Acute Chest Pain Evaluation
in the ED
18th Annual Primary Care and Cardiovascular Symposium
Acute Coronary Syndrome
• In the United States we see > 8 million
patients per year with chest pain.
• 1.6 million get hospitalized
• ~ 15% low risk, ~ 15% high risk
• Intermediate risk comprises ~ 70 % and
have a risk of death or MI of 8 - 10% at
30 days
• Patients without enzyme elevation still
have a risk ~ 5% of death or MI at 30 days.
• AMI is present around 6% with a normal or
non-diagnostic ECG.
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Malpractice
• 2 - 8% of patients with AMI are sent home
with an associated risk of death ~ 10%
(1/5 of all malpractice dollars)
• In one insurance industry–based study,
the physician group most likely to be
sued for missed myocardial infarction
(MI) was family practitioners (32%),
followed by general internists (22%)
and ED physicians (15%).
• To meet this challenge, an increasing array
of diagnostic modalities have been
investigated during the past 2 decades.
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Patient’s Understanding
“Am I having a heart attack?”
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History
• One of the most predictive of ACS
(substernal 1, provoked by exertion or rest2 and
relieved by NTG3)
• At least an intermediate probability if age >
30
• Atypical (lacks 1 of 3)
• Intermediate if male > 30 or woman > 50
• Cardiac Risk Factors
• Predict lifetime risk but not acute episode
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ECG
• Mainstay in Screening
• Only diagnostic in a minority of cases
• Ischemic changes are apparent at the time of
presentation in only 20% to 30% of patients who have
an acute MI
• Conversely, 5% to 10% of patients with MI have normal
findings on ECG at presentation.
• If abnormal, offer prognostic information
• With Pain
• Can diagnose only 35% of the time
• Physician + ECG
• Increases diagnostic ability to only 52%
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Cardiac Markers
Even minor elevation in Troponin places
the patient at increased risk for a
coronary event
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SPECT Imaging
Single Photon Emission Computed Tomography
• Injected with non-diagnostic ECG and
active chest pain
• Detects 96% of CAD
• Subsequent cardiac events
predicts 92%
• Negative scan
• < 2% in hospital event
• Safely discharged from
Emergency Department
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SPECT Scan
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Nuclear Imaging
Before Intervention
After Intervention
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Echocardiography
• User Dependent (Chest pain & non-diagnostic ECG)
• Sensitivity of 88%
• Specificity 78%
• Sensitivity Varies with MI size
• 100% sensitive with Ant MI with > 18% involvement
of LV mass
• With only 1-6 % of LV mass
• Hypokinesis occurs in 30%
• Dyskinesis in 10% (only > 20% of transmural
thickness)
• Cannot effectively distinguish acute ischemia from
infarction: limiting its role in patients with chest
pain and history of coronary artery disease
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Echocardiography
• Useful with ongoing atypical chest
pain to view
• Valvular disease
• Dissections
• Ventricular or aortic aneurysms
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Stress Testing
• Major hemodynamic consequence of CAD is decreased
cardiac output
• Results in decreased exercise capacity
(METs)
• While exercising the probability and severity of CAD is
related to
• ST depression or
ST downslope
• Sensitivity 67%
• Specificity 72%
• IF 1 mm ST depression
• 50-70% single vessel disease
• 80-90% three vessel disease
• To improve sensitivity routine stress
• is coupled with echo or nuclear
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ST Depression
ECG During Stress
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Duke Treadmill Score Sheet
DTS (Duke Treadmill Score) is
calculated as follows:
The Treadmill Angina Index
Duration of exercise in Minutes
Non-limiting angina = 1
MINUS
Exercise-limiting angina = 2
Maximal ST segment deviation
x5 during or after exercise in
millimeters
Results
Low Risk +5 to +15
MINUS
Moderate Risk +4 to -9
The Treadmill Angina Index x4
High Risk -10 or LESS
No angina = 0
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ECBCT
• The presence of calcium suggests coronary plaque
• Quantity of calcium correlates with histologic plaque
mass (Agatston score or Shemesh visual scoring
system)
• Serve as a marker for severity but does not directly
localize coronary stenosis
• Sensitivity 90-100% Specificity 60-70%
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Absence of Coronary Calcification
PA
AO
LMCA
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Moderate Coronary Calcification
PA
AO
LAD
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Severe Coronary Calcification
The relationship between
CAC and biologically “unstable”
coronary artery plaque prone to
rupture is still not totally understood.
No CAC or CACS 0 has a less < 1%
risk
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Coronary CT Angiography
• Noninvasive imaging modality which can
be used to evaluate the anatomy of the
coronary arteries. Need 64 slice CT
scanners
• Unlike coronary artery calcium scoring,
which utilizes noncontrast CT to assess
atherosclerotic disease burden, CCTA
allows direct visualization of the coronary
artery wall and lumen with the
administration of intravenous contrast.
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Coronary CT Angiography
• The degree of coronary luminal stenosis can
be reliably estimated, as can the presence or
absence of both calcified and non-calcified
plaques.
• When compared to invasive quantitative
coronary angiography, newer-generation CT
scanners have been found to have
sensitivities and specificities of over 90%,
and negative predictive values of up to 100%
for the exclusion of obstructive coronary
artery disease (CAD) for both native arteries
as well as bypass grafts.
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CTA
• Use in asymptomatic patients with traditional
risk factors is controversial, and has not been
widely recommended.
• The use of CCTA in high risk patients with chest
pain is generally not recommended, as these
patients often require cardiac catheterization.
• CCTA involves a significant radiation exposure,
on the order of 10 - 20 mSv (chest x-ray is about
0.05 mSv; technetium stress test is about 10 –
12 mSv; thallium stress test is about 25 - 30
mSv).
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Cardiac MRI
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MRI
• Limited Use Currently
• Awaiting faster scanners
• Have to maintain slower heart rate
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Angiography
• TIMI IIIb (unstable
•
angina or non Q MI)
•No significant
disease in 19%
•One vessel 38 %
•Two vessel in 29%
•Three vessel in 15%
•Left main 4%
Recommended for
patients with the
diagnosis of ACS &
pain > 1 hour after
initial aggressive
medical therapy
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Conclusion
• Each of these modalities have strengths &
weakness
• The cost of caring for patients admitted to
the hospital to r/o ACS is ~ 13 billion
dollars/year
• ED’s now have protocols that take
advantage of our current knowledge and
research
• By doing this patients can be safely
and expeditiously re-stratified into low,
intermediate and high risk groups.
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Disclosures
• None
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Any Questions ?
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