Basics
Description
- Chest discomfort, due to 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 with angina occurring with walking, climbing stairs, or emotional stress
- Class III: Severe limitation of ordinary physical activity with angina when walking 1-2 blocks on level surface or climbing 1 flight of stairs
- Class IV: Inability to carry on any physical activity without discomfort or angina symptoms occur at rest
- Typically categorized as either 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
- UA associated with increased risk of transmural myocardial infarction and cardiac death
Etiology
- Cardiac risk factors:
- Age
- Men >35 yr
- Postmenopausal in women
- Hypercholesterolemia
- DM
- HTN
- Smoking
- 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
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
- Relief with nitroglycerin in nondiagnostic
- Lasts more than a few minutes but <20 min
- Considered stable angina if no changes in pattern of frequency of symptoms
- Women, diabetics, ethnic minorities, and those >65 yr often present with atypical symptoms
- Prognosis is worse for people with atypical symptoms
Physical Exam
- "Levine Sign"Ł: Clenched fist over chest, classic finding
- BP often elevated during symptoms
- Physical exam often uninformative
- occasional S3/S4,
- mitral regurgitation or new murmur (papillary muscle dysfunction)
- diminished peripheral pulses
Essential Workup
ECG: á
- Standard 12 lead
- Ideally should be obtained and read within 10 min of presentation for patients with acute chest pain
- Mostly helpful in detecting acute MI, less so UA
- Compare to prior ECG if available
- If normal or unchanged, serial ECGs every 10-30 min
- New ST changes or T-wave inversion suspicious for UA
- T-wave flattening or biphasic T-waves
- ÔëĄ1 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
- 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 TW inversions and pulse rate depression
- Pulmonary embolus S1Q3T3 pattern, unexplained tachycardia and signs of right heart strain
- Patients with normal or nonspecific ECGs have a 1-5% incidence of AMI and 4-23% incidence of UA
Diagnosis Tests & Interpretation
Lab
- For stable angina, cardiac enzymes not indicated, but if history suspicious for acute MI, should obtain.
- CK-MB and troponin I or T
- <50% of patient with UA will have low level troponin elevations
- CK-MB peaks 12-24 hr, return to baseline in 2-3 days
- Troponin peaks in 12 hr, return to baseline 7-10 days
- Hematocrit (anemia increases risk of ischemia)
- Coagulation profile
- Electrolytes, especially Cr and K+
Imaging
- CXR:
- Usually nonrevealing
- May show cardiomegaly, or pulmonary edema, CHF suggests UA or MI
- 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 in patient if no coronary stenosis
- "Triple rule-out"Ł for ACS, PE, and aortic dissection
- Bedside echo: To detect wall motion abnormalities and other etiologies of shock, pericardial effusion, pneumothorax
- Technetium Tc-99 sestamibi (rest): Radionucleotide whose uptake by myocardium is dependent on perfusion
Diagnostic Procedures/Surgery
- Exercise stress testing:
- Not appropriate if active chest pain with moderate to high likelihood of ischemia
- Imaging stress test (sestamibi, thallium, or echo) if baseline ECG abnormalities
- Early positive (within 3 min) concerning for UA
- Coronary angiography:
- Gold standard of diagnosis for CAD
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
- IV access
- Aspirin
- Oxygen
- Vital signs and oxygen saturation
- Cardiac monitoring
- 12-lead ECG, if possible
- Sublingual nitroglycerin
Initial Stabilization/Therapy
- IV access
- Oxygen
- Cardiac monitoring
- Vital signs and continuous oxygen saturation
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
- Aspirin: 325 mg PO (chewed) or 81 mg Ś 4 (chewed)
- In patients with aspirin allergy: Clopidogrel (Plavix) 300-600 mg PO, also consider prasugrel 60 mg PO or 180 mg PO 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 ╬╝g/min IV USE NON-PVC tubing, titrating to effect
- 1-2 in of nitro paste
- Hold for low BP (can severely drop BP)
- Beware if pt has history of erectile dysfunction and use of phosphodiesterase inhibitors like sildenafil (Viagra) or tadalafil (Cialis) can last 48 hr
- Morphine
- 4 mg IV, titrate to relief of pain assuming no respiratory depression and SBP >90
- Consider beta blocker
- Metoprolol: 25-50 mg PO or 5 mg IV q5-15min for refractory HTN and tachycardia
- Contraindicated in reactive airway disease, active CHF, bradycardia, hypotension, heart block, cocaine use
- Does not necessarily need to be given while patient is in ED, suggested benefit within 24 hrs of AMI
Second Line
Anticoagulation á
- Does not alter mortality
- Consider conferring with cardiology prior to 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 <30mL/min
- Glycoprotein IIb/IIIa inhibitors: Primary benefit en route to cath
- Eptifibatide (Integrilin): 180 ╬╝g/kg bolus IV over 1-2 min, then 2 ╬╝g/kg/min up to 72 hr
- Tirofiban (Aggrastat): 0.4 ╬╝g/kg/min for 30 min, then 0.1 ╬╝g/kg/min for 48-108 hr
- Abciximab (Reopro): 0.25 mg/kg IV bolus, then 0.125 ╬╝g/kg/min, maximum dose 10 ╬╝g/min for 12 hr
- Bilvalirudin, fondaparinux
- Patients at risk for high risk for bleeding include the elderly, female, anemic, chronic renal failure
Follow-Up
Disposition
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 hospitalization for serial cardiac enzymes, ECG and stress testing/catheterization
Discharge Criteria
- Patients with stable angina
- Patients who are enzyme/stress testing or cath negative
Followup Recommendations
Patients with stable angina or workup negative chest pain should follow up with their PCP or cardiologist within several days of ED visit. á
Pearls and Pitfalls
- History is the most important factor in differentiating unstable from stable angina or noncardiac pain
- All patients with chest pain or symptoms concerning for a cardiac etiology should have an immediate ECG
- It the initial ECG is normal or unchanged, do serial ECGs 10-30 min apart
- A single set of negative cardiac enzymes may not rule out ACS in a patient with chest pain
- Women, diabetics, ethnic minorities, and patients >65 yr require a low threshold for ACS workup as they often have atypical presentations
Additional Reading
- 2012 Writing Committee Members, Jneid áH, Anderson áJL, 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.
- Marx áJA, Hockberger áRS, Walls áRM, eds. Rosens Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, PA: Mosby Elsevier; 2010.
- Mistry áNF, Vesely áMR. Acute coronary syndromes: From the emergency department to the cardiac care unit. Clinics. 2012;30:617-627.
- Swap áC, Nagurney áJT. Value and limitations of chest pain history in the evaluation of patients with suspected acute coronary syndromes. JAMA. 2005;294:2623-2949.
See Also (Topic, Algorithm, Electronic Media Element)
- ACS Myocardial Infarction
- ACS Coronary Vasospasm
- Cardiac Testing
Codes
ICD9
- 411.1 Intermediate coronary syndrome
- 413.1 Prinzmetal angina
- 413.9 Other and unspecified angina pectoris
ICD10
- I20.0 Unstable angina
- I20.1 Angina pectoris with documented spasm
- I20.9 Angina pectoris, unspecified
- I24.9 Acute ischemic heart disease, unspecified
SNOMED
- 194828000 Angina (disorder)
- 233819005 Stable angina (disorder)
- 4557003 Preinfarction syndrome (disorder)
- 87343002 Prinzmetal angina (disorder)
- 394659003 Acute coronary syndrome (disorder)