Angina Pectoris in Emergency Medicine Workup

Updated: Feb 18, 2015
  • Author: Marc D Haber, MD; Chief Editor: Barry E Brenner, MD, PhD, FACEP  more...
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Workup

Laboratory Studies

The laboratory workup of patients with angina includes the following tests:

  • CBC (anemia, leukocytosis may suggest an alternative diagnosis)
  • BUN and creatinine level, if intravenous contrast is anticipated
  • Electrolyte levels are of virtually no value unless the patient is on a diuretic and concern for an abnormality exists.
  • Cardiac enzyme levels, if positive may suggest non–ST-segment elevation myocardial infarction (NSTEMI); negative results do not rule out ischemia
  • Coagulation studies, if anticoagulation or antiplatelets are anticipated
  • Type and screen, if surgery or transfusions are considered
Next:

Imaging Studies

Chest radiography is used to rule out an alternative diagnosis or contributing factors (eg, pneumothorax [PTX], pneumonia [PNA], congestive heart failure); it is also used to evaluate the aorta prior to anticoagulant administration.

CT of the chest may be considered for evaluation of aortic or pulmonary disease; if evaluating the aorta, include the abdominal aorta. Of note, the forthcoming "triple rule out CT scan" exposes the patient to an exorbitantly high dose of radiation and should only be used in certain circumstances.

Limited CT coronary scans may help to reduce the posttest probability of coronary artery disease while utilizing potentially less radiation exposure than the "triple rule out scan." Coronary artery calcification suggests the presence of an atherosclerotic plaque. Calcium scores are determined by the density of calcium and the total area. Higher calcium scores may suggest a higher risk of current or future adverse cardiac events. Multiple sites are currently conducting trials to see if this modality will benefit patients in the emergency department.

Bamberg et al found that, in patients with acute chest pain and an inconclusive initial evaluation (nondiagnostic electrocardiographic findings, negative cardiac biomarkers), age and gender can serve as simple criteria to select patients who would derive the greatest diagnostic benefit from coronary computed tomographic angiography (CTA). [17] In an observational cohort study in 368 low-risk patients, positive findings on 64-slice coronary CTA led to restratification to high risk, and negative findings led to restratification to very low risk, in men younger than 55 years and women younger than 65 years. In contrast, in women older than 65 years and men older than 55 years, a negative result on CTA did not result in restratification to a low-risk category.

Nuclear imaging should include V/Q (PE evaluation) and resting Sestamibi (In the appropriate clinical setting, a normal study in a patient with ongoing chest pain may rule out myocardial ischemia. [18] ).

ECG results may be normal or show signs of ischemia. Main use is to establish a baseline and R/O acute ST-segment elevation myocardial infarction (STEMI).

Intraluminal coronary artery sonography (ICAS) is a highly invasive modality that may provide additional information to a patient's coronary artery anatomy and disease. Coronary atherosclerosis, which does not result in coronary artery narrowing, may be missed by conventional forms of coronary angiography. If clincially suspected, ICAS may be utilized to detect the presence or absence of such lesions. ICAS is not readily available; as such, it is highly unlikely that ICAS will be utilized from the emergency department in the foreseeable future.

The use of stress cardiac MRI in an observation unit may be a cost-saving alternative to inpatient management for emergency department patients with chest pain. In a randomized study in 110 patients, Miller et al reported that an observation unit strategy with stress cardiac MRI reduced median hospitalization cost by approximately $588, with no cases of missed acute coronary syndrome. [19]

While the recent ROMICAT trial showed the introduction of coronary CT imaging improved efficiency of the emergency clinical workup in comparison to the traditional ED care, patients who underwent cardiac CT imaging had increased subsequent workups and incurred a higher radiation burden without any reduction in overall cost. [20]

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