Acute Coronary Syndrome: Angina
Basics
Description
Description
- Chest discomfort, from imbalance of myocardial blood supply and oxygen requirements
- Canadian Cardiovascular Society classification for angina:
- Class I: No angina with ordinary physical activity
- Class II: Slight limitation of normal activity as angina occurs when walking, climbing stairs, or with emotional stress
- Class III: Severe limitation of ordinary physical activity as angina occurs on walking 1–2 blocks on level surface, climbing 1 flight of stairs
- Class IV: Inability to carry on any physical activity without discomfort, as angina symptoms occur at rest
- Typically categorized as stable or unstable
- Stable angina: Predictable, with exertion, and improves with rest
- Unstable angina (UA): New onset, increase in frequency, duration or lower threshold for symptoms, at rest, or >20 min
- UA associated with increased risk of transmural myocardial infarction (MI) and cardiac death
- New high-sensitivity cardiac biomarkers blurring boundaries between UA and NSTEMI
Etiology
Etiology
- Cardiac risk factors:
- Age
- Men >35 yr
- Postmenopausal in women
- Hypercholesterolemia
- HTN
- Smoking
- Age
- Atherosclerotic narrowing of coronary vessels:
- Stable angina: Chronic and leads to imbalance of blood flow during exertion
- UA: Acute disruption of plaque which can lead to worsening symptoms with exertion or at rest
- Vasospasm: Prinzmetal angina, drug related (cocaine, amphetamines)
- Microvascular angina or abnormal relaxation of vessels if diffuse vascular disease
- Arteritis: Lupus, Takayasu disease, Kawasaki disease, rheumatoid arthritis
- Anemia
- Hyperbarism, carboxyhemoglobin elevation
- Abnormal structure of coronaries: Radiation, aneurysm, ectasia
Diagnosis
Signs and Symptoms
HistorySigns and Symptoms
- Chest pain:
- Substernal pressure, heaviness, tightness, burning or squeezing
- Radiates to neck, jaw, left shoulder, or arm
- Poorly localized, visceral pain
- Anginal equivalents include:
- Dyspnea
- Epigastric discomfort
- Weakness
- Diaphoresis
- Nausea/vomiting
- Abdominal pain
- Syncope
- Symptoms usually reproduced by exertion, eating, cold exposure, emotional stress
- Symptoms not usually positional or pleuritic
- Usually relieved with rest or nitroglycerin
- For stable angina often lasts more than a few seconds but <20 min and no changes in pattern of frequency of symptoms
Geriatric Considerations
- Women, diabetics, ethnic minorities, and those >65 yr often with atypical symptoms
- Prognosis is worse for people with atypical symptoms
Physical Exam
- “Levine sign”: Clenched fist over chest, classic finding
- BP often elevated during symptoms
- Physical exam often uninformative
- Can look for S3/S4, papillary muscle dysfunction with mitral regurgitation or new murmur, diminished peripheral pulses
Essential Workup
Essential Workup
- ECG:
- Standard 12 lead should be obtained and read within 10 min of presentation for patients with acute chest pain
- Helpful in detecting acute MI, less so UA
- Important to compare to prior ECG if available
- New ST changes or TWI suspicious for UA:
- T-wave flattening or biphasic T waves
- ≤1-mm ST depression 80 msec from the J point, is characteristic in UA
- Can see evidence of old ischemia, strain or infarct, such as old TWI, Q wave, ST depression
- Serial ECGs helpful in distinguishing unstable from stable angina
- A single ECG for acute MI is about 60% sensitive and 90% specific
- ECG can also be helpful to diagnose other causes of chest pain:
- Pericarditis: Diffuse ST elevations, then TWIs and pulse rate depression
- Pulmonary embolus S1Q3T3 pattern, unexplained tachycardia, and signs of right heart strain
ALERT
Patients with normal or nonspecific ECGs have a 1–5% incidence of AMI and 4–23% incidence of UA.
Diagnostic Tests and Interpretation
LabDiagnostic Tests and Interpretation
- In stable angina, cardiac enzymes not indicated, but if history suspicious for acute MI, these should be obtained
- CK-MB and troponin I or T:
- High-sensitivity troponins changing positive threshold and timing of rule-out
- CK-MB peaks 12–24 hr, return to baseline in 2–3 d
- Troponin peaks in 12 hr, return to baseline 7–10 d
- Hematocrit (anemia increases risk of ischemia)
- Coagulation profile
- Electrolytes, especially Cr and K+
Imaging
- CXR:
- Usually nonrevealing
- May show cardiomegaly, or pulmonary edema; CHF can be suggestive of UA
- May be helpful in identifying other etiologies such as pneumonia, pneumothorax, or aortic dissection
- Coronary CTA:
- Good for low-risk patients with no known CAD to rule out ischemia as cause of pain if no coronary stenosis
- “Triple rule-out” for ACS, PE, and aortic dissection
- Bedside echo: To detect wall motion abnormalities and other etiologies of shock, pericardial effusion, pneumothorax
- Tc-99 sestamibi (rest): Radionucleotide whose uptake by myocardium is dependent on perfusion
Diagnostic Procedures/Other
- Exercise stress testing:
- Not appropriate for active chest pain with moderate to high likelihood of ischemia
- Imaging stress test (sestamibi, thallium, or echo) if baseline ECG abnormalities
- Other imaging modalities including MRI, PET have also been used
- Coronary angiography:
- Gold standard for diagnosis for CAD
Differential Diagnosis
Differential Diagnosis
- Anxiety and panic disorders
- Aortic dissection
- Biliary colic
- Costochondritis
- Esophageal reflux
- Esophageal spasm
- Esophagitis
- GERD
- Herpes zoster
- Hiatal hernia
- Mitral valve prolapse
- Musculoskeletal chest pain
- MI
- Myocarditis
- Nonatherosclerotic causes of cardiac ischemia:
- Coronary artery spasm
- Coronary artery embolus
- Congenital coronary disease
- Coronary dissection
- Valvular disease: AS, AI, pulmonary stenosis, mitral stenosis
- Congenital heart disease
- Peptic ulcer disease
- Pericarditis
- Pneumonia
- Psychogenic
- Pneumothorax
- Pulmonary embolism
Treatment
Pre Hospital
Pre Hospital
- IV access
- Aspirin
- Oxygen
- Vital signs and oxygen saturation
- Cardiac monitoring
- 12-lead ECG, if possible
- Sublingual nitroglycerin
Initial Stabilization/Therapy
Initial Stabilization/Therapy
- IV access
- Oxygen
- Cardiac monitoring
- Vital signs and continuous oxygen saturation
Ed Treatment/Procedures
Ed Treatment/Procedures
- All patients with chest pain in which cardiac ischemia is a consideration should receive an aspirin upon arrival to the ED
- Sublingual nitroglycerin: If symptoms persist after 3 sublingual doses, suggestive of UA, AMI, or noncardiac etiology
- Pain control
- Anticoagulation
Medication
First Line Medication:Medication
- Aspirin: 325 mg or 81 mg × 4 PO (chewed)
- In patients with aspirin allergy can give clopidogrel (Plavix) 300–600 mg PO, can also consider prasugrel 60 mg PO or ticagrelor
- Dual antiplatelet therapy should be given to patients with UA at medium to high risk who have been selected to have invasive strategy such as catheterization or surgery
- Nitroglycerin:
- 0.4 mg sublingual
- 5–10 mcg/min IV, titrating to effect
- 1–2 in of nitro paste
- Hold for low BP or if concern for preload dependence (RV infarct: Q in II, III, aVF; STE in right-sided V3, V4)
- Beware if patient has history of erectile dysfunction and use of phosphodiesterase inhibitors like sildenafil (Viagra) or tadalafil (Cialis) in last 48 hr
- Morphine:
- 4 mg IV, titrate to relief of pain assuming no respiratory depression and SBP >90
- Consider β-blocker:
- Metoprolol: 25–50 mg PO or 5 mg IV q5–15min for refractory HTN and tachycardia
- Contraindicated in active RAD, active CHF, bradycardia, hypotension, heart block, cocaine use
- Does not necessarily need to be given in ED, suggested benefit within 24 hr of AMI
Second Line Medication:
- Can vary by institution, recommend conferring with inpatient cardiologist regarding anticoagulation
- Heparin: 60-U/kg IV bolus, then 12 U/kg/hr (goal PTT 50–70)
- Enoxaparin: 1 mg/kg SC q12 or q24 if Cr clearance <30 mL/min
- Glycoprotein IIb/IIIa inhibitors:
- Eptifibatide (Integrilin): 180-ug/kg bolus IV over 1–2 min, then 2 ug/kg/min up to 72 hr
- Tirofiban (Aggrastat): 0.4 ug/kg/min for 30 min, then 0.1 ug/kg/min for 48–108 hr
- Abciximab (ReoPro): 0.25-mg/kg IV bolus, then 0.125 ug/kg/min
- Bivalirudin, fondaparinux
- Patients at high risk for bleeding include the elderly, female, anemic, CKD
- For stable angina, management consists of preventative therapies including aspirin, blood pressure control (β-blocker, calcium channel blocker, long-acting nitrates) and lifestyle modification (weight loss, decreased fat/sugar intake, smoking cessation):
- New antianginal medications including ranolazine may also be a part of management
Ongoing Care
Disposition
Admission CriteriaDisposition
- Patients with UA require admission to the hospital
- Early intervention with cardiac catheterization likely decreases mortality in patients with elevations in cardiac enzymes, persistent angina, or hemodynamic instability
- Patients with unclear diagnosis likely would benefit from admission to ED observation unit or hospital admission for serial cardiac enzymes, ECG, and stress testing/catheterization
Discharge Criteria
Patients with stable angina
Follow-Up Recommendations
Follow-Up Recommendations
Patients with stable angina should follow up with their PCP and a cardiologist.
Pearls and Pitfalls
- History is the most important factor in differentiating unstable from stable angina
- All patients with chest pain or symptoms concerning for a cardiac etiology should have an immediate ECG, and serial ECGs are essential for ACS workup
- A single set of negative cardiac enzymes may not rule out ACS in a patient with chest pain
- Women, diabetics, ethnic minorities, and patients >64 yr require a low threshold for ACS workup as they often have atypical presentations
- It is important to work with the inpatient cardiologist/interventionalist regarding anticoagulation regimen choice as this may vary by institution
Additional Reading
- 2012 Writing Committee Members, Jneid H, Anderson JL, et al. 2012 ACCF/AHA focused update of the guideline for the management of patients with unstable angina/Non-ST-elevation myocardial infarction (updating the 2007 guideline and replacing the 2011 focused update): A report of the American College of Cardiology Foundation/American Heart Association Task Force on practice guidelines. Circulation. 2012;126(7):857–910.
- Long B, Koyfman A. Best clinical practice: Current controversies in the evaluation of low-risk chest pain with risk stratification aids. Part 1. J Emerg Med. 2016;51:668–676.
- Long B, Koyfman A. Best clinical practice: Current controversies in the evaluation of low-risk chest pain with risk stratification aids. Part 2. J Emerg Med. 2017;52:43–51.
- Walls RM, Hockberger RS, Gausche-Hill M, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Mosby Elsevier; 2017.
See Also
See Also
Authors
Margaret J. Lin
Shamai A. Grossman
© Wolters Kluwer Health Lippincott Williams & Wilkins
Citation
Schaider, Jeffrey J., et al., editors. "Acute Coronary Syndrome: Angina." 5-Minute Emergency Consult, 6th ed., Lippincott Williams & Wilkins, 2020. Emergency Central, emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307630/all/Acute_Coronary_Syndrome:_Angina.
Acute Coronary Syndrome: Angina. In: Schaider JJJ, Barkin RMR, Hayden SRS, et al, eds. 5-Minute Emergency Consult. Lippincott Williams & Wilkins; 2020. https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307630/all/Acute_Coronary_Syndrome:_Angina. Accessed December 11, 2024.
Acute Coronary Syndrome: Angina. (2020). In Schaider, J. J., Barkin, R. M., Hayden, S. R., Wolfe, R. E., Barkin, A. Z., Shayne, P., & Rosen, P. (Eds.), 5-Minute Emergency Consult (6th ed.). Lippincott Williams & Wilkins. https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307630/all/Acute_Coronary_Syndrome:_Angina
Acute Coronary Syndrome: Angina [Internet]. In: Schaider JJJ, Barkin RMR, Hayden SRS, Wolfe RER, Barkin AZA, Shayne PP, Rosen PP, editors. 5-Minute Emergency Consult. Lippincott Williams & Wilkins; 2020. [cited 2024 December 11]. Available from: https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307630/all/Acute_Coronary_Syndrome:_Angina.
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