Elsevier

Canadian Journal of Cardiology

Volume 27, Issue 6, Supplement, November–December 2011, Pages S402-S412
Canadian Journal of Cardiology

Review
Assessment and Management of Acute Coronary Syndromes (ACS): A Canadian Perspective on Current Guideline-Recommended Treatment – Part 2: ST-Segment Elevation Myocardial Infarction

https://doi.org/10.1016/j.cjca.2011.08.107Get rights and content

Abstract

Acute ST-segment elevation myocardial infarction (STEMI) accounts for approximately 30% of all acute coronary syndromes (ACS). The high early mortality for patients with STEMI is largely due to the extent of the ischemic injury. However, immediate reperfusion either pharmacologically with fibrinolysis or mechanically by primary percutaneous coronary intervention (PCI) limits the size of the infarction and reduces mortality. Reperfusion therapy by primary PCI reduces mortality and the risk of reinfarction, beyond the benefits achieved by fibrinolysis, especially when the primary PCI is initiated within 90 minutes of first medical contact. The use of adjuvant therapy with antiplatelet and anticoagulant agents is essential to enhance the results of reperfusion, and/or maintain vessel patency following either mode of reperfusion.

This review discusses the assessment and management of the patient with an acute STEMI, using recommendations from the most recent American College of Cardiology/American Heart Association, European Society of Cardiology, and existing Canadian guidelines. It provides an updated perspective and critical appraisal with practical application of the recommendations within the Canadian Healthcare system.

Résumé

L'infarctus aigu du myocarde (IAM) avec sus-décalage du segment ST compte pour environ 30 % de tous les syndromes coronariens aigus (SCA). La mortalité précoce élevée chez les patients ayant un IAM avec sus-décalage du segment ST est en grande partie due à l'étendue de la lésion ischémique. Cependant, la reperfusion immédiate soit pharmacologique par une fibrinolyse ou mécanique par une intervention coronarienne percutanée (ICP) primaire limite la taille de l'infarctus et réduit la mortalité. Le traitement de reperfusion par une ICP primaire réduit la mortalité et le risque d'un nouvel infarctus, au-delà des avantages obtenus par la fibrinolyse, spécialement lorsque l'ICP primaire est réalisé dans les 90 minutes suivant le premier contact médical. L'utilisation d'un traitement adjuvant avec des agents antiplaquettaires et anticoagulants est essentielle pour améliorer les résultats de reperfusion ou maintenir la perméabilité du vaisseau, ou les deux, selon le mode de reperfusion.

Cette revue aborde l'évaluation et la gestion du patient ayant un IAM avec sus-décalage du segment ST, en utilisant les recommandations des lignes directrices canadiennes existantes les plus récentes et celles de l'American College of Cardiology, de l'American Heart Association et de l'European Society of Cardiology. Elles fournissent une perspective actualisée et une évaluation critique ainsi qu'une application pratique des recommandations au système de soins de santé canadien.

Section snippets

Identification of STEMI

The electrocardiogram (ECG) recorded at the time of first medical contact (Emergency Medical Service [EMS], emergency department, or physician's office) permits rapid triage to the optimal reperfusion strategy. When the ECG is performed in the prehospital phase, it allows initiation of prehospital fibrinolysis or selective transfer to a hospital with primary PCI facilities bypassing the emergency department which accelerates access to treatment. The ECG criteria for initiating reperfusion

Reperfusion Strategies

The patient with ischemic chest pain of onset in the past 12 hours and ECG abnormalities consistent with an acute STEMI should be considered for immediate reperfusion by either primary PCI or fibrinolysis. Rapid reperfusion is the key to improved outcomes. Consequently, it is important that timeliness to reperfusion to recommended targets remains an important goal and measure of quality of care.

A significant number of patients who are eligible are not offered reperfusion by either fibrinolysis

Fibrinolysis

Available fibrinolytic agents in Canada include streptokinase, reteplase (rPA), alteplase (tPA), and tenecteplase (TNK). Doses and administration schedules are shown in Table 5. Alteplase is superior to streptokinase,40 and reteplase (double bolus)41 and tenecteplase (single bolus)42 appear comparable to alteplase in efficacy although tenecteplase is a single bolus, weight-adjusted agent also associated with less major (nonintracerebral) bleeding.

Early invasive strategy

An early invasive strategy for the management of patients with STEMI is the use of angiography and PCI performed within a short time (eg, within 6 to 12 hours) after the administration of fibrinolysis. Initial studies of routine PCI after STEMI, and more recent trials that performed angiography and PCI immediately after fibrinolysis showed either harm or no benefit. In contrast, more recent studies examining the role of an early invasive strategy several hours postfibrinolysis have demonstrated

Treatment Options for Patients Presenting Late or Ineligible for Reperfusion Therapy

A review of therapy for STEMI patients who present late or who are ineligible for reperfusion therapy20 shows that there is good evidence for similar benefits for ASA, clopidogrel, heparin, low molecular weight heparin, fondaparinux, β-blocker, statin, and angiotensin converting enzyme inhibitor use in this population as in patients undergoing reperfusion. The ACC/AHA and ESC Guidelines recommendations for these therapies do not distinguish between patients that have had reperfusion therapy or

Discharge and Long-Term Treatment

Treatment and management strategies to improve long-term outcomes in patients with ACS are similar, whether the patient sustained a STEMI or a non-ST elevation ACS. Details of these strategies are found in Table 13 of Part 1.75 Additional Canadian recommendations for antiplatelet therapy after ACS are to be found in the recently published Canadian Cardiovascular Society Guidelines for antiplatelet therapy.70

Funding Sources

Publication of this article was supported by AstraZeneca Canada Inc. and Bristol-Myers Squibb Canada and sanofi-aventis Canada.

Disclosures

David Fitchett has received speaker honoraria from and served on advisory boards for Astra Zeneca, sanofi-aventis, Bristol-Myers Squibb, Eli Lilly, Merck, Novartis, Pfizer, Servier, Boehringer Ingelheim, Abbott, and Roche.

Pierre Theroux has served as a consultant for AstraZeneca, Bristol-Myers Squibb, Eli Lilly, Merck, and sanofi-aventis. Dr Theroux has also received speaker honoraria from AstraZeneca, Boeringher Ingelheim, Bristol-Myers Squibb, and sanofi-aventis, and he has received a

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