Evaluating Chest Pain Patients by rct20360

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									                                                        (+)Corey M. Slovis, MD, FACEP
                                                        Professor, Emergency Medicine and
                                                        Medicine; Chairman, Department of
                                                        Emergency Medicine, Vanderbilt
                                                        University Medical Center, Nashville,
                                                        Tennessee; Medical Director, Metro
                                                        Nashville Fire Department and Nashville
                                                        International Airport

    The Low-Risk Patient with Possible
     Acute Coronary Syndrome: How
      Much Evaluation Is Enough?
Missed myocardial infarction (MI) is a dreaded
event and responsible for the most malpractice
dollars awarded in the US. Many patients with chest
pain or other symptoms consistent with acute
coronary syndrome actually do not have the
diagnosis. How extensively should these patients be
evaluated to exclude this diagnosis? What is the
value of observation and noninvasive testing, and
when should it occur? Can a single cardiac marker
exclude MI in patients with prolonged chest pain?
How do nonmedical factors such as patient
preference, physician risk adversity, practice
setting, and availability of arbitration affect the
extent of evaluation?

•    Describe the assessment of pretest probability.
•    Describe the characteristics of patients with
     missed ACS.
•    Describe the appropriate use of noninvasive
     testing in patients at low risk for ACS.
•    Describe the necessary documentation in a
     patient who is discharged from the ED and what
     is an acceptably low risk for ACS.
•    Discuss the role of ED observation.




WE-176
October 10, 2007
9:00 AM - 9:50 AM
Washington State Convention and Trade Center



(+)No significant financial relationships to disclose
                    Evaluating Chest Pain Patients
                 Diagnosing AMI and Unstable Angina:
                   History, Physical and Laboratory
                               Corey M. Slovis, M.D.
                         Vanderbilt University Medical Center
                                   September 2007

       One of the most important things we do in the Emergency Department is
evaluate chest pain. Of the 130 million patients that come to EDs, between 8,000,000-
9,000,000 will have a chief complaint of chest pain. We will diagnose about 1 million
AMIs, 1.2 million cases of Unstable Angina (UA) and more than 6 million cases of non-
cardiac chest pain. Unfortunately we will also miss at least 40,000 cases of AMI, or
UA who develop either an AMI, ACS or have sudden death due to coronary disease.
       Missing the diagnosis of AMI and ACS ranks as one of the leaders in
malpractice losses for ED physicians. Some studies show it to be the number one
malpractice loss with ranges of 20-40% of all dollars lost by ED MDs and their insurers.

       Currently, the accepted miss rate of AMI is 0.0% by US citizens and their
lawyers. We don’t achieve this level of accuracy…
       This talk’s goal is for you to never miss an AMI or discharge a chest pain
patient (or anginal equivalent) who has an acute coronary syndrome.
                          Variables for Risk Stratification
                           •   Characteristics of Chest Pain and associated symptoms
                           •   Past History of Coronary Disease
                           •   Risk Factors
                           •   ECG
                           •   Enzymes

                Chest Pain Characteristics to Ask and Document
                           •   Quality—crushing, burning, knifelike…
                           •   Intensity—1-10 scale
                           •   Character—sudden, gradual
                           •   Duration—in minutes or hours
                           •   Radiation—to back, legs, neck?
                           •   Influencing factors—anything make it better or worse?
                           •   Associations—any associated symptoms?

                      Other Symptoms That = Consider ACS
                               •   Syncope, Presyncope, AMS
                               •   Nausea/Vomiting
                               •   Weakness
                               •   Diaphoresis
                               •   Shortness of Breath


                                             1
                    Classic Ischemic Chest Pain
                    • Crushing Substernal
                    • Radiating to the left arm and/or jaw
                    • Associated with:
                      - Nausea
                      - Weakness
                      - Diaphoresis
                    • Lasting 15-30 minutes
                    • Made better by rest, worse by exertion


Please read the following concepts to realize our problem:


                             Basic Concepts
       •   Almost all MI’s have chest pain
       •   Truly asymptomatic MI’s almost never happen
       •   Most AMI’s have typical pain
       •   ECG’s are almost never completely WNL in AMI
       •   CK-MB and/or Troponin values are close to 100% accurate by 6-9h

All of the above basic concepts are FALSE!


                              The History

                Chest Pain is the hallmark of AMI
                                      but
                      • May be absent
                      • May be fleeting
                      • May be different than substernal
                                  may be:
                      • Pleuritic, stabbing, or even palpable


                             Atypical Stuff
                      •   C.P. greater than 48 hours
                      •   Pain reproduced by palpation
                      •   Stabbing Pain
                      •   Age less than 40
                      •   Radiation to back, legs, abdomen




                                     2
Atypical Stuff - Probability of AMI in 6000 pts
                                                    NEJM 1994
                                                    Chest 1992

• C.P. greater than 48 hours           New ST              20%
                                       No New ST           1%
•   Pain reproduced by palpation                           1%
•   Stabbing Pain                                          3%
•   Age less than 40                                       2%
•   Radiation to back, legs, abdomen                       1%


               ACS Without Chest Pain
                                                     Chest 2004;126:461-469
•   Global Registry Study (GRACE)
•   20,881 patients with ultimately suspected ACS
•   8.4% (1783 pts.) had no chest pain, only “atypical symptoms”
•   ¼ of the patients without C.P. did not have ACS initially suspected
•   Mortality much higher if no C.P.: 13% vs. 4.3% (p < 0.0001)


        Elderly Patients with Suspected ACS
                                                       Acad Emerg Med 2007
•   10,126 ED R/0 ACS patients
•   1157 (8.3%) were 65 yo or older
•   Stabbing Pain
•   Elderly had 2x ACS incidence (14.5% vs. 7.4%)
•   But: - Less Chest Pain
         - Less Left Arm Pain
         - Less Typical Pain

               “ Atypical” Presentations
                    In the Elderly
                                                       J AM Geriatr Soc 1986
         • 777 AMI’s, ages 65-100
         • Chest pain was seen in only 66%
         • Frequency of C.P. decreases with age
                (75% age 70; 50% age 80)
         • Chest Pain Infrequent above age 85
                (38% above age 85)
         • Beware “Atypical” presentation




                               3
          “Typical” Symptoms of AMI in the Elderly
                                                               J AM Geriatr Soc 1986
              •   Dyspnea            40%
              •   Syncope            14%
              •   AMS                 7%
              •   Weakness            7%
              •   Giddiness           5%
              •   Stroke             4.5%


                     Beware Dyspnea in the Elderly




                              Missed AMI
These groups are repetitively cited as highest risk for missed ACS:
     •   The “wrong” age (less than 50 or older than 65-70)
     •   Atypical symptoms
     •   Less Symptoms
     •   No prior angina/CASHD hx
     •   WNL or Nonspecific ECG
     •   Female
     •   Minority


                         Discharging AMIs
                                                   Am J Cardiol 1987;60:219-224
     • Multi Center Study of 3077 patients
     •   Yale, Brigham and Womens, Univ. of Cinn., and 3 Community Hospitals
     •   Admitted 58% of pts., 26% of whom had AMI
     •   4.0% miss rate but “17 other missed AMIs were identified later
     •   7.3% overall AMI miss rate
     •   ½ of all misses could have been picked with better ECG reading skills


         A Study of 100 Autopsy Proven Missed AMIs
                                                      JAMA 1983;250:1177-1181
              • Almost ½ of AMIs missed (47/100)
              • Four key factors identified:
                     – Unjustified dependence on misleading lab
                     – Inattention to suggestive lab studies
                     – Atypical presentations
                     – Failure to consider AMI as a Dx possibility




                                    4
             Missing AMIs by Missing ECG
                                                Annals of EM 1993;22:579-582
  •   Multicenter CCU subset study
  •   Yale, Brigham and Womens, Univ of Cinn, and 3 Community Hospitals
  •   UA not studied
  •   ¼ of missed AMIs had ST elevation
  •   70% of missed AMIs had abnormal ECGs



                  Missing AMI Early in the ED
                                                          Cardiology 2002;98:75-80
          • 421 AMI pts., 22.3% with delayed admission
          • Four Factors lead to early miss
                  – Patient felt symptoms due to benign cause
                  – Had similar symptoms previously which improved
                  – Patient not upset by chest pain
                  – Symptoms disappeared while in ED
          • Patients perceptions affect us

What’s the Best We Can Hope for Without Objective Testing
                                                    Coron Artery Dis 2002;13:37-43
          • 5362 pts. from single hospital in Göteborg, Sweden
          • Hx, PE, ECG, CK-MB, Clinical Impression; No Troponins
          • 1% AMI miss rate; UA miss not evaluated


                  How Good Are the Canadians?
                                                         CMAJ 2004;170:1803-1807
  • 1819 patients with C.P. R/O ACS
  • 13.2% AMI (241 pts), 8.6% UA (157 pts.)
  • 4.6% AMI missed (11/241) and 6.4% UA missed (10/157)



  Value and Limitations of the Chest Pain History
                                               JAMA 2005 294:2623-2629

              •    Medline and OVID searched 1970 – 2005
              •    88 sources reviewed
              •    Up to 11,000 patients per characteristic
              •    Objectively evaluates ability of clinicians to Rule-In or
                   Rule-Out ACS




                                 5
                                    Details Evaluated in CP History

                              •   Quality                          Pleuritic
                              •   Location                         Positional
                              •   Radiation                        Palpable
                              •   Size of Area                     Exercise
                              •   Severity                         Emotional Stress
                              •   Time of Onset                    Relieving Factors
                              •   Duration                         Associated Symptoms
                              •   First Occurrence                 Similarity to Prior ACS

          Increased Likelihood of AMI (+LR)                          Decreased Likelihood of AMI
                                                                     (-LR)
          Radiation to R arm or shoulder                  4.7        Pleuritic            0.2
          Radiation to both arms or shoulder              4.1        Positional           0.3
          Associated with exertion                        2.4        Sharp                0.3
          Radiation to L arm                              2.3        Reproducible         0.3
                                                                     Palpation
          Diaphoresis                                     2.0        Inframammary         0.8
          Nausea or vomiting                              1.9        Not associated with 0.8
                                                                     exertion
          Worse than prior angina or AMI                  1.8
          Described as pressure                           1.3
                                                                         JAMA 2005:294: 2623-2629




                                             Probability of AMI
                                                                JAMA 2005:294:2623-2629


No Risk         Low Risk               Probable Low Risk          Probable High Risk            High Risk
               • Pleuritic              • Not exertional            • Pressure-like           • Radiates to
                                                                                                arms or
               •   Positional            •   Small area not          •    Similar to            shoulders
                                             inframammary                 prior ACS
               •   Reproducible                                                               •     Related to
                                                                     •    Associated                exertion
               •   Stabbing                                               with N/V or
                                                                          Diaphoresis




                                                      6
“No single element of the Chest Pain History is a powerful enough
predictor of non-ACS on non-AMI to allow clinicians to make
decisions according to it alone”            JAMA 2005;294:2623-2629



                             Atypical is Typical

           One missed AMI will change your life and your patient’s life Forever


        Missing an AMI is a common event. In general, about 1-2 in 100 AMI patients
are discharged from hospitals by competent physicians. If we appreciate that it could
happen to any of us and try to study how we miss AMI’s, then maybe we can make our
miss rate 1 in 1000 or 1 in 10,000.
               -Always err in a way that the patient suffers the least-
              (Commandment 10 of the Ten Commandments of Emergency Medicine)



                          R/O Dissection
      You Must Ask and Document This in All Chest Pain Patients
                             • Was it:
                                - tearing or ripping?
                                - start at maximal intensity?
                                - Radiate to back, abdomen and legs?

If you ask all 3, you will pick up 90% of Dissection, ¼ of us ask 0-1 of the questions…
                    Past History that Increases ACS Risks
                                    •   CABG
                                    •   Stent
                                    •   PCI
                                    •   Prior Abnormal Scan, Echo, or ETT
                                    •   Abnormal ECG
                  Did your doctor ever tell you to take ASA or NTG?


                               Major Risk Factors
              • Hypertension                       • Family History
              • Hyperlipedemia                     • Obesity, Inactivity, Habits
              • Diabetes Mellitus                  • Type A with high anger
                                                     (especially repressed anger)



                                            7
                                  Do Risk Factors Help?
                                                                     J Clin Epidemiol 1992;45:621-626
                        • Risk factor rarely helpful in the ED
                        • Men: DM, Family History minimally increase probability
                        • Women: No
Note: Risk factors are for use in populations. If a patient has no risk factors that does
not significantly decrease the risk of ACS in the specific patient you are evaluating.

                              TIMI Scoring (1 point Each)
                                                                        Annals of EM 2006;48:252-259

                        •   Age >65                        • Aspirin Use
                        •   Known CASHD                    • > 2 Anginal Events in 24 hours
                        •   > 3 Risk Factors               • Elevated Biomarkers
                        •   ST Segment Changes

       Note: TIMI Score of 0 in this study was associated with a 1.7% risk of adverse outcome.

                                           The ECG
                        •   Misreads are the single biggest cause of missing AMI
                        •   We must be as good as anyone in reading ECGs
                        •   Must specifically look for all 5 AMI patterns
                        •   Beware NSSTW ∆s…
                        •   Repeat ECGs!!


                The 5 ECG AMI Patterns on the 12 Lead ECG
                        • Anterior                         V Leads, 1, L
                        • Inferior                         2, 3, F
                        • Lateral                          I, L, V5, V6
                        • Right Sided                      Deep ST ↓ V1, V2 in inferior AMI
                        • Posterior                        V2: especially in inferior AMI
                                                               R>S
                                                               ST ↓
                                                               T wave upright

                        5 Ways to Diagnose an AMI on ECG
                        •   ST elevation in 2 or more anatomically contiguous leads
                        •   Reciprocal ST Depression
                        •   Q waves
                        •   Compared to prior ECGs (including new BBB)
                        •   Compare to next ECG in 10-20 minutes



                                                  8
                                 Value of Extra Leads
                                                           Curr Opin Cardiol 1998;13:248-253

      •   The 12 lead ECG may miss RV and Posterior AMIs
      •   Right sided (V4R, V5R, V6R) leads may help for R.V. AMI
      •   Posterior Lead (V7, V8, V9) could help for Posterior AMI
      •   Sensitivity ↑ by 8.4% but specificity ↓ by 7.0%
      •   Use when faced with non diagnostic inferior changes
      •   Look for subtle ST ↑, not massive
      •   Use as an aid to keep in ED rather than discharge.
      •   Best, easiest extra lead V4R: will Dx up to 80% of RV AMI

                        ECG Mistakes to NEVER Make
               • Not getting an ECG in a C.P. patient
               • Not getting an ECG in older patients Sx of:
                                 - Syncope, Presyncope, AMS
                                 - Weakness
                                 - Nausea, vomiting
                                 - Diaphoresis
                                 - Shortness of breath
               • Not carefully reading for all 5 AMI-Ischemic patterns
               • Not repeating ECGs, especially when not normal or in high risk patients.
               • Not comparing to old ECGs—use fax from other hospitals



                        ONE ECG BEGETS ANOTHER

Unfortunately, presenting ECGs may be WNL or Non-diagnostic for AMI and ACS.
We have known since the mid 1970s that a WNL ECG does NOT exclude an AMI.


                             Normal ECGs in AMI

                                 R/O AMI Admissions
                                    Normal ECGs
                                                    Br Heart J 1977;39:212-217

                             •   1578 Chest Pain patients
                             •   462 patients with WNL ECGs
                             •   117 (25%) admitted
                             •   21% WNL ECG patients had AMI




                                            9
                            R/O AMI Admissions
                        Normal and Near Normal ECGs
                                                         Am J Cardiol 1987;60:766-770

                            •   775 R/O AMI patients
                            •   107 WNL ECGs
                            •   73 “minimal non-specific changes”
                            •   10% of WNL ECGs had AMIs
                            •   8% of minimum change had AMIs



                           Normal ECG and AMI
       Author                   Journal          Yr        Patients           AMI
       Welch                JAMA               2001        733,191          4.4%
       Zalenski             Acad EM            1996          51               3%
       Hedges               Ann EM             1992         261               2%
       Fessmire             Arch IM            1989         459               4%
       Slater               Am J C             1987         775              10%
       Behar                Chest              1977         117               5%

The Milis study looked at 3697 patients admitted with R/O AMI to a CCU. Patients were
considered to be high risk for AMI due to prolonged C.P. (> 30 min).


                                    MI or Not?
                                    Milis Grp, 3697 pts, AJC 1983

                     ECG                          MI

                     WNL                          21%

                     Isolated ST9                 50%

                     Isolated ST8                 65%

                     Q waves                      75%

                     ST8 , Q                      90%+
                     ST8 , ST9                    90%+




                                          10
                                     Likelihood of MI

0-20%           50%           60%           75%           90%           90% - 95%


WNL             ST ↓           ST ↑           Q            ST ↑           ST ↑
                                                      Reciprocal Δ’s      Reciprocal ∆’s
                                                            or            Q Waves
                                                           ST ↑
                                                        Q Waves

             Using Continuous 12 Lead ECG Monitoring (SECG)
                •   SECGs now capable of continuous 12 lead ECGs
                •   Monitors ST changes Q 20 seconds or more often
                •   Alarms for 0.2 mV in 1 lead or 0.1 mV in 2 leads
                •   Utility of SECG is based on Patient’s Risk level:

• Low Risk ACS pts.—no significant increased utility over 12 lead ECG
                                                                        Ann Emerg Med 1995;25:1-8

• Intermediate Risk pts.—no added value over standardized work-up
                                                                  Ann Emerg Med 2003;41:342-345
• High Risk ACS pts.*—if not admitted, SECGs should be used; as high as 99.4% sensitivity for ACS
                                                                       Ann Emerg Med 1998;31:3-11
*This patient type almost always admitted
(prolonged ongoing, CP, CHF; Dynamic ST changes, Shock, etc.)


               Enzymes in Diagnosing AMI and ACS
       There are ways to try to help us be better in AMI diagnosis, one is enzymes.

                                          Myoglobin
                                 •   Small molecule (17,000 daltons)
                                 •   Easily enters coronary arteries
                                 •   Quickly cleared by kidneys
                                 •   Appears within one hour
                                 •   Peaks in 4-6 hours
                                 •   Gone in 24 hours
                                 •   Unfortunately only about 80% sensitive and specific
                                 •   Of no value to R/O ischemia
                                 •   A 0 and 2 hr ∆ CK-MB appears superior




                                                11
             Myoglobin’s Role: Optimal Marker Use
                                  CMAJ 2000;162:1561-1566
         • Compared in CK-MB vs. CK-MB + Trop I + Myoglobin
         • Did levels at 0 and 2 hours
         • No significant differences in time to Dx or Accuracy of Dx by adding
           myoglobin

                        Creatine Kinase (CK)
                       • Catalyzes reaction of ADP to ATP
                       • Three isoforms: MM muscle, including cardiac
                                              (70-85% of total CK)
                                        BB Brain, Bowel
                                        MB Cardiac
                                              (1% of skeletal CK is MB)

                                CK-MB’s
                       • Large molecule (34,000 - 42,000 daltons)
                       • Delayed appearance into blood
                       • Can be measured multiple ways

                          CK Measurements
Electrophoresis:   Oldest method - takes longest
Immunoassays:      Measures CK Mass
                   More accurate and quicker, immunoassasy most centers now use
Isoforms:          Newest, least available, probably most accurate


            Time Line for CK-MB Enzyme Rise
                                                       Circulation 1999;99:1671-1677

  100
   90                    CK-MB
   80
   70
   60
   50
   40
   30
   20
   10
    0

             2H          4H          6H         10 H         12 H


                                     12
                                                          Prog Cardiovasc Dis 2004;46:404-416



 Marker          Earliest Rise           Peak             Return to         Abnormal Value
                                                           Normal
Myoglobin            1-3 hrs            6-9 hrs             12 hrs               < 80 μ/mL
 CK-MB               4-8 hrs           12-24 hrs           2-4 days           > 10 μg/mL or >
                                                                                 3% of total
Total CK             3-6 hrs           24-36 hrs            12 hrs             > 150-180 u/L
 CTnT                3-4 hrs           10-24 hrs           1-3 wks              > 0.1 μg/mL
  Ctnl               3-4 hrs           10-24 hrs           1-3 wks              > 1.5 μg/mL
                                            Modified from AACN Clinical Issues 2004;15:547-557



                              CHECKMATE
                  Multimarker Testing for Risk Stratification
                                                               Circulation 2001;103:1832-1837
       •   Prospecitve study of 1005 pts. in 6 Chest Pain Units
       •   Compared CK-MB, myoglobin, and Troponin values
       •   Measured at 0,3,6,9-12,16-24 hrs. post admission
       •   Recommends multi-marker bedside testing
       •   Multimarkers > Single Assay in accuracy and time to Dx
       •   Myoglobin helped in quicker Dx (0.3 hrs) and in earlier presenters




                                            13
                 Isolated Troponin Evaluation in Chest Pain
                                                                 Am J Cardiol 2003;91:936-940
     •   1852 pts. with no ST ↑ from 3 ACS studies
     •   PARAGON B, GUSTO IIa and CHECKMATE
     •   Even if all presenting enzymes negative , 1.1% short-term risk of Death or AMI
     •   Event rate ↑ to 9.5% at 30d
     •   Trop+/CK-MB+ had worst prognosis
     •   Trop-/CK-MB+ had 30d 9.6% AMI or Death Rate

                                       Troponin
                             • Regulatory protein of myofibril
                             • Troponin -C binds calcium
                             • Troponin -T binds troponin and myosin
                                           (1-2% level found in skeletal muscle)
                             • Troponin -I is an inhibitor
                                                   (N terminal end specific for heart)


                                   Troponin in AMI
                             •   Early in AMI is less sensitive than myoglobin
                             •   Later is most sensitive enzyme marker currently available
                             •   50% sensitive at t = 3-6 hrs
                             •   Almost “100% sensitive” at t = 10 - 16 hrs
                             •   Lasts 7-10 days

                                 Troponin Falsehoods
                             •   100% sensitive for AMI
                             •   Picks up most unstable angina
                             •   No false positives
                             •   Easy to do
                             •   Negatives may allow ED discharge

                     Troponin “Unspoken” but should be
                     •   Is not a perfect test
                     •   Troponin T is currently superior to Troponin I
                     •   T uses recombinant human Troponin
                     •   T is more reliable at lower ranges
                     •   I comes from different batches
                     •   A single negative Troponin does not exclude AMI or ACS

“Negative results are associated with low risk and allow rapid and safe discharge...” NOT!!
                                                             N Engl J Med 1997;337:1648-1653




                                            14
                       Troponin in the ED
                          Be Careful
                                                       JACC 1998;32:8-14
                    • First Troponin misses 16-25% of AMIs*
                    • False positives as high as 3-13%*
                           * (0.4 ng/ml vs 1.5 ng/ml)



How Accurate is One CK-MB or Troponin to R/O ACS
                                                       Ann Emerg Med 2001;37:478-494
   • Meta analysis of 22 years of studies
   • A single set of enzymes will miss anywhere from 51-63% of all AMIs
   • Acute sampling of new onset symptoms yield the worst
     results for predicting AMI
   • Serial sampling will detect 79-93% of all AMIs
   • Serial sampling will only detect 31%-45% of all ACS


              Delta CK and Troponin in R/O AMI
                                                          Am Heart J 1998;136:237-244
            • Compares time 0 and Level 2 hours later
            • Move sensitive than single values
            • Delta CK-MB rise of 1.6 ng/ml > single 2 hour value of > 6


Delta CK-MB Outperforms Troponin and Delta Troponin
                                                          Am J Emerg Med 2000;18:1-8
   • 2 hr ∆ CK-MB mass of 1.6 most sensitive for AMI
   •   More sensitive than CK-MB of 6ng/ml
   •   More sensitive than ∆ Troponin I of 0.2 ng/ml
   •   87% of AMIs detected at 2 hours
   •   Only 61.4% for Troponin I at 2 hours
Delta CK Outperforms Myoglobin for Early AMI Detection


                 In Troponin I Negative Patients
                                                         Ann Emerg Med 2004;44:12-19
   • Used 0 and 2 hr. immunoassay CK-MB rise > 0.7 ng/ml
   • 93.2 Sensitive and 94.4% Specific for AMI
   • Myoglobin 75% sensitive; Delta myoglobin 77.3%
   • At only 2 hours 38.6% had CK-MB > 2.9 ng/ml




                                   15
Discordant Cardiac Biomarkers: Frequency and Outcomes in Emergency
                 Department Patients With Chest Pain
                                                               Ann Emerg Med 2006;48:660-5
          •   Study of 8769 pts.; 1614 had ACS
          •   CK-MB and Troponin discordant in 7%
          •   Both markers positive: 80% chance of ACS
          •   Both markers negative: 12.7% chance of ACS
          •   If Trop (+) but CK (-): 41% Risk
          •   If Trop (-) but CK (+): 24% Risk
          •   Beware discordant markers


                         Optimal Enzymes Testing
                   • No Consensus
                   •   0, 6, 12 → 0, 3, 6, 9 → 0, 2, 4
                   •   Strongly consider using “Delta” testing
                   •   Beware discordant CK-MB and Troponin
                   •   You must have at least one set, drawn at least 6 hours post
                       onset of CP


                            Conclusions on Enzymes

          • Can not use a single early assay to R/O AMI
          •   Excellent over time to Dx AMI
          •   Unreliable to R/O U.A.
          •   Only 1/4 – 1/3 of non-AMI ACS will have ↑ Troponin
          •   CK-MB will only rise with AMI
          •   Delta values are more accurate than single values
          •   Beware discordant markers


         Enzymes are rarely positive early in AMI.
Enzymes are almost never positive acutely in patients with non-
                     diagnostic ECGs



              ONE set of negative enzymes ≠ No ACS

  Many of us use response to NTG to help diagnose patients with WNL, or
                nonspecific ECGs, and negative enzymes.

        Using Response to NTG to Diagnose Ischemia


                                           16
              Usefulness as a Predictor of Ischemic C.P. in the ED
                                                                    Am J Med 2002;90:1264-65
•   223 ED pts. with chief complaint of C.P.
•   Ultimately 1/3 had Ischemic C.P. and 2/3 did not
•   Used ECG, Enzymes, Stress Testing (1/2) and Cath (29%)
•   90% of all pts. responded at NTG (88 vs. 92%)
•   Complete relief seen in 72% (70 vs. 73%) of all pts. whether they had ACS or no ACS


     “The practice of supporting or excluding the diagnosis of myocardial
    ischemia should not be based on a patient’s response to nitroglycerin”
                                                                  Am J Med 2002;90:1264-1265


    Chest Pain Relief by NTG Does Not Predict Active Coronary Disease
                                                                 Ann Int Med 2003;139:979-986
                •   459 admitted ED patients with C.P.
                •   Used 50% pain relief within 5 minutes
                •   Used stress testing, enzymes or cath in 39% overall
                •   35% of ACS pts. responded
                •   41% of Non-ACS pts. had pain relief

“Our data…strongly suggests that the response of chest pain to
nitroglycerin although therapeutically beneficial, has little diagnostic or
prognostic value”
                                                                 Ann Int Med 2003;139:979-986


             Changes in the Numeric Scale for Pain after SL NTG
                       Do not Predict Cardiac Etiology
                                                               Ann Emerg Med 2005;45:581-585
                         •   Conveinence sample of 664 pts. (52% F: 48% M)
                         •   18% had Cardiac Chest Pain
                         •   Used 11 point pan scale pre-post NTG
                         •   Troponin, Stress Testing, ECg changes and Cath used
                         •   28% had complete resolution; 22% moderate, 19% none
                         •   Response to NTG unrelated to presence or absence of ACS

                        Three Studies, Three Journals, Same Results



       NTG response can NOT be used to Diagnose or Exclude
             Active Ischemia, AMI, or lack of ACCS




                                              17
      The GI Cocktail to Help Diagnose Ischemic Chest Pain
                           Early Study Recommends Use
                                                                      JACEP 1976;5:981-983
               •   60 patients studied; average age 45
               •   37/60 had complete pain relief with 10-15 min.
               •   No “complete relief” pt. had AMI
               •   1 patient with “partial” relief had AMI
               •   Author says response is “an aid” and is safe

Note: “Xylocaine viscous in this context appears to be as useful as the “Levine test” in
      which angina lessens with carotid sinus pressure”
                                                                      JACEP 1976;5:981-983


                   Using the GI Cocktail: A Descriptive Study
                                                              Ann Emerg Med 1995;26:687-690
               •   97 Consecutive pts. with chest or abdominal pain
               •   Used antacid, viscous lidocaine and donnagel
               •   14% had myocardial ischemia; 53% had GI cause
               •   Exact responses and time intervals often vague or missing
               •   69% had symptomatic relief
               •   73% of admitted R/O ACS had positive response
               •   68% of discharged GI etiology pts., also had positive response


                               Conclusions on GI Cocktail

               • Works great on symptoms in up to 70% of all pts.
               • Documentation by ED MDs and RNs often incomplete
               • Response, partial response or NO response does NOT indicate
                 presence or absence of ACS.
               • Use for symptoms, NOT for diagnosis


 Just how good are we based on history, physical exam, ECG, serial ECGs and response
to NTG and the GI cocktail. Many of us rely on these tests to see who can be discharged,
                   admitted, or held for more tests +/or observation.

                                 Testing of Patients
        Because History, Physical Exam, ECG and Enzyme testing may not immediately
diagnose ACS. Additional testing strategies using ETT, Nuclear Studies,
Echocardiography and now in early trials CT Angio and MRI have been utilized to
improve diagnostic accuracy rates and to both decrease non-ACS chest pain admissions
to the hospital and more importantly to decrease inappropriate discharges.



                                            18
One answer to the problem is to create a Chest Pain Center. The first large center
        with a published large series was Brian Gibler’s in Cincinnati.


                                  Chest Pain Centers
                                Univ. Of Cinn. Heart ER
                                                           Ann Emerg Med 1995;25:1-8
                            •   1010 patients (512:498 m:f)
                            •   Low Risk Only; No CAD, No ST Changes
                            •   CK-MB at 3, 6, 9 Hr.
                            •   Continuous 12 Lead ST Monitoring
                            •   2-D Echo
                            •   ETT

                                 Chest Pain Centers
                                Univ. Of Cinn. Results
                                                           Ann Emerg Med 1995;25:1-8
                            •   829 (82.1%) Discharged
                            •   153 (15.1%) Admitted
                            •   1/3 of Admitted Patients had CAD
                            •   1 AMI in D/C’d, “negative” patient 3 days later
                            •   3 deaths at 1 mos; 1 was due to CAD



 Cost of a chest pain center has always been cited as why NOT to do a specialized area.

                       Yet admitting patients is very expensive.


                            Cost of Chest Pain Areas
                                                           JACC 1994;23:1016-1022

             Area                    Median Cost                   25th-75th
             ED                      $ 403                         (403-927)
             “Short Stay”            $1927                         (1455-3650)
             Ward Area               $4712                         (1868-11,187)
             Step Down               $4031                         (2069-9,169)
             CCU                     $9201                         (3171-20,011)

                            Cost of Chest Pain Areas
                                                           JACC 1994;23:1016-1022
                            • Short stay patients stay shorter
                            • Had same number of complications
                            • Saved $1,000,000 in 2 years




                                           19
                 Chest Pain Centers
                 Patient Satisfaction
                                             Annal EM 1997;29:116-125
             •   104 patients at Cook County Hospital
             •   36% of patients were employed
             •   Used four quality or satisfaction measures
             •   Better: comfort, communication, attention
             •   Designated Areas are Better Appreciated

- Why Stress testing of some type is so important -

       Symptoms vs Degree of Obstruction
             • At rest, patients may have up to 90%
                    obstruction and still be asymptomatic
             • With exertion, 50% stenosis may result
                    in symptoms and/or ECG changes

       Cost Effectiveness of Stress Testing
                   400 Patients
                                             Annal EM 1997;29:116-125
             •   240 ETTs ($125)
             •   158 Stress/dobutamine ECHOs ($275)
             •   2 Thallium Stress Tests ($550)
             •   $3125 is cost for 1 CAD Diagnosis
             •   Cost per year of life saved < $2000
             •   $894 per out-patient vs. $2364 for inpatient

              Low Risk Patients
            Immediate Stress Testing
                                             Annal EM 1998;32:1-7

             •   212 Patients (121:91 m:f)
             •   Results: 59% Negative, 28% Non-Dx, 13% Positive
             •   Half of Positives had CASHD (13/23)
             •   All patients with Negative Tests DC’d
             •   93% with Non-Diagnostic DC’d

                  Low Risk Candidates:

             •   WNL ECG or Minor NSSTWs
             •   WNL vital signs and physical exam
             •   Younger 40-50
             •   O or few risk factors*
                                           *6% pos for CAD


                            20
                                Immediate Stress Testing
                                   30d Follow-Up
                                                           Annal EM 1998;32:1-7

                            •   95% of patients had follow-up
                            •   No Mortality
                            •   1 of 23 positives got CHF
                            •   No 30d adverse events in patients WNL ETT

                    No Adverse Effects to Immediate Testing

                            •   No patient with CAD bumped their enzymes
                            •   3 patients were already having an AMI during ETT
                            •   Enzyme pattern typical in these 3
                            •   Non-diagnostic HR was <85%
                            •   Authors questions if 75% is acceptable target for HR
                            •   Most ETT Complications Occur
                                     During Recovery Period 5-10 minutes post ETT

Note: This group now waits for 1 set of enzymes pre-ETT


              What is the Negative Predictive Value of a Normal ETT

        Based on the University of Cincinnati Chest Pain study of 1,010 patients, the
Cook County data of 317 patients and the UC Davis study of 212 patients, a normal ETT
has an overall negative predictive value of 98%. With low risk patients who have a
normal ECG, no enzyme changes a low pretest probability, the risk of a 30d adverse
event is less than 1% (somewhere between less than 1 in 100 to less than 1 in 1000…)

    A negative ETT dramatically lowers risk of ACS…it does not eliminate it!!

           The next question is: Is there something even better?

                                 Sestamibi Scanning
                            • Technetium 99m labeled perfusion agent
                            • Distributes to well perfused areas
                            • 6 hour half-life
                            • Does require 60 minutes wait post injection
                            • Allows scan to be done 1-6 hrs. post injection
                            • Standard protocol: Rest scan followed by short wash-out
                                    period then higher dose administered and stress
                                    scan performed.
                            • Stress is either treadmill (preferred) or adenosine if
                                    patient can not exercise.



                                          21
                                  Thallium Scans
                           •   Nuclear Scan of Choice pre MIBI
                           •   Requires immediate scan post injection
                           •   Rest Thallium can precede Stress MIBI
                           •   Most centers now use only sestamibi


  Myocardial Perfusion Imaging for Evaluation and Triage of Patients with
                    Suspected Acute Cardiac Ischemia.
                     A Randomized Controlled Trial
                                                                JAMA 2002;288:2693-2700

                       •   Observational study at 7 academic centers
                       •   2475 Adult ED patients
                       •   Compared scan vs. no scan protocols
                       •   Used resting protocol only

                    Results
                       •   Normal rest scan 97% sensitive for ACS
                       •   99.4% Sensitive for AMI and ACS at 30d
                       •   Non-ACS Admissions 52% without Scanning
                       •   Non-ACS Admissions 42% with Rest Scanning
                       •   Scan positively rate: 14% (2 AMI, 12% UA)


       Using nuclear scanning results in decreased non-ACS Chest Pain admissions
and allows more safe discharges…It is cost effective


 Myocardial Perfusion Imaging With Technetium-99m Sestamibi in Patients
                   With Cocaine-Associated Chest Pain
                                                           Ann Emerg Med 1999;33:639-645
                       •   215 patients
                       •   5 positive rest scans
                       •   39/172 patients had outpatient stress studies – all WNL
                       •   No ACS in negative rest scan patients at 30 days




                                          22
                                Sestamibi Scanning
                                                             Annals EM 1997;29:88-97
       Author          Year                   N              Sens (%)          NPV
       Bilodeau        1991                    45             96                94
       Varetto          1993                   64            100                100
       Hilton          1994                   102             94                 99
       Varetto          1994                   27            100                     -
       Stowes          1995                   187             97                     -
       Tatum           1997                   438            100                 100
       Fesmire         2001                   805            97.3                99+
       Fesmire         2002                   2074           100 AMI             100 AMI
                                                             99.1 UA             99.8 UA

       A normal Rest-Stress protocol nuclear scan has a sensitivity of 99% and a
negative predictive value of at least 99%. A negative scan with good contractility in
a low risk patient almost completely rules out ACS and does R/O AMI.


                               Stress Echocardiography

       •   Useful in patients with an abnormal ECG
       •   More sensitive than treadmill testing, faster and cheaper than nuclear imaging.
       •   Adequate visualization is sometimes a problem.
       •   Not as well studied in ED Chest Pain Center Studies
       •   Operator Dependent
       •   Some centers prefer it

                                  Role of Stress Echo
                                                              Brown A.J. Card 1998

                               •Consistently misses >30% jeopardized myocardium
                               •Pos or Neg tests yield same prognosis in prior AMI pts
                               •5-7%/yr AMI or Deaths in prior AMI patients
                               •Increased further testing as compared to Nuclear testing




                                             23
                   Multi-Detector CT
                 Evaluation of Chest Pain
             •High Quality Non-invasive Coronary Imaging
             •64 Slice allows short breath hold
             •Allows for higher quality, more detailed imaging
             •Requires administration of IV or PO beta blockade
             •Best for ruling out obstructive lesions
             •Sometimes equivocal in patients with known CASHD
             •Increased calcium in coronary arteries complicates reading

                  Coronary CTA Limitations
             •Radiation with Iodinated Contrast
             •Reader Expertise (new test)
             •Ability to Breath Hold (now just 5-10 sec)
             •Need for Beta Blockers (HR below 60-65)
             •Increased Coronary Angioplasty in higher risk patients*

      *10% of Scans Inadequate; 10-20% “Intermediate”

                            No MDCT
             •No Elevated Biomarker (CK-MB or Trop)
             •No New ECG Changes
             •Not Hemodynamic Instability, Chest Pain, AFib
             •No Iodinated Contrast Allergy, Hyperthyroidism,
              Metaformin Use
             •Creatinine is not > 1.3 mg/dl (some use 1.5)

               64 Slice MDCT to R/O ACS
                                                 Acad Emerg Med 2007; 14: 112-116

 Author           Journal             n             PPV             NPV
Hoffman*        Circ 2006             103            61%           100%
Rubenstein      Circ 2007             58             87%           100%
Hollander     Acad EM 2007             54            80%           100%
Goldstein      JACC 2007              99            87.5%          100%




                                 24
                                  Total Body Radiation Doses
                                                                    Modified from J Nuc Cardiol 2006; 13: 19-23

                Diagnostic Studies                                            (mSv)
                PA/Lateral CXR                                                0.08
                Mammogram                                                     0.13
                Cardiac Catheterization                                       4-6
                CT Abdomen and Pelvis                                         7-8
                64 Slice MDCT (with ECG Pulsing)                              Male 4.8-10
                                                                              Female 6.8-14
                Tc-99 Rest-Stress MIBI                                        12

                                Estimating Risk of Cancer
                             Associated with 64 Slice Radiation
                                                                                       JAMA 2007; 298(3):317-232
                           •CTA Dosing:
                             - 42-91 mSv for lungs
                             - 50-80 mSv for breasts
                           •Increases cancer risk for 20 year old female to 1:143

         Note: Be sure your center is not doing this; specifically ask: 1) What doses are we using 2) Are
we trying to minimize dosing 3) Are we pulsing (also called gating) during diastole 4) Are we using breast
shields 5) Are we focusing on the coronary arteries.


                   Risk Stratification of Chest Pain Patients

                                      Chest Pain Patient/Possible ACS




                                                   History
                                                Physical Exam
                                             12-Lead ECG (serial)
                                                 Biomarkers




             High Risk of ACS             Intermediate Risk of ACS                    Low Risk of ACS
  Biomarkers elevated                 >10 minutes rest pain, now resolved   No intermediate or high risk features
  New or presumed new ST depression   Moderate to high likelihood of CAD    <10 minutes rest pain
  Recurrent ischemia despite OMT*     T wave inversion >2 mm                Risk factors for CAD
  Recurrent ischemia with HF          Biomarkers slightly elevated (e.g.    Nondiagnostic 12-lead ECG
  High risk findings on stress test   TnT >0.01 but <0.1 ng/mL)             Biomarkers WNL
  Depressed LVEF                                                            Age <70
  Hemodynamic instability
  Sustained VT
  PCI within last 6 months
  Prior CABG




                                                        25
                         Who is a Candidate for CTA?
          • Inclusion Criteria:
            - >5 min of chest pain within the previous 24 hours
            - No or nondiagnostic ECG changes
            - Normal initial cardiac biomarkers
            - Sinus rhythm
            - Ability to perform a breathold of 10-15 seconds
            - Meets Vanderbilt Radiology criteria for IV contrast administration



                            Who is Not a Candidate for CTA?

          • Exclusion Criteria:
            - Known CAD
            - Elevated Troponin or CK-MB
            - Diagnostic ECG changes
            - Homodynamic or clinical instability
            - Atrial fibrillation or markedly irregular rhythm
            - Contraindication to beta-blockers if heart rate >65 (e.g., sever
          bronchospasm or cocaine exposure)



                              Chest Pain Centers
Based on all of the available data, most centers now do risk stratification and decide
what patients get what tests.

       There are now many published chest pain protocols based on risk levels.
Caution: The lowest category patients fall into two groups “Very Low Risk” or Non
Cardiac Chest Pain with other obvious cause for symptoms.




                                           26
VUMC EMERGENCY DEPARTMENT CHEST PAIN RISK STRATIFICATION TABLE

                                                                                                                Revised 10/5/2006


Feature       Level I STEMI          Level II HigH RISK          Level IIIA                     LEVEL IIIB                Level IV
                                     ACS ( NSTEMI / USA)         INTERMEDIATE RISK:             INTERMEDIATE              LOW RISK
                                                                 CaRDIOLOGY                     RISK: ED
                                                                 CONSULTATION                   Observation
HPI           Symptom complex        Return of previous          Known CAD but with             Possible ischemic         Low clinical
              suggestive of ACS:     ischemic symptoms (see      different presenting           symptoms. and             suspicion for
              Chest discomfort       Level I) with known         symptoms (includes             Diabetes Mellitus or      ACS. and No
              with or without        coronary artery disease     patients with prior PCI or     Extra-cardiac             diabetes or
              radiation to arm(s),   (CAD).                      CABG). or Strong               vascular disease. or      known CAD.
              neck, jaw or                                       suspicion for ischemia in      Family history of
              epigastrium;                                       absence of known disease       premature CAD
              shortness of breath;                               (compelling clinical history
              weakness; nausea;                                  and risk factor profile). or
              diaphoresis;                                       Age > 70 without obvious
              lightheadedness;                                   non-cardiac cause of
              near-syncope or                                    symptoms.
              syncope.
Physical      May include            May include transient       May include evidence of        May include               Normal
Exam          transient MR,          MR, hypotension,            extra-cardiac vascular         evidence of extra-
              hypotension,           tachycardia, diaphoresis,   disease (i.e. bruits).         cardiac vascular
              tachycardia,           or pulmonary edema.                                        disease (i.e. bruits).
              diaphoresis, or
              pulmonary edema.
ECG           Must have ST           Transient ST segment ⇑      Fixed Q waves. or Chronic      Fixed Q waves. or         Normal
              segment ⇑ 1 mm or                                  ST segment &/or T wave         Chronic ST segment
                                     or ⇓ (0.05-1 mm). ST        changes (not acute). or        & /or T wave
              greater in 2 or more
              contiguous leads.      segment ⇓ (at least 0.5     May be normal.                 changes (not acute).
              OR New left            mm) in 2 or more                                           or May be normal.
              bundle branch          contiguous leads.
              block                  Ischemic-appearing T
                                     wave inversion. or May
                                     be normal
Markers                                                                                         Normal                    Normal
              ⇑ TnT &/or CK-                                     Normal or ⇑ TnT in
                                     ⇑ TnT &/or CK-MB
              MB May be normal                                   absence of chest pain or
                                     May be normal
              early                                              ECG changes

Action/       911 Cardiology         Urgent Cardiology                                          Observe in ED             Noninvasive
Disposition   (Response < 10         (Response < 30 min)                                        Noninvasive stress        stress testing
              min) ED attending      Admit Cardiology +/-                                       testing                   at the
              activates Cath Lab     Cath Lab                    Manage in CP CDU                                         discretion of
                                                                 Cardiology Consultation                                  the ED
                                                                 Cardiology attending                                     physician.
                                                                 evaluation & disposition.




                                                                 27
28
                Do Low Risk Patients Really Need to Be Tested
• No study has 0.0% miss rate without an objective test
• Misses are consistent and appear in every study that fails to perform
  objective testing
                                     Risk of AMI
                                     Hx, PE, ECG
                                                          7157 pts AJC 1991

                     •Obvious AMI           88% AMI       (245/288)
                     •Strong Suspicion      34% AMI       (478/1426)
                     •Vague Suspicion        8% AMI       (192/2519)
                     •*No Suspicion         1.2% AMI      (6/466)
              466 patient sample group had NO Suspicion, yet 1.2% had AMI
                            6% of AMI patients had WNL ECG



                The Largest Study of Missed Cardiac Ischemia
                                                          N Engl J Med 2000;342:1163-1170

                     •   10,689 patients
                     •   17% AMI or UA
                     •   8% Acute MI
                     •   9% Unstable Angina

                                    Testing Protocol

                     •   ECG, Repeat ECGs, SECG
                     •   Enzymes, Repeat enzymes
                     •   ACI-TIPI computer program assistance
                     •   6-12 hours observation
                     •   Study designed NOT to miss AMI-ACS
                     •   But no stress testing performed
                     Results:
                     • 2.1% of Acute MI’s Missed
                     • 2.3% of Unstable Angina Missed
          If this is “standard of care” don’t see 100 AMIs during your career

                               Ultra Low Risk Patients
                                                            Acad Emerg Med 2005;12:26-32

                     •   1023 Patients 34-39 years old
                     •   No Cocaine Use
                     •   Overall Risk for ACS 5.4%
                     •   2.2% 30D adverse event rate
                     •   1.7% AMI Rate
                                           29
                                     Lowest Risk Patients
                                        30 Day Risk
                          • No prior Cardiac History + No Risk Factors
                                 – 1.8%
                          • No prior Cardiac History + WNL ECG
                                 – 1.3%
                          • No History + No Risk Factors + WNL ECG
                                 – 1.0%
                          • No History + No Risk Factors + WNL ECG + WNL Enzymes
                                 – 0.14%


                        European Studies at Low Risk Patients
                                                                         Euro Heart J 2004;25:329-334
                                                                          Brit Med J 2001;323:372-374
        •   Two European studies
        •   D/C’d lowest risk patients without stress tests
        •   Euro H J: 716 pts. D/C’d : 4 MI + 2 ACS at 6 mos.
        •   BMJ: 292 pts.: 1 MI at 48 hrs; no other follow-up
        •   Better results than American and Canadian studies but both papers very brief
                 and general applicability to current practice in USA and Canada unclear.


                       Early Discharge Without Stress Testing
                                                                     Ann Emerg Med 2006;47:427-435
Evaluates sending home low risk patients who can then safely get stress testing at a later date.
This article should be carefully studied if its conclusions are to be used.
“for patients with chest pain and low risk for short-term cardiac events, outpatient stress testing
is feasible, safe...With an evidenced based protocol physicians can identify patients at low risk…”
All patients had:
        1) ECG
        2) Enzymes (Both CK-MB and Troponin at least 6 hours after onset of CP)
        3) Had risk stratified by detailed algorithm
PLEASE Look at the Algorithm. NOTE the key questions
        •   If a patient has extracardiac disease (CVA, PVD, Bruits) → No D/C
        •   If a patient has 2-3 Risk Factors → No D/C
        •   If a patient has Diabetes → No D/C
        •   If a patient has history of prior similar CP diagnosed as angina, MI, or PCI → No D/C

And finally most importantly: Chest or left arm pain or discomfort as chief symptom
(if clearly not cardiac wall pain), GERD or Pleurisy → No D/C




                                                  30
The Erlanger Chest Pain Evaluation Protocol: A One-Year Experience with Serial
 12-Lead ECG Monitoring, Two-Hour Delta Serum Marker Measurements, and
    Selective Nuclear Stress Testing to Identify and Exclude Acute Coronary
                                   Syndromes
                                                             Annals of Emerg Med 2002;40:584-594
                             • Erlanger Series
                             • 2074 Patients
                             • 100% sensitive for AMI
                             • 99.1% sensitive for ACS
                             • 12 Lead ECG
                             • Serial ECGs
                             • Physician Judgement
                             • Baseline Cardiac Enzymes
                             • Delta Cardiac Enzymes
                             • Nuclear Stress Testing
                    If no stress testing performed for ACS: 80.4% sensitivity

Note: In 614 category IV patients, the probable non-ACS chest patients, there were:

                        -   1.8% AMI
                        -   0.2 % Life Threatening Complications
                        -   1.3% Urgent PCI
                        -   0.5% CABG
                        -   0.2% Death
                        -   3.3% ACS

                Incremental Sensitivity for Detecting 30d ACS
                                                                    Ann Emerg Med 2002;40:584-594
        17.1%        37.6%          41.9%        66.12%                80.4%            99.1%



                 Baseline          Delta                           Physician ┼ Selective
       ECG                ┼ SECG ┼ Serum ┼
                 Markers                                           Judgment    Nuclear
                                   Markers                                     Stress
                                                                               Testing


                  Incremental Sensitivity for Detecting AMI
                                                                   Ann Emerg Med 2002;40:584-594

         26.3% 58.1%              64.4%             93.2%           97.6%            100%

                                                       Ann Emerg Med 2002;40:584-594

                 Baseline                         Delta     Physician   Selective
       ECG                ┼ SECG ┼                        ┼           ┼
                 Markers                          Serum     Judgment    Nuclear
                                                  Markers               Stress
                                                                        Testing


                                               31
         My “Simple” Recommendations on Specific Patient Types

Lowest Risk Patients (Atypical Symptoms, Non-Ischemic ECG, No History of Heart
Disease)
       1. Confirm one set of enzymes are negative
             - If young and healthy, WNL ECG and can run:
                      ETT
             - If healthy, abnormal non-ischemic ECG and can run:
                      Rest-Stress Nuclear Test or Stress Echo or CTA
             - If older and healthy and normal ECG:
                      ETT or Rest-Stress Nuclear or Stress Echo or CTA
             - If older and healthy and abnormal non-ischemic ECG
                      Rest-Stress Nuclear or Stress Echo; strongly consider CTA

Note: If a patient fits all low risk questions as described on page 28, you are at very,
very low risk to discharge if 1)you truly feel patient follow-up for out patient testing and
2) you have satisfied all criteria of article’s appendix. Must have Low Prob. Hx, no CC
of Substernal CP; No Risk Factors, WNL ECG and WNL Enzymes at 6 hours.


Intermediate Risk Patients (questionable ECG, more typical symptoms and/or
multiple risk factors)
               - Perform serial ECGs (at least two)
               - Perform Delta Enzymes
               - If negative do:
                 Rest-Stress Nuclear Protocol (some centers may choose stress echo) or
                                           CTA


Intermediate Risk Patients with prior negative nuclear study or echo
        -Excellent candidate for CTS or formally turn care over to cardiologist or
inpatient MD


High Risk Patients with non-diagnostic ECG but negative enzymes
             - You should not manage this patient without either formal, written
               involvement and transfer of ultimate disposition to a cardiologist or by
               admitting the patient to a CCU or step down unit where another MD is
               ready to immediately assume care. If you can get a completely negative
               CTA however, you can R/O ACS.




                                             32
                                      Conclusions

We can not exclude ischemia with 100% sensitivity

We are expected to exclude ischemia with 100% sensitivity

Do an objective test after one or more sets of enzymes shows patient is not infarcting
and you do not believe patient has unstable angina. Based on risk, do an:

                       •   ETT
                       •   Stress Echo
                       •   Nuclear Study
                       •   Cardiac Cath
                       •   Spiral CT of Coronary Arteries

If you can not test the patient with one of the modalities listed on the prior page and are
going to refer the patient for next day (or later) cardiac evaluation, consider doing the
next best thing to ETT testing:


               The Slovis Method of ETT Testing Without a Treadmill
                     • Only used After you decide to discharge a low risk patient
                     • Calculate maximal HR (220-Age)
                     • Calculate target HR: 75-80% of max HR
                     • Run patient at bedside till target HR obtained
                     • Repeat 12 lead ECG

                   If Chest Pain or New ST Changes; admit!!

                  If No Chest Pain and No New ST Changes;
                       Refer for Outpatient Follow-up.




                                            33
                            Summary and Conclusions
                                 5 Rules to Prevent a Mistake
• Atypical is Typical:
      - Do not use atypical characteristics to R/O the possibility of ischemia.
        I personally believe that with enough effort, you can always make something in
the patient’s history atypical. Don’t waste valuable time trying to find something to help
you not do the full work-up.


• The Elderly Present with Different Symptoms:
       - Shortness of breath, weakness, syncope-near syncope, diaphoresis and nausea-
vomiting all may equal R/O AMI
       The elderly, younger patients, women, non-english speaking patients, minorities
and smokers often are misdiagnosed due to “their” failure to read textbooks and know
how to present classic symptoms to us.

• ECGs need to be Repeatedly Read and Performed:
        - After you have read the ECG, re-read it specifically looking for the 5 patterns of
AMI and for any evidence of localized ischemia. Before you think about discharging a
patient, repeat the ECG and compare it to the previous ECG, once again specifically re-
looking in all 5 locations.
      One ECG begets another., We can probably decrease our miss rate by 25-50% if
we were more ECG attentive and expert.

• Perform Delta Enzyme Analysis:
      - One set of enzymes will be more likely to miss, rather than diagnose, an early
AMI.
      Make a repeat set of enzymes routine along with the repeat ECG.

• Do an Objective Test:
       - Have a Chest Pain protocol in place that allows for an evidenced based approach
for each step of the evaluation. Have a protocol based on risk, ECG, age and ability to
run. Do either an ETT, Nuclear Study, Echo or CTA.
       If everyone got an objective test, our miss rates would go from 1-2 % (or higher)
to 1/1000 or even less.

                     5 Steps to an Expert Cardiac Evaluation
               • Perform a Careful History and Physical
                        - specifically ask the 3 dissection questions
               •   Perform at least two ECGs
               •   Perform at least 2 enzyme determinations
               •   Assess risk, ECG and ability to run
               •   Perform an objective test, or in ultra low risk individuals;
                   refer for next day testing.
                                              34
                                             References:
Diagnosing AMI

Han J, Lindsell C, Storrow A, Luber S, Hoekstra J, Hollander J, Peacock W, Pollack C, Gibler W. The
Role of Cardiac Risk Factor Burden in Diagnosing Acute Coronary Syndromes in the Emergency
Department Setting. Ann Emerg Med 2007;49:145.

Han J, Lindsell C, Hornung R, Lewis T, Storrow A, Hoekstra J, Holander J, Miller C, Peacock W, Pollack
C, Gibler W. The Elder Patient with Suspected Acute Coronary Syndromes in the Emergency Department.
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