The search for the very low risk chest pain patient who goes homewho stays in

1
The search for the very low risk chest pain
patientwho goes home/who stays in?

• Stephen W. Smith, MD

2
Chest PainNo one factor can allow safe discharge

• History of pain
• Demographics age, sex
• Past Hx CAD, risk factors
• ECG
• Initial Biomarkers (troponin)

• Rest Sestamibi
• Serial troponins
• Stress echo
• Stress sestamibi
• CT angio
• Angiography

3
Endpoints for diagnosing ACS

• Death
• MI
• Revascularization
• Done for significant stenosis
• Stenosis can be present without ACS
• Injury biomarkers (e.g., Troponin) cannot detect
  stenosis

4
Case

• 40 yo with substernal chest pressure for 3 hours
• No radiation or associated symptoms
• Ongoing, not intermittent
• No cardiac history
• Cigarette smoker, no other risks
• ECG normal
• First trop

5
Lee GoldmanAnn Int Med 2003 139987

• The sobering bottom line is that 2 decades of
  research has taught us that without compelling
  evidence for a noncardiac cause, there is no
  absolutely fail-safe way to exclude myocardial
  ischemia or infarction at the time of a patient's
  initial presentation. A short period of
  monitoring and measuring serial biomarker levels
  in a chest pain evaluation unit is an attractive
  approach for patients with an uncertain
  diagnosis.

6
Life threatening causes of Chest Pain

• Coronary syndrome
• Pulmonary Embolus
• Aortic dissection
• Pericarditis
• Pneumonia
• Pneumothorax

7
Missed MIPope JH et al. NEJM 2000 3421163-1170

• Prospective multicenter study May 1993-December
  1993
• 10,689 CP patients
• 8 were proven to have AMI, 7 unstable angina.
• 21 other cardiac etiologies, 55 noncardiac
• 19 (2.1) of 889 patients with AMI were
  discharged home
• 17 of 19 ECGs no evidence of ischemia, and 2
  normal.
• 22 of 966 (2.3) with unstable angina were
  mistakenly discharged. In retrospect, none of
  the 22 patients ECGs showed evidence of
  ischemia and 2 were normal.
• Non-whites, women, chief complaint of dyspnea,
  and a normal ECG all correlated with mistaken
  discharge.

8
Most recent data, with troponinIs the initial
diagnostic impression of noncardiac chest pain
adequate to exclude cardiac disease? Miller CD,
Ann EM December 2004 44(6)565-574

• 17,000 patients with CP
• 1992 thought to be noncardiac (75 d/ced to
  home)
• Physicians blinded to trop results, did not use
  them
• Of 1992, 71 (2.4) had first trop 0.6 - 1.0
• Troponin assay is critical.
• Our trop today is a new generation high
  sensitivity troponin
• (Dade Stratus CS cTNI)
• Very sensitive, but how much more?

9
Inverse relation between with a "rule out MI
evaluation" and the miss MI rate.
Graff Am J Cardiol, Volume 80(5)563-568,
9/1/1997
10
Use of chest pain centers vs. admission
124 per patient cost savings
4.5 MI miss rate
0.4 MI miss rate
Graff Am J Cardiol, Volume 80(5)563-568,
9/1/1997
11
Risk factors for complicationsdeath, MI, CHF,
shock, v fib, v tach

• EKG
• ST elevation ST depression T wave inversion
• Normal has lower risk of complications, even if
  MI present
• h/o recent MI
• Rales above the bases
• Pain
• worse than previous angina
• Same as prior MI
• BP
• DM
• Active or recurrent pain

Brush JE et al. NEJM 3121137-1141, 1985.
Karlson BW et al. Eur Heart J 151558-65, 1994.
Yusuf S et al. Eur heart J 5690-96, 1984.
12
Patients with Acute MI sent home from the
EDMulticenter Chest Pain StudyLee TH., et al.
Clinical characteristics and natural history of
patients with acute myocardial infarction sent
home from the emergency room. Am J Cardiol 1987
60219-24.

• 2.5 of all patients sent home had MI's --26
  of these died
• 0.7 (n9) of chest pain patients who were sent
  home died
• Avg. EP 65 CP patients home per year
• 6 of 9 deaths were misread ECG's
• 13 of 35 MI's sent home had evidence of acute
  ischemia
• 5 of 35 were less than 42 years old

13
39 yo with atypical CP
14
Diagnostic ECG

• New Q-waves
• ST-T abnormalities not secondary to abnormal
  depolarization (i.e., abnormal QRS, e.g., LVH)
• ST depression / 1 mm in 2 consecutive leads
  (corresponds to a coronary distribution)
• Not otherwise explained
• Changed from previous ECG
• T-wave inversion / 1 mm in 2 consecutive leads
• Not otherwise explained
• Changed from previous ECG
• In anatomic distribution

15
Normal ECG

•   Sinus rhythm with normal p-waves
•   ST elevation/depression corresponding PR segments.
•   No LVH, abnormal Q-waves, or conduction
  abnormalities (QRS must be
•   Size of T-waves is proportional to R-waves and
  T-wave axis is close to QRS axis
•   Normal R-wave progression

16
Nondiagnostic ECG

• Old Q-waves
• ST-T abnormalities secondary to abnormal
  depolarization (i.e., abnormal QRS, e.g., LVH)
• Minor, non-dynamic ST or T-wave abnormalities,
  such as ST depression flattening or inversion
• not otherwise explained
• May be changed from previous ECG, but is not
  specific for ischemia or infarction

17
Sensitivity and specificity of ECGfor MI as
diagnosed by CK-MB
Goldman L Ann Int Med 2003 139987
18
Normal or Nondiagnostic ECGKarlson and Rouan
combined dataAMI as defined by CK-MB, MI rate
will be higher in this age of troponin definition
of MI

• CP 11,805
• AMI 1962
• Diagnostic ECG 2979 (STEMI or UA/NSTEMI)
• nl ECG 3635
• nl ECG AMI 125 (6.4 of AMI, 3.4 of nl ECG,
  1.1 of all pts with CP)
• NS ECG 5191
• NS ECG AMI 442 (23 of AMI, 9 of NS ECG,
  3.7 of all pts. with CP)
• Nl or NS ECG 8826
• Nl or NS ECG AMI 567 (29 of all AMI, 6.4
  of all nl or NS ECG, 4.8 of all pts with CP)

19
Diagnostic vs. nondiagnostic (nonspecific)
ECGMI Diagnosis by CK-MB (Trop)

• Approx 45 (25) of AMI has diagnostic STE
• Approx 26 (15) of AMI has diagnostic ST
  depression or T-wave inversion
• Approx 23 (50) of AMI is abnormal but
  nondiagnostic
• 8-15 some evidence of ischemia or infarction not
  known to be old
• Approx 6 (10) of AMI has normal ECG
• Normal with pain vs. without pain
• Chase et al. Acad EM 131034, Oct 2006

Welch RD et al. JAMA Oct. 2001286(16)1977-1984
20
Continuous 12-lead or ST segment monitoring

• Non-diagnostic ECG may turn diagnostic
• Labor and equipment intensive
• Routine use is for high risk patients
• In high risk patients with ongoing symptoms
• Increases sensitivity for STEMI from 46 to 62
  (33) of all MI as measured by CK-MB
• Use serial EKGs every 15 minutes

Fesmire et al. Ann Emerg Med 1998 313-11
21
Atypical Symptoms of MICanto JG, Shlipak MG,
Roger WJ, et al. Prevalence, clinical
characteristics, and mortality among patients
with myocardial infarction presenting without
chest pain. JAMA 2000 2833223-3229. NRMI data.

• 33 of patients with MI (by CK-MB) present
  without chest pain
• Both NSTEMI and STEMI
• Other studies confirm this
• Of MI patients, 42 of those age 75 years and
  63-75 of those age 85 years do not complain
  of chest pain (CP)
• Up to 30 of MI is silent

22
Atypical Symptoms (continued--Canto et al.)
Characteristic No Chest Pain (33) Chest Pain
(67)
Mean age 74 years 67 years Received
reperfusion 25 74 Adjusted in-hospital
mortality 23.3 9.3 (OR 2.17-2.26)
Women 49 38 Prior Heart
Failure 26 12 ST elevation on initial
ECG 23 47 LBBB on initial
ECG 10 5.4

23
History Alternans

• Kappa values for historical and physical
  examination vary widely for different signs and
  symptoms
• Pleuritic, positional, and sharp chest pain have
  poor interphysician reliability (K0.27 to 0.44).
• S3 gallop, 0.14 to 0.37
• rales, 0.12 to 0.31
• neck vein distention, 0.31 to 0.51
• hepatomegaly, 0.00 to 0.16
• dependent edema, 0.27 to 0.64
• Hickan DH, Sox HC, Sox CH. Systematic bias in
  recording the history in patients with chest
  pain. J Chronic Dis. 19853891-100.
• Gadsboll N, et al. Symptoms and signs of heart
  failure in patients with myocardial infarction
  reproducibility and relationship to chest x-ray,
  radionuclide ventriculography and right heart
  catheterization. Eur Heart J. 1989101017-1028.

24
Risk of MI with Chest PainLee TH, et al. Acute
chest pain in the emergency room. Identification
and examination of low-risk patients. Arch Int
Med 1985 14565-69

• increased with history of known angina
• increased when identical to previous MI
• Deceptive
• "burning," "indigestion," (23 with MI) and
  "numbness" or inability to characterize the pain
  (23 with MI) are as likely to be MI as
  "pressure," "tightness", "crushing (24 with MI)
  
• 5 prob. if pain was "sharp" or "stabbing"

25
Chest Pain characteristics and MILee TH, et al.
Acute chest pain in the emergency room.
Identification and examination of low-risk
patients. Arch Int Med 1985 14565-69

• with ACS if pain is pleuritic, positional, or
  reproducible
• 13 (n 96) if pain partly pleuritic or
  positional
• 0 (n 36) fully pleuritic or positional
• 24 (n158) if pain is partly reproduced on exam
• 7 (n 124) if fully reproduced
• greater with radiation to left arm, shoulder or
  neck
• less with radiation to back, abdomen, or legs
• Probability of MI
• greater with duration 60 minutes

26
Positive Likelihood Ratios for MIPanju AA,
Hemmelgarn BR, Guyatt GH, Simel DL. Is this
patient having a myocardial infarction? JAMA
1998 Oct 14280(14)1256-63.

• new ST-segment elevation 11.2 (LR range,
  5.7-53.9)
• New ST depression, T wave inversion
• new Q wave 7.0 (LR range, 5.3-24.8)
• new conduction defect 6.3 (LR range 2.5-15.7)
• chest pain radiating to both the left and right
  arm simultaneously 7.1 (3.6-14.2)
• radiation to left (2.3) or right arm (2.9)
• presence of a third heart sound 3.2 (LR, 3.2)
• hypotension 3.1 (LR, 1.8-5.2).
• crackles 2.1 (1.4-3.1)
• diaphoresis 2.0 (1.9-2.2)

27
Negative Likelihood Ratios for MIPanju AA,
Hemmelgarn BR, Guyatt GH, Simel DL. Is this
patient having a myocardial infarction? JAMA
1998 Oct 14280(14)1256-63.

• a normal ECG result (LR, 0.2)
• pleuritic chest pain (LR, 0.2)
• sharp or stabbing chest pain (LR, 0.3)
• positional chest pain (LR, 0.3)
• chest pain reproduced by palpation (LR, 0.3)
• Not associated with exertion (LR, 0.8)
• Infra-mammary location (LR, 0.8)
• These calculations did not distinguish between
  partial or full reproducibility

28
Right arm involvementBerger JP, et al. Right
arm involvement and pain extension can help to
differentiate coronary diseases from chest pain
of other origin a prospective emergency ward
study of 278 consecutive patients admitted for
chest pain. Int Med 1990 March
227(3)165-72Everts B. et al., Localization of
pain in suspected acute myocardial infarction in
relation to final diagnosis.Heart and Lung 1996
25430-7.

• Berger Most important in this study was wide
  radiation that included the right arm of 51
  patients with R arm involvement, 48 had coronary
  disease and 41 had MI.
• Everts pain in both right and left arms was the
  only distinguishing characteristic of
  localization that differed between those with and
  without MI

29
Low risk Features, summary (ECG must be normal
or nonspecific)

• Right side only
• Pain primarily in middle or lower abdomen
• Pain lasts seconds only
• While the patient has this pain, it improves with
  exertion
• (e.g. goes away if I play basketball)
• clear non-ischemic cause for pain is found
• Chest wall trauma or chest x-ray abnormality
• GI etiology is NEVER a clear alternative Dx
• Palpation reproduces pain exactly on multiple
  exams
• Pain is pleuritic
• Pain is brought on by changes in position or
  movement
• Pain is localized to a fingertip
• Sharp (stabbing) pain

30
Typical Symptoms (higher probability that
cardiac ischemia is the etiology)

• 1. Same as symptoms of previous proven cardiac
  ischemia
• 2. Substernal or left-sided, poorly localized
  discomfort, with or without radiation
• Indigestion
• Pressure
• Burning
• Tightness
• Crushing
• Nondescript discomfort
• 3. Brief, sudden, unexplained dyspnea
• Other typical features
• 1. During episode of pain, is worsened by
  exertion and improved by rest
• 2. Radiation to left or right or especially both
  arms or shoulders

31
Significant Risk Factors

• Any one of
• Age 50 (male), 55 (female)
• / 2 risk factors (other than diabetes)
• Smoking (RR 1.5, CI 1.0-2.4)
• Hypertension (NS)
• Hyperlipidemia (NS)
• high cholesterol (total, LDL-cholesterol
  LDL-C), low high-density lipoprotein (HDL), and
  high triglyceride levels
• Family history (RR 2.1, 1.4-3.3)
• Diabetes mellitus (RR 2.4, 1.2-4.8)

Jayes RL, J Clin Epidem 45621, 1992
32
Pitfalls in diagnosis of ischemia

• Pts. often interpret "sharp" to mean severe
• Therapeutic trials may be very misleading
• Nitroglycerin no different from placebo
• Henrickson, CA.  Chest Pain relief by
  Nitroglycerin Does Not Predict Active Coronary
  Artery Disease.  Ann Int Med 139(12)979-986,
  Dec. 16, 2003
• Antacids may improve up to 25 of MI pain
• Up to 33 of pts. with ACS have some chest wall
  tenderness, (24 partly, 7 fully reproducible)
• Lee TH, Arch Int Med 14565-69, 1985.
• Fully v. partly pleuritic or positional pain

33
Pitfalls (contd)

• Unchanged ECG, even normal ECG
• with an atypical history, a normal ECG is rarely
  an MI, but not so rarely unstable angina
• Clinical presentation particularly variable in
  the elderly
• 40-50 fail to c/o chest pain
• Bayer AJ et al. J Am Soc Geriatr 34263-266
• Common atypical symptoms--shortness of breath,
  abdominal pain, dizziness, arm/shoulder/jaw pain
  
• Pain that persists in ED or recurs in ED
• associated with 3.8 x the risk of complications
  (Fesmire FM. Wears RL. Am J Em Med 1989 July
  7(4)372-377)

34
Previous negative stress testingNerenberg,
Smith, Engineer

• Imaging, sestamibi or echo
• 85 sensitive for significant stenosis
• Non-imaging (ECG) stress tests
• 70 sensitive
• They only look for fixed stenosis
• 5 incidence of MI within 3 years of negative
  stress imaging test
• Nevertheless it has some (unknown) negative LR
  ( 0.5?)

35
Previous normal angiogram

• "Normal" was formerly used for coronaries with
  small nonobstructive (e.g.
• 20-50 lesions progress and are known to
  fissure/ulcerate and form clot.
• 50 (70) may be flow-limiting and correlates
  with stable angina
• Totally normal means no luminal narrowing
• Does not rule out extraluminal atheroma which can
  ulcerate
• Diagnosis by IVUS (intravascular ultrasound),
  maybe CT/MRI
• If patient presents for same pain which led to
  the angiogram
• Then a "negative" angiogram is very helpful (high
  negative LR).
• If the new pain is different and typical
• it may well be due to coronary syndrome
• If the patient had a truly normal angiogram
• then even at 5 years from angiogram, new CAD is
  unlikely
• Syndrome X (disease of small vessels) and Spasm

36
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38
Young patients (8(7)703-8, July 2001, Vancouver rule validates
this Christensen J et al. Ann EM 471-10, 2006

• 527 presentations, 30 day f/u on 507
• 210 patients without a cardiac history and
  without cardiac risk factors 0.5 (n1) with
  ACS, none with 30-day adverse outcome
• 312 patients without a cardiac history and with
  normal ECGs 0.3 (n1) with ACS, none with
  30-day adverse event
• No cardiac history and
• Normal ECG or
• No risk factors and nonspecific ECG
• Very low risk (0.3-0.5)

39
CP not clearly non-cardiacCan any score get
probability 40? No

• Clinical (Chest pain story ECG)
• Risk factors
• Goldman
• ACI-TIPI
• Neuro Network
• TIMI Risk score

40
Goldman's Computer Protocol Goldman L., et al.
A computer protocol to predict myocardial
infarction in ED patients with chest pain. N
Engl J Med 1988 Mar 31 318(13)797-803

• With a non-specific ECG, the probability of MI
  was 7 if
• the pain duration was
• 1) h/o angina or MI
• and longest pain episode was 1 hour
• and pain is worse than prior angina or same as
  prior MI
• 2) no h/o angina or MI, but
• pain radiates to neck, L shoulder, or L arm
• and age / 40
• and not reproduced by palpation
• and does not radiate to back, abd or legs
• and is not "stabbing

41
Goldman's Computer Protocol

• Concluded that patients with probability 7
  should be admitted to a CCU.
• Other admissions should be to a step-down unit.
• The protocol was superior to physician judgment.
• Did not address discharge/admission
• Did not address unstable angina
• Did not address outcome

42
Goldman risk troponinLimkakeng A et al. Acad EM 2001
8696-702

• Goldman MI risk of 4 (?) and
• Single initial negative cTnI
• 2.0 ng/mL, not 0.3 ng/ml
• 3.7 risk of ACS
• risk for death (0.6)
• MI (1.7)
• revascularization (1.4) at 30 day
• Used high trop cutoff
• Bad Assay
• Old assay

43
Acute cardiac ischemia time-insensitive
predictive instrumentSelker Ann Intern Med,
Volume 129(11).December 1, 1998.845-855Patients
with Symptoms suggestive of ischemia

• Age
• Sex
• presence of chest pain
• chest pain as the chief symptom
• a history of heart attack or nitroglycerine use
• ST-segment or T-wave abnormalities
• Presence of Q waves

44
Acute cardiac ischemia time-insensitive
predictive instrument (ACI-TIPI)
electrocardiogram. Selker Ann Intern Med, Volume
129(11).December 1, 1998.845-855
45
ACI-TIPIUsed at several hospitals, compared to
months when not available

• Reduced CCU admissions 15 to 12
• Reduced step-down unit admissions
• Increased ED discharge rate 49 to 52
• No increase in inappropriate discharge (4 for
  both)
• Advocated by Agency for Health Care Quality and
  Research as effective and inexpensive

46
Interstudy reliability

• Goldman risk score / 7
• sensitivity for predicting MI was 88 to 91
• The Acute Cardiac Ischemia Time-Insensitive
  Predictive Instrument (ACI-TIPI)
• sens 86 to 95 for prediction of ACS when
  combined with physician impression
• When these algorithms were analyzed by different
  investigators
• Goldman risk score of 7 or greater
• sens of 74
• ACI-TIPI score of 25 or greater
• sens of 62
• 1. Goldman. N Engl J Med 1988 Mar 31
  318(13)797-803
• 2. Lau J, et al. Ann Emerg Med. 200137453-460.
• 3. Baxt WG, et al. Ann Emerg Med.
  200239366-373.
• 4. Baxt WG. Society of Academic Emergency
  Medicine annual meeting May 2001 Atlanta, GA.

47
Derivation of the Four Initial Risk Groups on the
Basis of Data Available at the Time of
Presentation in the Emergency Department
Risk factors 1) BP bases bilaterally 3) Known unstable ischemic
heart disease ---worsening of previously stable
angina ---new onset of postinfarction
angina ---angina after a coronary-revascularizatio
n procedure 4) Pain the same as that associated
with a prior myocardial infarction.
Risk of major event within 12 hours 0.2
0.5 1.1 7.6
Goldman, L. et al. N Engl J Med 19963341498-1504
3341498 Goldman 1996
48
TIMI Risk ScorePollack CV et al. Acad EM 2006
1313-18
Risk of ACS 2.1 with TIMI score 0 5 with
score 1 10 with score 2 Troponin assay and
cutoff not in methods or results
49
Sanchis Score Better than TIMI score Sanchis J,
Bodi V, Nunez J, et al. New risk score for
patients with acute chest pain, non-ST-segment
deviation, and normal troponin concentrations a
comparison with the TIMI risk score. J Am Coll
Cardiol. 200546443-449.
Chest Pain Score
646 pts with neg ECG and neg initial trop.
Death or MI at one year 0 in the 111 (17)
who had a score of 0
66 yo (0) with one episode (0) of severe (2)
substernal (3) tightness (2) radiating to left
(2) arm without relieving or exac factors or
assoc. Sxs or history of angina, who has no h/o
CAD or DM score 0
50
Vancouver ruleVery low risk of ACS Christensen
J et al. Ann EM 471-10, 2006

• age younger than 40 years
• normal initial ECG
• no previous ischemic chest pain
• / 40 years old
• normal ECG
• No previous ischemic chest pain
• low-risk pain characteristics
• Non-radiating, not pleuritic or reproducible
• CK-MB
• 3.0 mcg/L, but no increase at 2 hours
• Uncertain how to substitute troponin for this

51
Vancouver Rule
52
Chest Pain UnitMany articles

• Low risk chest pain patient
• Most after Biomarker rule out
• Then
• Stress
• ECG-GXT
• Stress imaging
• Sestamibi
• Echo

53
Immediate ED GXTKirk JD, Annals EM 321-7, July
98

• 212 Low risk patients
• Normal or minor Nonspecific ECG abnormalities
• Before any biomarkers returned
• No LVH or BBB
• No complications
• Positive in 23 13 of 23 with later proven CAD
  (PPV of 57)
• No negative had ACE-30

54
ED GXTLewis WR. Immediate exercise testing of
low risk patients with known coronary artery
disease presenting to the emergency department
with chest pain. JACC 33(7)1843-7, 1999 Jun.

• 20 of screened patients
• Usually after at least one biomarker negative
• Safe
• Effective for risk stratifying

55
ED GXT

• Need treadmill in ED
• Need at least 16 hour availability of
• Technician and interpreter
• Interpreter
• Cardiology
• ED staff can successfully read stress ECGs.
• Kirk JD. Interpretation of immediate exercise
  treadmill test interreader reliability between
  cardiologist and noncardiologist in a chest pain
  evaluation unit. Ann Emerg Med 36(1)10-4, 2000
  Jul.
• Stress ECHO or sestamibi necessary in most
  women-- difficult to do and interpret

56
Rest SPECT Sestamibi 1) Bilodeau L, et al.
Technetium-99m sestamibi tomography in patients
with spontaneous chest pain correlations with
clinical, electrocardiographic, and angiographic
findings. J Am Coll Cardiol 1991181684-1691.
n 452)Stowers SA, et al. Technetium-99m
sestamibi SPECT and technetium-99m tetrofosmin
SPECT in prediction of cardiac events in patients
injected during chest pain and following
resolution of pain (abstract). J Nucl Med
19953688P-89P

• Controversy and uncertainty about sens. when
  injected without active pain
• Rest sestamibi, injection up to 4 hours after
  pain resolution
• sensitivity for CAD (50 stenosis)
• 96 (vs. 35 for ECG) if injection during pain
• Decreases to 65 (1) and 38 (2) if injection is
  after resolution of pain
• Cannot distinguish old from new MI

57
Rest SestamibiVaretto T., et al. Emergency room
technetium-99m sestamibi imaging to rule out
acute myocardial ischemic events in patients with
nondiagnostic electrocardiograms. J Am Coll
Cardiol 221804-1808, 1993.

• 100 sensitivity if injected within the past 12
  hours during an episode of chest pain that lasted
  30 min.
• 64 pts.
• Identified all 27 with acute ischemia
• 3 false positives (specificity 92)

58
Tatum JL, et al. Comprehensive strategy for the
evaluation and triage of the chest pain patient.
Ann Emerg Med 1997 Jan 29(1)116-125.Strategy
based on rest only sestamibi

• Low prob of AMI
• Low to mod prob of Unstable Angina
• short duration of typical symptoms
• prolonged atypical symptoms in pt without h/o CAD
  and with nonspecific ECG
• 253 with neg. sestamibi--went home--no cardiac
  events
• 2 with MI (both normal ECG and low risk,
  identified by sestamibi)
• 29 positive sestamibi, 8 with cardiac endpoints

59
Rest Sestamibi drawbacks

• Radionuclide had 6-12 hour shelf life and
  30-minute preparation time
• need to constantly renew the supply to have it
  ready for a patient with pain
• 24-hour nuclear technician on call
• Expertise in reading
• Pts. with a previous MI are excluded (unless
  there is a previous scan for comparison)
• Controversy over timing of injection

60
Incremental value of ED data for detection of MI
Fesmire et al. Erlanger protocol. Ann Emerg Med
2002 40584-94
61
Incremental value of ED data for detection of
30-day adverse outcome(death, MI, PCI, CABG, 70
stenosis, life-threatening complication)
62
Outcome of ED patients discharged home after a
negative troponin ISmith SW, et al. J Emerg
Med May 2004, retrospective

• Hamm et al.
• CP or other Sx compatible with ischemia, at least
  6 hours
• Low risk and nondiagnostic ECG
• Adverse cardiac event at 30 daysdeath or MI (pos
  cTnI)
• Follow-up by chart or telephone
• 663 patients identified, 588 (89) with follow-up
  (493 by chart, 95 by telephone). Death records
  negative.
• Mean age 48, CP 66, Abd pain 4, back or ext.
  pain 5, SOB 4, dysrhythmia 3, other 15
• Previous CAD 25 both CP and CAD (n104) 18
• 2 adverse cardiac events 2 non Q-wave AMI (both
  cTnI
• 2 others with positive GXT, 1 non-cardiac death

63
Chest Pain Patients Dec 1996 and July
1999 Total 6802 Admitted 3596
(53) cTnI drawn 3779 (56) cTnI drawn and
patient admitted 3343 (49) Discharged (none
discharged prior to return of cTnI) With or
without cTnI 3206 (48) Without cTnI
determination 2770 (41) After an increased
cTnI 0 (0) After a normal cTnI 436
(6.4) (13.4 of discharges) After normal
cTnI, followup obtained 390 (5.7) (12.2 of
discharges)
64
Recent Datahigh sensitivity troponinShort Stay
Jan.-Dec. 2003

• 1232 patients
• 1081 with all three trops negative (
• 102 pt's with a positive first trop
• 41 Pt's with a positive second trop
• (CSSU had 5 rule-in rate, 49/1130)
• 8 pts with a positive third trop (8 hours)
• 2 with ACS had age
• Both had either 3 risk factors and/or h/o CAD
• Newer, higher sensitivity data still to come
• On our present assay Dade Stratus CS cTNI
• Normal

65
Telemetry

• 8,932 patients admitted to telemetry
• One (1) (0.02) (95 CI 0 to 0.05) had a
  cardiac arrest that was detected by the monitor
  and led to survival.
• Routine telemetry offers little cardiac arrest
  survival benefit to most monitored patients, and
  a more selective policy for telemetry use might
  safely avoid ECG monitoring for many patients.

Schull MJ. DA Acad Emerg Med. 2000
Jun7(6)647-52.
66
Telemetry

• 1029 low risk CP patients admitted to telemetry
  (Goldman risk 2.0 ng/ml)
• No sustained v tach or v fib
• 2 deaths, neither cardiovascular or preventable
  by monitoring
• Conclusion The routine use of telemetry
  monitoring for low-risk patients with chest pain
  is of limited utility.
• Hollander JE. Ann Emerg Med 43(1)71-6, January
  2004

67
ED EBCT study Laudon DA. Use of electron-beam
computed tomography in the evaluation of chest
pain patients in the emergency department Annals
Emerg Med. 33(1)15-21, 1999 Jan.

• 105 ED pts with CP, () defined as Ca score 0
• 100 underwent stress test in 58, angiography in
  25, radionuclide in 19, and echocardiography in
  11
• EBCT and cardiac testing were negative
• Negative for both in 53 patients (53)
• positive for both in 14 (14)
• positive for tomography and negative for cardiac
  testing in 32 (32),
• negative for tomography with a (false) positive
  for cardiac testing in only 1 patient
• Sensitivity of EBCT was 100 (95 CI, 77 to
  100)
• negative predictive value of 100 (95 CI, 94 to
  100).
• Specificity was 63 (95 CI, 54 to 75)

68
McLaughlin V.V. et al. Am J Cardiol 84327

• 134 admitted chest pain patients
• Normal or NSECG
• No prior history of CAD
• Normal CK-MB
• Calcium present if CS 0
• 48 (36) with negative scans (small n)
• 30-day event rate 1 of 48 (2), in a cocaine
  user who continued use and had normal coronaries
  at angiogram

69
CT coronary angiogramnondiagnostic ECG and 2
negative trops (

No h/o obstructive CAD

Not high risk

No prior angiogram

No CTA in last year

No atrial fib Able to hold breath No contrast
allergy Weight contraindication to beta-blockers
1.         Rubinshtein R, et al. Circulation
2007 1151762-8. 2.         Goldstein JA, et al.
J Am Coll Cardiol 2007 49863-71. 3.        
Gallagher MJ, et al. Ann Emerg Med 2007
49125-36. 4.         Hollander JE, et al. Acad
Emerg Med 2007 14112-6.
70
CT coronary angiogramnondiagnostic ECG and 2
negative trops (

Any stenosis 50--Admit with Dx of ACS

Any stenosis 25-50--Aspirin, Cards clinic ASAP

Soft plaque--Aspirin, Cardiology clinic ASAP

Significant coronary calcium ( 100?)

Aspirin, Cardiology clinic ASAP

Any stenosis 0-25--

Risk factor management, aspirin, PMD

1.         Rubinshtein R, et al. Circulation
2007 1151762-8. 2.         Goldstein JA, et al.
J Am Coll Cardiol 2007 49863-71. 3.        
Gallagher MJ, et al. Ann Emerg Med 2007
49125-36. 4.         Hollander JE, et al. Acad
Emerg Med 2007 14112-6.
71
CT angio signif cancer risk

• National Academies' Biological Effects of
  Ionizing Radiation report.
• lifetime risk for cancer from a single CTCA
• Women lung and breast account for 80
• 1 in 143 at age 20
• 1 in 284 at age 40
• 1 in 466 at age 60
• Men's risks were considerably lower
• 1 in 686 at age 20, 1 in 1007 at age 40, and 1 in
  1241 at age 60.
• Women
• greater radiosensitivity of their lungs
• breast lies in the field irradiated during CTCA.
• The authors note that CTCA "should be used
  particularly cautiously in the evaluation of
  young individuals, especially women."
• JAMA. 2007298317-323

72
Case

• 40 yo with substernal chest pressure for 3 hours
• No radiation or associated symptoms
• Ongoing, not intermittent
• No cardiac history
• Cigarette smoker, no other risks
• ECG normal
• First trop
• Management very different if quality of CP
  atypical

73
Summary

• ECG is critical first datayou must be proficient
• Symptom characteristics are important
• Low risk patients with a normal or NS ECG and a
  negative troponin at 6-9 hours (or zero and 4)
  are at very low risk for adverse events
• Patients with serially negative troponins (MI
  ruled out) may still have life-threatening
  unstable angina
• May need stress test or CTA, or angiogram if
  mod-high risk
• The more patients observed, the fewer MIs sent
  home
• There are multiple strategies of observation,
  rest imaging, and stress imaging to help to
  identify those at higher risk of ACS
• These strategies have many limitations/false
  positives/false negatives
• No perfect strategy exists
• Risk stratification is all that can be achieved