LOW RISK CHEST PAIN SEMINAR

Emily McLaren, PGY 3 7 February 2013

What are the history and physical characteristics of patients presenting to an ED with chest pain that is low risk for ACS?

Objectives   What is the role of the H&P in identifying LRCPPTS?   What is the role of classic cardiac risk factors in risk stratification of ACS?   What clinical decision tools are available to aid in risk stratification of LRCPPTS?

What is low risk chest pain?   Typical chest pain   Heberden 1768   A painful sensation in the breast accompanied by a strangling sensation, anxiety, and occasional radiation of pain to the L arm   Associated with exertion, relieved with rest

  Atypical or low risk chest pain   Everything else?

Why do we care?   We miss about 2-5% of ACS   Most CP admissions are for non-cardiac chest pain   H+P, RF, and decision tools are available to aid in our decision making

Chest Pain History

  JAMA 2005   Literature review of prospective and retrospective observational studies and systematic reviews

Chest Pain Characteristics

Chest Pain Radiation   Typical CP: radiation to L neck, shoulder or arm    ACS   To R arm, shoulder (PLR 4.7)   To both arms (PLR 4.1)   To L arm, shoulder (PLR 2.3)

Chest Pain Quality   Typical CP: pressure, ache    ACS   Same as prior MI (PLR 1.8)   Pressure (PLR 1.3)

   ACS   Sharp, stabbing (PLR 0.3)

Chest Pain Location   Typical CP: substernal, L chest   Poorly studied   Poor predictive value   Substernal CP   Region of infarction (exception: inferior AMI)

   ACS: Inframammary (PLR 0.8)

Area of Chest Pain   Typical CP: diffuse    ACS: < size of coin (PRL 0.6 with CI 0.3-1)   Everts et al, 822 pts   Non-AMI 11% vs AMI 7%

Chest Pain Severity

×

Time Course   ACS: crescendo pattern   Non-ACS: maximal intensity at onset   Duration   Seconds – non-ACS   2-10 min – angina   10-30 min – unstable angina   > 30 min – AMI vs non-ACS (GI)   Recurrent, hrs-days – non-ACS

Palliative/Provocative Factors and Associated Symptoms

Palliative Factors   Nitro   GI Cocktail   Rest

×

 Provocative Factors    ACS   Exertion (PLR 2.4)

  Equivocal   Emotion   Stress

Provocative Factors    ACS   Pleuritic (PLR 0.2)   Positional (PLR 0.3)   Reproducible (PLR 0.3)   Non-exertional (PLR 0.8)

  Lee et al (1985) – 22% of pts with sharp pain dx with ACS (13% pleuritic, 7% reproducible)   Lee et al (1987) – 3 Ps + no hx of CAD, none dx with MI

Associated Symptoms    ACS   Diaphoresis (PLR 2)   Nausea/vomiting (PLR 1.9)

  Disappears with multivariable testing

Conclusions

Conclusions   Individual elements are assoc with increased or decreased risk of ACS   No element of chest pain quality alone or in combination identify patients that can be safely discharged without further diagnostic testing

Limitations   Characteristics treated as independent, rather than interdependent variables   Quality is subjective   Only addresses CP, not other anginal equivalents

Physical Exam

HIGH LIKELIHOOD •  Pulmonary edema •  New or worsening MR •  S3 •  Hypotension •  Brady or tachycardia

INTERMEDIATE LIKELIHOOD

LOW LIKELIHOOD

•  Extracardiac vascular disease (bruit)

  Reproducible CP

  PE is usually normal in uncomplicated ACS

May point to non-ACS Dx   Unequal pulses - dissection   Murmurs - endocarditis   Friction rub - pericarditis   Fever, rhonchi - pneumonia   Reproducible CP - MSK

Cardiac Risk Factors

Risk Factors   Age, Male Gender, HTN, HLP, DM, smoking, and family history   Framingham study: 2+ risk factors = higher lifetime risk of CAD

  Jayes et al, 1992   1743 pts   What to RF add to hx and EKG when diagnosing ACS?

Jayes et al

  Han et al, 2007   Retrospective analysis of 10,806 patients with suspected ACS   8.1% met end point: ACS within 30 days (PCI, biomarkers, death)

Conclusions

Conclusions   Cardiac RF have limited value in diagnosing ACS

in ED patients older than 40

Conclusions -LR 0 RF

+LR 4+ RF

< 40

0.17 (0.04-0.66)

7.39 (3.09-17.67)

40-65

0.53 (0.4-0.71)

2.13 (1.66-2.73)

> 65

0.96 (0.74-1.23)

1.09 (0.64-1.62)

Limitations   RF given equal weight   Verification bias

Clinical Decision Tools

Early Risk Scores   Pozen et al, 1980: created a ‘mathematical predictive instrument’ to decrease CCU admissions   Selker et al, 1998: ACI-TIPI   Goldman et al, 1988: < 7% risk of AMI   Limkakeng et al, 2001: < 4.9% risk of AMI

TIMI Risk Score   Developed to categorize risk of death or ischemic events in pts with NSTEMI or UA   Used as basis for MDM

  Chase et al, 2006   First prospective observational cohort to validate TIMI in ED pts   1458 pts

Chase et al, 2006

Chase et al, 2006

TIMI Score 0 = 1.7% event rate

Chase et al

Similar Studies   Pollack et al, 2006   3929 patients   TIMI 0 = 2.1% risk

Conclusions   TIMI risk score does correlate with outcome   Identified large group of pts that are low risk for primary outcome at 30 days   Cannot be used in isolation to determine dispo

“Manchester” Modified TIMI   Body et al, 2009   Pts with positive troponin or EKG changes may only have TIMI = 1   Prospective cohort   796 pts

Body et al

TIMI < 3 = sensitivity of 96%

  Hess et al, 2010   Prospective observational study   1017 pts

Hess et al, 2010

  Than et al, 2011   3582 pts in 14 EDs, 9 countries   TIMI + biomarker panel at 0 and 2 hrs   2 hr TIMI 0 = 0.9% risk (9.8% of pts)

Than et al

  Aldous et al, 2012   1000 from ASPECT   Primary outcome in 36.2%   Also included high sensitivity Troponin T   2 hr TIMI 0 = 0.8% risk (12.3% pts)

GRACE   Global Registry of Acute Coronary Events   Prospective multinational observational study of hospitalized pts with ACS   8 variables          

Age HR SBP Cr Killup score

  ST segment depression   Elevated biomarkers   Cardiac arrest

  Looks at in-hospital and 6 month all-cause mortality

  Lyon et al, 2006   Retrospective cohort   1000 pts   TIMI = GRACE

  Lee et al 2011   TIMI vs GRACE vs PURSUIT   Prospective cohort study   4723 pts

PURSUIT

Lee et al TIMI = 0 in 39%

GRACE < 41 in 4.5%

Lee et al

  Kline et al, 2005   Prospective database of 8 variables from 14,796 pts   Attribute matching vs ACI-TIPI

Attributes matching

Kline et al

  Mitchell et al, 2006   1114 pts   Attributes matching vs. ACI-TIPI vs. physician estimate

Mitchell et al

Sanchis Rule   Sanchis et al, 2005   646 pts   Focuses on clinical history   Excludes EKG changes and (+) troponin   Primary end point at 1 year, secondary at 14 days

Chest Pain Score

Hospital Course and Results   322 had exercise ST: (-) 190, (+) 52   216 pts early D/C   430 pts hospitalized   227 cardiac cath   68 PCI   31 CABG

  Primary end point: 1 yr (6.7%), 14 days (5.4%)

Calculated risk score   CP score > 10   > 2 pain episodes in 24 hrs   Age > 67   IDDM   Prior PCI

1 point 1 point 1 point 2 points 1 point

In pts with negative troponin and no EKG changes

Calculated Risk Score Score

Event Rate

Stress Results

0

0%

1

3.1%

2 3

5.4% 17.6%

Negative Inconclusive Positive Not done

>4

29.6%

Score of 0 = 17.2% of pts

Event Rate 1.6% 3.9% 9.6% 10%

Limitations   Complicated CP score   Subjective

Vancouver Rule   Christenson et al, 2006   Prospective cohort, 769 pts   Screened 123 potential predictor variables   Clinical decision tool that is 98.8% sensitive and allows for D/C of VLRCP pts within 2-3 hrs (32.5%)

Other similar studies   Marsan et al (2005): age < 40, no CAD hx, normal EKG OR no CAD RF, normal initial biomarkers = ACS rate 0.14%, no CV events at 30 days   Collin et al (2011): no events for same patients at 1 year

Limitations   Outdated biomarkers   Detroit ≠ Vancouver

  Six et al, 2008   120 pts   Clinical questions   Why do we admit to CCU?   Predictors of 90 day events?

Six et al 0-3: 2.5% risk (32.5% of pts) 4-6: 20.3% risk 7-10: 72.7% risk

Six et al   Conclusion – can use HEART to determine early D/C vs. early intervention   Limitations   Small study   Use CP hx

  PURSUIT vs TIMI vs GRACE vs FRISC vs HEART   Uses c-statistic to claim HEART superiority

  Mahler et al, 2011   Prospective cohort   1070 CP Obs pts (TIMI < 2 and clinically low risk)   Outcome   HEART < 3: 0.6% events   HEART < 3 + 4-6 hr troponin: 0 events

  Fesmire et al, 2012   Retrospective study   2148 pts   Weighted HEART + 3 S’s   Sex   Serial troponin and EKG   Decreased weight of RF, age and CAD hx   Increased weight on chest pain hx

Fesmire et al HEARTS3 < 2 = 0 events (14% vs 8%)

Fesmire et al   Older troponin   Retrospective study

  Hess et al, 2012   Prospective observational cohort of 2,718 patients   12% met primary outcome (ACS, revascularization, death) within 30 days   Identified patients with zero risk for 30 day ACS

Conclusions

  Developed a highly sensitive clinical decision tool to identify very low risk patients for ACS

Limitations   Does not include pts at risk for ACS with non-chest pain CC   Evaluation bias: not all patients underwent definitive testing   What is typical chest pain?   Needs prospective multicenter validation

  Aldous et al, 2012   Post hoc analysis of ASPECT trial   Primary endpoint in 36.2%

Study Population

Results

Results

Conclusions   Several elements of CP hx and multiple decision tools available to aid in dx of ACS   Classic CAD risk factors less impt in acute setting   Ultimately unlikely to change our clinical practice

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Swap and Nagurney. Value and Limitations of Chest Pain History in the Evaluation of Patient With Suspected Acute Coronary Syndrome. JAMA. November 23/30. Vol 294. pp 2623-2629.

2. 

Fesmire et al. Improving risk stratification in patients with chest pain: the Erlander HEARTS3 score. American Journal of Emergency Medicine. 2012. pp 1829-1837.

3. 

Sanchis et al. New risk score for patients with acute chest pain, non-ST- segment deviation, and normal troponin concentrations: a comparison with the TIMI risk score. J Am Coll Cardiology 2005;46:443-449.

4. 

Christenson et al. A clinical prediction rule for early discharge of patients with chest pain. Annals of Emergency Medicine. 2006;47:1-10.

5. 

Backus et al. Chest pain in the emergency department: a multicenter validation of the HEART score. Crit Pathw Cardiol 2010;9:164-9.

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Mahler et al. Can the HEART score safely reduce stress testing and cardiac imaging in patients at low risk for major adverse cardiac events. Crit Pathw Cardiol 2011;10:128-33.

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Han et al. The Role of Cardiac Risk Factor Burden in Diagnosing Acute Coronary Syndromes in the Emergency Department Setting. Annals of Emergency Medicine. Vol 49, No 2. pp 145-152.

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Kline et al. Pretest probability assessment derived from attribute matching. BioMed Central. August 2005.

2. 

Mitchell et al. Prospective Multicenter Study of Quantitative Pretest Probability Assessment to Exclude Acute Coronary Syndrome for Patients Evaluated in Emergency Department Chest Pain Units. Annals of Emergency Medicine. 2006;47:438-447.

3. 

Selker et al. Use of the Acute Cardiac Ischemia Time-Insensitive Predictive Instrument (ACI-TIPI) to Assist with Triage of Patients with Chest Pain or Other Symptoms Suggestive of Acute Cardiac Ischemia: A Multicenter Clinical Trial. Annals of Internal Medicine, Dec 1998. Vol 129, No 11.

4. 

Marsan et a. Evaluation of a clinical decision rule for young adult patients with chest pain. Acad Emergency Medicine. 2005;12:26-31.

5. 

Collin et al. Young patients with chest pain: 1-year outcomes. Am J Emerg Med. 2011;29:265-270.

6. 

Goldman et al. A computer protocol to predict myocardial infarction in emergency department patients with chest pain. N Engl J Med. 1988;318:797-803.

7. 

Limkakeng et al. Combination of Goldman risk and initial cardiac troponin I for emergency department chest pain patient risk stratification. Acad Emerg Med. 2001;8:696-702.

8. 

Pollack et al. Application of the TIMI Risk Score for Unstable Angina and Non-ST elevation Acute Coronary Syndrome to an Unselected Emergency Department Chest Pain Population. Academic Emergency Medicine. 2006;13:13-18.

9. 

Aldous et al. A 2-hour thrombolysis in myocardial infarction score outperforms other risk stratification tools in patients presenting with possible acute coronary syndromes: Comparison of chest pain risk stratification tools. American Heart Journal. 2012. Vol 164, No 4. pp 516-523.

10. 

Than et al. A 2-h diagnostic protocol to assess patients with chest pain symptoms in the Asia-Pacific region (ASPECT): a prospective observational validation study. Lancet 2011;377:1077-84.

11. 

Aldous et al. A new improved accelerated diagnostic protocol safely identifies low risk patients with chest pain in the emergency department. Academic Emergency Medicine. 2012;19:510-6.

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Body et al. Can a modified thrombolysis in myocardial infarction risk score outperform the original for risk stratifying emergency department patients with chest pain? Emerg Med J. 2009;26:95-99.

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