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Clinical practice guidelines serve as an educational reference, and do not supersede
the clinical judgment of the treating physician with respect to appropriate and necessary
care for an individual patient. In the event that HMSA policies differ from the clinical
practice guidelines, for benefit purposes, HMSA policies shall supersede the clinical
practice guidelines.
Guideline summary
This guideline focuses on secondary prevention of acute myocardial infarction.
Recommended medical therapy for patients with previous AMI:
ASA
ACE inhibitors
Beta-blockers
Statin therapy for LDL < 100 mg/dL
Introduction
Acute myocardial infarction (AMI) is one of the most common diagnoses of hospitalized
patients in industrialized countries. In the United States, approximately 1.5 million
myocardial infarctions occur each year. The mortality rate of AMI is approximately 30
percent, with more than half of these deaths occurring before the stricken individual
reaches the hospital.
In recent decades in-hospital mortality has decreased. Approximately 1 in 25 patients
who survives the initial hospitalization dies in the first year after myocardial infarction.
Survival is markedly decreased in elderly patients older than 65 whose mortality rate is
20% at one month and 35% at one year. Secondary prevention measures have been
shown to affect the mortality rate in patients who have experienced a myocardial
infarction.
Goals/desired outcomes
Increase the timely initiation of treatment to reduce post-infarction mortality in patients
with AMI. Possible measurable results:
Percentage of patients with AMI receiving beta-blockers initiated prior to discharge, for
whom this treatment is appropriate.
Percentage of patients with AMI placed on prophylactic aspirin initiated prior to
discharge, for whom this treatment is appropriate.
Percentage of patients with AMI receiving ACE inhibitors initiated prior to discharge, for
whom this treatment is appropriate.
Percentage of patients with AMI receiving statin agent initiated prior to discharge, for
whom this treatment is appropriate.
Treatment
The approach to secondary prevention for patients with a previous AMI but without a
history of percutaneous transluminal coronary angioplasty (PTCA) or coronary artery
bypass graft (CABG) includes attention to indicated medications, management of
comorbid conditions and counseling about lifestyle changes. The following is a list of
recommended therapies for patients who have had a previous AMI.
The American Heart Association and American College of Cardiology recommend
influenza immunization with inactivated vaccine (administered intra-muscularly) as part
of comprehensive secondary prevention in persons with coronary and other
atherosclerotic vascular diseases.
Indicated medications
Beta- blockers: Beta-blockers reduce future events in post-AMI patients and in patients
with revascularization. The benefit of beta-blockers occurs in patients with diabetes or
reactive airways. Patients with comorbid conditions (diabetes or chronic obstructive
pulmonary disease) should be tried on beta-blockers, with the medication discontinued
only if there are clinical side effects of the therapy. Propranolol, timolol and metoprolol
have been used in the largest randomized controlled trials, but there is no evidence that
the benefits are not a class effect. Patients who prove intolerant of a beta-blocker after a
large infarction should be reconsidered for beta-blocker therapy after discharge.
Acetylsalicylic acid: As treatment, acetylsalicylic acid (ASA) has been shown to
reduce events in the primary prevention of heart attacks. Six randomized studies have
established an approximate 13 percent relative risk reduction in post-infarct patients
with long-term use. The secondary prevention dosage range was 300 to 1500 mg/day.
A more recent study shows a 34 percent improvement in nonfatal AMIs and death using
a dose of 75 mg/day. The lower dose is as effective with fewer side effects and is
generally the recommended dose. Studies have not shown that other antiplatelet agents
have advantages over aspirin.
ACE inhibitors: The long-term use of an angiotensin converting enzyme (ACE)
inhibitor reduces mortality in post-AMI patients. There appears to be a beneficial
physiologic effect of the post-MI cardiac remodeling. Current literature supports the use
of ACE inhibitors in all patients with MIs or decreased left ventricular ejection fraction.
Maximum risk reduction is in patients with congestive heart failure. If patients are unable
to tolerate ACE inhibitors, angiotensin receptor blockers should be used in addition to
beta-blockers, when possible.
Statin therapy: The large majority of patients who have an acute MI have high serum
lipid levels. Lipid treatment, including administration of statins, should be addressed as
soon as possible. A patient’s lipid status should be determined within the first 24 hours.
If the LDL level is > 100 mg / dL, the patient should be started on a statin.
If patient has heart disease, diabetes, or a risk score higher than 20% in which they are
at high risk, LDL goal is less than 100 mg/dL*.
(*If at very high risk or if patient has heart disease alone, set LDL goal even lower, to
less than 70 mg/dL.)
Aspirin: Patients with chest pain symptoms in the emergency department receive early
therapy including intravenous access, oxygen, nitroglycerin, morphine and a chewable
aspirin on arrival.
FDA drug warning: Reduced effectiveness of Plavix in patients who are poor
metabolizers of the drug.
Management of comorbid conditions
Hypertension - evaluation and treatment: The goal for post-AMI patients should be
blood pressure <140/90, or <130/80 in diabetic patients. (See Hypertension.)
Hyperlipidemia - evaluation and treatment: The goal for post-AMI patients should be
LDL below 100 mg/dL.
Diabetes - evaluation and treatment: The goal for post-AMI patients should be HbA1c
below 7 percent. (See Diabetes, Hawaii State Practice Recommendations)
Obesity: Patients should be counseled to reduce weight to a BMI of 18.5 - 24.9 kg/ m2.
Hormonal Replacement Therapy (HRT) after AMI: Postmenopausal women who
already are taking HRT with estrogen plus progestin should stop HRT after acute
events.
Counseling about lifestyle changes
Recommendations for appropriate use of cardiac rehabilitation should be made at
discharge.
Smoking cessation: Patients who smoke need to be continually counseled to stop
smoking. (See Smoking Cessation)
Exercise: Patients, particularly those who are obese, should initiate and maintain an
exercise regimen in accordance with their current health conditions and under their
physician’s guidance. See Primary Preventive Services - Men, Women and Children
Diet: It is generally prudent to recommend a diet low in salt and with less than 30
percent of calories from fat.
Clinical practice guidelines serve as an educational reference, and do not supersede
the clinical judgment of the treating physician with respect to appropriate and necessary
care for an individual patient. In the event that HMSA policies differ from the clinical
practice guidelines, for benefit purposes, HMSA policies shall supersede the clinical
practice guidelines.
Sources
Institute for Clinical Systems Improvement. (2009). Diagnosis and treatment of chest
pain and acute coronary syndrome. Copyright 2008. Institute for Clinical Systems
Improvement. Used with Permission.
Institute for Clinical Systems Improvement. (2009). Lipid Management in Adults.
Copyright 2009. Institute for Clinical Systems Improvement. Used with Permission.
References
Smith SC, Blair SN, Bonow RO, Brass LM, Cerqueira MD, Dracup K, Fuster V, Gotto A,
Grundy SM, Miller NH, Jacobs A, Jones D, Krauss RM, Mosca L, Ockene I, Pasternak
RC, Pearson T, Pfeffer MA, Starke RD, Taubert KA. (2001). AHA/ACC Guidelines for
preventing heart attack and death in patients with atherosclerotic cardiovascular
disease: 2001 update: A statement for health care professionals from the American
Heart Association and the American College of Cardiology. Circulation, 104:1577.
Braunwald E, Antman EM. (1997). Evidence-based coronary care. Annals of Internal
Med, 126(7):551-3.
American Heart Association, American College of Cardiology. (1999). 1999 update:
Guidelines for the management of patients with acute myocardial infarction: Executive
summary and recommendations. Circulation, 100:1016-30.
Guideline review date: July 13, 2010
Rev#: Date:
Nature of Change:
1.0
01/21/2009 Treatment section, added: The American Heart Association and
American College of Cardiology recommend influenza immunization
with inactivated vaccine (administered intra-muscularly) as part of
comprehensive secondary prevention in persons with coronary and
other atherosclerotic vascular diseases. Reference section, added
reference #5 on ACC and AHA article on influenza vaccine as
secondary prevention for cardiovascular disease. Updated
Guideline review date.
1.1
11/02/2010 Minor updates to document and statin therapy section.
02/15/2005
First
Published:
11/02/2010
Latest
Revision:
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CPT codes and descriptions contained herein are copyright 2009, American Medical Association. All
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