II. Precautions: Atypical Chest Pain
- Atypical Chest Pain is avoided as a diagnosis due to misinterpretation by patients as a benign findings
- Define Low Risk Chest Pain into one of three categories
- Cardiac Chest Pain
- Possible Cardiac Chest Pain
- Noncardiac Chest Pain
III. Indications: Electrocardiogram (EKG) suggestive of Low Risk Chest Pain
- Normal or unchanged Electrocardiogram
- ST Depression 0.5 to 1.0 mm
-
T Wave Inversion (<0.2 mV) or flattening
- Leads with dominant R Wave
IV. Contraindications: Moderate or Intermediate Risk patient (or other concerning findings)
- See Moderate Risk Acute Coronary Syndrome Management
- Concerning history findings
- Unstable Angina (low threshold or increased frequency of provoked Angina)
- New onset Angina
- Significant comorbidity
- Coronary Artery Disease
- Peripheral Vascular Disease
- Prior PCI (stenting) or Coronary Artery bypass (especially if in last 6 months)
- Heart Failure
- Structural heart disease (e.g. Aortic Stenosis)
- Pulmonary Hypertension
- Concerning examination findings
- Hemodynamic abnormalities (e.g. Hypotension)
- Syncope
- Pulmonary Edema
- Ill appearing
- Concerning diagnostic findings
- Troponin Increased
- Significant EKG changes (e.g. ST Segment Elevation or T Wave Inversion)
- Arrhythmia
- Factors that may require additional vigilence but may not absolutely contraindicate following the low risk protocol
- Diabetes Mellitus (especially if longstanding >10 years or uncontrolled)
- Typical Chest Pain (central, heavy, crushing, pressure or squeezing pain)
- Especially if associated with Dyspnea, diaphoresis, Nausea or Vomiting
- Higher risk presentation than Atypical Chest Pain (sharp, localized or lateral Chest Pain)
V. Labs: Based on Standard Troponin
- Highly sensitive Troponin Is sufficiently sensitive to replace all other biomarkers (e.g. CK-MB, Myoglobin, CRP)
- Decision rules are used by accelerated protocols to shorten time between Troponins
- HEART Score 0-3 (and normal first Troponin)
- Three hours between standard Troponins (Used by University of Maryland)
- One normal Troponin and a HEART Score 0-3 has a risk of major adverse cardiac event rate of 1.7% at 30 days
- Two Troponins at 3 hours apart lowers the major adverse cardiac event rate risk to <1% at 30 days
- TIMI Score 0
- Two hours between Troponins (Used by some centers)
- However TIMI Score was not intended for risk stratification in undifferentiated Chest Pain
- TIMI Score is not for risk stratification in 2018 ACEP guidelines
- Berg and Orman in Herbert (2014) EM:Rap 14(9): 3-4
- HEART Score 0-3 (and normal first Troponin)
- Presentation >6 hours from Chest Pain onset (IF Chest Pain stopped more than 6 hours prior to presentation)
- Single Troponin Typically rules-out acute Myocardial Infarction
- However, if Chest Pain present in last 6 hours, or waxing and waning during this time, repeat Troponin at 3 hours
- Presentation <6 hours from Chest Pain onset
- Precaution
- Pathway assumes decision rules (see above) to shorten the duration between Troponins to 2-3 hours
- HEART Score of 0-3: May follow accelerated pathway
- Lowers the major adverse cardiac event rate risk at 30 days to less than 1%
- HEART Score >3: Observation stay with standard serial Troponins is typically pursued
- Highly sensitive Troponin
- See protocols below
- Obtain two High Sensitivity Troponins 2 hours apart
- Standard Troponin
- Precaution
- References
VI. Labs: Based on High Sensitivity Troponin (hs-Troponin)
- hs-Troponin on arrival
- Normal if first hs-Troponin undetectable or <6 to 22 ng/L (upper normal range varies by gender, assay)
- Sufficient to exclude ACS if >3 hours of symptoms, low HEART Score, EKG negative for significant findings
- Intermediate range hs-Troponin If <52 ng/L (indication for repeat testing)
- Positive hs-Troponin If >52 ng/L
- Normal if first hs-Troponin undetectable or <6 to 22 ng/L (upper normal range varies by gender, assay)
- Indications for a second hs-Troponin at least 1 hour from first hs-Troponin
- Abnormal first hs-Troponin
- First hs-Troponin performed <3 hours from onset of symptoms
- A single negative hs-Troponin Is sufficient if >3 hours from onset
- References
- Swaminathan and Mattu (2020) EM:Rap 20(6): 4-5
- Januzzi (2019) J Am Coll Cardiol 73(9):1059-77 [PubMed]
- Baugh (2019) Crit Pathw Cardiol 18(1):1-4 [PubMed]
VII. Diagnostics
- Cardiac Monitoring (Telemetry)
- Vital Signs including Heart Rate and Blood Pressure
- Continuous ST Segment monitoring
- Cardiac Monitoring discontinuation
- Indications to discontinue monitoring (Ottawa Chest Pain Cardiac Monitoring Rule)
- No current Chest Pain AND
- Normal or non-sepcific EKG (no prolonged interval, no LVH, no LBBB) AND
- No Arrhythmia in first 8 hours of emergency department presentation
- Syed (2017) CMAJ 189(4): E139-45 +PMID:28246315 [PubMed]
- Low risk patients do not require telemetry (however often performed in standard practice)
- Goldman Risk Score <8% and
- Troponin I <0.3 ng/ml and
- CK-MB <5 ng/ml
- Hollander (2004) Ann Emerg Med 43:71-6 [PubMed]
- Indications to discontinue monitoring (Ottawa Chest Pain Cardiac Monitoring Rule)
- Serial Electrocardiogram (EKG)
- EKG Test Sensitivity is only 90% for Myocardial Infarction (normal EKG despite true MI in 10% of cases)
- ACS should not be excluded based on a single EKG
- Perform EKG at time of serial Troponins AND
- Perform EKG with changes in patient symptoms (e.g. increased Chest Pain)
- Positive examples are not uncommon with multiple (e.g. 3-5 q5-10 min) serial EKGs
- Ongoing Chest Pain with ischemia seen only on the last EKG is not a rare phenomenon
- However ACC/AHA protocols do not require more than one Electrocardiogram (EKG)
- EKG normal, unchanged, or nominally changed (T Wave Flattening, <1 mm ST depression)
- Continue with the low risk protocol (see below)
- EKG with significant change (symmetric ST Segment change >1mm, T Wave Inversion >0.2 mV)
VIII. Imaging
- Approach
- Age <65 years or lower suspicion for obstructive Coronary Artery Disease
- Start with Coronary CT Angiogram (CTCA)
- Consider Stress Testing if CCTA equivocal
- Age >65 years or higher suspicion for obstructive Coronary Artery Disease
- Start with stress testing
- Consider Coronary CT Angiogram (CTCA) if stress testing equivocal
- Age <65 years or lower suspicion for obstructive Coronary Artery Disease
- Stress Testing
- Precautions
- Test Sensitivity for Ischemic Heart Disease: 85-90% (esp if evaluation delayed from time of symptoms)
- Best Test Sensitivity for coronary lesions >70% (but MI may occur with 30-50% stenosis)
- Normal stress test may offer 1 year reassurance for similar symptom presentations
- Poor Test Specificity in low risk populations
- Exercise caution in stress testing low risk patients (high False Positive Rate)
- Test Sensitivity for Ischemic Heart Disease: 85-90% (esp if evaluation delayed from time of symptoms)
- Tests
- Exercise Treadmill Test (Test Sensitivity 50-80%)
- Stress Echocardiogram
- Perfusion Radionuclide scan (SPECT, Stress Cardiolite, Test Sensitivity >90%)
- Pharmacologic Stress Test (e.g. Lexiscan)
- Precautions
- Resting Echocardiogram (for wall motion abnormality)
- Efficacy is typically not sufficient to rule-in or rule out ACS
- Does not distinguish between old and new Myocardial Infarction
- Decreased Test Sensitivity if patients present after symptom resolution
- Resting Sestamibi (e.g. Cardiolite, SPECT)
- Negative test confers a good prognosis for the next 12 months
- Positive test is highly predictive of major adverse cadiac events
- Test Sensitivity 71%, Test Specificity 92%
- Amsterdam (2010) Circulation 122:1756-76 [PubMed]
- Kosnik (1999) Acad Emerg Med 6(10):998-1004 [PubMed]
-
Coronary CT Angiogram (CTCA)
- Indications
- Single elevated or equivocal serum Troponin without other findings of ischemia
- Alternative to stress test per 2007 AHA guidelines in low to intermediate risk patients
- Consider in patients under age 65 years old without known coronary disease
- Advantages
- May decrease Chest Pain admission rates
- Lower radiation dose than angiography (3 to 5 mSv compared with 4 to 10 mSv)
- Disadvantages
- Increased radiation exposure and intravenous radiographic contrast load
- Test efficacy for coronary ischemia decreases with Triple Screen (ACS, PE, Aortic Dissection)
- Associated with greater intervention rate for PCI and CABG (due to False Positives) without decreased MI
- Indications
- Angiography
- Indicated for high suspicion cases such as unequivocally positive ekg or cardiac biomarker for ischemia
- References
- Orman, Mattu and Swaminathan in Herbert (2016) EM:Rap 16(10): 8-9
- (2016) J Am Coll Radiol 13(2): e1-29 +PMID:26810814 [PubMed]
IX. Evaluation
- Initial evaluation for high risk, intermediate risk and Low Risk Chest Pain begins the same
- See Acute Coronary Syndrome Immediate Management (includes giving Aspirin 325 mg)
- Low Risk Chest Pain protocol is only per indications listed above
- Approach
- Assess Angina Diagnosis likelihood
- Consider Chest Pain differential diagnosis
- Decision Rules
- See Chest Pain Decision Rules
- Preferred, validated tests in Low Risk Chest Pain risk stratification (accelerated diagnostic protocols)
- Other tests that have been used in Low Risk Chest Pain risk stratification
- Precautions
- Cardiac Risk Factors are not useful in the exclusion of acute coronary disease in the emergency department
- Despite the evidence, Cardiac Risk Factors are included in most decision rule calculators
- Body (2008) Resuscitation 79(1): 41-5 [PubMed]
- Patel (2000) West J Med 173(6): 423-4 [PubMed]
- As of 2017, HEART Score is the most used for risk stratification but does not appear to alter management
- Compared to usual care, HEART Score did not result in worse outcomes, but did not decrease resource use
- HEART Score assigns an objective score to clinical gestalt and is useful for documenting decision making
- Poldervaart (2017) Ann Intern Med 166(10): 689-97 +PMID: 28437795 [PubMed]
- Cardiac Risk Factors are not useful in the exclusion of acute coronary disease in the emergency department
X. Management: Patient Triage Based on Findings
- Findings suggestive of Myocardial Ischemia or NSTEMI (e.g. EKG change or Troponin Increase)
- Findings without signs of ACS or Myocardial Ischemia
- High risk for adverse event in near future (based on decision rules listed above)
- See Myocardial Ischemia Protocol
- Treat same as signs of Myocardial Ischemia above
- Intermediate risk for adverse event in near future
- Consider early discharge with expedited stress testing (see protocol below)
- Consider Stress Imaging prior to discharge (See imaging above)
- Recent stress testing does not exclude a subsequent Acute Coronary Syndrome presentation
- Avoid repeat stess test (same modalilty, e.g. cardiolite) if negative or nondiagnostic within prior 12 months
- Unlikely to be diagnostic if done for similar symptoms
- Consider alternative testing (e.g. CT angiogram)
- Consider admission to Chest Pain unit
- Consider Coronary CT Angiogram (CCTA)
- May be preferred in stable Chest Pain with intermediate risk
- Reassuring history that may allow for early discharge
- Negative prior myocardial perfusion scan does not alter disposition
- Prior negative coronary angiogram in last 5 years
- Stenosis <50% should have expedited follow-up and testing as indicated (but no admission)
- Prior negative Coronary CT Angiogram (CCTA) in the last 2 years
- Should have expedited follow-up and testing as indicated (but no admission)
- Orman and Mattu in Herbert (2017) EM:Rap 17(6): 5
- Low risk for adverse event in near future (TIMI Score 0 or HEART Score <3)
- Discharge from Emergency Department
- Close follow-up with primary physician
- Discuss warning signs
- Discuss Chest Pain differential diagnosis
- Consider outpatient Exercise Stress Testing
- Stress testing is not required in very low risk patients (e.g. TIMI Score 0)
- Low risk patients (<1% risk of major cardiac event at 30 days) do not require urgent follow-up
- High risk for adverse event in near future (based on decision rules listed above)
XI. Management: Early Disposition of Low Risk Chest Pain in an Intermediate Risk Patient
- Indications
- Intermediate risk for adverse event in near future (see above)
- See Moderate Risk Factors listed above
- Patient has Cardiac Risk Factors, but is risk stratified to low risk protocol
- Risk based on patients stratified to low risk
- TIMI score of 0
- HEART Score of 0-3
- EDACS <16, nonischemic EKG and 0 and 2 hour Troponin negative
- T-Macs <1%
- Intermediate risk for adverse event in near future (see above)
- Exclusion criteria
- See contraindications listed above
- Follow Moderate Risk Acute Coronary Syndrome Management instead if any are true
- Unreliable patient
- Hypotension with systolic Blood Pressure <110
- Congestive Heart Failure
- Pulmonary rales
- Known previous Myocardial Infarction
- Worsening Angina
- Positive Troponin
- Significantly abnormal Electrocardiogram (symmetric ST Segment change >1mm, T Wave Inversion >0.2 mV)
- Other criteria met for Moderate Risk Acute Coronary Syndrome Management
- Evaluation
- See diagnostics above including monitoring and cardiac biomarker (Troponin) timing
- Disposition (based on protocol listed above under labs)
- Contraindications
- Exclusion criteria met
- Protocol
- Confirm patient hemodynamically stable with negative Troponins and no exclusion criteria present
- Discharge to home with precautions, Nitroglycerin and close interval follow-up
- Outpatient expedited stress testing
- Stress test timing had been recommended within 72 hours and was controversial
- Some argue removing the time stipulation (as has been done in Europe)
- Study with no outcome difference between early (<3 days), late (<30 days) and no stress testing
- Education
- Alert the patient that you are still concerned about their heart
- Cannot fully exclude Angina in the Emergency Department
- Warn the patient
- Return to the Emergency Department for changes or worsening ("listen to your body")
- Discuss with patient the overall risk of cardiovascular event before work-up complete
- Between early emergency department discharge and stress testing on follow-up
- For every 100 people with lower risk Chest Pain
- Adverse Event: 2 had a heart or pre-heart attack within 45 days
- No Adverse Event: 98
- Patient is given choice
- Choices from the University of Maryland protocol (see links below)
- Based on a TIMI score or 0, or a HEART Score of 0-3
- I would like a repeat Troponin blood test (e.g. in 3 hours)
- If the Troponin blood test is negative I will be discharged for follow-up
- I understand my risk of heart attack or heart complications is <1% in the next 30 days
- I will see either my primary care doctor or cardiologist for follow-up
- I would like to be placed in observation for further testing
- This testing may include urgent cardiac stress testing
- I understand this may increase the cost of my evaluation
- I understand this may increase the duration of my emergency stay
- I will decline a repeat Troponin blood test (e.g. in 3 hours)
- I will see either my primary care doctor or cardiologist for follow-up
- I understand my risk for a heart attack or heart complications is ~2% in the next 30 days
- Choices from the University of Maryland protocol (see links below)
- Consider demonstrating this in the form of a graphical card
- References
- Alert the patient that you are still concerned about their heart
- Rationale
- Risk of short-term Myocardial Infarction or death in this cohort is less than 1%
- Stress testing does not effectively risk stratify this low risk cohort further
- Hospital observation is not without risk
- Overall risk of in-hospital death due to iatrogenic complication is as high as 1 in 160
- Positive stress testing in low risk patients does not improve outcomes
- No intervention was done in 90% of low risk patients with a positive stress test
- Low risk patients who undergo PCI have worse outcomes
- For every stress test in low risk patients, 90 more angiograms, 11 more stents, no prevented MIs
- Missed acute cardiac ischemia, NSTEMI or Unstable Angina in low risk patients
- Does not significantly impact outcomes
- Pope (2000) N Engl J Med 342(16): 113-70 [PubMed]
- Montelescot (2009) JAMA 302(9):947-54 [PubMed]
- Chest Pain units are often used because of availability, but may not be indicated
- Up to 50% of patients admitted to Chest Pain unit would have been discharged if not available
- Blecker (2016) Ann Emerg Med 67(6): 706-13 +PMID: 26619756 [PubMed]
- Contraindications
- References
- Newman, Shreves and Weingart in Majoewsky (2012) EM:Rap 12(11): 5-7
- Berg and Orman in Herbert (2014) EM:Rap 14(9): 3-4
XII. Management: Empiric Management of Diagnoses of Exclusion
- Chest Wall Pain
-
Gastroesophageal Reflux
- Gastrointestinal causes may be responsible for up to 20% of Chest Pain presentations
-
Anxiety Disorder or Panic Attacks
- Consider in Low Risk Chest Pain (e.g. low HEART Score) when other serious conditions have been excluded
- Many low-risk Chest Pain patients will present with a self-diagnosis of stress and anxiety
- Consider asking Low Risk Chest Pain patients about stress and anxiety
- Consider recommending Mindfulness strategies (e.g. breathing Exercises)
- Consider outpatient mental health referral (or at the very least primary care follow-up)
- Musey (2017) J Emerg Med 52(3): 273-9 +PMID:27998631 [PubMed]
XIII. References
- Avellino (2014) Crit Dec Emerg Med 28(2): 2-9
- Mattu in Swadron (2022) EM:Rap 22(5): 13-5
- Mattu and Swaminathan in Swadron (2023) EM:Rap 23(3): 17-8
- Orman and Mattu in Herbert (2017) EM:Rap 17(2): 9-11
- (2021) J Cardiovasc Comput Tomogr 16(1):54-122 +PMID: 34955448 [PubMed]
- (2021) J Am Coll Cardiol 78(22):e187-285 +PMID: 34756653 [PubMed]
- (2018) Ann Emerg Med 72(5):e65-e106 +PMID:30342745 [PubMed]
- Hollander (2016) Circulation 134(7): 547-64 +PMID:27528647 [PubMed]
- Musey (2021) Acad Emerg Med 28(7): 718-44 +PMID: 34228849 [PubMed]