other studies for coronary arteries to thrombose and cause myocardial infarction in the morning hours. Circadian variations have been defined for a number of hemostatic and physiologic factors that would predispose toward clotting in the late morning, and converse circadian patterns have been described for a number of factors associated with thrombolysis that would predispose towards enhanced fibrinolysis in the evening hours. Methods by which efficacy of lytic therapy potentially could be enhanced include development of tPA variants or adjunctive agents that eliminate the circadian nadirs of efficacy, modification of dosage or choice of lytic agent as a function of time of treatment, and selection between pharmacologic lysis and direct angioplasty as a function of time of day.

Circadian variations of onset of acute myocardial infarction and efficacy of thrombolytic therapy

OBJECTIVES

The present study investigated whether the onset of acute myocardial infarction and resistance to thrombolysis have similar circadian variations.

BACKGROUND

Circadian variations of the onset of acute myocardial infarction and resistance to thrombolysis in the early morning have been reported. Some studies have also reported a secondary peak incidence in late evening; however, it is not known whether the resistance to thrombolysis has a similar circadian variation in these patients.

METHODS

Six hundred eight Japanese patients with an acute myocardial infarction were the subjects of the study. Two hundred forty-four of the 608 patients were treated with thrombolysis within 12 h of the onset of symptoms. One hundred thirteen patients received urokinase, and 131 patients received tissue-type plasminogen activator (t-PA) over 60 min. Patency of the infarct-related artery, the primary end point of the study, was evaluated at 60 min after the initiation of thrombolytic therapy, and Thrombolysis in Myocardial Infarction (TIMI) grade 0, 1 or 2 was defined as resistant to thrombolysis.

RESULTS

The onset of acute myocardial infarction and resistance to thrombolysis showed circadian variations with early morning and late evening peaks (p<0.001 and p<0.05, respectively). These circadian patterns showed similar distributions as evaluated with Spearman's method (r=0.70, p<0.05), although resistance to thrombolysis showed a phase difference of about 2 h earlier than the infarction incidence. The circadian variation of the resistance to thrombolysis was independent of the types of thrombolytic agents (urokinase or t-PA).

CONCLUSIONS

These findings suggest that adjustment of treatment based on the time of the onset of symptoms may be warranted for the patients with acute myocardial infarction.

Serial changes of plasma plasminogen activator inhibitor activity in acute myocardial infarction: difference between thrombolytic therapy and direct coronary angioplasty

The fibrinolytic system is impaired in patients with acute myocardial infarction (AMI). The primary regulatory element of fibrinolytic activity is plasminogen activator inhibitor (PAI). There are no reports, however, on the serial changes of PAI activity after thrombolysis or coronary angioplasty in patients with AMI undergoing emergency coronary angiography. This study was designed to examine the difference in the change of fibrinolytic activity between patients with AMI who underwent thrombolytic therapy with recombinant tissue-plasminogen activator (rTPA) and those who underwent direct percutaneous coronary angioplasty (PTCA). We measured the serial changes of PAI activity and tissue plasminogen activator (TPA) antigen after rTPA therapy or direct PTCA. Twenty-two patients received emergency coronary angiography and were treated with rTPA intravenously. Twenty patients underwent direct PTCA. Plasma PAI activity levels were increased on admission and further increased within 24 hours in patients treated with rTPA and in those treated with direct PTCA. In the thrombolysis group, there were two peaks in plasma PAI activity levels (IU/ml) at 4 hours (27.0 +/- 2.9) and at 16 hours (25.6 +/- 2.5) after the initiation of rTPA infusion. However, in the direct PTCA group, there was one peak of PAI activity (IU/ml) at 16 hours (23.9 +/- 2.7) after the initiation of direct PTCA. In conclusion, the PAI activity has two peaks in the thrombolysis group and one peak in the direct PTCA group.

Circadian variation in the efficacy of tissue-type plasminogen activator

BACKGROUND

The frequency of onset of acute myocardial infarction follows a circadian pattern, with a peak incidence between 6:00 AM and noon. Circadian variations have been defined for platelet aggregation, plasminogen-activator inhibitor, and a number of hemostatic and physiological factors, all of which might predispose toward clotting in the late morning and thrombolysis in the evening. Thus, the hypothesis for this retrospective analysis was that tissue-type plasminogen activator (TPA) has greater efficacy when administered between noon and midnight, as measured by coronary patency 90 minutes after initiation of treatment.

METHODS AND RESULTS

Seven hundred twenty-eight patients were enrolled in either of two studies in which TPA was administered under a uniform protocol for the treatment of acute myocardial infarction. Of these, 692 patients had qualifying arteriograms that allowed standardized assessment by a core angiographic laboratory of the primary end point of 90-minute patency. TPA has a circadian pattern of efficacy, with greater TIMI grade 3 patency when administered between noon and midnight (P < .001). When TPA was given within 2 hours of symptoms (n = 127), the total patency was highest and there was a trend (P = .055) toward the greatest magnitude difference occurring between AM and PM patency. The onset of myocardial infarction was confirmed to have a marked circadian variation with a peak incidence about 10:00 AM. The peak efficacy of TPA was about 8:00 PM, representing a phase difference of about 10 hours after peak infarction incidence.

CONCLUSIONS

There is a circadian variation in the ability of TPA to rapidly open coronary arteries, with highest efficacy between noon and midnight. This complements clinical and in vitro knowledge of increased morning thrombosis and is concordant with knowledge of increased morning thrombosis and is concordant with knowledge of a fibrinolytic profile that is more favorable for evening lysis. This finding has implications for understanding the circadian pathophysiology of myocardial infarction and for its chronotherapy.

Induction of plasminogen activator inhibitor type-1 (PAI-1) by proinsulin and insulin in vivo

BACKGROUND

Fasting hyperinsulinemia (reflected by elevations in immunoreactive "insulin") is typical of patients with non-insulin-dependent diabetes mellitus (NIDDM) and is often associated with obesity and hypertension. The elevated concentrations detected are indicative not only of insulin but also of its immunologically cross-reactive precursors, including proinsulin. Fasting hyperinsulinemia appears to be associated with decreased fibrinolytic activity in blood, which results from increased activity of plasminogen activator inhibitor type-1 (PAI-1), a potential independent risk factor for coronary artery disease. Patients who were given proinsulin in a previous clinical study by others exhibited an increased incidence of cardiovascular events. Thus, a "proinsulin-PAI-1 axis" may predispose to coronary thrombosis. To define the possible presence of such an axis, this study was designed to determine whether insulin, its precursors, or both increase the concentrations of PAI-1 in rabbits in vivo.

METHODS AND RESULTS

Equimolar proinsulin (n = 10), insulin (n = 11), C-peptide (n = 4), or vehicle alone (n = 10) was administered intravenously over 1 hour to euglycemic, conscious rabbits. Plasma PAI-1 activity increased 3.8-fold with proinsulin (P = .002) and 3.6-fold with insulin (P = .002). By contrast, no increase occurred after C-peptide or vehicle was administered. The increased PAI-1 activity was shown to be attributable to PAI-1 protein by reverse fibrin autography. As judged from changes in mRNA in tissues, proinsulin and insulin increased PAI-1 gene expression within 3 hours by 2.1- and 2.1-fold, respectively, in aorta (P = .025 each) and by 1.9- and 2.4-fold in liver (P = .015 and P = .001), with return of values to baseline within 24 hours (n = 4 experiments in each case).

CONCLUSIONS

These results extend our previous observations from studies in vitro and suggest that hyperinsulinemia attributable to augmented concentrations of proinsulin and insulin in plasma increase plasma PAI-1 activity and may contribute to acceleration of atherosclerosis and impairment of coronary thrombolysis in patients with NIDDM.

Expression of PAI-1, t-PA and u-PA in cultured human umbilical vein endothelial cells derived from racial groups

To determine whether inherent fibrinolytic differences may exist in racial groups (black americans, BA vs. white americans, WA), 55 different individual racially-derived human umbilical vein endothelial cell (HUVEC) cultures (35 BA and 20 WA) were analyzed in terms of their fibrinolytic protein (t-PA, u-PA and PAI-1) antigen and mRNA levels. Values (mean +/- SD) for measured fibrinolytic component levels include: cell-associated t-PA antigen (ELISA), 1.14 +/- 0.82 ng/ml/8.6 x 10(5) cells/24 hr in BA and 0.70 +/- 0.85 ng/ml in WA (p = 0.0624); secreted t-PA antigen, 18.65 +/- 17.06 ng/ml in BA and 10.37 +/- 6.38 ng/ml in WA (p = 0.0422); t-PA/cyclophilin mRNA ratios (Northern blot analysis), 1.90 +/- 1.34 in BA and 1.32 +/- 0.70 in WA (p = 0.0776); cell-associated PAI-1 antigen, 71.10 +/- 30.16 ng/ml/8.6 x 10(5) cells/24 hr in BA and 108.85 +/- 56.89 ng/ml in WA (p = 0.0022); secreted PAI-1 antigen, 1,582.13 +/- 612.67 ng/ml in BA and 1,992.17 +/- 711.50 ng/ml in WA (p = 0.0285); 2.4 kb PAI-1/cyclophilin mRNA ratios, 0.59 +/- 0.39 in BA and 0.79 +/- 0.31 in WA (p = 0.1085); 3.4 kb PAI-1/cyclophilin mRNA ratios, 0.70 +/- 0.47 in BA and 0.77 +/- 0.54 in WA (p = 0.6322). These combined data suggest that cultured HUVECs from BA express significantly higher levels of t-PA, lower levels of PAI-1 and approximately 1.72-fold lower molar ratio of PAI-1/t-PA antigen (183.99 +/- 168.81 vs. 315.92 +/- 164.99) (p < 0.05) than cultured HUVECs from WA, presumably reflecting an apparent inherent increased fibrinolytic potential in cultured HUVEC derived from BA.

Fibrinolysis and thrombosis

In conclusion, venous and arterial thrombi contain significant amounts of fibrin. There is evidence that defective fibrinolytic mechanisms may participate in their genesis or persistence in the body. Some evidence suggests that defective fibrinolysis may presage and predict both arterial and venous thrombi; this is stronger evidence of a causal link with thrombosis. Thrombi protect themselves from lysis by incorporating inhibitors (plasminogen activator inhibitor-1 and alpha 2-antiplasmin) in their structure. Fibrinolytic mechanisms may play a role in the genesis or development of atherosclerotic lesions, in addition to thrombosis. Thrombolytic agents lyse both arterial and venous thrombi when administered shortly after their development. If it proves possible in future to enhance natural fibrinolytic mechanisms and to sustain this enhancement by pharmacological or other means, the interesting prospect of harnessing the fibrinolytic system to prevent thrombus formation, as well as to treat it, will arise.

Autologous cord blood transfusion

Newborn piglets were exsanguinated (60% of blood volume) and retransfused 1 h later. One test group received adult pig red blood cells, the other piglet cord blood cells; controls were infused with plasma. While all controls died, satisfactory results were achieved in piglets transfused with either adult or foetal blood. The feasibility of collecting human cord blood for transfusion was assessed in 100 samples of human cord blood. Blood was collected aseptically and aerobic and anaerobic cultures set up. All samples of cord blood were sterile, and all were Mycoplasma negative. Coagulation parameters were analysed in eight cord plasma samples stored at -20 degrees C for 45 days. No significant abnormalities were found immediately after birth or after storage.

Enzymatic evidence of impaired reperfusion in diabetic patients after thrombolytic therapy for acute myocardial infarction: a role for plasminogen activator inhibitor?

OBJECTIVE

To compare the activity of plasminogen activator inhibitor (PAI-1) in diabetic and non-diabetic patients admitted with acute myocardial infarction and to determine whether PAI-1 activity influences reperfusion after thrombolytic therapy.

DESIGN

Prospective study of patients admitted with acute myocardial infarction.

SETTING

District general hospital.

MAIN OUTCOME MEASURES

Reperfusion assessed by time to peak release of creatine kinase-MB isoenzyme.

RESULTS

Baseline PAI-1 activity and antigen concentrations were significantly higher in diabetic patients (n = 45) than in non-diabetic patients (n = 110) (24.6 (6.9) v 18.6 (7.9) AU/ml (AU = arbitrary units) (p = 0.0001) and 58.8 (13.1-328.8) v 41.0 (10.9-125.4) ng/ml (p = 0.004). Time to peak release of creatine kinase-MB was calculated in 123 (80%) patients. In 98 who received thrombolytic therapy the median time to peak enzyme release was 15.5 h (7.5-24 h) in diabetic patients (n = 26) and 12 h (5-26 h) in non-diabetic patients (n = 72) (p = 0.005). In those with a time to peak release of < or = 12 h, indicating likely successful reperfusion, PAI-1 activity was 17.5 (7.8) AU/ml compared with 22.8 (7.7) AU/ml in those with a time to peak release of > 12 h (p = 0.001). In multiple regression analysis both diabetes (p = 0.0001) and PAI-1 activity at admission (p = 0.029) were independently related to successful reperfusion. In 13 patients with evidence of reinfarction in hospital PAI-1 activity on day 3 was 26.7 (6.4) AU/ml compared with 21.7 (6.3) AU/ml in those without evidence of reinfarction (p = 0.032).

CONCLUSION

Both raised PAI-1 activity on admission and diabetes were associated with a reduced likelihood of enzymatic evidence of reperfusion after thrombolytic therapy. Increased PAI-1 activity on day 3 was associated with an increased risk of reinfarction. Diabetic patients had higher PAI-1 activity on admission. This may partly explain their reduced likelihood of reperfusion.

Predictive value for thrombotic disease of plasminogen activator inhibitor-1 plasma levels

Plasminogen activator inhibitor-1 plays a major role in the fibrinolytic system as the main physiological inhibitor of both tissue-type and urinary-type plasminogen activators. The inhibitor is present in plasma in small amounts and derives mainly from endothelial cells. Positive correlations have been reported between plasma levels and different parameters, such as serum triglycerides, insulin plasma levels and body mass index. Moreover, high plasma inhibitor concentrations have been observed in different disease states, but it must be stressed that plasminogen activator inhibitor-1 behaves as an acute-phase reactant and measurement of plasma levels is not significant in the acute phase of the disease. A possible predictive value of inhibitor levels for thrombotic events such as deep vein thrombosis and ischemic heart disease has been studied. On the basis of available studies, the predictive value is not clear for venous thrombosis, whereas plasminogen activator inhibitor-1 levels can predict some coronary events, at least in subgroups of young patients with a first myocardial infarction. It remains to be established if treatments able to reduce plasma inhibitor levels lead to a decrease in the risk of thromboembolic events.

Difference in plasminogen activator inhibitor activity between non-Q-wave infarction and Q-wave infarction

We examined the plasma levels of tissue plasminogen activator antigen and plasminogen activator inhibitor activity in 14 patients with non-Q-wave infarction and in 27 patients with Q-wave infarction before the start of thrombolytic therapy and in 34 control subjects. The mean level of plasma tissue plasminogen activator antigen (ng/ml) was higher (P < 0.01) both in the patients with non-Q-wave infarction and in those with Q-wave infarction than in the control subjects (10.3 +/- 1.9, 9.5 +/- 0.8 vs. 5.8 +/- 0.3), and there was no difference in the level between the patients with non-Q-wave infarction and those with Q-wave infarction. The mean level of plasma plasminogen activator inhibitor activity (IU/ml) was lower (P < 0.01) in the patients with non-Q-wave infarction than in those with Q-wave infarction (7.3 +/- 2.0 vs. 17.1 +/- 2.2), and there was no difference in the level between the patients with non-Q-wave infarction and the control subjects (7.3 +/- 2.0 vs. 4.1 +/- 2.6). The patency rate of infarct-related coronary artery before thrombolytic therapy was higher (P < 0.01) in the patients with non-Q-wave infarction than in those with Q-wave infarction (54% vs. 15%). We conclude that plasminogen activator inhibitor activity was lower in non-Q-wave infarction than in Q-wave infarction and this may be related to the higher patency rate of infarct-related coronary artery in non-Q-wave infarction.

Plasminogen activator inhibitor: a risk factor for myocardial infarction in diabetic patients

OBJECTIVE

To determine whether diabetic patients admitted with acute myocardial infarction have impaired fibrinolytic activity due to raised plasminogen activator inhibitor compared with non-diabetic patients.

SETTING

A district general hospital.

PATIENTS

90 non-diabetic and 38 diabetic patients admitted with acute myocardial infarction.

RESULTS

Both plasminogen activator inhibitor activity and antigen were significantly higher in diabetic than in non-diabetic patients (24.7 (6.8) v 18.5 (6.8) AU/ml; p = 0.0001 and 64.2 (range 13.1 to 328.8) v 38.5 (range 10.9 to 173.7 ng/ml; z = 3.3; p = 0.0008) with a positive correlation between activity and antigen (rs = 0.51; p = 0.0001). In both groups, activity and antigen concentrations were significantly higher than in diabetic and non-diabetic subjects without coronary artery disease (p = 0.002 to 0.0001 for each comparison). Plasminogen activator inhibitor activity correlated significantly with admission plasma glucose (r = 0.32; p = 0.0001), glycated haemoglobin (r = 0.32; p = 0.0001), admission plasma insulin (rs = 0.48; p = 0.001), and Killip grade of heart failure both on admission (rs = 0.27; p = 0.001) and on discharge (rs = 0.22; p = 0.006), but not with cumulative creatine kinase MB isoenzyme release (rs = -0.08). There were similar but weaker correlations between tissue plasminogen activator antigen and admission plasma glucose, glycated haemoglobin, and insulin. In 18 patients (12 non-diabetic and six diabetic) plasminogen activator inhibitor activity was measured between six and 12 months (8.3 (1.6)) after the acute infarct and remained similar to activity on admission (24.8 (1.9) AU/ml (NS) for diabetic and 17.9 (6.9) AU/ml (NS) for non-diabetic patients) and was still significantly higher in diabetic than in non-diabetic patients (p = 0.007).

CONCLUSION

These results show that diabetic patients have higher plasminogen activator inhibitor activity than non-diabetic patients both on admission with acute myocardial infarction and at follow up six to 12 months later. Raised plasminogen activator inhibitor activity may predispose diabetic patients to myocardial infarction and may also impair pharmacological and spontaneous reperfusion after acute myocardial infarction thus contributing to the poor outcome in these subjects.

Association of patency of the infarct-related coronary artery with plasma levels of plasminogen activator inhibitor activity in acute myocardial infarction

To examine the fibrinolytic capacity in patients with acute myocardial infarction (AMI), baseline levels of plasma plasminogen activator inhibitor (PAI) activity and tissue-type plasminogen activator (t-PA) antigen were measured in 47 patients with Q-wave AMI who underwent emergent coronary angiography 3.0 +/- 0.2 hours after the symptom onset. They received intracoronary injection of urokinase if their infarct-related arteries were occluded. They were classified into 3 groups according to the patency of the infarct-related artery before and after thrombolytic therapy: the patent group (13 patients), the recanalized group (23 patients) and the occluded group (11 patients). The mean level of plasma PAI activity (IU/ml) was higher in patients with AMI as a whole than in the control group (12.8 +/- 1.6 vs 5.4 +/- 0.5, p less than 0.01). The level was lower in the patent group (3.0 +/- 1.1) and higher in the recanalized (18.6 +/- 2.2) and occluded (10.8 +/- 2.5) groups than in the control group (each p less than 0.01). The level was lower in the occluded than in the recanalized group (p less than 0.01) and 62% of the patients in the occluded group had levels within range of the control group. The mean level of plasma t-PA antigen (ng/ml) was higher in patients with AMI as a whole than in the control group (10.3 +/- 0.8 vs 5.8 +/- 0.3, p less than 0.01). There was no difference in the level among the 3 groups with AMI.(ABSTRACT TRUNCATED AT 250 WORDS)