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3. Management Before STEMI
One third of patients who experience STEMI will die within 24 hours
of the onset of ischemia, and many of the survivors will suffer
significant morbidity (24). For
many patients, the first manifestation of CHD will be sudden death.
The major risk factors for development of CHD and STEMI are well
established. Clinical trials have demonstrated that modification
of those risk factors can prevent the development of CHD (primary
prevention) or reduce the risk of experiencing STEMI in patients
who have CHD (secondary prevention). All practitioners should emphasize
prevention and refer patients to primary care providers for appropriate
long-term preventive care. In addition to internists and family
physicians, cardiologists have an important leadership role in primary
(and secondary) prevention efforts.
3.1. Identification of Patients at
Risk of STEMI
Class I
1. Primary care providers should evaluate the presence and status
of control of major risk factors for CHD for all patients at regular
intervals (approximately every 3 to 5 years). (Level of Evidence:
C)
2. Ten-year risk (National Cholesterol Education Program [NCEP]
global risk) of developing symptomatic CHD should be calculated
for all patients who have 2 or more major risk factors to assess
the need for primary prevention strategies (59).
(Level of Evidence: B)
3. Patients with established CHD should be identified for secondary
prevention, and patients with a CHD risk equivalent (e.g., diabetes
mellitus, chronic kidney disease, or 10-year risk greater than 20%
as calculated by Framingham equations) should receive equally intensive
risk factor intervention as those with clinically apparent CHD.
(Level of Evidence: A)
Major
risk factors for developing CHD (i.e., smoking, family history,
adverse lipid profiles, and elevated blood pressure) have been established
from large long-term epidemiological studies (59,60).
These risk factors are predictive for most populations in the United
States. Primary prevention interventions aimed at these risk factors
are effective when used properly. They can also be costly in terms
of primary care physician time, diversion of attention from other
competing and important healthcare needs, and expense, and they
may not be effective unless targeted at higher-risk patients (61).
It is therefore important for primary care providers to make identifying
patients at risk, who are most likely to benefit from primary prevention,
a routine part of everyone’s health care. The Third Report
of the NCEP provides guidance on identifying such patients (59).
Patients with 2 or more risk factors who are at increased 10-year
risk will have the greatest benefit from primary prevention, but
any individual with a single elevated risk factor is a candidate
for primary prevention. Waiting until the patient develops multiple
risk factors and increased 10-year risk contributes to the high
prevalence of CHD in the United States (59,62).
Such patients should have their risk specifically calculated, by
any of the several available valid prognostic tools available in
print (59,63),
on the internet (64), or for use
on a personal computer or PDA (Personal Digital Assistant) (59).
Patients’ specific risk levels determine the absolute risk
reductions they can obtain from preventive interventions and guide
selection and prioritization of those interventions. For example,
target levels for lipid lowering and for antihypertensive therapy
vary by patients’ baseline risk. A specific risk number can
also serve as a powerful educational intervention to motivate lifestyle
changes (65).
3.2. Interventions to Reduce Risk
of STEMI
The benefits of prevention of STEMI in patients with CHD are well
documented and of large magnitude (62,66-68).
Patients with established CHD should be identified for secondary
prevention, and patients with a CHD risk equivalent (e.g., diabetes
mellitus, chronic kidney disease, or 10-year risk greater than 20%
as calculated by Framingham equations) should receive equally intensive
risk factor intervention for high-risk primary prevention regardless
of sex (69). Patients with diabetes
and peripheral vascular disease have baseline risks of STEMI similar
to patients with known CHD, as do patients with multiple risk factors
predicting calculated risk of greater than 20% over 10 years as
estimated by the Framingham equations (59).
Such patients should be considered to have the risk equivalents
of CHD, and they can be expected to have an absolute benefit similar
to those with established CHD.
All patients who smoke should be encouraged to quit and should be
provided with help in quitting at every opportunity. Even a single
recommendation by a clinician to quit smoking can have a meaningful
impact on the rate of cessation of smoking. The most effective strategies
for encouraging quitting are those that identify patients’
level or stage of readiness and provide information, support, and,
if necessary, pharmacotherapy targeted at the individual’s
readiness and specific needs (66,70).
Pharmacotherapy may include nicotine replacement or withdrawal-relieving
medication such as bupropion. Most patients require several attempts
before succeeding in quitting permanently. Additional discussion
in this area can be found in the ACC/AHA 2002 Guideline Update for
the Management of Patients With Chronic Stable Angina (71).
All patients should be instructed in and encouraged to maintain
appropriate low-saturated-fat and low-cholesterol diets high in
soluble (viscous) fiber and rich in vegetables, fruits, and whole
grains. The statin drugs have the best outcome evidence supporting
their use and should be the mainstay of pharmacological intervention
(62). The appropriate levels for
lipid management are dependent on baseline risk; the reader is referred
to the NCEP report for details (59).
Primary
prevention patients with high blood pressure should be treated according
to the recommendations of the Seventh Joint National Committee on
High Blood Pressure (JNC-7) (72,73).
Specific treatment recommendations are based on the level of hypertension
and the patient’s other risk factors. A diet low in salt and
rich in vegetables, fruits, and low-fat dairy products should be
encouraged for all hypertensive patients, as should a regular aerobic
exercise program. Most patients will require more than 1 medication
to achieve blood pressure control, and pharmacotherapy should begin
with known outcome-improving medications (primarily thiazide diuretics
as first choice, with the addition of betablockers, ACE inhibitors,
angiotensin receptor blockers, and long-acting calcium channel blockers)
(72,74).
Systolic hypertension is a powerful predictor of adverse outcome,
particularly among the elderly, and should be treated even if diastolic
pressures are normal (75).
Aspirin prophylaxis can uncommonly result in hemorrhagic complications
and should only be used in primary prevention when the level of
risk justifies it. Patients whose 10-year risk of CHD is 6% or more
are most likely to benefit, and aspirin 75 to 162 mg/d as primary
prophylaxis should be discussed with such patients (76-79).
3.3.
Patient Education for Early Recognition and Response to STEMI
Class I
1. Patients with symptoms of STEMI (chest discomfort with or without
radiation to the arms[s], back, neck, jaw, or epigastrium; shortness
of breath; weakness; diaphoresis; nausea; lightheadedness) should
be transported to the hospital by ambulance rather than by friends
or relatives. (Level of Evidence: B)
2. Healthcare providers should actively address the following issues
regarding STEMI with patients and their families:
a. The patient’s heart attack risk (Level of Evidence:
C)
b. How to recognize symptoms of STEMI (Level of Evidence: C)
c. The advisability of calling 9-1-1 if symptoms are unimproved
or worsening after 5 minutes, despite
feelings of uncertainty about the symptoms and fear of potential
embarrassment (Level of Evidence: C)
d. A plan for appropriate recognition and response to a potential
acute cardiac event, including the phone number to access EMS, generally
9-1-1 (80) (Level of Evidence:
C)
3. Healthcare providers should instruct patients for whom nitroglycerin
has been prescribed previously to take ONE nitroglycerin dose sublingually
in response to chest discomfort/pain. If chest discomfort/pain is
unimproved or worsening 5 minutes after 1 nitroglycerin dose has
been taken, it is recommended that the patient or family member/friend
call 9-1-1 immediately
to access EMS. (Level of Evidence: C)
Morbidity and mortality from STEMI can be reduced significantly
if patients and bystanders recognize symptoms early, activate the
EMS system, and thereby shorten the time to definitive treatment.
Patients with possible symptoms of STEMI should be transported to
the hospital by ambulance rather than by friends or relatives, because
there is a significant association between arrival at the ED by
ambulance and early reperfusion therapy (81-84).
In addition, emergency medical technicians (EMTs) and paramedics
can provide life-saving interventions (e.g., early cardiopulmonary
resuscitation [CPR] and defibrillation) if the patient develops
cardiac arrest. Approximately 1 in every 300 patients with chest
pain transported to the ED by private vehicle goes into cardiac
arrest en route (85).
Several studies have confirmed that patients with STEMI usually
do not call 9-1-1 and are not transported to the hospital by ambulance.
A follow-up survey of chest pain patients presenting to participating
EDs in 20 US communities who were either released or admitted to
the hospital with a confirmed coronary event revealed that the average
proportion of patients who used EMS was 23%, with significant geographic
difference (range 10% to 48%). Most patients were driven by someone
else (60%) or drove themselves to the hospital (16%) (86).
In the National Registry of Myocardial Infarction 2, just over half
(53%) of patients with STEMI were transported to the hospital by
ambulance (82).
Even in areas of the country that have undertaken substantial public
education on warning signs of STEMI and the need to activate the
EMS system rapidly, either there were no increases in EMS use (87-91)
or EMS use increased (as a secondary outcome measure) but was still
suboptimal, with a 20% increase from a baseline of 33% in all 20
communities in the Rapid Early Action for Coronary Treatment (REACT)
study (92) and an increase from
27% to 41% in southern Minnesota after a community campaign (93).
Given the importance of patients using EMS for possible acute cardiac
symptoms, communities, including medical providers, EMS systems,
healthcare insurers, hospitals, and policy makers at the state and
local level, need to have agreed-upon emergency protocols to ensure
patients with possible heart attack symptoms will be able to access
9-1-1 without barriers, to secure their timely evaluation and treatment
(94).
As
part of making a plan with the patient for timely recognition and
response to an acute event, providers should review instructions
for taking nitroglycerin in response to chest discomfort/pain. If
a patient has previously been prescribed nitroglycerin, it is recommended
that the patient be advised to take ONE nitroglycerin dose sublingually
promptly for chest discomfort/pain. If symptoms are unimproved or
worsening 5 minutes after ONE nitroglycerin dose has been taken,
it is also recommended that the patient be instructed to call 9-1-1
immediately to access EMS. Although the traditional recommendation
is for patients to take 1 nitroglycerin dose sublingually, 5 minutes
apart, for up to 3 doses before calling for emergency evaluation,
this recommendation has been modified by the writing committee to
encourage earlier contacting of EMS by patients with symptoms suggestive
of STEMI. Self-treatment with prescription medication, including
nitrates, and with nonprescription medication (e.g., antacids) has
been documented as a frequent cause of delay among patients with
STEMI, including those with a history of MI or angina (95,96).
Both the rate of use of these medications and the number of doses
taken were positively correlated with delay time to hospital arrival
(95).
Family members, close friends, or advocates should be included in
these discussions and enlisted as reinforcement for rapid action
when the patient experiences symptoms of a possible STEMI (3,80,97)
(Figure 4). For patients known
to their providers to have frequent angina, physicians may consider
a selected, more tailored message that takes into account the frequency
and character of the patient’s angina and their typical time
course of response to nitroglycerin. Avoidance of patient delay
associated with self-medication and prolonged re-evaluation of symptoms
is paramount.
Taking an aspirin in response to acute symptoms by patients has
been reported to be associated with a delay in calling EMS (86).
Patients should focus on calling 9-1-1, which activates the EMS
system, where they may receive instructions from emergency medical
dispatchers to chew aspirin (162 to 325 mg) while emergency personnel
are en route, or emergency personnel can give an aspirin while transporting
the patient to the hospital (98). Alternatively,
patients may receive an aspirin as part of their early treatment
once they arrive at the hospital if it has not been given in the
prehospital setting (3).
Providers should target those patients at increased risk for STEMI,
focusing on patients with known CHD, peripheral vascular disease,
or cerebral vascular disease, those with diabetes, and patients
with 10-year Framingham risk of CHD of greater than 20% (99).
They should stress that the chest discomfort will usually not be
dramatic, such as is commonly misrepresented on television or in
the movies as a “Hollywood heart attack.” Providers
should also describe anginal equivalents and the commonly associated
symptoms of STEMI (e.g., shortness of breath, a cold sweat, nausea,
or lightheadedness) in both men and women (83),
as well as the increased frequency of atypical symptoms in elderly
patients (100).
In
September 2001, the NHAAP and the AHA launched a campaign urging
patients and providers to “Act in Time to Heart Attack Signs”
(101). The campaign urges both
men and women who feel heart attack symptoms or observe the signs
in others to wait no more than a few minutes, 5 minutes at most,
before calling 9-1-1 (101,102).
Campaign materials point out that patients can increase their chance
of surviving a STEMI by learning the symptoms and filling out a
survival plan. They also are advised to talk with their doctor about
heart attack and how to reduce their risk of having one. The patient
materials include a free brochure about symptoms and recommended
actions for survival, in English (103)
and Spanish (104), as well as a
free wallet card that can be filled in with emergency medical information
(105). Materials geared directly
to providers include a Patient Action Plan Tablet (106),
which contains the heart attack warning symptoms and steps for developing
a survival plan individualized with the patient’s name; a
quick reference card for addressing common patient questions about
seeking early treatment to survive a heart attack (107),
including a palm pilot version (108);
and a warning signs wall chart (109).
These materials and others are available on the “Act in Time”
Web page (www.nhlbi.nih.gov/actintime)
(51,101)
(Figure 5).
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