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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thrombolytic therapy with streptokinase and other agents reduces mortality and is now well accepted as the mainstay of revascularisation options for most patients after an acute myocardial infarction. Streptokinase is as efficacious as alteplase (recombinant tissue plasminogen activator; rt-PA) when given as a 3-hour infusion, anistreplase, reteplase and saruplase in reducing mortality. However, in the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO) trial, an accelerated alteplase regimen (1.5-hour infusion) plus intravenous heparin demonstrated a statistically significant 1% absolute mortality reduction compared with streptokinase plus heparin. Treatment with streptokinase is consistently clinically superior to conventional treatment and is cost effective: the marginal cost per year of life saved (cost/YLS) is less than $US/$Can20,000 (1990 or 1991 currency) assuming 5-year survival. In addition, streptokinase treatment is associated with fewer intensive care days and total days spent in hospital and a decrease in the use of intensive care services compared with conventional therapy. Importantly, the cost/YLS of treating older patients (70 to 80 years) with streptokinase is similar to that in younger patients (approximately $US22,000, 1990 currency). In 1 study, the cost of in-hospital treatment and associated 1-year follow-up costs did not differ significantly regardless of whether patients received streptokinase or anistreplase. In the most comprehensive cost-effectiveness analysis to date, GUSTO investigators determined that the incremental cost/YLS in patients who received the accelerated alteplase regimen instead of streptokinase was $US32,678 (1993 currency); the projected life expectancy was about 15 years. Thrombolytic therapy is generally more cost effective in patients at high risk than in those at low risk. The cost effectiveness of streptokinase is dependent on infarct location and time to treatment, but is more favorable in patients with anterior than inferior infarctions and those treated as soon as possible after symptom onset. There are as yet no comparative data to indicate a clinical benefit for one thrombolytic agent over another in patients treated more than 6 hours after symptom onset; therefore, in all likelihood, streptokinase will be preferred on the basis of cost minimisation. Streptokinase is associated with a slightly higher rate of severe bleeding than alteplase but a lower incidence of stroke. Although quality-of-life information comparing thrombolytics is unavailable, most patients who received streptokinase or alteplase rated their quality of life as high on the basis of results from time trade-off assessments and health surveys. In summary, streptokinase is undeniably cost effective compared with conventional treatment. It is up to individual healthcare systems to determine whether the mortality advantage and cost differential of the accelerated alteplase regimen over streptokinase, as seen in the GUSTO trial, are affordable and justifiable. However, it is important to realise that treatment options may be limited by healthcare resources; thus, streptokinase can be regarded as a cost-effective thrombolytic strategy which is both efficacious and affordable within the constraints of most healthcare budgets.
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PMID:Streptokinase. A pharmacoeconomic appraisal of its use in the management of acute myocardial infarction. 1016 75

Alteplase (recombinant tissue plasminogen activator; rt-PA) is a thrombolytic agent that when given in an accelerated regimen with intravenous heparin has survival advantages compared with streptokinase in the treatment of acute myocardial infarction, as shown by the results of the Global Utilisation of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO) trial. Although alteplase is more fibrin-specific than streptokinase, alteplase therapy is associated with a small relative increase in the incidence of haemorrhagic stroke, but appears to cause a small relative decrease in the incidence of major bleeding. Because alteplase has a higher acquisition cost than alternative thrombolytic agents, analyses have been undertaken to assess whether administration of alteplase after myocardial infarction is a cost-effective use of healthcare resources. In retrospective analyses undertaken before completion of the GUSTO trial, it was generally assumed, on the basis of better 90-minute patency rates, that alteplase would provide survival advantages compared with streptokinase or conventional nonthrombolytic therapy. Alteplase had acceptable cost-effectiveness ratios compared with conventional therapy and streptokinase therapy from both third-party payer and hospital perspectives. Subgroup analyses demonstrated that alteplase was more cost effective when given early after symptom onset and when given to patients with large infarcts. Prospective evaluations of the cost effectiveness of alteplase in 3-hour and accelerated regimens have similarly demonstrated that alteplase therapy after myocardial infarction improves survival at an 'acceptable' cost. The largest prospective evaluation undertaken to date was performed in conjunction with the GUSTO trial. Primary analysis, on the basis of the clinical findings of the GUSTO trial and prospective collection of cost data from US patients, revealed that the cost-effectiveness ratio for accelerated alteplase therapy compared with streptokinase was $US32,687 (1993 dollars) per year of life saved (YLS). This value is most relevant for US patients and lies within the definition of 'cost effective' if $US50,000/YLS is the benchmark for acceptable use of resources. The cost-effectiveness ratio for alteplase was most sensitive to assumptions regarding long term survival and cost differences after the first year following treatment. In subgroup analyses, alteplase was a cost-effective treatment option for all elderly patients (> 60 years of age) and all patients > 40 years of age with anterior infarction. Alteplase therapy appears to have in-hospital costs/charges similar to those for primary percutaneous transluminal coronary angioplasty (PTCA), mainly because PTCA appears to have a favourable effect on duration of hospitalisation. Given the technical expertise and facilities required for PTCA, it is likely that thrombolytic therapy will remain the management option of choice in most centres. In conclusion, under the conditions of the GUSTO study, accelerated alteplase in combination with intravenous heparin confers survival advantages compared with streptokinase therapy. While decision-makers must choose how best to use their available healthcare resources, pharmacoeconomic evaluations have confirmed that, on the basis of accepted benchmark values, alteplase therapy is a cost-effective therapeutic option for the treatment of acute myocardial infarction, especially in elderly patients with either anterior or inferior infarcts and nearly all patients with anterior myocardial infarction. Thus, on the basis of clinical and economic data, predominantly provided by the GUSTO trial, alteplase is a cost-effective first-line management option for acute myocardial infarction.
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PMID:Alteplase: a pharmacoeconomic evaluation of its use in the management of myocardial infarction. 1017 69

Two commonly used thrombolytic agents are streptokinase (SK) and tissue plasminogen activator (t-PA), which have different impacts on the incidence of mortality and thrombolysis-related acute intracranial hemorrhage. A decision-analytic model was developed to compare the use of SK and t-PA in the treatment of a patient with suspected acute myocardial infarction (AMI). The outcome was health-related quality of life as quantified in a measure of utility from the patient's point of view. The model included three outcome states: death, nonfatal yet disabling stroke, and survival with no disabling stroke. The utility for disabling stroke was determined relative to the reference states of no disabling stroke (1.00) and death (0.00) by means of the time trade-off estimation technique. Probabilities were derived from the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Artery trial, which revealed that although administering t-PA results in a lower percentage of deaths compared to SK, it may lead to a higher percentage of strokes. A decision tree was constructed to model the options and outcomes. The tree was analyzed by standard decision analytic techniques using SMLTREE software, and the stability of the results was examined as values of parameters were varied systematically in a sensitivity analysis. In the baseline analysis, SK yielded 0.9235, whereas t-PA yielded 0.9329. The sensitivity analysis revealed that if the probability of a disabling stroke attributable to t-PA were greater than 2.08%, SK would yield the higher expected utility. This threshold value, however, was much greater than the probability established in major trials. The administration of t-PA leads to a slightly better outcome than does the administration of SK in a patient with suspected AMI.
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PMID:Thrombolytic therapy with streptokinase and tissue plasminogen activator in a patient with suspected acute myocardial infarction: A decision analysis. 1054 80

The thrombotic risk of carrying plasminogen activator inhibitor-1-675 4G allele was found to be controversial in previous studies. The aim of this study was to evaluate the possible effect of plasminogen activator inhibitor-1 4G/5G polymorphism in the pathogenesis of childhood stroke. The case-control study included 43 patients with cerebral infarct who were below the age of 18 years (range, 10 months to 18 years) and 113 healthy unrelated individuals without family histories of thrombosis. Plasminogen activator inhibitor-1 4G/5G polymorphism was analyzed according to a previously described method. There was no statistically significant difference in patient and control groups for the distribution of plasminogen activator inhibitor-1 4G/5G polymorphism (P = .75) (allele frequency 4G controls: 0.50; patients: 0.53). However, there was a significant difference for the factor V (FV) 1691 A mutation for both groups (P = .0007).
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PMID:Plasminogen activator inhibitor-1 4G/5G polymorphism in Turkish children with cerebral infarct and effect on factor V 1691 A mutation. 1133 66

Low fibrinolytic activity may increase the risk of thrombosis. Plasminogen activator inhibitor-1 (PAI-1) is an inhibitor of the fibrinolytic system. We examined the PAI-1 levels in patients with ischemic stroke. Plasma levels of PAI-1 were measured using enzyme-linked immunosorbent assay (ELISA) in 55 consecutive patients (age 60.2 +/- 11.4, 40 males and 15 females) with ischemic stroke. The PAI-1 assessments as well as neurological examinations using validated stroke scales were conducted at admission and 1 week, 1 month, and 3 months after stroke. Sex- and age-matched controls (+/- 4 years) underwent plasma PAI-1 measurement once. Etiology of the stroke was classified using the Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria. All pertinent stroke risk factors were recorded. All patients were contacted 3 years after stroke for recurrent vascular thrombotic disease. The plasma PAI-1 levels were 17.2 +/- 7.8 IU at admission, 11.2 +/- 9.2 IU at 1 week, 14.4 +/- 7.9 IU at 1 month, and 17.8 +/- 7.8 IU at 3 months among patients and 11.8 +/- 9.5 IU among controls (p values are < .002, .7, .12, and < .0005, respectively). As a rule, the neurological scores did not show a correlation to the PAI-1 levels. Presence of diabetes, hypertension, obesity, smoking, anticoagulant treatment, and sleep apnea did not affect the PAI-1 levels at any time point. Females had slightly higher PAI-1 levels. Age was a strong determinant for PAI-1 levels being higher in younger patients at every sampling time point (p values .02, .02, .02, and .03 respectively). The etiology of the ischemic stroke did not have an impact on PAI-1 levels. In 16 patients recurrent thrombosis had occurred. The high PAI-1 levels at admittance may reflect either an acute phase response or a chronic state. Normalized levels at 1 week and 1 month may be due to hospital diet, antithrombotic medication, weight loss, active physical therapy, and better care for diabetes. PAI-1 levels at 3 months after stroke did not predict recurrent thrombosis.
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PMID:Plasminogen activator inhibitor-1 in patients with ischemic stroke. 1145 24

To investigate gender differences in conventional, coagulation and fibrinolytic factors in South Asian ischaemic stroke patients, we compared these variables in 50 South Asian females (SAFP) with 90 South Asian males (SAMP) with ischaemic stroke and in 52 females (SAFC) and 38 males (SAMC) without stroke. Plasminogen activator inhibitor-1 (PAI-1) antigen levels were significantly higher in SAFP compared with SAMP (18.2 vs. 13.3 U/ml, P = 0.04) even after adjustment for known covariates, but there was no difference in PAI-1 antigen levels between males and females in the control group. South Asian females exhibited higher levels of factor VII antigen and FVII:C activity in both stroke patients (114 vs. 99% in males, P = 0.01; 116 versus 104% in males, P = 0.04) and controls (116 vs. 97% in males, P = 0.004; 115 vs. 93% in males, P = 0.01). There were no significant differences in the levels of fibrinogen (3.8 vs. 3.7 g/l), FXIIa (2.2 vs. 2.4 ng/ml), von Willebrand factor (1.8 vs. 1.9 IU/ml) and tissue plasminogen activator (11.4 vs. 12.0 ng/ml) in SAMP and SAFP respectively. These results suggest that South Asian females have increased FVII levels and that females with a history of ischaemic stroke have a decreased fibrinolytic potential in comparison with males.
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PMID:Decreased fibrinolytic potential in South Asian women with ischaemic cerebrovascular disease. 1147 61

The best conventional fibrinolytic regimens succeed in restoring unimpeded coronary flow (i.e., TIMI grade 3 reperfusion) in only about 50% of lytic-eligible patients. In experienced hands, percutaneous coronary intervention (angioplasty + stent implantation) can restore TIMI 3 flow in more than 80% of patients; however, it is not universally available, and usually cannot be performed as promptly as fibrinolytic therapy. Researchers now recognize that one key reason fibrinolytic therapy fails is that it does not adequately address the role of platelets in both the initial formation and posttreatment recurrence of coronary thrombus activated, aggregating platelets at the site of plaque fissure or rupture form the core ("white" clot) of an intracoronary thrombus. The platelets contribute to the further development of a meshwork of fibrin, thrombin, and entrapped blood cells ("red" clot), which usually makes up the bulk of an occlusive coronary thrombus. Plasminogen activators, such as alteplase and reteplase, lyse fibrin in the red thrombus but leave the platelet-rich core intact. The glycoprotein (GP) IIb/IIIa antagonists abciximab, tirofiban, and eptifibatide bind to GP IIb/IIIa receptors on the surfaces of activated platelets. By preventing the receptors from binding to fibrinogen (and, hence, to each other) GP IIb/IIIa inhibitors block the "final common pathway" to platelet aggregation. Combining fibrinolysis with GP IIb/IIIa blockade to treat acute myocardial infarction could, theoretically, yield a number of benefits. It would attack both red and white components of the occlusive thrombus, help suppress the thrombotic rebound effect of fibrinolytics by preventing platelet activation in response to newly exposed thrombin, improve reperfusion and microvascular flow, reduce the incidence of postfibrinolytic hemorrhagic stroke (currently approximately 1%) if combination therapy permits use of lower dosages of fibrinolytic agents. Two phase II trials of fibrinolytic therapy plus GP IIb/IIIa blockade have recently been reported. In TIMI 14, the reduced-dose combinations of alteplase plus abciximab produced TIMI 3 rates higher than the control group. In the TIMI 14 reteplase substudy, TIMI 3 flow rates with reteplase at 90 min was 70% for standard dose reteplase alone, 70% for reteplase 5 IU + 5 IU plus abciximab, and 77% for reteplase 10 IU + 5 IU plus abciximab. In the SPEED pilot study the highest TIMI 3 rates was seen with the regimen of 5 IU + 5 IU double-bolus reteplase plus abciximab (54 vs 47%). The findings of both the SPEED and TIMI 14 trials were incorporated into the design of the large (approximately 17,000 patients) GUSTO V mortality trial, which compared standard reteplase therapy with abciximab plus low-dose reteplase. Unfortunately, the results did not confirm the favorable angiographic findings of the phase II trials reported above, because the two strategies showed the same mortality rate at 30-day follow-up. The present review will try to shed light on the "dark side of the moon" of the association between IIb/IIIa inhibitors and fibrinolytic drugs in order to understand the unexpected GUSTO V results, now matched by the ASSENT-3 disappointing results with tenecteplase plus abciximab.
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PMID:[Combination therapy for acute myocardial infarction with glycoprotein IIb/IIIa inhibitors and fibrinolysis]. 1206 94

Plasminogen activators (PA) are unique agents that are currently applied as thrombolytic therapy to achieve rapid vascular reperfusion. Regimens of PA plus anticoagulants and antiplatelet drugs have attained a high degree of sophistication and predictable rates of positive clinical outcomes for acute myocardial infarction (MI), ischemic stroke, pulmonary embolism (PE), deep vein thrombosis (DVT), and thrombosed catheters. Included in the repertoire are newly approved mutants of tissue plasminogen activator (TPA), which have biochemical advantages that allow for bolus administration. Yet, despite tremendous effort devoted to enormous trials to establish the clinical efficacy of these agents in acute MI, mortality results are not superior to those with native TPA or streptokinase (SK). Furthermore, all PAs have the potential for hemorrhagic complication, most critically intracranial hemorrhage (ICH), occurring in 0.9% of patients treated with native or mutant TPA. It is possible that a limit of clinical effectiveness has been reached, beyond which more potent PAs do not achieve greater benefit without a serious increase in risk of bleeding. A breakthrough is possible, however, if the risk of ICH could be avoided. One solution is the application of the direct-acting thrombolytic enzyme, plasmin. While intravenous plasmin is not effective when administered systemically, regional infusion to a thrombus induces local thrombolysis. Unlike the PAs, plasmin treatment should not cause hemorrhage from vascular trauma sites, as it is neutralized by antiplasmin in the blood. Animal studies are fully consistent with this approach, which offers potential for achieving a truly regional thrombolytic treatment.
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PMID:Towards safer thrombolytic therapy. 1212 83

Plasminogen activators have immense clinical significance as thrombolytic agents for management of stroke and myocardial infarction. Tissue-type plasminogen activator (tPA) is generally preferred as being effective and safer than either urokinase or streptokinase type activators. Large-scale production of tPA became possible through groundbreaking developments in cell lines and bioprocess technology. Nevertheless, at thousands of dollars per treatment, tPA remains expensive. Enhancing cellular productivity and downstream product recovery through new approaches continue to be major challenges as discussed in this review. Recent clinical experience suggests the need for yet better fibrinolytic agents and attempts are underway to modify the tPA molecule to second generation products. Emerging trends in this field are outlined.
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PMID:Tissue-type plasminogen activator: characteristics, applications and production technology. 1453 55

The spontaneously hypertensive stroke-prone rat (SHR-SP) is an experimental model of malignant hypertension which lead to secondary alterations of the extracellular matrix. Our aim was to determine ACE-inhibitor related changes of proteases involved in the reconstruction of the extracellular matrix in the brain. Twelve SHR-SP rats were randomized into two groups. Each group was treated with either an antihypertensive dose of ramipril or placebo for 6 months. Brain tissue plasminogen activator (t-PA) and urokinase (u-PA) were quantified by using casein-dependent plasminogen zymography, matrix metalloproteinase (MMP)-2 and MMP-9, by MMP-zymography, and tissue inhibitor of MMP (TIMP)-1 and -2, by reverse zymography. The amounts of u-PA, t-PA, and MMPs were significantly reduced in animals treated with ACE inhibitor. Plasminogen zymography showed a 39% reduction of u-PA in the basal ganglia (p < 0.0001); t-PA expression was reduced by 26% in the cortex and by 33% in the basal ganglia (p < 0.0001). MMP-2 expression was reduced by 15% in the cortex (p < 0.05) and by 10% in the basal ganglia (p < 0.05); MMP-9 expression significantly decreased by 37% in the cortex and by 25% in the basal ganglia (p < 0.0001 each). No differences were observed in the amount of TIMP-1 or TIMP-2. These findings provide new insights into the biochemical mechanisms underlying extracellular matrix proliferation and its modulation by ACE inhibitors. Therapeutic alterations that influence the proteolytic systems might prove important in the prevention of extracellular matrix accumulation and secondary microvascular vessel wall changes.
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PMID:ACE inhibition reduces activity of the plasminogen/plasmin and MMP systems in the brain of spontaneous hypertensive stroke-prone rats. 1572 Dec 22


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