1.
Preamble
It is important that the medical profession play a significant role
in critically evaluating the use of diagnostic procedures and therapies
in the detection, management, or prevention of disease states. Rigorous
and expert analysis of the available data documenting relative benefits
and risks of those procedures and therapies can produce helpful
guidelines that improve the effectiveness of care, optimize patient
outcomes, and generally have a favorable impact on the overall cost
of care by focusing resources on the most effective strategies.
The American College of Cardiology (ACC) and the American Heart
Association (AHA) have jointly engaged in the production of such
guidelines in the area of cardiovascular disease since 1980. This
effort is directed by the ACC/AHA Task Force on Practice Guidelines,
whose charge is to develop and revise practice guidelines for important
cardiovascular diseases and procedures. Experts in the subject under
consideration are selected from both organizations to examine subject-specific
data and write guidelines. The process includes additional representatives
from other medical practitioner and specialty groups where appropriate.
Writing groups are specifically charged to perform a formal literature
review, weigh the strength of evidence for or against a particular
treatment or procedure, and include estimates of expected health
outcomes where data exist. Patientspecific modifiers, comorbidities
and issues of patient preference that might influence the choice
of particular tests or therapies are considered as well as frequency
of follow-up. When available, information from studies on cost will
be considered, however review of data on efficacy and clinical outcomes
will be the primary basis for preparing recommendations in these
guidelines.
The ACC/AHA Task Force on Practice Guidelines makes every effort
to avoid any actual or potential conflicts of interest that might
arise as a result of an outside relationship or personal interest
of a member of the writing panel. Specifically, all members of the
writing panel are asked to provide disclosure statements of all
such relationships that might be perceived as real or potential
conflicts of interest. These statements are reviewed by the parent
task force, reported orally to all members of the writing panel
at the first meeting, and updated and reviewed by the writing committee
as changes occur.
These
practice guidelines are intended to assist healthcare providers
in clinical decision making by describing a range of generally acceptable
approaches for the diagnosis, management, and prevention of specific
diseases or conditions. These guidelines attempt to define practices
that meet the needs of most patients in most circumstances. These
guideline recommendations reflect a consensus of expert opinion
after a thorough review of the available, current scientific evidence
and are intended to improve patient care. If these guidelines are
used as the basis for regulatory/payer decisions, the ultimate goal
is quality of care and serving the patient’s best interests.
The ultimate judgment regarding care of a particular patient must
be made by the healthcare provider and patient in light of all of
the circumstances presented
by that patient. There are circumstances where deviations from these
guidelines are appropriate.
The
executive summary and recommendations are published in the August
4, 2004, issue of the Journal of the American College of Cardiology
and August 3, 2004, issue of Circulation. The full text is published
on the ACC and AHA World Wide Web sites. Copies of the full text
and the executive summary are available from both organizations.
Elliott
M. Antman, MD, FACC, FAHA
Chair, ACC/AHA Task Force on Practice Guidelines
1.1.
Introduction
The process of guideline development for management of patients
with acute myocardial infarction (AMI) has undergone substantial
evolution since the inaugural publication entitled “Guidelines
for the Early Management of Patients with Acute Myocardial Infarction”
in 1990 under the auspices of the ACC/AHA Task Force on Assessment
of Diagnostic and Therapeutic Cardiovascular Procedures (Chairman,
Dr. Rolf Gunnar; Figure 1) (1).
Subsequently, the ACC/AHA Task Force on Practice Guidelines convened
a committee (Chairman, Dr. Thomas J. Ryan) in 1994 to revise the
1990 guidelines. In the 1996 guideline publication, “ACC/AHA
Guidelines for the Management of Patients with Acute Myocardial
Infarction,” the term acute coronary syndrome was used, reflecting
the emerging overarching concept that disruption of a vulnerable
or high-risk plaque causes an episode of ischemic discomfort (2).
Emphasis was placed on the 12-lead electrocardiogram (ECG) that
was used to categorize patients into 2 broad cohorts: those presenting
with ST elevation and those presenting without ST elevation (ultimately
diagnosed as unstable angina or non–Qwave myocardial infarction
(MI) depending on whether a biomarker of necrosis was detected in
the patient’s blood). The 1996 guidelines discussed the management
of both the ST-elevation and non–ST-elevation presentations
of the acute coronary syndromes. The same approach was taken in
the 1999 update of the guideline (also chaired by Dr. Ryan) that
was posted as an electronic update on the ACC and AHA
World Wide Web sites (3).
In parallel to the above efforts, in 1994, the Agency for Health
Care Policy and Research and the National Heart, Lung, and Blood
Institute jointly published guidelines for the diagnosis and management
of patients with unstable angina (Chairman, Dr. Eugene Braunwald).
In recognition of rapid advances in the understanding and management
of patients with acute coronary syndromes, the ACC/AHA Task Force
on Practice Guidelines convened a committee (also chaired by Dr.
Braunwald) to revise the 1994 unstable angina guideline. That committee
focused on patients presenting without ST elevation and introduced
the nomenclature of unstable angina/non–ST-elevation MI (UA/NSTEMI).
The “ACC/AHA Guidelines for the Management of Patients with
UA/NSTEMI” were published in 2000 and were updated in electronic
form in 2002 (4).
Although considerable improvement has occurred in the process of
care for patients with ST-elevation MI (STEMI), room for improvement
exists (5-7).
The purpose of the present guideline is to focus on the numerous
advances in the diagnosis and management of patients with STEMI
since 1999. This is reflected in the changed name of the guideline:
“ACC/AHA Guidelines for the Management of Patients With ST-Elevation
Myocardial Infarction” (Figure
1). It is recognized that there are areas of overlap among this
guideline on patients with STEMI, the guideline on patients with
UA/NSTEMI, and other guidelines. The committee has handled this
overlap by reiterating important concepts and recommendations in
this guideline and by providing cross-references
to other guidelines.
The final recommendations for indications for a diagnostic procedure,
a particular therapy, or an intervention in patients with STEMI
summarize both clinical evidence and expert opinion. Once recommendations
were written, a Classification of Recommendation and Level of Evidence
grade was assigned to each recommendation. Classification of Recommendations
and Level of Evidence are expressed in the ACC/AHA format as follows:
Classification of Recommendations
Class I: Conditions for which there is evidence and/or general agreement
that a given procedure or treatment is beneficial, useful, and effective.
Class II: Conditions for which there is conflicting evidence and/or
a divergence of opinion about the usefulness/efficacy of a procedure
or treatment.
Class
IIa: Weight of evidence/opinion is in favor of usefulness/efficacy.
Class IIb: Usefulness/efficacy is less well established by evidence/opinion.
Class
III: Conditions for which there is evidence and/or general agreement
that a procedure/ treatment is not useful/effective and in some
cases may be harmful.
Level
of Evidence
• Level of Evidence A: Data derived from multiple randomized
clinical trials or meta-analyses.
•
Level of Evidence B: Data derived from a single randomized trial,
or nonrandomized studies.
• Level of Evidence C: Only consensus opinion of experts,
case studies, or standard-of-care.
The schema for classification of recommendations and level of evidence
is summarized in Table 1, which
also illustrates how the grading system provides an estimate of
the size of the treatment effect and an estimate of the certainty
of the treatment effect.
The committee recognizes the importance of timely reperfusion for
patients with STEMI and spent considerable effort reviewing the
literature published since 1999 when formulating recommendations.
Along with reperfusion by pharmacological and catheter-based means,
the committee emphasized the use of established therapies such as
aspirin, beta-adrenoceptor–blocking agents, vasodilator therapy,
angiotensin converting enzyme (ACE) inhibitors, and cholesterol-lowering
therapy. To provide clinicians with a set of recommendations that
can easily be translated into the practice of caring for patients
with STEMI, this guideline is organized around the chronology of
the interface between the patient and the clinician (Figure
2) (8-10).
Thus, readers will find material on prevention of STEMI, patient
education, prehospital issues, initial recognition and management
in the emergency department (ED), hospital management, and long-term
management after treatment for the index STEMI event. The reorganization
of the material in this guideline along the timeline noted above
necessitated considerable modification of the sequence of text presented
in the 1996 and 1999 guidelines on AMI. Whenever possible, the writing
committee used the term STEMI rather than AMI. Given the reorganization
of the guideline along the chronology of clinical care of patients
with STEMI and the anticipated desire of readers to search the guideline
for specific advice on management of patients with STEMI at different
phases of their illness, in a few selected instances, recommendations
and, to a lesser extent, some portions of the text are repeated.
Although these guidelines on STEMI have been shaped largely within
the context of evidence-based medical practice, the committee clearly
understands that variations in inclusion and exclusion criteria
from one randomized trial to another impose some limitation on the
generalizability of their findings. Likewise, in its efforts to
reconcile conflicting data, the committee emphasized the importance
of properly characterizing the population under study.
Writing committee members were selected with attention to cardiovascular
subspecialties, broad geographical representation, and involvement
in academic medicine and primary practice, including neurology,
emergency medicine, and nursing. The Writing Committee on the Management
of Patients with ST-Elevation Myocardial Infarction also included
members of the ACCF Board of Governors, the American Academy of
Family Physicians (AAFP), and the Canadian Cardiovascular Society
(CCS).
The
committee conducted comprehensive searching of the scientific and
medical literature on AMI, with special emphasis on STEMI. Literature
searching was limited to publications on humans and in English from
1990 to 2004. In addition to broad-based searching on MI, specific
targeted searches were performed on MI and the following subtopics:
9-1-1, patient delays, emergency medical services (EMS), prehospital
fibrinolysis, prehospital ECG, ED, supplemental oxygen, nitroglycerin,
ASA, clopidogrel, arrhythmia, reperfusion, fibrinolysis/fibrinolytic
therapy, angioplasty, stent, coronary artery bypass graft surgery
(CABG), glycoprotein (GP) IIb/IIIa, pericarditis, beta-blockers,
ischemia, intraarterial pressure monitoring, ACE inhibitors, amiodarone,
procainamide, lidocaine, electrical cardioversion, atropine, temporary
pacing, transvenous pacing, permanent pacing, cardiac repair, heparin,
low-molecular-weight heparin (LMWH), unfractionated heparin (UFH),
ramipril, calcium channel blockers, verapamil, nifedipine, magnesium,
stress ECG, invasive strategy, secondary prevention, statins, and
cholesterol. The complete list of keywords is beyond the scope of
this section. The committee reviewed all compiled reports from computerized
searches and conducted additional searching by hand. Literature
citations were generally restricted to published manuscripts appearing
in journals listed in Index Medicus. Because of the scope and importance
of certain ongoing clinical trials and other emerging information,
published abstracts were cited when they were the only published
information available.
This document was reviewed by 3 outside reviewers nominated by the
ACC and 3 outside reviewers nominated by the AHA, as well as 1 reviewer
each from the AAFP and the CCS, and 58 individual content reviewers.
(See Appendix 2 for details.)
This document was approved for publication by the governing bodies
of the American College of Cardiology Foundation and the American
Heart Association and endorsed by the Canadian Cardiovascular Society.
These guidelines will be reviewed annually by the ACC/AHA Task Force
on Practice Guidelines and will be considered current unless they
are revised or withdrawn from distribution.
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