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Basics

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Author:

Margaret J.Lin

Shamai A.Grossman


Description!!navigator!!

Etiology!!navigator!!

Diagnosis

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Signs and Symptoms!!navigator!!

History

  • 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!!navigator!!

ALERT
Patients with normal or nonspecific ECGs have a 1-5% incidence of AMI and 4-23% incidence of UA.

Diagnostic Tests & Interpretation!!navigator!!

Lab

  • 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:
  • 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/Surgery

  • 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 stand ard for diagnosis for CAD

Differential Diagnosis!!navigator!!

Treatment

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Prehospital!!navigator!!

Initial Stabilization/Therapy!!navigator!!

ED Treatment/Procedures!!navigator!!

Medication!!navigator!!

First Line

  • 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:
  • 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

  • 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

Follow-Up

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Disposition!!navigator!!

Admission Criteria

  • 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!!navigator!!

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

See Also (Topic, Algorithm, Electronic Media Element)

Codes

ICD9

ICD10

SNOMED