Continuous Medical EducationHospital Serdang

07 April 2009

Which chest pain can be safely Which chest pain can be safely

discharged from the ED?discharged from the ED?

Dr. Rashidi AhmadDr. Rashidi AhmadMD(USM), MD(USM), MMedMMed(USM), AM(Mal)(USM), AM(Mal)

Department of Emergency MedicineDepartment of Emergency Medicine

Health Campus USM,Health Campus USM, KelantanKelantan

ObjectivesObjectives

Understanding the magnitude of CP in Understanding the magnitude of CP in

EDED

Understanding the limitations of CP Understanding the limitations of CP

assessment (suspected ACS) in EDassessment (suspected ACS) in ED

ED diagnostic strategyED diagnostic strategy

The flow of patients via the emergency care system

Prehospital care

ED care

Specialist care

Epidemiology of Chest pain in ED

Buntinx F, et al. Chest pain in general practice or in the hospital emergency department: is it the same? Fam Pract 2001;18:586-9.

Facts and figuresFacts and figures

In UK, ~ ½ million patients with CP attend In UK, ~ ½ million patients with CP attend ED each year ED each year 2020--30% medical admissions ~ 50% had 30% medical admissions ~ 50% had

ACS ACS 6% of discharged patients had 6% of discharged patients had

significant myocardial damagesignificant myocardial damage

BMJ Publishing Group Jul 20, 2002BMJ Publishing Group Jul 20, 2002

Cont…Cont…

In US, 100 millions ED visits; 8% had CP In US, 100 millions ED visits; 8% had CP

5 million admissions5 million admissions

30% CCU admission (AMI); only 50-60% had ACI

24% of AMI patients inappropriately discharged 24% of AMI patients inappropriately discharged from EDfrom ED

20% of malpractice claims against EPs relate to the management of ACS

Western Journal of MedicineWestern Journal of Medicine 2000; 172:3292000; 172:329--3131

30%

60%

H. Domanovits et al. / Resuscitation 55 (2002) 9 /16

What are the Characteristics of What are the Characteristics of Misdiagnosed AMI Patients?Misdiagnosed AMI Patients?

Misdiagnosed AMI is more likely to Misdiagnosed AMI is more likely to occur among: occur among: ~ younger patients ~ younger patients ~ atypical symptoms ~ atypical symptoms ~ less experienced physicians ~ less experienced physicians ~ fewer screening ~ fewer screening ECGsECGs orderedordered

Murata, West J Med 1993; 159 (10): 61-68 Review

What are the Characteristics of What are the Characteristics of Misdiagnosed AMI Patients?Misdiagnosed AMI Patients?

Retrospective studyRetrospective study10,689 patients evaluated ACS 10,689 patients evaluated ACS Independent predictors of unrecognized cardiac Independent predictors of unrecognized cardiac ischemia ischemia

-- Women < 55 yrs (OR, 6.7)Women < 55 yrs (OR, 6.7)-- NonNon--whitewhite--race (OR, 2.2) race (OR, 2.2) -- Chief complaint of SOB (OR, 2.7) Chief complaint of SOB (OR, 2.7)

-- Normal ECG (OR, 3.3)Normal ECG (OR, 3.3)

Pope et al. Missed diagnoses of cardiac ischaemia at the ED.NEJM 2000; 342:1163-70

The failure to diagnoseThe failure to diagnoseACS is routinely listedACS is routinely listed

among the top five reasons for aamong the top five reasons for amalpractice suite.malpractice suite.

Reigelman R, Minimizing medical mistakes :

The Art of Medical Decision Making

Diagnostic challengesDiagnostic challenges

Lack of specificity and sensitivity of the

historical data, the physical findings, and the

laboratory tests currently available.

Wagner JM, et al. JAMA 1996;276:1589-94The American Journal of Emergency MedicineVolume 23, Issue 4 , July 2005, Pages 483-487

Accuracy of history/PEAccuracy of history/PE

AMI Odds ratio (CI)

ACS Odds ratio (CI)

Chest pain radiation

Left arm 1.5 (0.6-4.0) 1.7 (0.9-3.1)

Right arm 3.2 (0.4-27.4) 2.5 (0.5-11.9)

Both left and right arm 7.7 (2.7-21.9) 6.0 (2.8-12.8)

Nausea or vomiting 1.8 (0.9-3.6) 1.0 (0.6-1.7)

Diaphoresis 1.4 (0.7-2.9) 1.2 (0.8-1.9)

Exertional pain 3.1 (1.5-6.4) 2.5 (1.5-4.2)

Burning/indigestion pain 4.0 (0.8-20.1) 1.5 (0.5-4.5)

Crushing/squeezing pain 2.1 (0.4-10.9) 0.9 (0.4-2.9)

Relief with nitroglycerin 0.9 (0.1-6.5) 2.0 (0.6-4.9)

Pleuritic pain 0.5 (0.1-2.5) 0.5 (0.2-1.3)

Tender chest wall 0.2 (0.1-1.0) 0.6 (0.3-1.2)

Sharp /stabbing pain 0.5 (0.1-2.8) 0.8 (0.3-2.1)

Goodacre S, et al. How useful are clinical features in the diagnosis of acute, undifferentiated chest pain? Acad Emerg Med 2002 Mar;9(3):203-208.

How do traditional coronary risk factors How do traditional coronary risk factors predict ACS in acute CP?predict ACS in acute CP?

These risk factors identified in longitudinal These risk factors identified in longitudinal studies to predict development of CAD over studies to predict development of CAD over decadesdecades-- not the likelihood of ACS in acute CPnot the likelihood of ACS in acute CPAt least 2 studies have confirmed that the At least 2 studies have confirmed that the absence of risk factors does not exclude ACI absence of risk factors does not exclude ACI as an etiology for patient’s CPas an etiology for patient’s CP

Jayes et al. J Clin Epidemol 1992 ; 45 (6); Singh et al. Acad Emerg Med 2002 ;9;398-402

ElectrocardiogramElectrocardiogram

~ 50% with a proven AMI have positive initial ~ 50% with a proven AMI have positive initial ECG indicating the disorderECG indicating the disorderUp to 76% of ACS Up to 76% of ACS –– normal an initial ECG, non normal an initial ECG, non specific, or unchanged from previous ECG specific, or unchanged from previous ECG Around 5% of CP patients with normal ECG who Around 5% of CP patients with normal ECG who were discharged from the ED were ultimately were discharged from the ED were ultimately found to have ACSfound to have ACS

Mc Carthy B, Wong J. Detecting acute ischaemia in ED. J Gen Int Med 1990; 5: 381-8

Relation between time & Relation between time & ECG changesECG changes

Time Indication of infarct in ECG

1st to 3 hours 40%

4th to 6th hour 50%

7th to 9th hour 90%

10th to 12th hour Up to 100%

ECG is a fairly specific but relatively insensitive test ECG is a fairly specific but relatively insensitive test for diagnosis of myocardial for diagnosis of myocardial ischemiaischemia

Cardiac markers

Hours since Hours since infarct...infarct... 0–4 4–8 8–12 12–24 24–48 48–72 >72

Patients (Patients (nn)) 34 26 41 76 76 69 67

MyoglobinMyoglobin (%)(%) 55.8 92.3 85.4 75.0 43.4 20.3 14.0

95% CI95% CI 38.1–72.4 73.4–98.7 70.1–93.9 63.5–83.9 32.3–55.2 11.0–32.0 6.7–25.0

CKMB mass (%)CKMB mass (%) 44.1 96.2 97.6 97.4 93.4 71.0 22.8

95% CI95% CI 27.6–61.9 78.4–99.8 85.6–99.9 90.0–99.5 84.7–97.6 58.7–81.0 13.2–34.8

TroponinTroponin--I (%)I (%) 35.3 80.7 92.7 97.4 96.1 97.1 93.0

95% CI95% CI 20.3–53.4 60.0–92.7 79.0–98.1 90.0–99.5 88.1–99.0 89.0–99.5 82.2–97.4

Combined (%)Combined (%) 61.8 96.2 97.6 97.4 98.7 98.6 94.7

95% CI95% CI 43.6–77.3 78.4–99.8 85.6–99.9 90.0–99.5 91.9–99.9 91.1–99.9 84.4–98.4

A. Chiu et al. Q J Med 1999; 92: 711-718

Serum markers for myocardial necrosis detect, Serum markers for myocardial necrosis detect, at best, 66%at best, 66% of patients with AMI on arrivalsof patients with AMI on arrivals

Western Journal of MedicineWestern Journal of Medicine 2000; 172:3292000; 172:329--3131

Prediction rule: TIMI Risk ScorePrediction rule: TIMI Risk Score

Age > 65Age > 65

3 or more Traditional Risk Factors (HTN, DM, 3 or more Traditional Risk Factors (HTN, DM, HypercholHyperchol, , FH, Smoking)FH, Smoking)

Known coronary Known coronary stenosisstenosis of 50% or greaterof 50% or greater

STST--segment deviation on ECGsegment deviation on ECG

2 or more 2 or more anginalanginal events in past 24 hoursevents in past 24 hours

ASA use during past weekASA use during past week

Elevated Cardiac EnzymesElevated Cardiac Enzymes

3 or more of seven variables predicts increased risk of death or MI

(JAMA 2000; 284, p. 835)

TIMI Score

Rate of death, MI, revascularizationat 30 days

0 2.1 % (1.4-2.8)

1 5% (3.8-6.2)

2 10% (7.8-12.4)

Acad Emerg Med 2006;13(1):13

TIMI Score

Rate of death, MI, revascularization at 30 days

0 1.7 % (0.42-2.95)

1 8.2% (5.27-11.04)

2 8.6% (5.02-12.08)

in this study, age>65 fell out.

Ann Emerg Med 2006;48:252

Which chest pain can be safely Which chest pain can be safely discharged from the ED?discharged from the ED?

It is not an easy answer!!Over admission – not cost effectivenessInappropriate discharge – misdiagnosis/

mortality, law suitED workout – overcrowding/over burden

The traditional approach to CP is both time-consuming and expensive

ED past and presentED past and present

In the past: no true urgency in making a In the past: no true urgency in making a rapid or definitive diagnosis of myocardial rapid or definitive diagnosis of myocardial ischemiaischemia

Recent ED: rapid diagnosis of ACS in ED is Recent ED: rapid diagnosis of ACS in ED is vital (new medications, thrombolytic vital (new medications, thrombolytic therapy, emergency revascularization)therapy, emergency revascularization)

Diagnostic strategy in EDDiagnostic strategy in ED

Rule out AMI in appropriate patientsRule out AMI in appropriate patientsRule out USA in appropriate patientsRule out USA in appropriate patientsRule out clinically significant CAD in Rule out clinically significant CAD in appropriate patientsappropriate patientsIdentify nonIdentify non--cardiac etiology of symptoms cardiac etiology of symptoms in appropriate patientsin appropriate patients

Suspected ACSSuspected ACS

Can we safely discharge young Can we safely discharge young patients with CP?patients with CP?

1023 patientsIf a patient was between 24 and 39 years old, had no known cardiac history, either no classic cardiac risk factors or a normal ECG, and initially normal cardiac marker studies, the risk of ACS is only 0.14%. No 30-day adverse cardiovascular events in these patients.

Marsan RJ et al. Evaluation of a clinical decision rule for young adult patients with CP. Acad Emerg Med 2005; 12: 26-31.

ChristensonChristenson J,J, InnesInnes G, McKnight D, et al: A clinical prediction rule for early G, McKnight D, et al: A clinical prediction rule for early discharge of patients with chest pain. Anndischarge of patients with chest pain. Ann EmergEmerg Med. 2006;47:1Med. 2006;47:1--10.10.

EchocardiographyEchocardiography

ACI a/w regional myocardial wall motion ACI a/w regional myocardial wall motion abnormalitiesabnormalitiesCaveat: high false negative in EDCaveat: high false negative in EDHighly technical, difficult to interpretHighly technical, difficult to interpretAMI: AMI: sen sen –– 93%; spec 93%; spec –– 66%66%USA: USA: sen sen –– 70%; spec 70%; spec –– 87%87%

Loandis et al. Ann Emerg Med 2001;37:478-94

Stress testStress test

Explored the issue of appropriate discharge after ED Explored the issue of appropriate discharge after ED evaluation in an OU for outpatient risk stratification via ESTevaluation in an OU for outpatient risk stratification via EST

340 patients; 2 patients: fatal out340 patients; 2 patients: fatal out--ofof--hospital cardiac eventshospital cardiac events

27 subsequent chest pain visits to ED 27 subsequent chest pain visits to ED

Suggestions: a negative ED evaluation (serial ECG & Suggestions: a negative ED evaluation (serial ECG & biomarkers) can identify patients at very low risk of shortbiomarkers) can identify patients at very low risk of short--term cardiac events and appropriately selected patients can term cardiac events and appropriately selected patients can be safely discharged for subsequent outpatient testing be safely discharged for subsequent outpatient testing

Lai C, Noeller TP, Schmidt K, King P, Emerman CL: Short-term risk after initial observation for chest pain. J Emerg Med. 2003;25:357-62

Cont..Cont..

Chan et al evaluated patients admitted to monitored Chan et al evaluated patients admitted to monitored telemetry beds who received inpatient telemetry beds who received inpatient vsvs outpatient outpatient vsvs no stress testing and found no difference in 30no stress testing and found no difference in 30--day outcome measures. day outcome measures. Smith et al examined the incidence of AMI in patients Smith et al examined the incidence of AMI in patients with a documented negative stress test within the with a documented negative stress test within the previous 3 years and found that 4.8% of them were previous 3 years and found that 4.8% of them were diagnosed with AMI. diagnosed with AMI. This implies that a recent negative stress test does This implies that a recent negative stress test does not conclusively rule out AMI when a patient has a not conclusively rule out AMI when a patient has a new episode of symptoms.new episode of symptoms.

Chan GW et al. Am J Emerg Med 2003;21:282 - 7.Smith SW et al. Acad Emerg Med 2005;12:51

Stress Echocardiography Stress Echocardiography

LowLow--risk patients with a negative risk patients with a negative stress echo have <1% rate for AMI and stress echo have <1% rate for AMI and cardiac death in the subsequent yearcardiac death in the subsequent year

MarwickMarwick et al. J Amet al. J Am Coll CardiolColl Cardiol 1997;30(1):831997;30(1):83--9090

Use of 64-Section CT in Low-to-Moderate Risk ED Patients Suspected of Having ACS

Coronary CT angiography was performed in 201 consecutive low-to-moderate risk ACS patients. A triple rule-out protocol was used to evaluate for coronary disease, pulmonary embolism, aortic dissection, and other thoracic disease. Subjects underwent a 30-day follow-up.

Takakuwa and Halpern. Radiology 2008: Vol 248: No, 2:438-46

ResultsResults

A disease process other than coronary atherosclerosis that explained the presenting symptoms was diagnosed in 22 (11%) of 197 patients. Clinically important non-coronary diagnoses that did not explain patient symptoms were identified in 27 (14%) of 197 additional patients.

With respect to coronary artery disease:- 10 patients severe disease (70% stenosis)- 12 had moderate disease (50%– 70% stenosis) - 46 had mild disease (up to 50% stenosis)- 129 had no disease.

At 30-day follow-up, the negative predictive value of coronary CT angiography with no more than mild disease was 99.4%. There were no adverse outcomes at 30 days.

Takakuwa and Halpern. Radiology 2008: Vol 248: No, 2:438-46

European Heart Journal (2004) 25, 329–334

Graber & et al. Emergency Medicine April 2001

Prior probability

Medical College of Virginia

International Journal of Cardiology 122 (2007) 170–172