Antman
et al., Management
of Patients With STEMI: Executive Summary
J
Am Coll Cardiol 2004;44:671-719
ACC/AHA
Guidelines for the Management of Patients With ST-Elevation Myocardial
Infarction—Executive Summary
A
Report of the American College of Cardiology/American Heart Association
Task Force on Practice Guidelines (Writing Committee to Revise the
1999 Guidelines for the Management of Patients With Acute Myocardial
Infarction)
Developed
in Collaboration With the Canadian Cardiovascular Society
Initial
Recognition and Management in the Emergency Department
A. Optimal Strategies for Emergency Department
Triage
Class I
1. Hospitals should establish multidisciplinary teams (including
primary care physicians, emergency medicine physicians, cardiologists,
nurses, and laboratorians) to
develop guideline-based, institution-specific written protocols
for triaging and managing patients who are seen in the prehospital
setting or present to the ED with symptoms suggestive of STEMI.
(Level of Evidence: B)
B. Initial Patient Evaluation
Class
I
1. The delay from patient contact with the healthcare system (typically,
arrival at the ED or contact with paramedics)
to initiation of fibrinolytic therapy should be less than 30 minutes.
Alternatively, if PCI is chosen, the delay from patient contact
with the ealthcare system (typically, arrival at the ED or contact
with paramedics) to balloon inflation should be less than 90 minutes.
(Level of Evidence: B)
2. The choice of initial STEMI treatment should be made by the emergency
medicine physician on duty based on a predetermined, institution-specific,
written protocol that is a collaborative effort of cardiologists
(both those involved in coronary care unit management and interventionalists),
emergency physicians, primary care physicians, nurses, and other
appropriate personnel. For cases in which the initial diagnosis
and treatment plan is unclear to the emergency physician or is not
covered directly by the agreed-on protocol, immediate cardiology
consultation is advisable. (Level of Evidence:
C)
Regardless
of the approach used, all patients presenting to the ED with chest
discomfort or other symptoms suggestive of STEMI or unstable angina
should be considered high priority triage cases and should be evaluated
and treated based on a predetermined, institution-specific chest
pain protocol. The goal for patients with STEMI should be to achieve
a door-to-needle time within 30 minutes and a door-to-balloon time
within 90 minutes (Figure 1) (25).
1.
History
Class I
1. The targeted history of STEMI patients taken in the ED should
ascertain whether the patient has had prior episodes of myocardial
ischemia such as stable or unstable angina, MI, CABG, or PCI. Evaluation
of the patient’s complaints should focus on chest discomfort,
associated symptoms, sex- and age-related differences in presentation,
hypertension, diabetes mellitus, possibility of aortic dissection,
risk of bleeding, and clinical cerebrovascular disease (amaurosis
fugax, face/limb weakness or clumsiness, face/limb numbness or sensory
loss, ataxia, or vertigo). (Level of Evidence: C)
2.
Physical Examination
Class
I
1. A physical examination should be performed to aid in the diagnosis
and assessment of the extent, location, and presence of complications
of STEMI. (Level of Evidence: C)
2. A brief, focused, and limited neurological examination to look
for evidence of prior stroke or cognitive deficits should be performed
on STEMI patients before administration of fibrinolytic therapy.
(Level of Evidence: C)
A brief physical examination may promote rapid triage, whereas a
more detailed physical examination aids in the differential diagnosis
and is useful for assessing the extent, location, and presence of
complications of STEMI.
3.
Electrocardiogram
Class I
1. A 12-lead ECG should be performed and shown to an experienced
emergency physician within 10 minutes of ED arrival for all patients
with chest discomfort (or anginal equivalent) or other symptoms
suggestive of STEMI. (Level of Evidence: C)
2. If the initial ECG is not diagnostic of STEMI but the patient
remains symptomatic, and there is a high clinical suspicion for
STEMI, serial ECGs at 5- to 10-minute intervals or continuous 12-lead
ST-segment monitoring should be performed to detect the potential
development of ST elevation. (Level of Evidence: C)
3. In patients with inferior STEMI, right-sided ECG leads should
be obtained to screen for ST elevation suggestive of right ventricular
(RV) infarction. (See Section 7.6.6 of the full-text guidelines
and the ACC/AHA/ASE 2003 Guideline Update for the Clinical Application
of Echocardiography.) (Level of Evidence: B)
The 12-lead ECG in the ED is at the center of the therapeutic decision
pathway because of the strong evidence that ST-segment elevation
identifies patients who benefit from reperfusion therapy (28).
4. Laboratory Examinations
Class I
1. Laboratory examinations should be performed as part of the management
of STEMI patients but should not delay the implementation of reperfusion
therapy. (Level of Evidence: C)
In addition to serum cardiac biomarkers for cardiac damage, several
routine evaluations have important implications for management of
patients with STEMI. Although these studies
should be ordered when the patient is first seen, therapeutic decisions
should not be delayed until results are obtained because of the
crucial role of time to therapy in STEMI.
5. Biomarkers of Cardiac Damage
Class I
1. Cardiac-specific troponins should be used as the optimum biomarkers
for the evaluation of patients with STEMI who have coexistent skeletal
muscle injury. (Level of Evidence: C)
2. For patients with ST elevation on the 12-lead ECG and symptoms
of STEMI, reperfusion therapy should be initiated as soon as possible
and is not contingent on a biomarker assay. (Level of Evidence:
C)
Class IIa
1. Serial biomarker measurements can be useful to provide supportive
noninvasive evidence of reperfusion of the infarct artery after
fibrinolytic therapy in patients not undergoing angiography within
the first 24 hours after fibrinolytic therapy. (Level of Evidence:
B)
Class
III
1. Serial biomarker measurements should not be relied on
to diagnose reinfarction within the first 18 hours after the onset
of STEMI. (Level of Evidence: C)
For patients with ST-segment elevation, the diagnosis of
STEMI is secure; initiation of reperfusion therapy should not be
delayed to wait for the results of a cardiac biomarker assay (29).
Quantitative analysis of cardiac biomarker measurements provides
prognostic information and a noninvasive assessment of the likelihood
that the patient has undergone successful reperfusion when fibrinolytic
therapy is administered.
a. Bedside Testing for Serum
Cardiac Biomarkers
Class I
1. Although handheld bedside (point-of-care) assays may
be used for a qualitative assessment of the presence of an elevated
level of a serum cardiac biomarker, subsequent measurements of cardiac
biomarker levels should be performed with a quantitative test. (Level
of Evidence: B)
2. For patients with ST elevation on the 12-lead ECG and symptoms
of STEMI, reperfusion therapy should be initiated as soon as possible
and is not contingent on a bedside biomarker assay. (Level of
Evidence: C)
A positive bedside test should be confirmed by a conventional quantitative
test. However, reperfusion therapy should not be delayed to wait
for the results of a quantitative assay.
6. Imaging
Class I
1. Patients with STEMI should have a portable chest X-ray, but this
should not delay implementation of reperfusion therapy (unless a
potential contraindication, such as aortic dissection, is suspected).
(Level of Evidence: C)
2. Imaging studies such as a high-quality portable chest X-ray,
transthoracic and/or transesophageal echocardiography, and a contrast
chest computed tomographic scan or a MRI scan should be used to
differentiate STEMI from aortic dissection in patients for whom
this distinction is initially unclear. (Level of Evidence: B)
Class IIa
1. Portable echocardiography is reasonable to clarify the
diagnosis of STEMI and allow risk stratification of patients with
chest pain on arrival at the ED, especially if the diagnosis of
STEMI is confounded by left bundlebranch block (LBBB) or pacing,
or there is suspicion of posterior STEMI with anterior ST depressions.
(See Section 7.6.7 Mechanical Causes of Heart Failure/Low Output
Syndrome of the full-text guidelines.) (Level of Evidence: B)
Class III
1. Single-photon emission computed tomography
(SPECT) radionuclide imaging should not be performed to diagnose
STEMI in patients for whom the diagnosis of STEMI is evident on
the ECG. (Level of Evidence: B)
C.
Management
1. Routine Measures
a. Oxygen
Class I
1. Supplemental oxygen should be administered to patients
with arterial oxygen desaturation (SaO2 less than 90%). (Level
of Evidence: B)
Class IIa
1. It is reasonable to administer supplemental oxygen to
all patients with uncomplicated STEMI during the first 6 hours.
(Level of Evidence: C)
b.
Nitroglycerin
Class I
1. Patients with ongoing ischemic discomfort should receive
sublingual nitroglycerin (0.4 mg) every 5 minutes for a total of
3 doses, after which an assessment should be made about the need
for intravenous nitroglycerin. (Level of Evidence: C)
2. Intravenous nitroglycerin is indicated for relief of ongoing
ischemic discomfort, control of hypertension, or management of pulmonary
congestion. (Level of Evidence: C)
Class III
1. Nitrates should not be administered to patients with systolic
blood pressure less than 90 mm Hg or greater than or equal to 30
mm Hg below baseline, severe bradycardia (less than 50 bpm), tachycardia
(more than 100 bpm), or suspected RV infarction. (Level of Evidence:
C)
2. Nitrates should not be administered to patients who have received
a phosphodiesterase inhibitor for erectile dysfunction within the
last 24 hours (48 hours for tadalafil). (Level of Evidence:
B)
Nitroglycerin may be administered to relieve ischemic pain and is
clearly indicated as a vasodilator in patients with STEMI associated
with left ventricular (LV) failure. Nitrates in all forms should
be avoided in patients with initial systolic blood pressures less
than 90 mm Hg or greater than or equal to 30 mm Hg below baseline,
in patients with marked bradycardia or tachycardia (30),
and in patients with known or suspected RV infarction. In view of
their marginal treatment benefits, nitrates should not be used if
hypotension limits the administration of beta-blockers, which have
more powerful salutary effects.
c. Analgesia
Class I
1. Morphine sulfate (2 to 4 mg IV with increments of 2 to
8 mg IV repeated at 5- to 15-minute intervals) is the analgesic
of choice for management of pain associated with STEMI. (Level
of Evidence: C)
d.
Aspirin
Class I
1. Aspirin should be chewed by patients who have not taken
aspirin before presentation with STEMI. The initial dose should
be 162 mg (Level of Evidence: A) to 325 mg (Level of
Evidence: C).
Although some trials have used enteric-coated aspirin for initial
dosing, more rapid buccal absorption occurs with non–enteric-coated
aspirin formulations.
In a dose of 162 mg or more, aspirin produces a rapid clinical antithrombotic
effect caused by immediate and near-total inhibition of thromboxane
A2 production. Aspirin now forms part of the early management of
all patients with suspected STEMI and should be given promptly,
and certainly within the first 24 hours, at a dose between 162 and
325 mg and continued indefinitely at a daily dose of 75 to 162 mg
(31). Although some trials have
used enteric-coated aspirin for initial dosing, more rapid buccal
absorption occurs with non–enteric-coated formulations (32).
e. Beta-Blockers
Class I
1. Oral beta-blocker therapy should be administered promptly
to those patients without a contraindication, irrespective of concomitant
fibrinolytic therapy or performance of primary PCI. (Level of
Evidence: A)
Class IIa
1. It is reasonable to administer IV beta-blockers promptly
to STEMI patients without contraindications, especially if a tachyarrhythmia
or hypertension is present. (Level of Evidence: B)
Immediate beta-blocker therapy appears to reduce the magnitude of
infarction and incidence of associated complications in subjects
not receiving concomitant fibrinolytic therapy, the rate of reinfarction
in patients receiving fibrinolytic therapy, and the frequency of
life-threatening ventricular tachyarrhythmias.
f. Reperfusion
GENERAL CONCEPTS
Class I
1. All STEMI patients should undergo rapid evaluation for
reperfusion therapy and have a reperfusion strategy implemented
promptly after contact with the medical system. (Level of Evidence:
A)
Evidence exists that expeditious restoration of flow in the obstructed
infarct artery after the onset of symptoms in STEMI patients is
a key determinant of short- and long-term outcomes regardless of
whether reperfusion is accomplished by fibrinolysis or PCI (33–35).
As discussed previously (also see Section 4.1 of the full- text
guidelines), efforts should be made to shorten the time from recognition
of symptoms by the patient to contact with the medical system. All
healthcare providers caring for STEMI patients from the point of
entry into the medical system must recognize the need for rapid
triage and implementation of care in a fashion analogous to the
handling of trauma patients. When considering recommendations for
timely reperfusion of STEMI patients, the Writing
Committee reviewed data from clinical trials, focusing particular
attention on enrollment criteria for selection of patients for randomization,
actual times reported in the trial report rather than simply the
allowable window specified in the trial protocol, treatment effect
of the reperfusion strategy on individual components of a composite
primary end point (eg, mortality, recurrent nonfatal infarction),
ancillary therapies (eg, antithrombin and antiplatelet agents),
and the interface between fibrinolysis and referral for angiography
and revascularization. When available, data from registries were
also reviewed to assess the generalizability of observations from
clinical trials of reperfusion to routine practice. Despite the
wealth of reports on reperfusion for STEMI, it is not possible to
produce a simple algorithm, given the heterogeneity of patient profiles
and availability of resources in various clinical settings at various
times of day. This section introduces the recommendations for an
aggressive attempt to minimize the time from entry into the medical
system to implementation of a reperfusion strategy using the concept
of medical system goals. More detailed discussion of these goals
and the issues to be considered in selecting the type of reperfusion
therapy are discussed in the Selection of Reperfusion Therapy section
of VI.C.1.f (Section 6.3.1.6.2 of the full-text guidelines), followed
by a discussion of available resources.
The medical system goal is to facilitate rapid recognition and treatment
of patients with STEMI such that door-to-needle (or medical contact–to-needle)
time for initiation of fibrinolytic therapy can be achieved within
30 minutes or that door-toballoon (or medical contact–to-balloon)
time for PCI can be kept under 90 minutes. These goals may not be
relevant for the patients with an appropriate reason for delay,
such as uncertainty about the diagnosis (particularly for the use
of fibrinolytic therapy), need for the evaluation and treatment
of other lifethreatening conditions (eg, respiratory failure), or
delays associated with the patient’s informed choice to have
more time to consider the decision. In the absence of such types
of circumstances, the emphasis is on having a system in place such
that when a patient with STEMI presents for medical care, reperfusion
therapy is able to be provided as soon as possible within these
time periods. Because there is not considered to be a threshold
effect for the benefit of shorter times to reperfusion, these goals
should not be understood as “ideal” times but the longest
times that should be considered acceptable. Systems that are able
to achieve even more rapid times for patients should be encouraged.
Also, this goal should not be perceived as an average performance
standard but a goal of an early treatment system that every hospital
should seek for every appropriate patient.
SELECTION OF REPERFUSION STRATEGY.
Several issues should be considered in selecting the type of reperfusion
therapy.
-
Time From Onset of Symptoms. Time from onset of symptoms
to fibrinolytic therapy is an important predictor of MI size and
patient outcome (36). The efficacy
of fibrinolytic agents in lysing thrombus diminishes with the
passage of time (37). Fibrinolytic
therapy administered within the first 2 hours (especially the
first hour) can occasionally abort MI and dramatically reduce
mortality (23,38).
In contrast, the ability to produce a patent infarct artery is
much less dependent on symptom duration in patients undergoing
PCI. Several reports claim no influence of time delay on mortality
rates when PCI is performed after 2 to 3 hours of symptom duration
(39,40).
Importantly, after adjustment for baseline characteristics, time
from symptom onset to balloon inflation is significantly correlated
with 1-year mortality in patients undergoing primary PCI for STEMI
(41). The Task Force on the Management
of Acute Myocardial Infarction of the European Society of Cardiology
(42) and this Committee both recommend
a target of medical contact–to-balloon or door-to-balloon
time within 90 minutes.
- Risk
of STEMI. Several models have been developed that assist
clinicians in estimating the risk of mortality in patients with
STEMI (43–47).
Although these models vary somewhat in the factors loaded into
the risk-prediction tool and also vary with respect to statistical
measures of their discriminative power (eg, C statistic), all
the models provide clinicians with a means to assess the continuum
of risk from STEMI. When the estimated mortality with fibrinolysis
is extremely high, as is the case in patients with cardiogenic
shock, compelling evidence exists that favors a PCI strategy.
- Risk
of Bleeding. Choice of reperfusion therapy is also affected
by the patient’s risk of bleeding. When both types of reperfusion
are available, the higher the patient’s risk of bleeding
with fibrinolytic therapy, the more strongly the decision should
favor PCI. If PCI is unavailable, then the benefit of pharmacological
reperfusion therapy should be balanced against the risk.
- Time
Required for Transport to a Skilled PCI Laboratory. The availability
of interventional cardiology facilities is a key determinant of
whether PCI can be provided. For facilities that can offer PCI,
the literature suggests that this approach is superior to pharmacological
reperfusion (48). The trials comparing
pharmacological and PCI strategies, however, were conducted before
the advent of more recent pharmacological and PCI strategies.
When a composite end point of death, nonfatal recurrent MI, or
stroke is analyzed, much of the superiority of a PCI strategy
is driven by a reduction in the rate of nonfatal recurrent MI
(Figure 2) (36).
The rate of nonfatal recurrent MI can be influenced both by the
adjunctive therapy used and by the proportion of patients who
are referred for PCI when the initial attempt at fibrinolysis
fails or myocardial ischemia recurs after initially successful
pharmacological reperfusion.
The experience and location of the PCI laboratory also plays a
role in the choice of therapy. Not all laboratories can provide
prompt, high-quality primary PCI. Even centers with interventional
cardiology facilities may not be able to provide the staffing
required for 24-hour coverage of the catheterization laboratory.
Despite staffing availability, the volume of cases in the laboratory
may be insufficient for the team to acquire and maintain skills
required for rapid PCI reperfusion strategies.
A decision must be made when a STEMI patient presents to a center
without interventional cardiology facilities. Fibrinolytic therapy
can generally be provided sooner than primary PCI. As the time
delay for performing PCI increases, the mortality benefit associated
with expeditiously performed primary PCI over fibrinolysis decreases
(49). Compared with a fibrin-specific
lytic agent, a PCI strategy may not reduce mortality when a delay
greater than 60 minutes is anticipated versus immediate administration
of a lytic.
Given the current literature, it is not possible to say definitively
that a particular reperfusion approach is superior for all patients,
in all clinical settings, at all times of day (Danchin N; oral
presentation at American Heart Association Scientific Sessions
2003, Orlando, FL, November 2003) (50–52).
The main point is that some type of reperfusion therapy should
be selected for all appropriate patients with suspected STEMI.
The appropriate and timely use of some reperfusion therapy is
likely more important than the choice of therapy, given the current
literature and the expanding array of options. Clinical circumstances
in which fibrinolytic therapy is generally preferred or an invasive
strategy is generally preferred are shown in Figure
3.
Available Resources
Class I
1. STEMI patients presenting to a facility without the
capability for expert, prompt intervention with primary PCI within
90 minutes of first medical contact should undergo fibrinolysis
unless contraindicated. (Level of Evidence: A)
PHARMACOLOGICAL REPERFUSION.
Indications for Fibrinolytic Therapy
Class I
1. In the absence of contraindications, fibrinolytic therapy should
be administered to STEMI patients with symptom onset within the
prior 12 hours and ST elevation greater than 0.1 mV in at least
2 contiguous precordial leads or at least 2 adjacent limb leads.
(Level of Evidence: A)
2. In the absence of contraindications, fibrinolytic therapy should
be administered to STEMI patients with symptom onset within the
prior 12 hours and new or presumably new LBBB. (Level of Evidence:
A)
Class IIa
1. In the absence of contraindications, it is reasonable to administer
fibrinolytic therapy to STEMI patients with symptom onset within
the prior 12 hours and 12-lead ECG findings consistent with a true
posterior MI. (Level of Evidence: C)
2. In the absence of contraindications, it is reasonable to administer
fibrinolytic therapy to patients with symptoms of STEMI beginning
within the prior 12 to 24 hours who have continuing ischemic symptoms
and ST elevation greater than 0.1 mV in at least 2 contiguous precordial
leads or at least 2 adjacent limb leads. (Level of Evidence:
B)
Class III
1. Fibrinolytic therapy should not be administered to asymptomatic
patients whose initial symptoms of STEMI began more than 24 hours
earlier. (Level of Evidence: C)
2. Fibrinolytic therapy should not be administered to patients whose
12-lead ECG shows only ST-segment depression except if a true posterior
MI is suspected. (Level of Evidence: A)
Because the benefit of fibrinolytic therapy is directly
related to the time from symptom onset, treatment benefit is maximized
by the earliest possible application of therapy. The constellation
of clinical features that must be present (although not necessarily
at the same time) to serve as an indication for fibrinolysis includes
symptoms of myocardial ischemia and ST elevation greater than 0.1
mV, in at least 2 contiguous leads, or new or presumably new LBBB
on the presenting ECG (23,54).
Contraindications/Cautions
Class I
1. Healthcare providers should ascertain whether the patient has
neurological contraindications to fibrinolytic therapy, including
any history of intracranial hemorrhage (ICH), significant closed
head or facial trauma within the past 3 months, uncontrolled hypertension,
or ischemic stroke within the past 3 months. (See Table
2 for a comprehensive list.) (Level of Evidence: A)
2. STEMI patients at substantial (greater than or equal to 4%) risk
of ICH should be treated with PCI rather than with fibrinolytic
therapy. (See Figure 3 for further
management considerations.) (Level of Evidence: A)
A detailed list of contraindications and cautions for the use of
fibrinolytic therapy is shown in Table
2.
Complications of Fibrinolytic Therapy: Neurological and Other
Class I
1. The occurrence of a change in neurological status during
or after reperfusion therapy, particularly within the first 24 hours
after initiation of treatment, is considered to be due to ICH until
proven otherwise. Fibrinolytic, antiplatelet, and anticoagulant
therapies should be discontinued until brain imaging scan shows
no evidence of ICH. (Level of Evidence: A)
2. Neurology and/or neurosurgery or hematology consultations should
be obtained for STEMI patients who have ICH as dictated by clinical
circumstances. (Level of Evidence: C)
3. In patients with ICH, infusions of cryoprecipitate, fresh frozen
plasma, protamine, and platelets should be given, as dictated by
clinical circumstances. (Level of Evidence: C)
Class IIa
1. In patients with ICH, it is reasonable to:
a. Optimize blood pressure and blood glucose levels. (Level
of Evidence: C)
b. Reduce intracranial pressure with an infusion of mannitol, endotracheal
intubation, and hyperventilation. (Level of Evidence: C)
c. Consider neurosurgical evacuation of ICH. (Level of Evidence:
C)
Combination
Therapy With Glycoprotein IIb/IIIa Inhibitors
Class IIb
1. Combination pharmacological reperfusion with abciximab and half-dose
reteplase or tenecteplase may be considered for prevention of reinfarction
(Level of Evidence: A) and other complications of STEMI
in selected patients: anterior location of MI, age less than 75
years, and no risk factors for bleeding. In two clinical trials
of combination reperfusion, the prevention of reinfarction did not
translate into a survival benefit at either 30 days or 1 year (54a).
(Level of Evidence: B)
2. Combination pharmacological reperfusion with abciximab and half-dose
reteplase or tenecteplase may be considered for prevention of reinfarction
and other complications of STEMI in selected patients (anterior
location of MI, age less than 75 years, and no risk
factors for bleeding) in whom an early referral for angiography
and PCI (ie, facilitated PCI) is planned. (Level of Evidence:
C)
Class III
1. Combination pharmacological reperfusion with abciximab and half-dose
reteplase or tenecteplase should not be given to patients aged greater
than 75 years because of an increased risk of ICH. (Level of
Evidence: B)
PERCUTANEOUS CORONARY INTERVENTION
Coronary Angiography
Class
I
1. Diagnostic coronary angiography should be performed:
a. In candidates for primary or rescue PCI. (Level of Evidence:
A)
b. In patients with cardiogenic shock who are candidates for revascularization.
(Level of Evidence: A)
c. In candidates for surgical repair of ventricular septal rupture
or severe mitral regurgitation (MR). (Level of Evidence: B)
d. In patients with persistent hemodynamic and/or electrical instability.
(Level of Evidence: C)
Class III
1. Coronary angiography should not be performed in patients with
extensive comorbidities in whom the risks of revascularization are
likely to outweigh the benefits. (Level of Evidence: C)
Primary PCI
Class I
1. General considerations: If immediately available, primary
PCI should be performed in patients with STEMI (including true posterior
MI) or MI with new or presumably new LBBB who can undergo PCI of
the infarct artery within 12 hours of symptom onset, if performed
in a timely fashion (balloon inflation within 90 minutes of presentation)
by persons skilled in the procedure (individuals who perform more
than 75 PCI procedures per year). The procedure should be supported
by experienced personnel in an appropriate laboratory environment
(performs more than 200 PCI procedures per year, of which at least
36 are primary PCI for STEMI, and has cardiac surgery capability).
(Level of Evidence: A)
2. Specific considerations:
a. Primary PCI should be performed as quickly as possible, with
a goal of a medical contact–toballoon or door-to-balloon time
of within 90 minutes. (Level of Evidence: B)
b. If the symptom duration is within 3 hours and the expected door-to-balloon
time minus the expected door-to-needle time is:
i) within 1 hour, primary PCI is generally preferred. (Level
of Evidence: B)
ii) greater than 1 hour, fibrinolytic therapy (fibrin-specific agents)
is generally preferred. (Level of Evidence: B)
c. If symptom duration is greater than 3 hours, primary PCI is generally
preferred and should be performed with a medical contact–to-balloon
or door-to-balloon time as brief as possible, with a goal of within
90 minutes. (Level of Evidence: B)
d. Primary PCI should be performed for patients younger than 75
years old with ST elevation or LBBB who develop shock within 36
hours of MI and are suitable for revascularization that can be performed
within 18 hours of shock, unless further
support is futile because of the patient’s wishes or contraindications/unsuitability
for further invasive care. (Level of Evidence: A)
e. Primary PCI should be performed in patients with severe CHF and/or
pulmonary edema (Killip class 3) and onset of symptoms within 12
hours. The medical contact–to-balloon or door-to-balloon time
should be as short as possible (ie, goal within 90 min). (Level
of Evidence: B)
Class IIa
1. Primary PCI is reasonable for selected patients 75 years or older
with ST elevation or LBBB or who develop shock within 36 hours of
MI and are suitable for revascularization that can be performed
within 18 hours of shock. Patients with good prior functional status
who are suitable for revascularization and agree to invasive care
may be selected for such an invasive strategy. (Level of Evidence:
B)
2. It is reasonable to perform primary PCI for patients with onset
of symptoms within the prior 12 to 24 hours and 1 or more of the
following:
a. Severe CHF (Level of Evidence: C)
b. Hemodynamic or electrical instability (Level of Evidence:
C)
c. Persistent ischemic symptoms. (Level of Evidence: C)
Class IIb
1. The benefit of primary PCI for STEMI patients eligible for fibrinolysis
is not well established when per-formed by an operator who performs
fewer than 75 PCI procedures per year. (Level of Evidence: C)
Class III
1. PCI should not be performed in a noninfarct artery at the time
of primary PCI in patients without hemodynamic compromise. (Level
of Evidence: C)
2. Primary PCI should not be performed in asymptomatic patients
more than 12 hours after onset of STEMI if they are hemodynamically
and electrically stable. (Level of Evidence: C)
Primary PCI has been compared with fibrinolytic therapy in 22 randomized
clinical trials (50,52,55–74). An additional trial, SHOCK
(SHould we emergently revascularize Occluded Coronaries for cardiogenic
shocK?) (75). that compared medical
stabilization with immediate revascularization for cardiogenic shock
was included along with the above 22 trials in an overview of primary
PCI versus fibrinolysis (76). These
investigations demonstrate that PCI-treated patients experience
lower short-term mortality rates, less nonfatal reinfarction, and
less hemorrhagic stroke than those treated by fibrinolysis but have
an increased risk for major bleeding (76).
These results have been achieved in medical centers with experienced
providers and under circumstances in which PCI can be performed
promptly after patient presentation (Figure
2) (76).
Additional considerations that affect the magnitude of the difference
between PCI- and fibrinolysis-treated patients include the fact
that unfractionated heparin (UFH) was used as the antithrombin with
fibrinolytics (as opposed to other antithrombins such as enoxaparin
[see Ancillary Therapy in Section VI.C.1.f and also Section 6.3.1.6.8.1.1
of the full-text guidelines] or bivalirudin [see Section 6.3.1.6.8.1.2
of the full-text guidelines] that are associated with a reduction
in the rate of recurrent MI after fibrinolysis), a smaller but still
statistically significant advantage for PCI compared with a fibrin-specific
lytic versus streptokinase, and variation among the PCI arms as
to whether a stent was implanted or glycoprotein (GP) IIb/IIIa antagonists
were administered. Figure 2 shows
the short- and long-term outcomes of patients with STEMI treated
by fibrinolysis versus PCI and the number of patients who need to
be treated to prevent 1 event or cause 1 harmful complication when
selecting PCI instead of fibrinolysis as the reperfusion strategy
(Figure 2) (76).
Of note, when primary PCI is compared with tissue plasminogen activator
(tPA) and the SHOCK trial is excluded, the mortality rate is 5.5%
versus 6.7% (odds ratio 0.81%, 95% confidence interval [CI] 0.64
to 1.03, P equals 0.081 (76a).
There is serious and legitimate concern that a routine policy of
primary PCI for patients with STEMI will result in unacceptable
delays in achieving reperfusion in a substantial number of cases
and produce less than optimal outcomes if performed by less-experienced
operators. The mean time delay for PCI instead of fibrinolysis in
the randomized studies was approximately 40 minutes (76).
Strict performance criteria must be mandated for primary PCI programs
so that long door-to-balloon times and performance by low-volume
or pooroutcome operators/laboratories do not occur. Interventional
cardiologists and centers should strive for outcomes to include
(1) medical contact–to-balloon or door-to-balloon times less
than 90 minutes; (2) TIMI (Thrombolysis In Myocardial Infarction)
2/3 flow rates obtained in more than 90% of patients; (3) emergency
CABG rate less than 2% among all patients undergoing the procedure;
(4) actual performance of PCI in a high percentage of patients (85%)
brought to the laboratory; and (5) risk-adjusted in-hospital mortality
rate less than 7% in patients without cardiogenic shock. This would
result in a risk-adjusted mortality rate with PCI comparable to
that reported for fibrinolytic therapy in fibrinolytic-eligible
patients (76) and would be consistent
with previously reported registry experience (77–80).
Otherwise, the focus of treatment should be the early use of fibrinolytic
therapy (Figure 2) (76).
PCI appears to have its greatest mortality benefit in high-risk
patients. In patients with cardiogenic shock, an absolute 9% reduction
in 30-day mortality with coronary revascularization instead of immediate
medical stabilization was reported in the SHOCK trial (75).
Time from symptom onset to reperfusion is an important predictor
of patient outcome. Two studies (81,82)
have reported increasing mortality rates with increasing door-to-balloon
times. Other studies have shown smaller infarct size, better LV
function, and fewer complications when reperfusion occurs before
PCI (83–85). An analysis of
the randomized controlled trials comparing fibrinolysis with a fibrin-specific
agent versus primary PCI suggests that the mortality benefit with
PCI exists when treatment is delayed by no more than 60 minutes.
Mortality increases significantly with each 15-minute delay in the
time between arrival and restoration of TIMI-3 flow (doorto–TIMI-3
flow time), which further underscores the importance of timely reperfusion
in patients who undergo primary PCI (86).
Importantly, after adjustment for baseline characteristics, time
from symptom onset to balloon inflation is significantly correlated
with 1-year mortality in patients undergoing primary PCI for STEMI
(relative risk equals 1.08 for each 30-minute delay from symptom
onset to balloon inflation; P equals 0.04) (35,41).
Given that the medical contact–to-needle time goal within
30 minutes, this Writing Committee joins the Task Force on the Management
of Acute Myocardial Infarction of the European Society of Cardiology
in lowering the medical contact–to-balloon or door-to-balloon
time goal from within 120 minutes to
within 90 minutes in an attempt to maximize the benefits for reperfusion
by PCI (42).
If the expected door-to-balloon time exceeds the expected door-to-needle
time by more than 60 minutes, fibrinolytic treatment with a fibrin-specific
agent should be considered unless it is contraindicated. This is
particularly important when symptom duration is less than 3 hours
but is less important with longer symptom duration, when less ischemic
myocardium can be salvaged.
PRIMARY PCI IN FIBRINOLYTIC-INELIGIBLE PATIENTS
Class I
1. Primary PCI should be performed in fibrinolyticineligible
patients who present with STEMI within 12 hours of symptom onset.
(Level of Evidence: C)
Class
IIa
1. It is reasonable to perform primary PCI for fibrinolytic-ineligible
patients with onset of symptoms within the prior 12 to 24 hours
and 1 or more of the following:
a. Severe CHF (Level of Evidence: C)
b. Hemodynamic or electrical instability (Level of Evidence:
C)
c. Persistent ischemic symptoms. (Level of Evidence: C)
Randomized controlled trials evaluating the outcome of PCI for patients
who present with STEMI but who are ineligible for fibrinolytic therapy
have not been performed. Few data are available to characterize
the value of primary PCI for this subset of STEMI patients; however,
the recommendations in Section IV.A (and Section 4.2 of the full-text
guidelines) are applicable to these patients. Nevertheless, these
patients are at increased risk for mortality (87),
and there is a general consensus that PCI is an appropriate means
for achieving reperfusion in those who cannot receive fibrinolytics
because of increased risk of bleeding (88–91).
PRIMARY PCI WITHOUT ON-SITE CARDIAC SURGERY
Class IIb
1. Primary PCI might be considered in hospitals without
on-site cardiac surgery, provided that there exists a proven plan
for rapid transport to a cardiac surgery operating room in a nearby
hospital with appropriate hemodynamic support capability for transfer.
The procedure should be limited to patients with STEMI or MI with
new, or presumably new, LBBB on ECG, and should be done in a timely
fashion (balloon inflation within 90 minutes of presentation) by
persons skilled in the procedure (at least 75 PCIs per year) and
at hospitals that perform a minimum of 36 primary PCI procedures
per year. (Level of Evidence: B)
Class III
1. Primary PCI should not be performed in hospitals without on-site
cardiac surgery and without a proven plan for rapid transport to
a cardiac surgery operating room in a nearby hospital or without
appropriate hemodynamic support capability for transfer. (Level
of Evidence: C)
From clinical data and expert consensus, the Committee recommends
that primary PCI for acute STEMI performed at hospitals without
established elective PCI programs should be restricted to those
institutions capable of performing a requisite minimum number of
primary PCI procedures (36 per year) with a proven plan for rapid
and effective PCI and rapid access to cardiac surgery in a nearby
hospital. The benefit of primary PCI is not well established for
operators who perform fewer than 75 PCIs per year or in a hospital
that performs fewer than 36 primary PCI procedures per year. In
addition, the benefit of timely reperfusion of the infarct artery
by primary PCI at sites without on-site surgery must be weighed
against the small but finite risk of harm to the patient related
to the time required to transfer the patient to a site with CABG
surgery capabilities (92,93).
INTERHOSPITAL TRANSFER FOR PRIMARY PCI
To achieve optimal results, time from the first hospital door to
the balloon inflation in the second hospital should be as short
as possible, with a goal of within 90 minutes. Significant reductions
in door-to-balloon times might be achieved by directly transporting
patients to PCI centers rather than transporting them to the nearest
hospital, if interhospital transfer will subsequently be required
to obtain primary PCI.
Primary Stenting
Primary stenting has been compared with primary angioplasty in 9
studies (94–103). There were
no differences in mortality (3.0% versus 2.8%) or reinfarction (1.8%
versus 2.1%) rates. However, major adverse cardiac events were reduced,
driven by the reduction in subsequent target-vessel revascularization
with stenting.
Preliminary reports suggest that compared with conventional bare
metal stents, drug-eluting stents are not associated with increased
risk when used for primary PCI in STEMI patients (104).
Postprocedure vessel patency, biomarker release, and the incidence
of short-term adverse events were similar in patients receiving
sirolimus (n equals 186) or bare metal (n equals 183) stents. Thirty-day
event rates of death, reinfarction, or revascularization were 7.5%
versus 10.4%, respectively (P equals 0.4) (104).
Facilitated PCI
Class IIb
1.
Facilitated PCI might be performed as a reperfusion strategy
in higher-risk patients when PCI is not immediately available and
bleeding risk is low. (Level of Evidence: B)
Facilitated PCI refers to a strategy of planned immediate PCI after
an initial pharmacological regimen such as full-dose fibrinolysis,
half-dose fibrinolysis, a GP IIb/IIIa inhibitor, or a combination
of reduced-dose fibrinolytic therapy and a platelet GP IIb/IIIa
inhibitor. A strategy of facilitated PCI holds promise in higher-risk
patients when PCI is not immediately available. Potential risks
include increased bleeding complications, especially in patients
who are at least 75 years of age (see Pharmacological Reperfusion
in Section VI.C.1.f and Section 6.3.1.6.3.8. of the full-text guidelines),
and potential limitations include added cost. Several randomized
trials of facilitated PCI with a variety of pharmacological regimens
are in progress.
Rescue PCI
Class I
1. Rescue PCI should be performed in patients less than 75 years
old with ST elevation or LBBB who develop shock within 36 hours
of MI and are suitable for revascularization that can be performed
within 18 hours of shock, unless further support is futile because
of
the patient’s wishes or contraindications/unsuitability for
further invasive care. (Level of Evidence: B)
2. Rescue PCI should be performed in patients with severe CHF and/or
pulmonary edema (Killip class 3) and onset of symptoms within 12
hours. (Level of Evidence: B)
Class IIa
1. Rescue PCI is reasonable for selected patients 75 years
or older with ST elevation or LBBB or who develop shock within 36
hours of MI and are suitable for revascularization that can be performed
within 18 hours of shock. Patients with good prior functional status
who are suitable for revascularization and agree to invasive care
may be selected for such an invasive strategy. (Level of Evidence:
B)
2. It is reasonable to perform rescue PCI for patients with 1 or
more of the following:
a. Hemodynamic or electrical instability (Level of Evidence:
C)
b. Persistent ischemic symptoms. (Level of Evidence: C)
Rescue PCI refers to PCI within 12 hours after failed fibrinolysis
for patients with continuing or recurrent myocardial ischemia.
A major problem in adopting a strategy of rescue PCI lies in the
limitation of accurate identification of patients for whom fibrinolytic
therapy has not restored antegrade coronary flow. In a prior era
in which the practice of PCI was less mature, immediate catheterization
of all patients after fibrinolytic therapy to identify those with
an occluded infarct artery was found to be impractical, costly,
and often associated with bleeding complications (105,106).
This strategy is being reevaluated in clinical trials testing facilitated
PCI in the contemporary PCI setting.
There are no convincing data to support the routine use of late
adjuvant PCI days after failed fibrinolysis or for patients who
do not receive reperfusion therapy. Nevertheless, this is being
done in some STEMI patients as an extension of the invasive strategy
for non-STEMI patients. The Occluded Artery Trial (OAT) is currently
randomizing patients to test whether routine PCI days to weeks after
MI improves long-term clinical outcomes in asymptomatic high-risk
patients with an occluded infarct artery (107).
PCI for Cardiogenic Shock
Class I
1. Primary PCI is recommended for patients less than 75
years old with ST elevation or LBBB who develop shock within 36
hours of MI and are suitable for revascularization that can be performed
within 18 hours of shock, unless further support is futile because
of the patient’s wishes or contraindications/unsuitability
for further invasive care. (Level of Evidence: A)
Class IIa
1. Primary PCI is reasonable for selected patients aged 75 years
or older with ST elevation or LBBB who develop shock within 36 hours
of MI and who are suitable for revascularization that can be performed
within 18 hours of shock. Patients with good prior functional status
who are suitable for revascularization and agree to invasive care
may be selected for such an invasive strategy. (Level of Evidence:
B)
Observational
studies support the value of PCI for patients who develop cardiogenic
shock in the early hours of STEMI. In the SHOCK trial (75),
the survival curves continued to progressively diverge such that
at 6 months and 1 year, there was a significant mortality reduction
with emergency revascularization (53% versus 66%, P less than 0.03)
(108). The prespecified subgroup
analysis of patients less than 75 years old showed an absolute 15%
reduction in 30-day mortality (P less than 0.02), whereas there
was no apparent benefit for the small cohort (n equals 56) of patients
more than 75 years old. These data strongly support the approach
that patients younger than 75 years with STEMI complicated by cardiogenic
shock should undergo emergency revascularization and support measures.
Three registries (109–111)
have demonstrated a marked survival benefit for elderly patients
who are clinically selected for revascularization (approximately
1 of 5 patients), so age alone should not disqualify a patient from
early revascularization. (See Section VII.F.5 and also Section 7.6.5
of the full-text guidelines.)
Percutaneous Coronary Intervention After Fibrinolysis
Class I
1. In patients whose anatomy is suitable, PCI should be
performed when there is objective evidence of recurrent MI. (Level
of Evidence: C)
2. In patients whose anatomy is suitable, PCI should be performed
for moderate or severe spontaneous or provocable myocardial ischemia
during recovery from STEMI. (Level of Evidence: B)
3. In patients whose anatomy is suitable, PCI should be performed
for cardiogenic shock or hemodynamic instability. (See section on
PCI for Cardiogenic Shock in Section VI.C.1.f.) (Level of Evidence:
B)
Class IIa
1. It is reasonable to perform routine PCI in patients with LV ejection
fraction (LVEF) less than or equal to 0.40, CHF, or serious ventricular
arrhythmias. (Level of Evidence: C)
2. It is reasonable to perform PCI when there is documented clinical
heart failure during the acute episode, even though subsequent evaluation
shows preserved LV function (LVEF greater than 0.40). (Level
of Evidence: C)
Class IIb
1. Routine PCI might be considered as part of an invasive strategy
after fibrinolytic therapy. (Level of Evidence: B)
Immediately After Successful Fibrinolysis. Randomized prospective
trials examined the efficacy and safety of immediate PCI after fibrinolysis
(105,106,112).
These trials showed no benefit of routine PCI of the stenotic infarct
artery immediately after fibrinolytic therapy. The strategy did
not appear to salvage myocardium, improve LVEF, or prevent reinfarction
or death. Those subjected to this approach appeared to have an increased
incidence of adverse events, including bleeding, recurrent ischemia,
emergency CABG, and death. These studies have not been repeated
in the modern interventional era with improved equipment, improved
antiplatelet and anticoagulant strategies, and coronary stents,
thus leaving the question of routine PCI early after successful
fibrinolysis unresolved in contemporary practice. Studies of facilitated
PCI are enrolling patients (113–116).
Hours to Days After Successful Fibrinolysis. Great improvements
in equipment, operator experience, and adjunctive pharmacotherapy
have increased PCI success rates and decreased complications. More
recently, the invasive strategy for NSTEMI patients has been given
a Class I recommendation by the ACC/AHA Guidelines for the Management
of Patients With Unstable Angina/Non-STEMI (117).
STEMI patients are increasingly being treated similarly as an extension
of this approach. Although 6 published reports (115,118
–121,123) and 1 preliminary
report (122) support this strategy,
randomized studies similar to those in NSTEMI need to be performed.
ACUTE SURGICAL REPERFUSION
Class I
1.
Emergency or urgent CABG in patients with STEMI should be undertaken
in the following circumstances:
a. Failed PCI with persistent pain or hemodynamic instability in
patients with coronary anatomy suitable for surgery. (Level
of Evidence: B)
b. Persistent or recurrent ischemia refractory to medical therapy
in patients who have coronary anatomy suitable for surgery, have
a significant area of myocardium at risk, and are not candidates
for PCI or fibrinolytic therapy. (Level of Evidence: B)
c. At the time of surgical repair of postinfarction ventricular
septal rupture (VSR) or mitral valve insufficiency. (Level of
Evidence: B)
d. Cardiogenic shock in patients less than 75 years old with ST
elevation, LBBB, or posterior MI who develop shock within 36 hours
of STEMI, have severe multivessel or left main disease, and are
suitable for revascularization that can be performed within 18 hours
of shock, unless further support is futile because of the patient’s
wishes or contraindications/unsuitability for further invasive care.
(Level of Evidence: A)
e. Life-threatening ventricular arrhythmias in the presence of greater
than or equal to 50% left main stenosis and/or triple-vessel disease.
(Level of Evidence: B)
Class IIa
1. Emergency CABG can be useful as the primary reperfusion strategy
in patients who have suitable anatomy, who are not candidates for
fibrinolysis or PCI, and who are in the early hours (6 to 12 hours)
of an evolving STEMI, especially if severe multivessel or left main
disease is present. (Level of Evidence: B)
2. Emergency CABG can be effective in selected patients 75 years
or older with ST elevation, LBBB, or posterior MI who develop shock
within 36 hours of STEMI, have severe triple-vessel or left main
disease, and are suitable for revascularization that can be performed
within 18 hours of shock. Patients with good prior functional status
who are suitable for revascularization and agree to invasive care
may be selected for such an invasive strategy. (Level of Evidence:
B)
Class III
1. Emergency CABG should not be performed in patients with persistent
angina and a small area of risk if they are hemodynamically stable.
(Level of Evidence: C)
2. Emergency CABG should not be performed in patients with
successful epicardial reperfusion but unsuccessful microvascular
reperfusion. (Level of Evidence: C)
PATIENTS WITH STEMI NOT
RECEIVING REPERFUSION
Guideline-based recommendations for nonreperfusion treatments should
not vary whether or not patients received reperfusion therapy. The
major difference is that patients not receiving reperfusion therapy
are considered to have a higher risk for future adverse events (124).
ASSESSMENT OF REPERFUSION
Class IIa
1. It is reasonable to monitor the pattern
of ST elevation, cardiac rhythm, and clinical symptoms over the
60 to 180 minutes after initiation of fibrinolytic therapy. Noninvasive
findings suggestive of reperfusion include relief of symptoms, maintenance
or restoration of hemodynamic and or electrical stability, and a
reduction of at least 50% of the initial ST-segment elevation injury
pattern on a follow-up ECG 60 to 90 minutes after initiation of
therapy. (Level of Evidence: B)
Persistence of unrelenting ischemic chest pain, absence of resolution
of the qualifying ST-segment elevation, and hemodynamic and/or electrical
instability are generally indicators of failed pharmacological reperfusion
and the need to consider rescue PCI. Aggressive medical support
may be necessary in the interim. (See Rescue PCI in Section in VI.C.I.f.)
ANCILLARY THERAPY
Antithrombins as Ancillary Therapy to Reperfusion Therapy
UNFRACTIONATED HEPARIN AS ANCILLARY THERAPY TO REPERFUSION THERAPY
Class I
1. Patients undergoing percutaneous or surgical revascularization
should be given UFH. (Level of Evidence: C)
2. UFH should be given intravenously to patients undergoing reperfusion
therapy with alteplase, reteplase, or tenecteplase, with dosing
as follows: bolus of 60 U/kg (maximum 4000 U) followed by an initial
infusion of 12 U/kg per hour (maximum 1000 U/hr) adjusted to maintain
activated partial thromboplastin time (aPTT) at 1.5 to 2.0 times
control (approximately 50 to 70 seconds). (Level of Evidence:
C)
3.
UFH should be given intravenously to patients treated with nonselective
fibrinolytic agents (streptokinase, anistreplase, or urokinase)
who are at high risk for systemic emboli (large or anterior MI,
atrial fibrillation, previous embolus, or known LV thrombus). (Level
of Evidence: B)
4. Platelet counts should be monitored daily in patients given UFH.
(Level of Evidence: C)
Class IIb
1. It may be reasonable to administer UFH intravenously to patients
undergoing reperfusion therapy with streptokinase. (Level of
Evidence: B)
Because of the evidence that the measured effect of UFH on the aPTT
is important for patient outcome and that the predominant variable
mediating the effect of a given dose of heparin is weight (125),
it is important to administer the initial doses of UFH as a weight-adjusted
bolus (126). For fibrin-specific
(alteplase, reteplase, and tenecteplase) fibrinolytic-treated patients,
a 60 U/kg bolus followed by a maintenance infusion of 12 U/kg per
hour (with a maximum of 4000 U bolus and 1000 U/h initial infusion
for patients weighing greater than 70 kg) is recommended. The recommended
weight-adjusted dose of UFH, when it is administered without fibrinolytics,
is 60 to 70 U/kg IV bolus and 12 to 15 U/kg per hour infusion (117).
LOW-MOLECULAR-WEIGHT HEPARIN AS ANCILLARY THERAPY TO REPERFUSION
THERAPY
Class IIb
1. LMWH might be considered an acceptable alternative to
UFH as ancillary therapy for patients less than 75 years of age
who are receiving fibrinolytic therapy, provided that significant
renal dysfunction (serum creatinine greater than 2.5 mg/dL in men
or 2.0 mg/dL in women) is not present. Enoxaparin (30 mg IV bolus
followed by 1.0 mg/kg subcutaneous injection every 12 hours until
hospital discharge) used in combination with full-dose tenecteplase
is the most comprehensively studied regimen in patients less than
75 years of age. (Level of Evidence: B)
Class III
1. LMWH should not be used as an alternative to UFH as ancillary
therapy in patients over 75 years of age who are receiving fibrinolytic
therapy. (Level of Evidence: B)
2. LMWH should not be used as an alternative to UFH as ancillary
therapy in patients less than 75 years of age who are receiving
fibrinolytic therapy but have significant renal dysfunction (serum
creatinine greater than 2.5 mg/dL in men or 2.0 mg/dL in women).
(Level of Evidence: B)
The available data suggest that the rate of early (60 to 90 minutes)
reperfusion of the infarct artery, either assessed angiographically
or by noninvasive means, is not enhanced by administration of an
LMWH. However, a generally consistent theme of a lower rate of reocclusion
of the infarct artery, reinfarction, or recurrent ischemic events
emerges in patients receiving LMWH regardless of whether the control
group was given placebo or UFH.
DIRECT ANTITHROMBINS AS ANCILLARY THERAPY TO REPERFUSION THERAPY
Class IIa
1. In patients with known heparin-induced thrombocytopenia,
it is reasonable to consider bivalirudin as a useful alternative
to heparin to be used in conjunction with streptokinase. Dosing
according to the HERO (Hirulog and Early Reperfusion or Occlusion)-2
regimen (a bolus of 0.25 mg/kg followed by an intravenous infusion
of 0.5 mg/kg per hour for the first 12 hours and 0.25 mg/kg per
hour for the subsequent 36 hours) (127)
is recommended but with a reduction in the infusion rate if the
PTT is above 75 seconds within the first 12 hours. (Level of
Evidence: B)
On the basis of the data in the HERO-2 trial, the Writing Committee
believed that bivalirudin could be considered an acceptable alternative
to UFH in those STEMI patients who receive fibrinolysis with streptokinase,
have heparin-induced thrombocytopenia, and who, in the opinion of
the treating physician, would benefit from anticoagulation.
Antiplatelets
ASPIRIN
Class I
1. A daily dose of aspirin (initial dose of 162 to 325 mg
orally; maintenance dose of 75 to 162 mg) should be given indefinitely
after STEMI to all patients without a true aspirin allergy. (Level
of Evidence: A)
As discussed, aspirin should be given to the patient with suspected
STEMI as early as possible and should be continued indefinitely,
regardless of the strategy for reperfusion and
regardless of whether additional antiplatelet agents are administered.
True aspirin allergy is the only exception to this recommendation.
THIENOPYRIDINES
Class I
1.
In patients who have undergone diagnostic cardiac catheterization
and for whom PCI is planned, clopidogrel should be started and continued
for at least 1 month after bare metal stent implantation, for several
months after drug-eluting stent implantation (3 months for sirolimus,
6 months for paclitaxel), and for up to 12 months in patients who
are not at high risk for bleeding. (Level of Evidence: B)
2. In patients taking clopidogrel in whom CABG is planned, the drug
should be withheld for at least 5 days, and preferably for 7, unless
the urgency for revascularization outweighs the risks of excess
bleeding. (Level of Evidence: B)
Class IIa
1. Clopidogrel is probably indicated in patients receiving
fibrinolytic therapy who are unable to take aspirin because of hypersensitivity
or major gastrointestinal intolerance. (Level of Evidence: C)
Clopidogrel combined with aspirin is recommended for STEMI patients
who undergo coronary stent implantation (128–132).
There are no safety data available regarding the combination of
fibrinolytic agents and clopidogrel, but ongoing trials will provide
this information in the future. However, in patients in whom aspirin
is contraindicated because of aspirin sensitivity, clopidogrel is
probably useful as a substitute for aspirin to reduce the risk of
occlusion (133). There are no safety
data comparing 300 and 600 mg as loading doses for clopidogrel.
We do not recommend routine administration of clopidogrel as pretreatment
in patients who have not yet undergone diagnostic cardiac catheterization
and in whom CABG surgery would be performed within 5 to 7 days if
warranted (134).
GLYCOPROTEIN IIb/IIIa INHIBITORS
Class IIa
1. It is reasonable to start treatment with abciximab as
early as possible before primary PCI (with or without stenting)
in patients with STEMI. (Level of Evidence: B)
Class IIb
1. Treatment with tirofiban or eptifibatide may be considered before
primary PCI (with or without stenting) in patients with STEMI. (Level
of Evidence: C)
The Writing Committee believes that it is reasonable to start treatment
with abciximab as early as possible in patients undergoing primary
PCI (with or without stenting) but, given the size and limitations
of the available data set, assigned a Class IIa recommendation to
this treatment. The data on tirofiban and eptifibatide in primary
PCI are far more limited than for abciximab. However, given the
common mode of action of the agents, a modest amount of angiographic
data (135), and general clinical
experience to date, tirofiban or eptifibatide may be useful as antiplatelet
therapy to support primary PCI for STEMI (with or without stenting)
(Class IIb recommendation).
OTHER PHARMACOLOGICAL MEASURES
Inhibition of Renin-Angiotensin-Aldosterone System
Class I
1. An angiotensin converting enzyme (ACE) inhibitor should
be administered orally within the first 24 hours of STEMI to patients
with anterior infarction, pulmonary congestion, or LVEF less than
0.40, in the absence of
hypotension (systolic blood pressure less than 100 mm Hg or less
than 30 mm Hg below baseline) or known contraindications to that
Class of medications. (Level of Evidence: A)
2. An angiotensin receptor blocker (ARB) should be administered
to STEMI patients who are intolerant of ACE inhibitors and who have
either clinical or radiological signs of heart failure or LVEF less
than 0.40. Valsartan and candesartan have established efficacy for
this recommendation. (Level of Evidence: C)
Class IIa
1. An ACE inhibitor administered orally within the
first 24 hours of STEMI can be useful in patients without anterior
infarction, pulmonary congestion, or LVEF less than 0.40 in the
absence of hypotension (systolic blood pressure less than 100 mm
Hg or less than
30 mm Hg below baseline) or known contraindications to that class
of medications. The expected treatment benefit in such patients
is less (5 lives saved per 1000 patients treated) than for patients
with LV dysfunction. (Level of Evidence: B)
Class III
1. An intravenous ACE inhibitor should not be given to patients
within the first 24 hours of STEMI because of the risk of hypotension.
(A possible exception may be patients with refractory hypertension.)
(Level of Evidence: B)
A number of large, randomized clinical trials have assessed
the role of ACE inhibitors early in the course of acute MI. All
trials with oral ACE inhibitors have shown benefit from their early
use, including those in which early entry criteria included clinical
suspicion of acute infarctions. Data from these trials indicate
that ACE inhibitors should generally be started within the first
24 hours, ideally after fibrinolytic therapy has been completed
and blood pressure has stabilized. ACE inhibitors should not be
used if systolic blood pressure is less than 100 mm Hg or less than
30 mm Hg below baseline, if clinically relevant renal failure is
present, if there is a history of bilateral stenosis of the renal
arteries, or if there is known allergy to ACE inhibitors.
The use of ARBs has not been explored as thoroughly as ACE inhibitors
in STEMI patients. However, clinical experience in the management
of patients with heart failure and data from clinical trials in
STEMI patients (see Sections 7.4.3 and 7.6.4 of the full-text guidelines)
suggest that ARBs may be useful in patients with depressed LV function
or clinical heart failure but who are intolerant of an ACE inhibitor.
Use of aldosterone antagonists in STEMI patients is discussed in
Sections 7.4.3 and 7.6.4 of the full-text guidelines.
Metabolic Modulation of the Glucose-Insulin Axis
STRICT GLUCOSE CONTROL DURING STEMI
Class I
1.
An insulin infusion to normalize blood glucose is recommended for
patients with STEMI and complicated courses. (Level of Evidence:
B)
Class
IIa
1. During the acute phase (first 24 to 48 hours) of the management
of STEMI in patients with hyperglycemia, it is reasonable to administer
an insulin infusion to normalize blood glucose, even in patients
with an uncomplicated course. (Level of Evidence: B)
2. After the acute phase of STEMI, it is reasonable to individualize
treatment of diabetics, selecting from a combination of insulin,
insulin analogs, and oral hypoglycemic agents that achieve the best
glycemic control and are well tolerated. (Level of Evidence:
C)
Compelling
evidence for tight glucose control in patients in the intensive
care unit (a large proportion of whom were there after cardiac surgery)
supports the importance of intensive insulin therapy to achieve
a normal blood glucose level in critically ill patients (136,136a).
Magnesium
Class IIa
1. It is reasonable that documented magnesium deficits be
corrected, especially in patients receiving diuretics before the
onset of STEMI. (Level of Evidence: C)
2. It is reasonable that episodes of torsade de pointes-type ventricular
tachycardia (VT) associated with a prolonged QT interval be treated
with 1 to 2 g of magnesium administered as an intravenous bolus
over 5 minutes. (Level of Evidence: C)
Class III
1. In the absence of documented electrolyte deficits or torsade
de pointes-type VT, routine intravenous magnesium should not be
administered to STEMI patients at any level of risk. (Level
of Evidence: A)
Calcium Channel Blockers
Class IIa
1. It is reasonable to give verapamil or diltiazem to patients in
whom beta-blockers are ineffective or contraindicated (e.g., bronchospastic
disease) for relief of ongoing ischemia or control of a rapid ventricular
response with atrial fibrillation or flutter after STEMI in the
absence of CHF, LV dysfunction, or atrioventricular (AV) block.
(Level of Evidence: C)
Class III
1. Diltiazem and verapamil are contraindicated in patients with
STEMI and associated systolic LV dysfunction and CHF. (Level
of Evidence: A)
2. Nifedipine (immediate-release form) is contraindicated in treatment
of STEMI because of the reflex sympathetic activation, tachycardia,
and hypotension associated with its use. (Level of Evidence:
B)
See the full-text guidelines for further explanation. |
