Unstable angina
Unstable angina is acute myocardial ischemia from a non-occlusive coronary thrombus causing rest, new, or crescendo angina without a troponin rise, placing it on the acute coronary syndrome spectrum just short of NSTEMI. Diagnosis is clinical with ischemic ECG changes and negative serial troponins, and management mirrors NSTE-ACS with antithrombotic therapy and risk-guided angiography.
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What this article covers
- Overview
Definition: unstable angina is acute myocardial ischemia caused by a non-occlusive coronary thrombus, presenting as rest, new-onset, or crescendo angina without myocardial necrosis.
- Epidemiology
A common ACS presentation, though high-sensitivity troponin assays now reclassify many former cases as NSTEMI.
- Risk factors
Atherosclerotic risk factors: smoking, diabetes, hypertension, dyslipidemia, and family history.
- Pathophysiology
Non-occlusive thrombus: plaque rupture or erosion produces a partially occlusive thrombus that limits flow without causing necrosis.
- Clinical features
Rest angina: ischemic pain occurring at rest, usually lasting more than 20 minutes.
- Differential diagnosis
NSTEMI: identical presentation but with a troponin rise (NSTEMI).
- Diagnosis
Establish clinically as ischemia without infarction: unstable angina is diagnosed by rest, new, or crescendo anginal symptoms with or without ischemic ECG changes (ST depression or T-wave inversion)…
- Management
First, give antiplatelet and anticoagulant therapy: Aspirin 325 mg chewed once, then 81 mg PO daily indefinitely.
- Complications
Progression to myocardial infarction: the principal risk.
- Prognosis
Elevated short-term risk of infarction and death, quantified by risk scores.
- Prevention
Secondary prevention: aspirin, high-intensity statin to an LDL goal below 70 mg/dL, dual antiplatelet therapy for the recommended duration.
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