Meta-analysis of randomized trials comparing enoxaparin versus unfractionated heparin as adjunctive therapy to fibrinolysis in ST-elevation acute myocardial infarction

Anticoagulation in the management of ST-segment elevation myocardial infarction

Patients with ST-segment elevation myocardial infarction (STEMI) require immediate reperfusion therapy in order to salvage ischemic myocardial tissue and reduce mortality. Reperfusion therapy can be provided mechanically with primary percutaneous coronary intervention (PCI), or pharmacologically with fibrinolysis. Regardless of the reperfusion strategy selected, the appropriate use of anticoagulant therapy is critical to its success. There have been a number of clinical trials evaluating the different anticoagulants in patients with STEMI, as well as recent updates to the guidelines for management of patients with STEMI and on the use of PCI. When making clinical decisions on the use of anticoagulant therapy in the management of patients with STEMI, it is important to not only understand the contents of these consensus guidelines but to also have an appreciation of the details of the clinical trials that have evaluated the different anticoagulants. In this review, the reader will find an evaluation of the current guidelines concerning the use of anticoagulant therapy in patients with STEMI as well as a detailed examination of the literature with critical analysis on issues that should be considered when deciding on the appropriate implementation of anticoagulant therapy in patients with STEMI undergoing either mechanical or pharmacologic reperfusion.

Management of acute coronary syndrome in a tertiary care general medical unit in Sri Lanka: how closely do we follow the guidelines?

BACKGROUND AND OBJECTIVES

Acute coronary syndrome (ACS) is a leading cause of death. Correct implementation of evidence-based guidelines should improve outcome. We conducted this study to determine to what extent management of ACS in a tertiary care medical ward in Sri Lanka adhered to current guidelines.

STUDY METHODS

This prospective observational study was carried out in the University Medical Unit of the National Hospital, Colombo, Sri Lanka, for a 5-month period commencing April 2008. All patients presenting with ACS to the unit were included.

RESULTS

During the period of study, there were 101 admissions of confirmed ACS. Thirty-one (30.6%) and 40 (39.6%) patients had not received the required correct loading dose of aspirin and clopidogrel, respectively. There were 34 cases of ST-elevation myocardial infarction (STEMI); 26 patients were eligible for thrombolysis and streptokinase was given to 22 (84.6%). The rest were treated with low-molecular-weight heparin (LMWH). Of the 67 patients who did not have STEMI, 66 received the correct dose of LMWH. Fifty-two patients (51.4%) were started on a b-blocker at presentation. None of the patients received intravenous b-blockers. Seventy-four patients (73.2%) were started on either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker on presentation. None of the patients underwent primary percutaneous intervention.

CONCLUSION

Adherence to guidelines is limited by lack of funds and resources in our setting; however, attention must be paid to non-costly easily correctable deficits.

Cost-effectiveness of enoxaparin compared with unfractionated heparin in ST elevation myocardial infarction patients undergoing pharmacological reperfusion: a Canadian analysis of the Enoxaparin and Thrombolysis Reperfusion for Acute Myocardial Infarction Treatment - Thrombolysis in Myocardial Infarction (ExTRACT-TIMI) 25 trial

OBJECTIVE

To evaluate the cost-effectiveness of enoxaparin versus unfractionated heparin in conjunction with fibrinolysis in ST elevation myocardial infarction patients within Canada.

DESIGN

Based on the Enoxaparin and Thrombolysis Reperfusion for Acute Myocardial Infarction Treatment - Thrombolysis in Myocardial Infarction (ExTRACT-TIMI) 25 trial, a model was created to analyze the cost-effectiveness of enoxaparin compared with unfractionated heparin in conjunction with fibrinolysis among ST elevation myocardial infarction patients within Canada. Clinical outcomes were derived from published results of the main trial. Resource use costs were first assessed based on United States Diagnosis-Related Group values for hospitalizations and Current Procedural Terminology codes for outpatient visits and tests. Both were then converted using Canadian local costs. Survival and life expectancy were estimated from Framingham survival data. The incremental cost-effectiveness ratio was expressed as cost per life year gained.

RESULTS

Through 30 days after random assignment, the primary composite end point favoured the enoxaparin group over the unfractionated heparin group (death or recurrent myocardial infarction rate 9.9% versus 12.0%, P<0.001), and was associated with a modest increased cost of $169.50 ($8,757.00 versus $8,587.50, respectively). Life years gained as a result of treatment with enoxaparin was increased by 0.11 years (P<0.05). Enoxaparin was found to be cost-effective, as indicated by an incremental cost-effectiveness ratio of $4,930 with a 99% probability of costing less than $20,000.

CONCLUSIONS

Although associated with modest increased direct medication costs, enoxaparin following fibrinolysis improved the clinical efficacy in STEMI patients and increased the life years gained.

[Enoxaparin vs. non-fractionated heparin in primary angioplasty of acute myocardial infarction]

OBJECTIVE

The objective of this study is to compare the effectiveness of intravenous enoxaparin (ENX) and Non-fractionated Heparin (NFH) in primary angioplasty (PA) of acute myocardial infarction (PA-AMI).

DESIGN

A prospective, observational study.

PATIENTS AND METHODS

A total of 191 patients admitted at the hospital with the diagnosis of Acute Myocardial Infarction (AMI) and treated with primary angioplasty were included. ENX was used in 91 patients (47.6%) and NFH in 100 patients (52.4%). Choice of treatment was based on the operator's opinion. Patients with cardiogenic shock were excluded. The first group received an intravenous bolus of ENX (0.75-1 mg/Kg) and the second one NFH (70-100 u/Kg), depending on whether it was associated with abciximab or not. In-hospital follow-up was performed, evaluating mortality and bleeding complications of both treatments.

RESULTS

In-hospital mortality was 1.1% for the ENX group and 3.3% for NFH one. No significant differences were found in the number of bleeding complications with ENX (4.4%) and NFH (9.0%). There was one subacute thrombosis of stent for the ENX group and 3 thrombosis in the NFH-treated group. No significant differences were found in size of infarction measure with troponin I level (63.1 for ENX and 54.8 for the NFH) or in the left ventricle ejection fraction on hospital discharge (51% for ENX and 49.4% for the NFH).

CONCLUSIONS

Primary angioplasty can be safely sued with the intravenous administration of ENX, no significant differences being found between both treatments in mortality and bleeding complications.

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.

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.

Use of Unfractionated Heparin and a??Low-Molecular-Weight Heparin following Thrombolytic Therapy for??Acute ST-Segment Elevation Myocardial Infarction1

BACKGROUND

Acute myocardial infarction (AMI) is one of the most serious cardiovascular diseases, with acute ST-segment elevation myocardial infarction (STEMI) showing a higher mortality rate than non-ST-segment elevation myocardial infarction (NSTEMI). There is evidence that low-molecular-weight heparin (LMWH) shows greater efficacy than unfractionated heparin (UFH). This open-label, single-centre, randomised study was conducted to compare the efficacy and safety of parnaparin sodium, a LMWH, with UFH in patients with STEMI.

PATIENTS AND METHODS

Patients with STEMI were randomised to receive either parnaparin sodium (4250IU aXa subcutaneously every 12 hours for 7 days, initiated 12 hours after thrombolysis) or UFH (100 U/kg intravenous bolus, initiated 12 hours after thrombolytic therapy, followed by 1000 U/hour as a continuous infusion for 3 days, then 7500U subcutaneously every 12 hours for 4 days). Patients were followed up for 45 days (> or =14 days in hospital).

RESULTS

In total, 186 patients were randomised to receive parnaparin sodium (n = 96) or UFH (n = 90). A significantly greater reduction in the composite primary endpoint (sum of all deaths, first occurrence of recurrent MI, and first occurrence of emergency revascularisation) was seen with parnaparin sodium compared with UFH at day 45 (27.08% vs 42.22%; p = 0.03). A lower incidence of composite endpoint was seen as early as day 2 with parnaparin sodium, but this did not reach significance versus UFH. The rate of individual endpoint events (death, first occurrence of non-fatal recurrent MI and first occurrence of emergency revascularisation) was lower in the parnaparin sodium group than the UFH group at 2, 7, 14 and 45 days, but the differences were not statistically significant. At day 7, the incidences of any bleeding and heparin-induced thrombocytopenia were also lower in the parnaparin sodium group compared with the UFH group (3.13% vs 10.0%; p = 0.06 and 0% vs 3.33%; p = 0.07, respectively).

CONCLUSION

The results of this study indicate that parnaparin sodium is more effective than UFH in reducing composite cardiac events in patients with STEMI following thrombolytic therapy. There was also a lower incidence of bleeding and heparin-induced thrombocytopenia with parnaparin sodium than with UFH. In view of these findings, parnaparin sodium represents an effective, convenient and well tolerated alternative to UFH.

Unfractionated and low-molecular-weight heparin as adjuncts to thrombolysis in aspirin-treated patients with ST-elevation acute myocardial infarction: a meta-analysis of the randomized trials

BACKGROUND

There is uncertainty about the role of intravenous unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) in patients with ST-elevation myocardial infarction (STEMI) treated with aspirin and thrombolysis.

METHODS AND RESULTS

We performed a meta-analysis of the randomized trials to assess the effect of UFH and LMWH on reinfarction, death, stroke, and bleeding. Fourteen trials involving a total of 25,280 patients were included (1239 comparing intravenous UFH versus placebo or no heparin; 16,943 comparing LMWH versus placebo; and 7098 comparing LMWH versus intravenous UFH). Intravenous UFH during hospitalization did not reduce reinfarction (3.5% versus 3.3%; odds ratio [OR], 1.08; 95% CI, 0.58 to 1.99) or death (4.8% versus 4.6%; OR, 1.04; 95% CI, 0.62 to 1.78) and did not increase major bleeding (4.2% versus 3.4%; OR, 1.21; 95% CI, 0.67 to 2.18) but increased minor bleeding (19.6% versus 12.5%; OR, 1.72; 95% CI, 1.22 to 2.43). During hospitalization/at 7 days, LMWH compared with placebo reduced the risk of reinfarction by approximately one quarter (1.6% versus 2.2%; OR, 0.72; 95% CI, 0.58 to 0.90; number needed to treat [NNT]=167) and death by &10% (7.8% versus 8.7%; OR, 0.90; 95% CI, 0.80 to 0.99; NNT=111) but increased major bleeding (1.1% versus 0.4%; OR, 2.70; 95% CI, 1.83 to 3.99; number needed to harm [NNH]=143) and intracranial bleeding (0.3% versus 0.1%; OR, 2.18; 95% CI, 1.07 to 4.52; NNH=500). The reduction in death with LMWH remained evident at 30 days. LMWH compared with UFH during hospitalization/at 7 days reduced reinfarction by &45% (3.0% versus 5.2%; OR, 0.57; 95% CI, 0.45 to 0.73; NNT=45), did not reduce death (4.8% versus 5.3%; OR, 0.92; 95% CI, 0.74 to 1.13) or increase major bleeding (3.3% versus 2.5%; OR, 1.30; 95% CI, 0.98 to 1.72), but increased minor bleeding (22.8% vs 19.4%; OR, 1.26; 95% CI, 1.12 to 1.43). The reduction in reinfarction remained evident at 30 days.

CONCLUSIONS

In aspirin-treated patients with STEMI who are treated with thrombolysis, intravenous UFH has not been shown to prevent reinfarction or death. LMWH given for 4 to 8 days compared with placebo reduces reinfarction by approximately one quarter and death by &10% and when directly compared with UFH reduces reinfarction by almost one half. These data suggest that LMWH should be the preferred antithrombin in this setting.

Early reperfusion strategies after acute ST-segment elevation myocardial infarction: the importance of timing

Acute ST-segment elevation myocardial infarction is estimated to occur in more than 500,000 people in the US every year. With the introduction of reperfusion therapy by fibrinolysis or primary angioplasty, mortality has significantly fallen. Although fibrinolysis is more readily available than primary angioplasty, the latter is more effective and results in better short-term and long-term outcomes if performed in a timely manner by an experienced operator and hospital team. The ischemic time, door-to-balloon time and clinical risk are important determinants of favorable outcome. Primary angioplasty is the preferred reperfusion strategy when symptom onset is longer than 3 h, in high-risk patients, such as those with cardiogenic shock, congestive heart failure or elderly age, and those with contraindications for fibrinolysis. Primary angioplasty is the preferred strategy in interventional facilities, with a goal door-to-balloon time of less than 90 min. For patients who present to noninterventional facilities, transfer to a hospital capable of primary angioplasty is safe and effective if the additional treatment delay is less than 90 min. Facilitated percutaneous coronary intervention has been shown in several small trials to offer early vessel patency and improve outcomes compared with fibrinolysis alone, but has not been shown to reduce mortality. Larger trials are ongoing to evaluate the benefit of this approach. The establishment of an effective and efficient system for the rapid transport of patients to centers capable and experienced in primary angioplasty is severely needed to provide optimum treatment and outcomes to patients with ST-segment elevation acute myocardial infarction.

Low-molecular-weight heparin vs. unfractionated heparin in percutaneous coronary intervention: A combined analysis

This meta-analysis assessed the rates of the efficacy and safety endpoints with intravenous low-molecular-weight heparin (LMWH) compared with unfractionated heparin (UFH) in patients undergoing percutaneous coronary intervention (PCI). Subcutaneous LMWH has compared favorably with UFH, but limited experience exists with intravenous LMWH for immediate anticoagulation in PCI. The meta-analysis included data from eight randomized trials in which patients received LMWH (n = 1,037) or UFH (n = 978) during PCI. Seven additional nonrandomized studies/registries were analyzed to assess the efficacy and safety of LMWH during PCI. Efficacy endpoints were ischemic events (usually a composite of death, myocardial infarction, and urgent revascularization) and the safety endpoint was bleeding (major, minor, or all bleeding). In the randomized studies, LMWH was comparable with UFH in terms of efficacy (6.2% vs. 7.5%) and major bleeding (0.9% vs. 1.8%). The analysis of pooled data, randomized or not, suggests potential improved efficacy (5.8% vs. 7.6%) and reduced major bleeding (0.6% vs. 1.8%) with LMWH (n = 3,787) compared with UFH (n = 978). During PCI, intravenous LMWH without coagulation monitoring has the potential to be at least as safe and efficacious as intravenous UFH. Further studies of LMWHs in PCI are therefore required.

Low-molecular-weight heparins in ischemic heart disease

PURPOSE OF REVIEW

The objective of this review was to summarize the recent developments regarding the use of low-molecular-weight heparins in the management of acute coronary syndromes.

RECENT FINDINGS

In the setting of unstable angina and non-ST-elevation myocardial infarction, enoxaparin is superior to unfractionated heparin in reducing death, myocardial infarction, and recurrent ischemia both in the short-term and to 1 year. However, this does not necessarily imply a class effect of low-molecular-weight heparins in general. When combined with glycoprotein IIb/IIIa inhibitors, enoxaparin appears to be effective and safe even for patients treated according to an early invasive strategy. In patients receiving fibrinolytics for ST-elevation myocardial infarction, low-molecular-weight heparins are as effective as unfractionated heparin in maintaining patency of the infarct-related artery and in reducing the composite endpoint of death and reinfarction. However, serious bleeding is more common, especially among the elderly, and the optimal dosing regimen in ST-elevation myocardial infarction remains to be defined.

SUMMARY

Low-molecular-weight heparins are safe and effective in the management of unstable angina and non-ST-elevation myocardial infarction, with or without concurrent administration of glycoprotein IIb/IIIa inhibitors. Ongoing studies will clarify the role of low-molecular-weight heparins as adjunctive therapy for fibrinolysis.

Evolving Role of Low-Molecular-Weight Heparins in ST-Elevation Myocardial Infarction

OBJECTIVE:

To review the available literature on the efficacy and safety of low-molecular-weight heparin (LMWH) in the treatment of ST-elevation myocardial infarction (STEMI) in patients treated with fibrinolytic therapy or conservative medical management.

DATA SOURCES:

A MEDLINE search (1966–March 2004) using the key words myocardial infarction, STEMI, LMWH, enoxaparin, and dalteparin identified pertinent articles. The references of these articles were reviewed for additional pertinent references.

STUDY SELECTION AND DATA EXTRACTION:

All human trials of LMWH in STEMI were evaluated. All pertinent studies were included in the review.

DATA SYNTHESIS:

LMWH did not show a benefit in STEMI without fibrinolytic therapy. Enoxaparin is similar to intravenous unfractionated heparin (UFH) in combination with nonspecific fibrinolytic therapy with regard to invasive reperfusion markers and 30-day clinical outcomes. Enoxaparin decreases composite endpoints in combination with fibrin-specific fibrinolytic therapy compared with UFH, primarily through a reduction in the incidence of reinfarction at 30 days. Bleeding rates with LMWH in combination with fibrinolytic agents are not greater than those with UFH.

CONCLUSIONS:

Enoxaparin is a reasonable alternative to UFH in patients with STEMI treated with fibrin-specific fibrinolytic therapy. LMWH in patients managed with nonspecific fibrinolytic therapy or conservative medical treatment does not provide an advantage over standard management. Large clinical trials are ongoing which will provide more definitive recommendations.

Antiplatelet and Antithrombin Therapy for Early Management of Acute Coronary Syndromes

Acute coronary syndromes (ACS) are defined as either unstable angina (UA), non-ST-segment elevation myocardial infarction (NSTEMI), or ST-segment elevation myocardial infarction (STEMI). Their management is continuously evolving in terms of pharmacologic therapy. The usual cause of ACS is the disruption of an atherosclerotic plaque leading to formation of a thrombus within a coronary artery. Initial antiplatelet and antithrombin therapy for patients with ST-segment elevation (STE) ACS includes aspirin and unfractionated heparin (UFH). Patients presenting to the hospital early may undergo percutaneous intervention (PCI) with administration of additional medications such as clopidogrel and abciximab or may receive a fibrinolytic agent. Patients with non-ST-segment elevation (NSTE) ACS receive aspirin, clopidogrel, either a low-molecular-weight heparin or UFH, and, in selected patients, a glycoprotein (GP) IIb/IIIa receptor blocker. All of these agents have shown benefit when administered to patients with ACS, but results vary depending on the type of syndrome, timing of administration, and patient’s overall risk. Their mechanism of action, role in ACS, clinical practice recommendations, adverse effects, and monitoring are reviewed. Some inherent limitations to agents such as aspirin and UFH require the need for newer treatment approaches. Therefore, newer classes of drugs such as the direct thrombin inhibitor bivalirudin and the selective factor Xa inhibitor fondaparinux are being explored as alternatives to heparins for ACS management.

Low molecular weight heparin treatment in elderly subjects with or without renal insufficiency: new insights between June 2002 and March 2004

PURPOSE OF REVIEW

Low molecular weight heparin has become the treatment of choice for venous thromboembolism events and acute coronary syndromes. In contrast to unfractionated heparin, low molecular weight heparins are mainly excreted by the kidney. Thus, repeated administration of therapeutic doses of low molecular weight heparins may lead to overdosage and/or an accumulation effect in patients with renal impairment, such as the elderly. Moreover, older patients are often excluded from clinical trials. Little evidence is available to assess the risk/benefit ratio of low molecular weight heparins used at therapeutic dosages in elderly patients with or without renal insufficiency in normal clinical practice.

RECENT FINDINGS

Pharmacovigilance data, case reports, and observational studies reporting major bleeding complications in the elderly highlight the potential risk of using low molecular weight heparins at therapeutic dosages in these patients. An evaluation of renal function is thus essential before therapy with low molecular weight heparins is begun. Moreover, multiple-dose pharmacokinetic studies in the elderly have shown that the pharmacokinetic response to impaired renal function, especially the risk of accumulation effect, may differ among preparations of low molecular weight heparins.

SUMMARY

Three approaches to improve the safety of low molecular weight heparins in the elderly are discussed: (1) to replace low molecular weight heparin therapy with monitored unfractionated heparin therapy in cases of severe renal insufficiency, but comparative studies are necessary to clarify whether unfractionated heparin offers better safety in this setting; (2) to use initial reduced dosages in elderly patients with or without renal failure, but these regimens have to be validated for each low molecular weight heparin in terms of efficacy in controlled trials; and (3) to monitor anti-Xa activity to detect any overdosage and/or any accumulation effect of low molecular weight heparins.

Low molecular weight heparin and atherosclerosis

Low molecular weight heparin (LMWH) has dramatically impacted the treatment of venous thromboembolic disease and acute coronary syndromes. Recent studies help define the role of these agents for patients undergoing percutaneous coronary interventions and for patients treated with thrombolytic agents for ST-segment elevation myocardial infarction. Recent studies also suggest potential usefulness of LMWH for patients with peripheral vascular disease and its limits of utility in stroke. This review summarizes the evidence about the use of LMWH in these clinical situations.

Antithrombotic Therapy for Acute Coronary Syndromes

OBJECTIVES

To review the role of antithrombotic therapy for treatment of acute coronary syndromes (ACS) in the hospital setting.

DATA SOURCES

Recent (1995-2003) published scientific literature, as identified by the authors through Medline searches, using the terms acute coronary syndromes, antithrombotic, antiplatelet, clinical trials, and reviews on treatment.

STUDY SELECTION

Recent systematic English-language review articles and reports of controlled randomized clinical trials were screened for inclusion.

DATA SYNTHESIS

For the patient with ST-segment elevation (STE) ACS, nonenteric-coated aspirin should be initiated immediately, if possible before arrival at the emergency department. In-hospital treatment is aimed at rapidly re-establishing coronary patency by means of percutaneous coronary intervention (PCI) or thrombolysis, preventing cardiac complications, and improving survival. Patients undergoing primary PCI should receive a glycoprotein IIb/IIIa receptor inhibitor, unfractionated heparin (UFH), and clopidogrel (Plavix--Bristol-Myers Squibb/Sanofi Pharmaceuticals Partnership) if bypass surgery is not urgently indicated; those undergoing thrombolysis should receive UFH. For the patient with non-ST-segment elevation (NSTE) ACS, beta-blockers, nitrates (also indicated for STE myocardial infarction), antiplatelet agents, and antithrombin therapy (UFH or low-molecular-weight heparin) are provided in standard care. Aspirin should be commenced immediately and continued indefinitely; in addition, clopidogrel is recommended for patients who are medically managed and those undergoing PCI. Glycoprotein IIb/IIIa receptor inhibitors (tirofiban [Aggrastat--Guilford Pharmaceuticals], eptifibatide [Integrilin--Millennium Pharmaceuticals], and abciximab [ReoPro--Lilly]) are of benefit in reducing ischemic complications in patients undergoing PCI.

CONCLUSION

Early reperfusion with thrombolytics or primary PCI is required in patients presenting with STE ACS. Early invasive management is recommended for high-risk patients with NSTE ACS; for lower-risk patients, either early invasive or early conservative therapy is recommended.