The search for the very low risk chest pain patient

who goes home/who stays in?

• Stephen W. Smith, MD

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

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

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 < .04

Lee GoldmanAnn Int Med 2003; 139:987

• 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.

Life threatening causes of Chest Pain

• Coronary syndrome

• Pulmonary Embolus

• Aortic dissection

• Pericarditis

• Pneumonia

• Pneumothorax

Missed MIPope JH et al. NEJM 2000; 342:1163-1170

• 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 ECG’s “no evidence of ischemia,” and 2 “normal.”

• 22 of 966 (2.3%) with unstable angina were mistakenly discharged. In retrospect, none of the 22 patient’s ECG’s showed evidence of ischemia and 2 were normal.

• Non-whites, women, chief complaint of dyspnea, and a normal ECG all correlated with mistaken discharge.

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/c’ed 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?

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

Use of chest pain centers vs. admission

4.5% MI miss rate

0.4% MI miss rate

Graff: Am J Cardiol, Volume 80(5):563-568, 9/1/1997

$124 per patient cost savings

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 < 110• DM• Active or recurrent pain

Brush JE et al. NEJM 312:1137-1141, 1985. Karlson BW et al. Eur Heart J 15:1558-65, 1994. Yusuf S et al. Eur heart J 5:690-96, 1984.

Patients with Acute MI sent home from the EDMulticenter Chest Pain Study

Lee TH., et al. Clinical characteristics and natural history of patients with acute myocardial infarction sent home from the emergency room. Am J Cardiol 1987;

60:219-24.

• 2.5% of all patients sent home had MI's --26% of these died

• 0.7% (n=9) 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

39 yo with atypical CP

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

Normal ECG

  Sinus rhythm with normal p-waves  ST elevation/depression < 0.5 mm relative to

corresponding PR segments.   No LVH, abnormal Q-waves, or conduction

abnormalities (QRS must be < 100 ms)  Size of T-waves is proportional to R-waves and

T-wave axis is close to QRS axis  Normal R-wave progression

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 < 1 mm and T-wave flattening or inversion < 1 mm– not otherwise explained

• May be changed from previous ECG, but is not specific for ischemia or infarction

Sensitivity and specificity of ECGfor MI as diagnosed by CK-MB

Goldman L; Ann Int Med 2003; 139:987

Normal or Nondiagnostic ECGKarlson and Rouan combined data

AMI 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)

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 13:1034, Oct 2006

Welch RD et al. JAMA Oct. 2001;286(16):1977-1984

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; 31:3-11

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; 283:3223-3229. 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”

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%

Atypical Symptoms (continued--Canto et al.)

History Alternans• Kappa values for historical and physical examination vary

widely for different signs and symptoms– < .40 = poor, .40-.60 = fair

• Pleuritic, positional, and sharp chest pain have poor interphysician reliability (K=0.27 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. 1985;38:91-100.

– 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. 1989;10:1017-1028.

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; 145:65-69

• 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"

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; 145:65-69

• % 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% (n=158) 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

Positive Likelihood Ratios for MIPanju AA, Hemmelgarn BR, Guyatt GH, Simel DL. Is this patient having a

myocardial infarction? JAMA 1998 Oct 14;280(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)

Negative Likelihood Ratios for MIPanju AA, Hemmelgarn BR, Guyatt GH, Simel DL. Is this patient having a

myocardial infarction? JAMA 1998 Oct 14;280(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

Right arm involvement:Berger 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; 25:430-7.

• 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

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

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

1. Same as symptoms of previous proven cardiac ischemia2. Substernal or left-sided, poorly localized discomfort, with or without

radiationa. “Indigestion”b. “Pressure”c. “Burning”d. “Tightness”e. “Crushing”f. “Nondescript discomfort”

3. Brief, sudden, unexplained dyspneaOther 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

Significant Risk Factors

• Any one of:• Age > 50 (male), > 55 (female)1. >/= 2 risk factors (other than diabetes)

a. Smoking (RR 1.5, CI = 1.0-2.4)b. Hypertension (NS)c. Hyperlipidemia (NS)

a. high cholesterol (total, LDL-cholesterol [LDL-C]), low high-density lipoprotein (HDL), and high triglyceride levels

d. Family history (RR = 2.1, 1.4-3.3)

2. Diabetes mellitus (RR = 2.4, 1.2-4.8)

Jayes RL, J Clin Epidem 45:621, 1992

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 145:65-69, 1985.

• Fully v. partly pleuritic or positional pain

Pitfalls (cont’d)• 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 34:263-266

• 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)

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?)

Previous “normal” angiogram• "Normal" was formerly used for coronaries with small

nonobstructive (e.g. <50%) lesions. – 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

Young patients (< 40yo)Walker NJ et al. Acad EM 8(7):703-8, July 2001, Vancouver rule

validates this: Christensen J et al. Ann EM 47:1-10, 2006

• 527 presentations, 30 day f/u on 507• 210 patients without a cardiac history and without

cardiac risk factors: 0.5% (n=1) with ACS, none with 30-day adverse outcome

• 312 patients without a cardiac history and with normal ECGs: 0.3% (n=1) 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%)

CP not clearly non-cardiac:Can any score get probability < 2% for those

with age > 40? No

• Clinical (Chest pain story + ECG)

• Risk factors

• Goldman

• ACI-TIPI

• Neuro Network

• TIMI Risk score

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 < 48 hours and:• 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”

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

Goldman risk < 4% and “negative” troponinLimkakeng A et al. Acad EM 2001; 8:696-702

• 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

Acute cardiac ischemia time-insensitive predictive instrument

Selker: Ann Intern Med, Volume 129(11).December 1, 1998.845-855

Patients 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

Acute cardiac ischemia time-insensitive predictive instrument (ACI-TIPI) electrocardiogram. Selker: Ann Intern Med, Volume

129(11).December 1, 1998.845-855

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

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. 2001;37:453-460.• 3. Baxt WG, et al. Ann Emerg Med. 2002;39:366-373.• 4. Baxt WG. Society of Academic Emergency Medicine annual meeting; May 2001;

Atlanta, GA.

Goldman, L. et al. N Engl J Med 1996;334:1498-1504

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 < 110 mm Hg

2) Rales above bases bilaterally

3) Known unstable ischemic heart disease

---worsening of previously stable angina

---new onset of postinfarction angina

---angina after a coronary-revascularization 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% 334:1498; Goldman 1996

TIMI Risk ScorePollack CV et al. Acad EM 2006; 13:13-18

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

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. 2005;46:443-449.

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. Sx’s or history of angina, who has no h/o CAD or DM: score = 0

Chest Pain Score

Vancouver ruleVery low risk of ACS

Christensen J et al. Ann EM 47:1-10, 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 or

• ≥ 3.0 mcg/L, but no increase at 2 hours• Uncertain how to substitute troponin for this

Vancouver Rule

Chest Pain UnitMany articles

• Low risk chest pain patient• Most after Biomarker rule out• Then

– Stress• ECG-GXT • Stress imaging

–Sestamibi–Echo

Immediate ED GXTKirk JD, Annals EM 32:1-7, 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

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

ED GXT

• Need treadmill in ED• Need at least 16 hour availability of:

– Technician and interpreter• Interpreter

– Cardiology– ED staff can successfully read stress ECG’s.

• 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

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 1991;18:1684-1691. 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 1995;36:88P-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

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 22:1804-1808, 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%)

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

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

Incremental value of ED data for detection of MI

Fesmire et al. Erlanger protocol. Ann Emerg Med 2002; 40:584-94

Modality Sens Spec +LR -LR

ECG 26.3 99.9 247 0.74Plus baseline serum markers (TnI > 2 ng/ml, CK-MB > 10 ng/ml)

58.1 99.4 90.7 0.42

Plus serial ECG 64.4 98.9 60.2 0.36Plus 2-hour delta CK-MB (+1.5 ng/ml) or TnI (+0.2 ng/ml)

93.2 93.9 15.3 0.07

Plus physician judgment 97.6 89.4 9.2 0.03Plus selective nuclear stress(reversible perfusion defect)

100 81.9 5.5 0

Incremental value of ED data for detection of 30-day adverse outcome

(death, MI, PCI, CABG, 70% stenosis, life-threatening complication)

Modality Sens Spec +LR -LR

ECG 17.1 100 ------ 0.83Plus baseline serum markers (TnI > 2 ng/ml, CK-MB > 10 ng/ml)

37.6 99.5 82.3 0.63

Plus serial ECG 41.9 99.1 48.9 0.59Plus 2-hour delta CK-MB (+1.5 ng/ml) or TnI (+0.2 ng/ml)

66.1 94.9 12.8 0.36

Plus physician judgment 80.4 92.2 10.3 0.21Plus selective nuclear stress 99.1 87.4 7.9 0.01

Outcome of ED patients discharged home after a negative troponin I

Smith 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 days—death 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 (n=104) 18%• 2 adverse cardiac events: 2 non Q-wave AMI (both cTnI <

2.0), both protocol violations– 2 others with positive GXT, 1 non-cardiac death

Chest Pain Patients: Dec 1996 and July 1999*

Total 6802Admitted* 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)

Recent Data—high sensitivity troponinShort Stay Jan.-Dec. 2003

• 1232 patients• 1081 with all three trops negative (<0.1)• 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 < 55– 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 < 0.04

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 Jun;7(6):647-52.

Telemetry• 1029 low risk CP patients admitted to

telemetry (Goldman risk < 8%, normal CK-MB and troponin I < 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

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%)

McLaughlin V.V. et al. Am J Cardiol 84:327

• 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

CT coronary angiogramnondiagnostic ECG and 2 negative trops (<.04).

• No h/o obstructive CAD• Not high risk• No prior angiogram• No CTA in last year• </= 2 risk factors

1.         Rubinshtein R, et al. Circulation 2007; 115:1762-8.2.         Goldstein JA, et al. J Am Coll Cardiol 2007; 49:863-71.3.         Gallagher MJ, et al. Ann Emerg Med 2007; 49:125-36.4.         Hollander JE, et al. Acad Emerg Med 2007; 14:112-6.

No atrial fib

Able to hold breath

No contrast allergy

Weight < 250 lbs.

No absolute contraindication to beta-blockers

CT coronary angiogramnondiagnostic ECG and 2 negative trops (<.04).

• 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; 115:1762-8.2.         Goldstein JA, et al. J Am Coll Cardiol 2007; 49:863-71.3.         Gallagher MJ, et al. Ann Emerg Med 2007; 49:125-36.4.         Hollander JE, et al. Acad Emerg Med 2007; 14:112-6.

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. 2007;298:317-323

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 < .04• Management very different if quality of CP atypical

Summary• ECG is critical first data—you 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 MI’s 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