Angiographic and Clinical Outcomes in Patients Receiving Low-Molecular-Weight Heparin Versus Unfractionated Heparin in ST-Elevation Myocardial Infarction Treated With Fibrinolytics in the CLARITY-TIMI 28 Trial

Antithrombotic therapy in the elderly and senile age: the consensus opinion of experts of the Russian Association of Gerontologists and Geriatricians and the National Society of Preventive Cardiology

В данном документе обсуждаются особенности АТТ у лиц пожилого и старческого возраста в различных клинических ситуациях.

Administration of low molecular weight and unfractionated heparin during percutaneous coronary intervention

This systematic review with meta-analysis sought to determine the efficacy and safety of unfractionated heparin (UFH) and low molecular weight heparin (LMWH) on clinical outcomes following percutaneous coronary intervention. Medline, Embase, Elsevier, and web of knowledge as well as Google scholar literature were used for selecting appropriate studies with randomized controlled design. After screening 445 studies, a total of 23 trials (including a total of 43,912 patients) were identified that reported outcomes. Pooled analysis revealed that LMWH compared to UFH could significantly increase thrombolysis in myocardial infarction grade 3 flow (p<0.001), which was associated with similar target vessel revascularization (p=0.6), similar incidence of stroke (p=0.7), and significantly lower incidence of re-myocardial infarction (p<0.001), major bleeding (p=0.02) and mortality (p<0.001). Overall, LMWH was shown to be a useful type of heparin for patients with MI undergoing PCI, due to its higher efficacy and lower rate of complication compared to UFH. It is also associated with increased myocardial perfusion, decreased major hemorrhage, and mortality.

ExTRACT-TIMI 25 trial: clarifying the role of enoxaparin in patients with ST-elevation myocardial infarction receiving fibrinolysis

Pharmacologic reperfusion remains the most common treatment strategy for ST-elevation myocardial infarction (STEMI) worldwide. Unfractionated heparin (UFH) is the established adjunctive antithrombotic agent used with fibrinolytic agents. Low-molecular-weight heparins (LMWHs) are a potential alternative to UFH, but have not been evaluated in large cohorts of patients. The Enoxaparin and Thrombolysis Reperfusion for Acute Myocardial Infarction Treatment (ExTRACT)-Thrombolysis in Myocardial Infarction (TIMI) 25 was a double-blind, double-dummy randomized controlled trial, of 20,479 patients, which demonstrated the superiority of enoxaparin over UFH in reducing death or nonfatal myocardial infarction (MI) at 30 days, with an increase in major bleeding. The composite of death, nonfatal MI and nonfatal intracranial hemorrhage, was reduced with enoxaparin. Elderly patients (> or = 75 years of age) received a novel enoxaparin dosing regimen and when compared with UFH, benefited from a lower relative bleeding risk than younger patients without compromising efficacy in preventing death or MI. Intracranial hemorrhage rates were similar. The net clinical benefit of enoxaparin over UFH was maintained regardless of whether patients were on clopidogrel or not, or whether percutaneous coronary intervention was performed. Enoxaparin is an appropriate choice for adjunctive therapy with fibrinolysis in patients with STEMI.

Acute coronary syndrome

Acute coronary syndrome (ACS) is a major health care and economic burden in the United States and accounts for more than 1 million hospitalizations annually. The morbidity and mortality due to ACS are substantial-nearly half of all deaths due to coronary heart disease occur following an ACS. This review provides an up-to-date summary of the pathophysiology, diagnosis, and treatment of ACS. We also provide an overview of the management of common hemodynamic disturbances and myocardial infarction complications that physicians often encounter in an intensive care setting.

Historical lessons in translational medicine: cyclooxygenase inhibition and P2Y12 antagonism

The development of drugs that inhibit platelets has been driven by a combination of clinical insights, fundamental science, and sheer luck. The process has evolved as the days of stumbling on therapeutic gems, such as aspirin, have long passed and have been replaced by an arduous process in which a drug is designed to target a specific protein implicated in a well-characterized pathophysiological process, or so we would like to believe. The development of antiplatelet therapy illustrates the importance of understanding the mechanisms of disease and the pharmacology of the compounds we develop, coupled with careful clinical experimentation and observation and, yes, still, a fair bit of luck.

Acute coronary syndromes: is there a place for a real pre-hospital treatment for patients "en route" to the coronary intensive care unit?

Acute initial management of patients with acute coronary syndrome (ACS) is based on a precise clinical and electrocardiographic diagnosis. Initial risk stratification in the pre-hospital phase is the key step. The last step, adequate patient routing, is decided based on emergency level and reperfusion strategies, considered right from the pre-hospital phase. The management of a patient with an ACS requires close collaboration between emergency physicians and cardiologists, according to simplified protocols for easier access to catheterisation. The next challenges for the pre-hospital management of ACS are based on: - precise knowledge of new antiplatelet and anticoagulant drugs by the emergency physicians, in order to adjust their prescriptions to the patient profile; - developing co-operation between hospitals, according to regional specificities (geographic considerations and distribution of PCI centres) in order to reduce access time to catheterisation rooms; - organising the healthcare network, where the SAMU has an essential role in coordinating the different medical actors; - regular analysis of the evolution of our professional practices, considering, e.g., the guidelines of the "HAS" (French official healthcare guidelines institute);- integrating pre-hospital medicine in health prevention programmes; - improving our understanding of the population's presentations of coronary artery disease, in order to encourage the patients and their families to call the EMS as soon as possible. The challenge of the emergency physician is to adapt the strategies to the patient's needs.

Efficacy and safety of enoxaparin versus unfractionated heparin during percutaneous coronary intervention: systematic review and meta-analysis

OBJECTIVE

To determine the efficacy and safety of enoxaparin compared with unfractionated heparin during percutaneous coronary intervention.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline and Cochrane database of systematic reviews, January 1996 to May 2011.

STUDY SELECTION

Randomised and non-randomised studies comparing enoxaparin with unfractionated heparin during percutaneous coronary intervention and reporting on both mortality (efficacy end point) and major bleeding (safety end point) outcomes.

DATA EXTRACTION

Sample size, characteristics, and outcomes, extracted independently and analysed.

DATA SYNTHESIS

23 trials representing 30,966 patients were identified, including 10,243 patients (33.1%) undergoing primary percutaneous coronary intervention for ST elevation myocardial infarction, 8750 (28.2%) undergoing secondary percutaneous coronary intervention after fibrinolysis, and 11,973 (38.7%) with non-ST elevation acute coronary syndrome or stable patients scheduled for percutaneous coronary intervention. A total of 13,943 patients (45.0%) received enoxaparin and 17,023 (55.0%) unfractionated heparin. Enoxaparin was associated with significant reductions in death (relative risk 0.66, 95% confidence interval 0.57 to 0.76; P<0.001), the composite of death or myocardial infarction (0.68, 0.57 to 0.81; P<0.001), and complications of myocardial infarction (0.75, 0.6 to 0.85; P<0.001), and a reduction in incidence of major bleeding (0.80, 0.68 to 0.95; P=0.009). In patients who underwent primary percutaneous coronary intervention, the reduction in death (0.52, 0.42 to 0.64; P<0.001) was particularly significant and associated with a reduction in major bleeding (0.72, 0.56 to 0.93; P=0.01).

CONCLUSION

Enoxaparin seems to be superior to unfractionated heparin in reducing mortality and bleeding outcomes during percutaneous coronary intervention and particularly in patients undergoing primary percutaneous coronary intervention for ST elevation myocardial infarction.

Low-molecular-weight heparins vs. unfractionated heparin in the setting of percutaneous coronary intervention for ST-elevation myocardial infarction: a meta-analysis

BACKGROUND

The aim of the current study was to perform two separate meta-analyses of available studies comparing low-molecular-weight heparins (LMWHs) vs. unfractionated heparin (UFH) in ST-elevation myocardial infarction (STEMI) patients treated (i) with primary percutaneous coronary intervention (pPCI) or (ii) with PCI after thrombolysis.

METHODS

All-cause mortality was the pre-specified primary endpoint and major bleeding complications were recorded as the secondary endpoints. Relative risk (RR) with a 95% confidence interval (CI) and absolute risk reduction (ARR) were chosen as the effect measure.

RESULTS

Ten studies comprising 16,286 patients were included. The median follow-up was 2 months for the primary endpoint. Among LMWHs, enoxaparin was the compound most frequently used. In the pPCI group, LMWHs were associated with a reduction in mortality [RR (95% CI) = 0.51 (0.41-0.64), P < 0.001, ARR = 3%] and major bleeding [RR (95% CI) = 0.68 (0.49-0.94), P = 0.02, ARR = 2.0%] as compared with UFH. Conversely, no clear evidence of benefits with LWMHs was observed in the PCI group after thrombolysis. Meta-regression showed that patients with a higher baseline risk had greater benefits from LMWHs (r = 0.72, P = 0.02).

CONCLUSIONS

LMWHs were associated with greater efficacy and safety than UFH in STEMI patients treated with pPCI, with a significant relationship between risk profile and clinical benefits. Based on this meta-analysis, LMWHs may be considered as a preferred anticoagulant among STEMI patients undergoing pPCI.

Warfarin and fibrinolysis--a challenging combination: an observational cohort study

Background

Patients presenting with ST-segment elevation myocardial infarction (STEMI) frequently use warfarin. Fibrinolytic agents and warfarin both increase bleeding risk, but only a few studies have been published concerning the bleeding risk of warfarin-prescribed patients receiving fibrinolysis. The objective of this study was to define the prevalence for intracranial haemorrhage (ICH) or major bleeding in patients on warfarin treatment receiving pre-hospital fibrinolysis.

Methods

This was an observational cohort study. Data for this retrospective case series were collected in Helsinki Emergency Medical Service catchment area from 1.1.1997 to 30.6.2010. All warfarin patients with suspected ST-segment elevation myocardial infarction (STEMI), who received pre-hospital fibrinolysis, were included. Bleeding complications were detected from Medical Records and classified as ICH, major or minor bleeding.

Results

Thirty-six warfarin patients received fibrinolysis during the study period. Fourteen patients had bleeding complications. One (3%, 95% CI 0-15%) patient had ICH, six (17%, 95% CI 7-32%) had major and seven (19%, 95% CI 9-35%) had minor bleeding. The only fatal bleeding occurred in a patient with ICH. Patients' age, fibrinolytic agent used or aspirin use did not predispose to bleeding complications. High International Normalized Ratio (INR) seemed to predispose to bleedings with values over 3, but no statistically significant difference was found.

Conclusions

Bleedings occur frequently in warfarin patients treated with fibrinolysis in the real world setting, but they are rarely fatal.

Acute coronary syndromes: Diagnosis and management, part II

At the most severe end of the spectrum of acute coronary syndromes is ST-segment elevation myocardial infarction (STEMI), which usually occurs when a fibrin-rich thrombus completely occludes an epicardial coronary artery. The diagnosis of STEMI is based on clinical characteristics and persistent ST-segment elevation as demonstrated by 12-lead electrocardiography. Patients with STEMI should undergo rapid assessment for reperfusion therapy, and a reperfusion strategy should be implemented promptly after the patient's contact with the health care system. Two methods are currently available for establishing timely coronary reperfusion: primary percutaneous coronary intervention and fibrinolytic therapy. Percutaneous coronary intervention is the preferred method but is not always available. Antiplatelet agents and anticoagulants are critical adjuncts to reperfusion. This article summarizes the current evidence-based guidelines for the diagnosis and management of STEMI. This summary is followed by a brief discussion of the role of noninvasive stress testing in the assessment of patients with acute coronary syndrome and their selection for coronary revascularization.

Definition, incidence, correlates, and clinical impact of "nuisance" bleeding in patients undergoing drug-eluting stent implantation

"Nuisance" bleeding, or superficial bleeding, after antiplatelet therapy is not well characterized despite its potential to affect patient compliance and premature cessation of oral antiplatelet therapy, which can lead to clinical events, such as stent thrombosis. In contrast to major, moderate, or minor bleeding, nuisance bleeding has never been included in the primary or secondary end points of antiplatelet and antithrombin trials and was not reported as an in-hospital or follow-up event in the pivotal pharmacology or device trials associated with percutaneous coronary intervention. Currently, the incidence and impact of these bleeds are not officially recorded and remain unknown. Indeed, there are challenges in the definition, in the acquisition of consistent phenomenon characteristics, and its attribution to major clinical adverse events. Nuisance bleeding is commonly seen in patients on dual antiplatelet therapy. It may be the cause of premature cessation of oral antiplatelet therapy, which is detrimental to prognosis after drug-eluting stent implantation. This article discusses the various definitions, incidence, correlates, and clinical impact of this phenomenon.

Efficacy of clopidrogel on reperfusion and high-sensitivity C-reactive protein in patients with acute myocardial infarction

We investigated the effects of clopidogrel on reperfusion and inflammatory process in STEMI. A total of 175 STEMI patients with similar clinical characteristics were included to this study. One was the standard pharmacological reperfusion therapy group (group 1, n : 90), who received 300 mg aspirin, 70 U/kg bolus, and 12 U/kg/hr continuous infusion of unfractioned heparin and accelerated t-PA. Clopidogrel 450 mg loading and 75 mg/d thereafter was added to standard reperfusion therapy in the other group (group 2, n : 85). The ST-segment resolution, CK-MB, and high-sensitive CRP (hs-CRP) parameters were measured. Complete ST resolution was observed in 32 patients (36.8%) in group 1 and 53 patients (63.8%) in group 2 (P < .001). Also in the first 24 hours, the CK-MB levels of patients in group 1 were significantly higher than those of group 2 (P = .001). The hs-CRP values were greater in group 1 than group 2 at 48th hour (gruop 1: 9.4 ± 0.1 mg/L, group 2: 3.7 ± 1.4 mg/L; P = .000). We concluded that adding clopidogrel to standard treatment in STEMI patients provided early reperfusion and suppression of inflammatory response.

[Coronary flow and hemorrhagic complications after alteplase and streptokinase administration in patients with acute myocardial infarction]

BACKGROUND/AIM

Up-to-date treatment of acute myocardial infarction (AIM) has been based on as early as possible establishment of circulation in ischemic myocardium whether by the use of fibrinolythic therapy and/or urgent coronary intervention which significantly changes the destiny of patients with AMI, but also increases the risk of bleeding. The aim of this study was to compare coronary flow and bleeding complications in patients with acute myocardial infarction with ST-elevation (STEMI) after administration of alteplase or streptokinase.

METHODS

The study included 254 patients with STEMI. The group I (n = 174) received streptokinase, and the group II (n = 80) received alteplase. We followed frequency of complications such as bleeding and hypotension in the investigated groups of patients, based on the TIMI classification of bleeding, as well as the transience of infarction artery in accordance with TIMI flow.

RESULTS

The patients with myocardial infarction after administration of alteplase had statistically significantly higher coronary flow (TIMI-3), 72.5% as compared to the patients who received streptokinase, 39.2%. Hypotension as complication of fibrynolythic therapy administration occurred in a significantly higher percentage in the group of patients who received streptokinase. There was no statistically significant difference in the appearance of major bleeding in the groups of patients who received streptokinasis and alteplase (6.9% and 7.5%, respectively). Also, there was no difference in the appearance of minor and minimal bleeding among the investigated groups of patients.

CONCLUSION

It was shown that alteplase in a higher number of patients provided TIMI-3 coronary flow as compared to streptokinese. In comparison with streptokinase, a combination of alteplase, enoxaparin and double antiplatelet therapy enabled earlier achievement of coronary flow through previously blocked coronary artery that was more complete (higher frequency of TIMI-3 flow). There were no statistically significant difference in frequency of bleeding, first of all major bleeding, between the groups treated by alteplase and streptokinase.

Immediate versus delayed angioplasty in infarct-related arteries with TIMI III flow and ST segment recovery: a matched comparison in acute myocardial infarction patients

BACKGROUND

Early management of patients with patent infarct-related artery (IRA) and optimal ST resolution in ST elevation myocardial infarction (STEMI) has never been assessed. We compared immediate vs delayed PCI in these patients.

METHODS

Matched comparison of immediate vs delayed (24 h) PCI in STEMI patients presenting with patent IRA, thrombus-containing lesion and ST resolution >or=70%. Patients were matched for duration of symptoms, intervention type, angiographic data, diabetes. Patients in immediate PCI group received standard therapy in the cathlab. Patients in delayed PCI group received dual antiplatelet therapy, antithrombins, and GPIIb-IIIa inhibitors until PCI. Primary endpoint was procedural success. Secondary endpoints were enzyme release and in-hospital adverse events.

RESULTS

Seventy-eight patients were included: 39 per group. Average age 62 years, 75% males. There was a significantly higher procedural success rate in the delayed PCI group (95% success, Vs. 77% in the immediate group, P = 0.008). Initial thrombus burden score did not differ between immediate and delayed PCI groups, but improved significantly in the delayed group between baseline angiography and time of PCI (P = 0.039). There was no difference in major adverse events or bleeding complications between groups. Peak CK levels were significantly higher in the immediate versus delayed PCI group (P = 0.02), although there was no difference between groups in peak CK-MB, peak troponin, or peak CK-MB ratio.

CONCLUSION

Our data suggest that in STEMI patients with patent IRA, optimal ST-segment resolution, and thrombus-containing lesion, deferred PCI when patients are given dual antiplatelet therapy, antithrombin agents, and GPIIb-IIIa inhibitors results in a higher procedural success rate, without an increased risk of MACE.

New data on early management of patients with ST-elevation myocardial infarction

The advances in the early treatment of ST-segment elevation acute myocardial infarction have resulted in a significant reduction in mortality. Early pharmacologic therapy with antiplatelet and antithrombotic therapy coupled with rapid and complete mechanical or pharmacologic reperfusion has been shown to reduce infarct size, improve left ventricular function, and reduce morbidity and mortality. Primary angioplasty, if done by an experienced team in a timely manner, has been found to be superior to fibrinolytic therapy and superior to facilitated angioplasty. The American College of Cardiology/American Heart Association guidelines recommend the goal of a door-to-balloon time of less than 90 minutes. National efforts to reduce delays and to improve access to timely therapy will significantly reduce mortality even further.

Reperfusion strategies in ST-elevation myocardial infarction--current status and perspectives for early and pre-hospital treatment

The latest guidelines on the emergency care of acute ST-elevation myocardial infarction were published by the European Resuscitation Council at the end of 2005. Since then, numerous studies have been presented, which have led to important conclusions. Among pharmacological interventions, the opinion on adjuncts to anticoagulant treatment in the area of thrombolysis as well as in primary coronary intervention seems to be moving away from unfractionated heparin towards low molecular weight heparin, and possibly even factor Xa-specific pentasaccharide or the direct antithrombin bivalirudin. Clopidogrel has developed to become an accepted standard alongside aspirin in thrombolytic therapy of ST-elevation myocardial infarction, even if some questions still remain open. The promising idea of "facilitated percutaneous coronary intervention" has shown itself to at least be problematic if performed immediately and routinely after thrombolysis; "rescue" intervention in the event of ineffective thrombolysis is, on the other hand, useful and effective. Apparently, a more individualistic approach is required, which combines new therapeutic options and patients' conditions on the one side with regional resources on the other, to produce an optimal and timely strategy, remembering that one size does not fit all.

Use of anticoagulants in ST-segment elevation myocardial infarction patients; a focus on low-molecular-weight heparin

INTRODUCTION

Primary percutaneous coronary intervention (PCI) is the treatment of choice for patients with ST-segment elevation myocardial infarction (STEMI), but given logistics, many patients are still managed with thrombolytics. Unfractionated heparin (UFH) is recommended for routine use in STEMI patients treated with thrombolytics. However, other anticoagulants have been evaluated for use in STEMI patients treated with thrombolysis, including the low-molecular-weight heparins (LMWHs, enoxaparin, dalteparin, and reviparin), fondaparinux and bivalirudin.

METHODS AND RESULTS

A review of the available randomized controlled study data shows that most evidence, in terms of number of trials and number of patients treated with anticoagulants in STEMI has accumulated for LMWHs. The use of enoxaparin and reviparin improves hard clinical efficacy endpoints although there is an excess of bleeding events. Trials with dalteparin have failed to demonstrate improvement in hard clinical efficacy endpoints compared with UFH.

SUMMARY

Enoxaparin is currently the only LMWH with FDA approval for use in STEMI patients and should be considered as a preferable alternative to UFH in STEMI patients treated with fibrinolysis.

[The safety of enoxaparine use in elderly with acute myocardial infarction]

BACKGROUND/AIM

Enoxaparin (ENOX), the low-molecular-weight heparin, used in acute myocardial infarction (AMI) could lead to hemorrhage. The aim of this study was to determine wether bleeding was more often in AMI patients older than 65 or 75 years who receive ENOX or unfractionated heparin (UFH).

METHODS

Among the patients with AMI hospitalized during three successive months receiving ENOX or UFH, three group of parameters were investigated: demographic, ischemic and bleeding TIMI criteria.

RESULTS

Among 85 hospitalized patients with signs of AIM, there were 35 (41.2%) old 65 years or less, 32 (38.5) old 66-75 years and 18 (21.2%) older than 75 years. In AMI elderly patients, according to the received ENOX/UFH: ischemic complication (18.2 vs. 21.4%) were insignificantly lower and the number of lethal outcomes (18.2 vs. 17.8%) were insignificantly more often in ENOX group; represented only by one patient (age beyond 75 years), major and non-major bleeding events occurred only in UFH group.

CONCLUSION

The ENOX usage in AMI in patients older than 65 years did not show any significant difference in efficacy and bleeding rate comparing to UFH.

[Acute coronary syndrome (ACS) with elevated ST segment: consensus strategy for early reperfusion. The Public Enterprise for Health Emergencies and the ARIAM Project Andalusia]

The two pillars of the appropriate management of patients with ST-elevation myocardial infarction (STEMI) are immediate access to defibrillation and early reperfusion. The Public Enterprise for Health Emergencies (EPES) and the Andalusian ARIAM (Analysis of the Delay in the Treatment of Acute Myocardial Infarction) Project aim to implement a common basic strategy that can be adapted to local situations in order to facilitate decision making about the treatment of these patients.

CONTEXT

The Autonomous Community of Andalusia.

PERIOD

March-May 2006.

PARTICIPANTS

Professionals that attend patients with STEMI: physicians in the EPES' work group on cardiological processes, emergency department physicians, and physicians working in the intensive care units in the hospitals of the public healthcare system of Andalusia.

APPROACH

Levels of evidence. The levels of evidence laid out in the 2004 ACC/AHA Clinical Practice Guidelines. REACHING A CONSENSUS: A meeting was held to discuss the aspects to be included in the document. A working document was drafted and distributed to the participants via email. The final consensus document was drafted at another meeting.

CONCLUSIONS

The consensus document establishes the following priorities: 1. To apply the set of general measures recommended for the care of STEMI patients strictly and appropriately 2. To foster the use of early reperfusion in as many patients as possible, promoting the extension of fibrinolysis outside of hospitals and referral to a center with facilities for primary percutaneous coronary intervention. 3. To monitor and evaluate the management of these patients, with special attention placed on outcome and safety.

Reperfusion strategies in acute ST-segment elevation myocardial infarction: a comprehensive review of contemporary management options

There are an estimated 500,000 ST-segment elevation myocardial infarction (STEMI) events in the U.S. annually. Despite improvements in care, up to one-third of patients presenting with STEMI within 12 h of symptom onset still receive no reperfusion therapy acutely. Clinical studies indicate that speed of reperfusion after infarct onset may be more important than whether pharmacologic or mechanical intervention is used. Primary percutaneous coronary intervention (PCI), when performed rapidly at high-volume centers, generally has superior efficacy to fibrinolysis, although fibrinolysis may be more suitable for many patients as an initial reperfusion strategy. Because up to 70% of STEMI patients present to hospitals without on-site PCI facilities, and prolonged door-to-balloon times due to inevitable transport delays commonly limit the benefit of PCI, the continued role and importance of the prompt, early use of fibrinolytic therapy may be underappreciated. Logistical complexities such as triage or transportation delays must be considered when a reperfusion strategy is selected, because prompt fibrinolysis may achieve greater benefit, especially if the fibrinolytic-to-PCI time delay associated with transfer exceeds approximately 1 h. Selection of a fibrinolytic requires consideration of several factors, including ease of dosing and combination with adjunctive therapies. Careful attention to these variables is critical to ensuring safe and rapid reperfusion, particularly in the prehospital setting. The emerging modality of pharmacoinvasive therapy, although controversial, seeks to combine the benefits of mechanical and pharmacologic reperfusion. Results from ongoing clinical trials will provide guidance regarding the utility of this strategy.

Thrombolysis in acute myocardial infarction: current status

ST-segment elevation myocardial infarction (STEMI) is still a major public health problem in the modern world. Therapeutic options have changed much over the last 20 years, with a shift in favor of mechanical reperfusion over pharmacologic reperfusion. Thrombolytic therapy still has much to offer in the management of STEMI, however, because many patients do not have timely access to a facility with the required expertise for establishing mechanical reperfusion. This review highlights the history of thrombolytic therapy, adjunctive therapies, the relationship with mechanical reperfusion, and potential roles for thrombolysis in the future.

Efficacy and Safety of Enoxaparin Versus Unfractionated Heparin in Patients With ST-Segment Elevation Myocardial Infarction Also Treated With Clopidogrel

OBJECTIVES

The purpose of this study was to determine the efficacy and safety of enoxaparin (ENOX) versus unfractionated heparin (UFH) in patients with ST-segment elevation myocardial infarction (STEMI) receiving fibrinolytic therapy with and without clopidogrel.

BACKGROUND

The efficacy and safety of ENOX and clopidogrel given together in STEMI remains to be defined.

METHODS

We compared the rates of major adverse cardiovascular events (MACE) as well as the rates of bleeding in medically managed patients randomized to ENOX versus UFH in the ExTRACT-TIMI 25 (Enoxaparin and Thrombolysis Reperfusion for Acute Myocardial Infarction Treatment-Thrombolysis In Myocardial Infarction 25) trial, stratified by concomitant clopidogrel use.

RESULTS

Enoxaparin significantly reduced the rate of the composite of death, recurrent myocardial infarction, myocardial ischemia, or stroke, compared with UFH, both in patients (n = 2,173) treated with clopidogrel (10.8% vs. 13.9%, adjusted odds ratio [OR(adj)] 0.70, p = 0.013) and in patients (n = 12,918) not treated with clopidogrel (13.3% vs. 15.3%, OR(adj) 0.85, p = 0.003) with no evidence of heterogeneity (p(interaction) = 0.21). The excess risk of TIMI major bleeding with ENOX versus UFH was numerically but not statistically significantly higher in patients treated with clopidogrel (2.7% vs. 1.0%) versus those who were not (2.1% vs. 1.2%) (p(interaction) = 0.61). Net clinical benefit (MACE and major bleeding) favored treatment with ENOX over UFH, either with concomitant clopidogrel (absolute risk reduction 2.4%, 95% confidence interval [CI] -0.5% to 5.3%) or without (absolute risk reduction 1.7%, 95% CI 0.5% to 3.0%) (p(interaction) = 0.61).

CONCLUSIONS

In patients with STEMI receiving fibrinolytic therapy, the net benefit of ENOX is similar in patients who are and are not treated with clopidogrel. The totality of trial data suggest that the combination of a fibrinolytic, aspirin, clopidogrel, and ENOX offers an attractive pharmacologic reperfusion strategy in STEMI.

Pharmacological antithrombotic adjuncts to percutaneous coronary intervention

Stent thrombosis is the major cause of early adverse events during percutaneous coronary intervention. Its incidence has fallen considerably in recent years, principally due to the introduction of effective antithrombotic therapies. The selection of an appropriate antithrombotic regimen is critical in achieving a balance between reducing ischaemic events and minimising bleeding complications in patients undergoing percutaneous coronary intervention. In this article, evidence for the role of antiplatelet and anticoagulant therapies is discussed, including the thienopyridines, glycoprotein IIb/IIIa receptor antagonists, direct thrombin inhibitors and pentasaccharides.

Early management of ST elevation myocardial infarction: a review of practice

The last two decades of the 20th century witnessed continuous evolution in the understanding of the pathophysiology of ST elevation myocardial infarction. In parallel, the management of these patients developed steadily throughout this time and into the early years of the 21st century. From humble beginnings involving oxygen therapy, bed rest and analgesia, the relative merits of different strategies to open 'infarct-related arteries' (IRAs) are now being debated: pharmacological reperfusion, mechanical reperfusion or a combination of both these modalities. The current understanding of the process of thrombotic occlusion of the coronary artery has led to the appreciation of the importance of not simply opening the IRA, but also maintaining its patency once opened. Considerable attention is now being afforded to the significant minority of patients who do not achieve early, complete myocardial reperfusion, despite restoration of adequate flow down the epicardial IRA. Those patients who fail to achieve myocardial reperfusion, either due to late presentation or failure of reperfusion therapy, and are left with permanent myocardial scarring can now be considered. This article critically appraises the recent and emerging evidence and clinical implications of the contemporary management of ST elevation myocardial infarction.

Improving the management of patients after myocardial infarction, from admission to discharge

BACKGROUND

Recent developments in pharmacologic and device therapy, as well as initiatives to increase the use of standard orders and promote in-hospital communication, have improved the care of patients with myocardial infarction (MI). The increased presence of hospitalists, physicians who provide in-hospital care as a specialty, promises to provide further improvements.

OBJECTIVE

This article reviews current information on evidence-based care of the hospitalized MI patient, with a particular emphasis on identifying left ventricular dysfunction (LVD) and appropriate treatments.

METHODS

MEDLINE was searched for all large-scale clinical trials providing information on the care of post-MI patients with or without LVD and/or heart failure (HF), with no limit on time period. The search terms were post-myocardial infarction, large-scale, randomized, clinical trial, left ventricular dysfunction, and/or heart failure. All trials investigating therapies currently recommended in the American College of Cardiology/American Heart Association ST-elevation MI (ACC/AHA STEMI) guidelines and including post-MI patients with or without LVD and/or HF, as indicated by signs and symptoms of HF or Killip class, were included.

RESULTS

In the acute setting, the ACC/AHA STEMI guidelines recommend the use of aspirin, clopidogrel, beta-blockers, angiotensin-converting enzyme inhibitors, heparin (low molecular weight or unfractionated), and glycoprotein IIb/IIIa inhibitors (if the patient is undergoing a percutaneous coronary intervention). The guidelines recommend use of aldosterone antagonists and statins at discharge, in addition to continuation of all acute therapies. The ACC/AHA guidelines apply to all patients after MI and do not specify whether the recommended therapies are effective in post-MI patients with LVD or HE Reviewing the trials that included post-MI patients with LVD and/or HF, it appears that in some cases, only certain agents within a class have been evaluated (eg, post-MI beta-blocker trials often excluded patients with LVD, and the efficacy of atenolol has not been evaluated in post-MI patients with LVD or HF), and some agents have not shown as much efficacy as others in this high-risk patient population (eg, metoprolol appeared to be associated with poorer outcomes in this population than carvedilol). Rather than recommending an entire class, hospital care maps and critical-care pathway tools should incorporate the use of evidence-based agents.

CONCLUSIONS

The use of evidence-based care in the hospital has the potential to substantially reduce morbidity and mortality in post-MI patients with LVD and/or HE The hospitalist can facilitate the best practices and best care of the post-MI patient through the use of in-hospital critical-care pathway tools.

Assessment of bleeding events in clinical trials--proposal of a new classification

Present classifications of bleeding events used in antithrombotic and/or antiplatelet clinical trials are based on the criteria developed by the Thrombolysis In Myocardial Infarction (TIMI) and Global Use of Strategies to Open Coronary Arteries (GUSTO) groups. Introduced more than a decade ago, the 2 classifications used the criteria to better categorize hemorrhagic events after therapy with thrombolytic agents. Recent advances in interventional cardiology, resulting in a domination of percutaneous intracoronary procedures over systemic drug-induced thrombolysis, have substantially changed the clinical characteristics and magnitude of bleeding complications. Moreover, disturbances of the coagulation cascade, as well as platelet inhibition caused directly by antithrombotic and antiplatelet agents, share very specific and well-recognized clinical features not reflected in the existing classifications. Bleeding events after aspirin or clopidogrel, and especially those after more delicate antiplatelet regimens with dipyridamole used in patients after ischemic stroke or transient ischemic attack, are impossible to classify by the present guidelines, other than categorically triaging them altogether to the "minor" category. Uniting entirely different bleeding events as "minor" under-rates their importance and diminishes affiliated risks, creating an illusion that they do not require monitoring and/or changes in antiplatelet or antithrombotic regimens. In reality, such unrecognized and unreported mild complications may transform into more serious bleeds or lead to noncompliance. Unauthorized withdrawal from antiplatelet agents in turn causes rebound platelet activation and higher risk for secondary vascular events. In conclusion, a new classification of bleeding events is introduced (the BleedScore), based on a point accumulation depending on the severity of hemorrhage, which is believed to be more suitable for the assessment of modern, more delicate antithrombotic and antiplatelet therapies, particularly for their realistic assessment in clinical trials.

A novel enoxaparin regime for ST elevation myocardial infarction patients undergoing primary percutaneous coronary intervention: A WEST sub-study

OBJECTIVE

To evaluate the anticoagulation effect of subcutaneous (SQ) and intravenous (IV) enoxaparin through systematic anti-Xa sampling during primary PCI for acute STEMI.

BACKGROUND

Although appropriate anticoagulation is essential to maximize the efficacy and safety of primary PCI, the optimal dosing of enoxaparin in this setting is unclear.

METHODS

STEMI patients randomized to primary PCI received ASA, clopidogrel 300 mg and enoxaparin 1 mg/kg SQ at earliest point of care, including prehospital. Plasma anti-Xa determination occurred just prior to and after primary PCI. Supplemental IV enoxaparin (0.3-0.5 mg/kg) and abciximab was encouraged prior to PCI.

RESULTS

The 1st anti-Xa level 56 min (median, IQR 47-77) post SQ enoxaparin was 0.28 U/ml (0.23-0.41); 85% of patients (28/33) were <0.5 U/ml (the recommended therapeutic level). Following PCI, 126 min (118-185) after SQ enoxaparin in those without IV dosing (8/33) the 2nd anti-Xa level was 0.44 U/ml (0.29-0.53); 6 of 8 patients remained <0.5 U/ml. With IV enoxaparin (25/33) the 2nd anti-Xa was 0.96 U/ml (0.82-1.16) 97 min (82-109) after SQ enoxaparin: all were >or=0.5 U/ml and 2 had levels 1.5 U/ml.

CONCLUSION

A single SQ enoxaparin dose fails to achieve anti-Xa levels >or=0.5 U/ml in the majority of STEMI patients. When combined with a strategy of supplemental IV enoxaparin, adequate anti-Xa levels were achieved in all patients with few having levels >1.5 U/ml. This regime of SQ injection with additional IV enoxaparin provides an attractive strategy enhancing effective early anti-thrombotic therapy at first medical contact prior to primary PCI.

Evolving management of ST-segment elevation myocardial infarction: update on recent data

Significant recent advances have been made in strategies for managing ST-segment elevation myocardial infarction (STEMI). Based on new findings, the American College of Cardiology (ACC) and the American Heart Association (AHA) have updated their guidelines for acute myocardial infarction (MI) with newer recommendations for STEMI management. Many of these recommendations focus on antithrombotic agents, with a movement toward lower doses of long-term aspirin and lower doses of unfractionated heparin (UFH). Studies have also been completed on the use of enoxaparin and fondaparinux as potential alternatives to heparin, and clinical trial data support the early use of glycoprotein IIb/IIIa inhibitors (along with aspirin, UFH, and clopidogrel) in patients undergoing primary percutaneous coronary intervention for acute STEMI. Clopidogrel has also been shown to improve angiographic and clinical outcomes in patients with STEMI who are undergoing thrombolysis or being treated medically. The new ACC/AHA recommendations support clopidogrel pretreatment and long-term therapy.

Age, outcomes, and treatment effects of fibrinolytic and antithrombotic combinations: findings from Assessment of the Safety and Efficacy of a New Thrombolytic (ASSENT)-3 and ASSENT-3 PLUS

BACKGROUND

Elderly patients with acute myocardial infarction are at particularly high risk for death and bleeding complications. The efficacy and safety of antithrombotic strategies in these patients remain unclear.

METHODS

To provide more insight into the risk and benefit of antithrombotic strategies in the elderly, we examined patients from the ASSENT-3 and ASSENT-3 PLUS trials with STEMI who were treated with tenecteplase (TNK) and unfractionated heparin (UFH) or enoxaparin, or half-dose TNK with abciximab and reduced-dose UFH.

RESULTS

Older patients had a higher risk profile, and lower use of concomitant therapies and revascularization procedures. We found an interaction between age and treatment effect for the efficacy end point (P = .0007) and the efficacy plus safety end point (P < .0001). Younger patients (<65 years) had a lower risk of the composite efficacy plus safety end point with enoxaparin (relative risk [RR] 0.84, 95% CI 0.74-0.94) or abciximab (RR 0.79, 95% CI 0.69-0.90) compared with UFH. In patients >65 years of age, the benefit of enoxaparin appeared to be offset by an increased risk of bleeding complications. The risk of the efficacy plus safety end point tended to be higher in elderly patients receiving abciximab and half-dose TNK (RR 1.18, 95% CI 0.91-1.51 for 76-85 years of age and RR 1.48, 95% CI 0.88-2.49 for >85 years of age).

CONCLUSIONS

Although TNK with either enoxaparin or abciximab appeared to be more effective than with standard UHF in younger patients, these combinations tended to be less effective and even may be unsafe in the elderly. Development of new combination strategies and dosing schemes of fibrinolytics and antithrombotics with improved efficacy and safety in the elderly remains a high priority.

Low-Molecular-Weight Heparins in Conjunction with Thrombolysis for ST-Elevation Acute Myocardial Infarction

BACKGROUND

Intravenous unfractionated heparin (UFH) is recommended in ST-elevation acute myocardial infarction (STEMI), following thrombolysis with fibrin-specific agents. Subcutaneous low-molecular-weight heparins (LMWH), previously proven effective in non-ST-elevation acute coronary syndromes, have been recently investigated in the setting of STEMI. We aimed at evaluating the current level of evidence supporting the use of LMWH in STEMI.

METHODS

A Medline search of the English language literature between January 1995 and December 2005 was performed and randomized clinical trials comparing LMWH to either placebo or UFH in conjunction with thrombolysis were selected.

RESULTS

About 26,800 patients treated with various thrombolytic regimens were included in 12 randomized clinical trials. Dalteparin was superior to placebo on left ventricular thrombosis/arterial thromboembolism, with no significant effect on the early patency rate of the infarct-related artery (IRA). Compared to UFH, dalteparin had no significant effect on clinical events and on the IRA late patency, although less thrombus was present. Enoxaparin was superior to placebo on the medium-term death/reinfarction/angina rate and late IRA patency, and superior also to UFH on in-hospital and medium-term occurrence of death/reinfarction/angina. The effect of enoxaparin on IRA patency rate was not univocal. Compared to placebo, reviparin significantly reduced early and medium-term mortality and reinfarction rates, without a substantial increase in overall stroke rate. As regards safety, bleedings were more frequent than placebo and comparable to UFH in LMWH groups, with the exception of the pre-hospital ASSENT-3 PLUS trial, where in elderly patients, enoxaparin had an incidence of intracranial hemorrhage twice higher than UFH.

CONCLUSIONS

In-hospital subcutaneous administration of dalteparin, enoxaparin or reviparin, as an adjunct to various thrombolytics in STEMI, appears feasible and at least as effective and safe as intravenous UFH. Before LMWH might be recommended, however, some yet unresolved issues (i.e. use in elderly patients, in severe renal insufficiency, in association with glycoprotein IIb/IIIa inhibitors and during interventional procedures), need to be addressed.