Modern Management of Acute Myocardial Infarction

https://doi.org/10.1016/j.cpcardiol.2006.08.004Get rights and content

Abstract

Acute myocardial infarction (AMI) is a subset of the acute coronary syndromes and can be classified as being either a ST-segment elevation myocardial infarction (STEMI) or a non-ST-elevation myocardial infarction (NSTEMI). A clear distinction between STEMI and NSTEMI is essential because of the differences in management. The purpose of this review was to first discuss the epidemiology, pathophysiology, and diagnosis of AMI. The risk stratification and therapy of patients with STEMI and NSTEMI will then be reviewed as well as the complications of AMI.

Section snippets

Epidemiology

Cardiovascular disease is the leading cause of morbidity and mortality in both men and women. It is estimated that 1.7 million Americans per year suffer from a myocardial infarction. Seventy percent of these events are due to NSTEMI and 30% to STEMI (which includes those with the new onset of left bundle branch in the setting of AMI).1 This distribution of AMI patients reflects a shift over the past 10 to 20 years. Data from the Minnesota Heart Survey during 1985 to 1990 showed that the 28-day

Pathophysiology

AMI occurs when profound and prolonged ischemia leads to irreversible myocardial cell damage and necrosis. In most cases, this is the result of a completely (STEMI4) or partially (UA/NSTEMI5) obstructive intracoronary thrombus. In a landmark study, DeWood and colleagues performed early coronary angiography in 322 patients with AMI.4 At 4 hours from symptom onset, total coronary occlusion was present in 87% and decreased to 65% at 12 to 24 hours. In addition, they retrieved thrombus from 52 of

Clinical Presentations

The classic symptom of AMI is discomfort in the central area of the chest that may radiate to the neck, back, or arms; is persistent (unrelieved by nitrates); and is frequently associated with diaphoresis, nausea, weakness, and fear of impending death. The discomfort usually achieves maximum intensity over several minutes.

At least one-fifth of MIs are clinically unrecognized because of atypical symptoms or absence of chest discomfort. Painless myocardial infarction is known to occur in the

Risk Stratification

Risk stratification of patients with STEMI can be based on physical exam findings at the time of presentation. The Killip classification (Table 1) is easy to use and provides a rapid method of risk-stratifying patients in the emergency department.15

Therapy

The therapeutic management strategy for STEMI patients can be divided into the following four major categories: (1) initial management; (2) reperfusion strategy; (3) additional antiplatelet therapy; and (4) management in the coronary care unit.

Risk Stratification

Risk stratification is pivotal in NSTEMI patients, because they represent a more heterogeneous group in terms of clinical outcomes. Specifically, risk stratification helps determine which patients benefit from the use of glycoprotein IIb/IIIa inhibitors and an early-invasive strategy. Risk stratification can be easily and quickly performed with use of the TIMI Risk Score or by assessing the initial ECG and cardiac biomarkers.

Complications of Myocardial Infarction

The potential complications of AMI can be divided into two main categories: mechanical complications and electrical complications.

Summary

Despite the numerous improvements in the management of AMI, it remains one of the leading causes of morbidity and mortality worldwide. The key steps in the management of these patients include rapid diagnosis, prompt delivery of initial therapeutic agents, immediate reperfusion of STEMI patients, and diligent in-hospital management. Future improvements in each of these categories need to be made if any significant reductions in the morbidity and mortality are to be obtained.

Elliott M. Antmann:

References (139)

  • S. Zorman et al.

    Effects of abciximab pretreatment in patients with acute myocardial infarction undergoing primary angioplasty

    Am J Cardiol

    (2002)
  • D.E. Cutlip et al.

    Effect of tirofiban before primary angioplasty on initial coronary flow and early ST-segment resolution in patients with acute myocardial infarction

    Am J Cardiol

    (2003)
  • D.E. Cutlip et al.

    Emergency room administration of eptifibatide before primary angioplasty for ST elevation acute myocardial infarction and its effect on baseline coronary flow and procedure outcomes

    Am J Cardiol

    (2001)
  • R.H. Mehta et al.

    Clinical and angiographic correlates and outcomes of suboptimal coronary flow inpatients with acute myocardial infarction undergoing primary percutaneous coronary intervention

    J Am Coll Cardiol

    (2003)
  • M.D. Kenner et al.

    Ability of the no-reflow phenomenon during an acute myocardial infarction to predict left ventricular dysfunction at one-month follow-up

    Am J Cardiol

    (1995)
  • E. Braunwald et al.

    ACC/AHA 2002 guideline update for the management of patients with unstable angina and non-ST-segment elevation myocardial infarction—summary article: a report of the American College of Cardiology/American Heart Association task force on practice guidelines (Committee on the Management of Patients With Unstable Angina)

    J Am Coll Cardiol

    (2002)
  • K.K. Ray et al.

    The potential relevance of the multiple lipid-independent (pleiotropic) effects of statins in the management of acute coronary syndromes

    J Am Coll Cardiol

    (2005)
  • S.G. Goodman et al.

    Randomized trial of low molecular weight heparin (enoxaparin) versus unfractionated heparin for unstable coronary artery disease: one-year results of the ESSENCE StudyEfficacy and Safety of Subcutaneous Enoxaparin in Non-Q Wave Coronary Events

    J Am Coll Cardiol

    (2000)
  • R.H. Hongo et al.

    The effect of clopidogrel in combination with aspirin when given before coronary artery bypass grafting

    J Am Coll Cardiol

    (2002)
  • P.A. McCullough et al.

    A prospective randomized trial of triage angiography in acute coronary syndromes ineligible for thrombolytic therapyResults of the medicine versus angiography in thrombolytic exclusion (MATE) trial

    J Am Coll Cardiol

    (1998)
  • K.A. Fox et al.

    Interventional versus conservative treatment for patients with unstable angina or non-ST-elevation myocardial infarction: the British Heart Foundation RITA 3 randomised trialRandomized Intervention Trial of unstable Angina

    Lancet

    (2002)
  • R.A. Nishimura et al.

    Papillary muscle rupture complicating acute myocardial infarction: analysis of 17 patients

    Am J Cardiol

    (1983)
  • M.B. Honan et al.

    Cardiac rupture, mortality and the timing of thrombolytic therapy: a meta-analysis

    J Am Coll Cardiol

    (1990)
  • E.M. Antman et al.

    ACC/AHA guidelines for the management of patients with ST-elevation myocardial infarction: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Revise the 1999 Guidelines for the Management of patients with acute myocardial infarction)

    J Am Coll Cardiol

    (2004)
  • P.G. McGovern et al.

    Recent trends in acute coronary heart disease—mortality, morbidity, medical care, and risk factorsThe Minnesota Heart Survey Investigators

    N Engl J Med

    (1996)
  • V.L. Roger et al.

    Trends in the incidence and survival of patients with hospitalized myocardial infarction, Olmsted County, Minnesota, 1979 to 1994

    Ann Intern Med

    (2002)
  • M.A. DeWood et al.

    Prevalence of total coronary occlusion during the early hours of transmural myocardial infarction

    N Engl J Med

    (1980)
  • M.A. DeWood et al.

    Coronary arteriographic findings soon after non-Q-wave myocardial infarction

    N Engl J Med

    (1986)
  • J.S. Alpert et al.

    Myocardial infarction redefined—a consensus document of The Joint European Society of Cardiology/American College of Cardiology Committee for the redefinition of myocardial infarction

    J Am Coll Cardiol

    (2000)
  • J.E. Adams et al.

    Diagnosis of perioperative myocardial infarction with measurement of cardiac troponin I

    N Engl J Med

    (1994)
  • M. Galvani et al.

    Prognostic influence of elevated values of cardiac troponin I in patients with unstable angina

    Circulation

    (1997)
  • L.K. Newby et al.

    Value of serial troponin T measures for early and late risk stratification in patients with acute coronary syndromesThe GUSTO-IIa Investigators

    Circulation

    (1998)
  • E.M. Ohman et al.

    Cardiac troponin T levels for risk stratification in acute myocardial ischemiaGUSTO IIA Investigators

    N Engl J Med

    (1996)
  • C.W. Hamm et al.

    The prognostic value of serum troponin T in unstable angina

    N Engl J Med

    (1992)
  • A.H. Wu et al.

    National Academy of Clinical Biochemistry Standards of Laboratory Practice: recommendations for the use of cardiac markers in coronary artery diseases

    Clin Chem

    (1999)
  • Randomised trial of intravenous streptokinase, oral aspirin, both, or neither among 17,187 cases of suspected acute myocardial infarction: ISIS-2

    Lancet

    (1988)
  • J. Lau et al.

    Cumulative meta-analysis of therapeutic trials for myocardial infarction

    N Engl J Med

    (1992)
  • N. Freemantle et al.

    Beta blockade after myocardial infarction: systematic review and meta regression analysis

    BMJ

    (1999)
  • R. Roberts et al.

    Immediate versus deferred beta-blockade following thrombolytic therapy in patients with acute myocardial infarctionResults of the Thrombolysis in Myocardial Infarction (TIMI) II-B Study

    Circulation

    (1991)
  • COMMIT (ClOpidogrel and Metoprolol in Myocardial Infarction Trial) collaborative groupEarly intravenous then oral metoprolol in 45,852 patients with acute myocardial infarction: randomised placebo-controlled trial

    Lancet

    (2005)
  • B.I. Jugdutt et al.

    Intravenous nitroglycerin therapy to limit myocardial infarct size, expansion, and complicationsEffect of timing, dosage, and infarct location

    Circulation

    (1988)
  • B.I. Jugdutt et al.

    Effect of intravenous nitroglycerin on collateral blood flow and infarct size in the conscious dog

    Circulation

    (1981)
  • E.M. Antman et al.

    Enoxaparin versus unfractionated heparin with fibrinolysis for ST-elevation myocardial infarctiondoi;10.1056/NEJMoa060898

    N Engl J Med

    (2006)
  • F.J. Van de Werf et al.

    Efficacy and safety of tenecteplase in combination with enoxaparin, abciximab, or unfractionated heparin: the ASSENT-3 randomised trial in acute myocardial infarction

    Lancet

    (2001)
  • F. Van de Werf et al.

    Reperfusion for ST-segment elevation myocardial infarction: an overview of current treatment options

    Circulation

    (2002)
  • F. Ribichini et al.

    Acute myocardial infarction: reperfusion treatment

    Heart

    (2002)
  • B.J. Gersh et al.

    Pharmacological facilitation of primary percutaneous coronary intervention for acute myocardial infarction: is the slope of the curve the shape of the future?

    JAMA

    (2005)
  • A comparison of reteplase with alteplase for acute myocardial infarction

    N Engl J Med

    (1997)
  • Single-bolus tenecteplase compared with front-loaded alteplase in acute myocardial infarction: the ASSENT-2 double-blind randomised trialAssessment of the Safety and Efficacy of a New Thrombolytic Investigators

    Lancet

    (1999)
  • G. De Luca et al.

    Time delay to treatment and mortality in primary angioplasty for acute myocardial infarction: every minute of delay counts

    Circulation

    (2004)
  • Cited by (20)

    • Nicorandil alleviates cardiac remodeling and dysfunction post -infarction by up-regulating the nucleolin/autophagy axis

      2022, Cellular Signalling
      Citation Excerpt :

      Myocardial infarction (MI) is the most serious form of coronary artery disease (CAD), and it is also the main cause of human death [1,2]. Although reperfusion measures, such as thrombolysis and rapid percutaneous coronary intervention, greatly improve the symptoms of MI patients and enhance the short-term survival rate of MI patients [3,4], MI survivors are often at a high risk of subsequent heart failure [5]. Pathological myocardial remodeling is responsible for heart failure and accounts for cardiovascular events after MI [6].

    • Modern Management of Acute Myocardial Infarction

      2012, Current Problems in Cardiology
    View all citing articles on Scopus

    The authors have no conflicts of interest to disclose.

    View full text