Chest Pain by chenshu

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									Chest Pain: New Methods
Applied to an Old Problem


 Jon W. Wahrenberger, MD
      January 23, 2003
                 Chest Pain

• 5 Million emergency department visits
• 2 million hospitalizations annually with cost
  of more than $8 billion
• Cardiac etiology found in less than one third
• 2% of patients with acute MI are unrecognized
  and discharged from the ED
                  Chest Pain

• Rapid Dx &Tx = saved muscle = improved
  outcome

• Largest category of loss from malpractice
  litigation in the emergency department
                        Goals

1. Rapid recognition of management of true ACS
2. Recognition of other life-threatening causes of
   chest pain
  • Aortic dissection
  • Pulmonary embolism
  • Tension pneumothorax
3. Minimize cost and hospitalization in patients
   with chest pain of benign etiology.
           Chest Pain Diagnosis

• Clinical diagnosis
• Diagnosis using computer algorithms
• Chest pain centers
Chest Pain: Clinical
    Diagnosis
             “Classic” Angina

• Location: central chest
• Quality: squeezing, heaviness
• Radiation: arm(s), neck, jaw
• Associated symptoms: dyspnea, diaphoresis,
  nausea
• Eliciting factors: exertion
• Relieving factors: rest, nitroglycerin
            Differential Diagnosis

• Musculoskeletal      • Psychiatric
• Gastrointestinal     • Pulmonary
• Cardiac              • Other/unknown
           Cardiovascular Chest Pain

• Coronary Heart Disease     • Myocarditis
  • Stable angina pectoris   • Valvular Heart Disease
  • Unstable angina            • Aortic stenosis
  • Myocardial infarction      • Mitral stenosis
• Coronary Vasomotor           • Hypertrophic
  Disease                        cardiomyopathy
  • Variant angina           • Aortic Dissection
  • Microvascular angina     • Post-pericardiotomy
• Pericarditis
• Cardiac or not?
• If cardiac, how to manage?
        Chest Pain Diagnosis: What are we
                    Seeking?


•   Pathologic: MI or No MI
•   Management Based: ST Elevation MI or not?
•   Prognostic
•   Anatomic: Correlating with cath findings
•   Functional: Correlating with ischemia
•   Detailed Diagnosis
    Traditional Classification of Pts with CP

     Group 1                     Group 2

• MI with ST elevation or   • Unstable angina-high
  new LBBB                    risk
• MI without ST elevation   • Unstable angina – low
                              risk
                            • Non-ischemic chest pain
      Ideal Categorization of Patients with CP

 Group 1        Group 2         Group 3      Group 4

 MI with ST     MI without      Unstable    Non-cardiac
  elevation      ST elevation
                 and no LBBB    angina –      chest pain
 New LBBB
                Unstable        low risk
                 angina –
                 high risk


Primary PCI                     Heparin,     Discharge
    or
                                admission       or
Thrombolytics    Heparin,
                                             Treat as
                GP IIbIIIa
                inhibitor                    condition
                                             warrants
         Clinical Evaluation of Chest Pain:
                   Meta Analysis
• Medline search from 1980-1998
• Inclusion Criteria:
  •   Evaluation of pts thought to have cardiac ischemia
  •   Tool: history, PE, ECG
  •   Outcome assessed: MI or no MI
  •   Sample size > 200 patients
• Statistical methods: pool studies and
  determine likelihood ratios
          Panju, et al. JAMA 1998;280:14:1256-1263
  Features Increasing Likelihood of AMI
Clinical Feature                    Likelihood Ratio (95% CI)
Pain in chest or left arm           2.7
Chest pain radiation
  Right Shoulder                    2.9 (1.4-6.0)
  Left arm                          2.3 (1.7-3.1)
  Both left and right arm           7.1 (3.6-14.2)
Chest pain most important symptom   2.0
History of MI                       1.5-3.0
Nausea or vomiting                  1.9 (1.7-2.3)
Diaphoresis                         2.0 (1.9-2.2)
Third heart sound                   3.2 (1.6-6.5)
Hypotension (SBP<80)                3.1 (1.8-5.2)
Pulmonary rales on exam             2.1 (1.4-3.1)
 Features Decreasing Likelihood of AMI


Clinical Feature                       Likelihood Ratio (95% CI)
Pleuritic chest pain                   0.2 (0.2-0.3)
Chest pain sharp or stabbing           0.3 (0.2-0.5)
Positional chest pain                  0.3 (0.2-0.4)
Chest pain reproduced with palpation   0.2-0.4




       Panju, et al. JAMA 1998;280:14:1256-1263
ECG Features Increasing Likelihood of
                 MI




  Panju, et al. JAMA 1998;280:14:1256-1263
      Clinical Symptoms and Angiographic
                    Disease
• Goal: determine correlation between clinical
  characteristics and angiographic disease
• Population:
  • 65 of 1022 patients undergoing angiography and with
    normal coronaries
  • 65 consecutive age-matched controls and with angiographic
    CAD (> 70 diameter narrowing)
• Method: all patients interviewed within 24 hours of
  angiogram by interviewers blinded to angio results

           Reference: Cook, et al. Heart 1997;78:142-6
       Clinical Symptoms and Angiographic
                     Disease
Results:
1. No correlation between site of pain, radiation, quality of
    pain, or relief with NTG and presence of disease
2. Only four clinical variables separated groups:
   a. Reproducibility with exercise (10/10 v. 1-9/10)
   b. Lack of rest symptoms (0-1/10 v. 2-10/10)
   c. Duration of 5 minutes or less (5 min. v > 5 min)
   d. Age (<55 v. ≥55)


             Reference: Cook, et al. Heart 1997;78:142-6
Clinical Symptoms and Angiographic
              Disease
 No Typical Symptoms     Probability (%) Of CAD
   <55 years:
        0/3              2%
        1/3              6-12%
        2/3              25-44%
        3/3              69%
   ≥55 years:
        0/3              12%
        1/3              29-48%
        2/3              69-84%
        3/3              93%

    Reference: Cook, et al. Heart 1997;78:142-6
      Clinical Symptoms and MI in Patient
            with Non-diagnostic ECG
Goal: measure ability of clinical features to predict
   AMI or ACS in those with non-diagnostic ECG
Study Population: 893 pts presenting to large teaching
   hospital in the UK with suspected AMI or ACS.
Study Protocol:
   History, PE, ECG & CXR
   Baseline CK-MB, Trop T at six hours
   If enzymes negative, stress test and discharge

   Reference: Goodacre, et al. Acad. Emerg Med 2002;9:20308
          Clinical Symptoms and ACS/MI
        in Patient with Non-diagnostic ECG

 •   Pain site             •   Associated symptoms
 •   Radiation             •   Pleuritic Nature
 •   Nature                •   Response to exercise
 •   Duration              •   Chest wall tenderness
                           •   Response to NTG
• Endpoints:
  • AMI by WHO criteria
  • ACS defined by AMI on presentation or w/i 6 mo.

     Reference: Goodacre, et al. Acad. Emerg Med 2002;9:20308
     Clinical Symptoms and ACS/MI
   in Patient with Non-diagnostic ECG




Reference: Goodacre, et al. Acad. Emerg Med 2002;9:20308
       Chest Pain: Evaluation Based on
                  Prognosis


    Prediction of Risk for Patients with
              Unstable Angina

Evidence Report/Technology Assessment No. 31
Agency for Healthcare Research and Quality
           AHRQ Meta Analysis

• MEDLINE search 1966-1998 of studies
  performing multivariate analysis of clinical
  and/or ECG predictors of adverse clinical
  events in patients with suspected or diagnosed
  unstable angina.
• Separate analysis of predictive value of
  troponin and Chest Pain Units
                 AHRQ Meta Analysis

Clinical Predictors:

•   Demographics (age, sex, ethnicity)
•   Medical history (prior MI, CHF, diabetes, etc)
•   Symptom Characteristics
•   Initial Exam findings
•   Initial ECG features

Outcomes: Cardiac death, MI, other major cardiac complications
            AHRQ Meta Analysis

• Demographic features correlating with poor
  prognosis:
  • Increasing age
  • Male gender
• Prior Medical Conditions:
  • Prior MI
  • Diabetes
  • (Prior CHF, HTN, smoking)

     1
            AHRQ Meta Analysis

• Symptom characteristics: not predictors
• Initial exam features:
  • Low BP
  • CHF
  • Cardiogenic shock




     1
      Clinical Diagnosis of Chest Pain

• Location, quality of pain generally not
  predictive of cardiac cause
• Response to nitroglycerine not a reliable
  predictor
• While radiation and associated symptoms may
  be predictive, their sensitivity and specificity
  are quite low
• More than a history and physical are needed!
           Chest Pain Diagnosis

• Clinical diagnosis
• Diagnosis using computer algorithms
• Chest pain center
   Computer Guided Chest Pain Diagnosis

• Goldman Chest Pain Protocol
• Acute Coronary Ischemia Time-insensitive
  Predictive instrument (ACI-TIPI)
       Goldman Chest Pain Protocol

• Computer derived decision aid
• Designed to improve triage to CCU
• Initially developed in prospective study of
  1379 patients presenting with acute chest pain
• “Recursive partitioning” used to divide
  subjects into subgroups correlating with high
  or low risk of MI

         Goldman, et al. N Engl J Med 1982;307:588-96
Goldman Chest Pain Protocol




Goldman, et al. N Engl J Med 1982;307:588-96
            Goldman Chest Pain Protocol

• Validated prospectively in second trial
  of 4770 patients
   Parameters     Physician     Goldman       P-value
                  Evaluation    Protocol
   Sensitivity    88            88            NS

   Specificity    71            74            <.00001

   Positive PV    29            32            .10

   Overall        73            76            <.00001
   Accuracy

           Goldman et al. N Engl J Med. 1988;318:797-803
       Goldman Chest Pain Protocol

• Advantages:
  • Higher specificity than MD
• Disadvantages:
  • Predicts only AMI (not USA)
  • Never shown to alter:
    • Hospitalization rate
    • Length of stay
    • Cost
                    ACI-TIPI
         (Acute coronary ischemia time-
       insensitive predictive instrument)

• Predictive protocol incorporated into
  electrocardiogram with automatic results
• “Time insensitive” so can be used either retro-
  or prospectively



       Selker, et al. Ann Intern Med 1998;129: 845-55
         ACI-TIPI: Clinical Variables

• Age                            • ECG Q waves or not
• Sex                            • Presence and degree of
• Presence of absence of           ST elevation or
  chest pain or pressure of        depression
  left arm pain                  • Presence or absence of
• Chest pain as most               T-wave elevation or
  important symptom                inversion

        Selker, et al. Ann Intern Med 1998;129: 845-55
                    ACI-TIPI

• Validated in 3 trials:
  • UCLA Harbor Medical Center N= 189
  • University of Geneva N=605
  • ACI-TIPI Trial N= 10,689
                  ACI-TIPI Trial

• Clinical trial at 10 U.S. hospitals
• ACI-TIPI protocol installed in all ED
  electrocardiograph machines
• Clinical intervention: 7 alternating months of:
  • ACI-TIPI probability of ischemia provided
  • ACI-TIPI probability of ischemia not provided
• 10,689 patients enrolled
        Selker, et al. Ann Intern Med. 1998;129:845-55
               ACI-TIPI Trial Results
               No Ischemia Stable    Acute MI or
                           Angina    Unstable
                                     Angina
CCU               -32%        -50%        0
Admission
Telemetry         -20%        +25%        0
Admission
Discharge to      +25%        +10%        0
Home
           ACI-TIPI Trial Results

• No difference in 30 day mortality
• No difference in in-hospital complications
• No difference in re-hospitalization rates
            Chest Pain Diagnosis

• Clinical diagnosis
• Diagnosis using computer
  algorithms
• Chest pain centers
           Chest Pain in the Emergency
                   Department

•   4.5 million annual ED visits for chest pain
•   About one fourth have true ACS
•   Treatments for ACS are time sensitive
•   About 2-4% of acute MIs are missed in the ED
•   Number one cause of ED related malpractice
•   Strong bias for admission
               Chest Pain Units
• Goal: accurately determine presence or
  absence of acute myocardial ischemia
  • Rapid efficient treatment of AMI
  • Avoid unnecessary hospitalization (and cost)
  • Avoid inappropriate discharge
• Logistics: Often associated with and staffed
  by Emergency room and include telemetry and
  resuscitation equipment
              Chest Pain Units

1. Heart attack program
2. Diagnostic (observational) program to rule
   out MI
3. Educational outreach program
             Diagnostic Strategies in ACS
•   Out of hospital ECG         •   Troponin T (presentation)
•   Continuous/serial ECG       •   Troponin T (serial)
•   Exercise stress ECG         •   Rest echocardiography
•   CPK (presentation)          •   Stress echocardiography
•   CPK (serial)                •   Sestamibi (rest)
•   CK-MB (presentation)        •   ACI-TIPI
•   CK-MB (serial)              •   Goldman Chest Pain Protocol
•   Myoglobin (presentation)    •   Algorithms/protocols
•   Myoglobin (serial)          •   Computer based decision aids
•   Troponin I (presentation)
•   Troponin I (serial)
University of Cincinnati
“Heart ER” Strategy
         Randomized Trials of Chest Pain Units
Author      Year     N     Intervention      Control     Follow-up

Farkouh     1998     424   Chest pain unit   Routine     30 days,
                           protocol          Hospital    6 month
                                             Admission
Gomez       1996     100   ED-Based rapid Routine        30 days
                           rule out protocol hospital
                                             care
Roberts     1997     165   ED-based          Telemetry   2 weeks
                           accelerated       Unit        3 weeks
                           diagnostic
                           protocol


  From Agency for Healthcare Research and Quality Report, 2000
   Randomized Trials of Chest Pain Units
         Chest pain evaluation unit versus usual care

      Author      Early      Late     Length of    Cost
                 Events     Events      Stay
    Farkouh       NS         NS          NS        61%


    Gomez         NS         NS                        


    Roberts       NS         NS                        



From Agency for Healthcare Research and Quality Report, 2000
         Randomized Trials of Chest Pain Units
Author      Year     N     Intervention      Control     Follow-up

Farkouh     1998     424   Chest pain unit   Routine     30 days,
                           protocol          Hospital    6 month
                                             Admission
Gomez       1996     100   ED-Based rapid Routine        30 days
                           rule out protocol hospital
                                             care
Roberts     1997     165   ED-based          Telemetry   2 weeks
                           accelerated       Unit        3 weeks
                           diagnostic
                           protocol


  From Agency for Healthcare Research and Quality Report, 2000
                  Conclusions

• Clinical characteristics are the least accurate
  predictor of the etiology of chest pain
• Pattern of pain may be most reliable
• Accurate diagnosis and management requires
  use of clinical history, ECG, and other highly
  specific marker of ischemia or infarction
• Computer aided algorithms may improve
  diagnostic accuracy and reduce missed dx
          Conclusions (continued)

• Chest pain units need further study but may
  be useful in:
  • Reducing unnecessary hospitalization
  • Reducing cost

								
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