From the Guidelines
Unstable angina requires prompt evaluation and treatment to prevent progression to myocardial infarction, and the most recent evidence supports an early invasive strategy with cardiac catheterization within 24-72 hours for high-risk patients 1.
Initial Workup
Initial workup includes:
- A thorough history and physical examination
- 12-lead ECG
- Cardiac biomarkers (troponin, CK-MB)
- Complete blood count
- Basic metabolic panel
- Chest X-ray
Treatment
Treatment begins with:
- Immediate administration of aspirin (325 mg loading dose, then 81 mg daily)
- Anticoagulation with unfractionated heparin (60-70 units/kg IV bolus, then 12-15 units/kg/hr) or low molecular weight heparin like enoxaparin (1 mg/kg subcutaneously twice daily)
- Dual antiplatelet therapy with clopidogrel (300-600 mg loading dose, then 75 mg daily) or ticagrelor (180 mg loading dose, then 90 mg twice daily)
- Additional medications include beta-blockers (metoprolol 25-50 mg orally every 6 hours), high-intensity statins (atorvastatin 40-80 mg daily), and nitroglycerin (0.4 mg sublingual as needed for chest pain, or IV infusion starting at 5-10 mcg/min)
- Supplemental oxygen should be provided if saturation is below 90%
Risk Stratification
High-risk patients, including those with recurrent ischemia, elevated troponin levels, haemodynamic instability, major arrhythmias, or early post-infarction unstable angina, should undergo coronary angiography as soon as possible 1.
Revascularization
Revascularization options include percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG), and the choice of procedure depends on the extent and characteristics of the lesions, as well as the patient's overall clinical condition 1. The weight of evidence favors an early invasive strategy for high-risk patients with unstable angina, and this approach is associated with improved outcomes in terms of morbidity, mortality, and quality of life 1.
From the FDA Drug Label
Clopidogrel tablets are indicated to reduce the rate of myocardial infarction (MI) and stroke in patients with non–ST-segment elevation ACS (unstable angina [UA]/non–ST-elevation myocardial infarction [NSTEMI]), including patients who are to be managed medically and those who are to be managed with coronary revascularization Clopidogrel tablets should be administered in conjunction with aspirin.
The treatment for unstable angina includes the administration of clopidogrel in conjunction with aspirin to reduce the rate of myocardial infarction and stroke.
- The dosage for acute coronary syndrome is a single 300 mg oral loading dose, followed by 75 mg once daily.
- Clopidogrel is indicated for patients with non-ST-segment elevation ACS, including those managed medically or with coronary revascularization 2.
- It is essential to consider the patient's CYP2C19 genotype, as poor metabolizers may have reduced antiplatelet activity 2.
From the Research
Treatment of Unstable Angina
- The standard of therapy in patients with unstable angina incorporates the combined use of potent antithrombotic (aspirin, clopidogrel, heparin and glycoprotein IIb/IIIa receptor antagonists) and anti-anginal (beta-blockade and intravenous nitrates) regimens complemented by the selective and judicious application of coronary revascularisation strategies 3.
- Rapid and intensive management of associated risk factors, such as hypercholesterolaemia, would appear to have potentially substantial benefits even within the acute in-hospital phase of unstable angina 3.
- New pharmacological agents have been developed for the treatment of acute coronary syndromes, including unstable angina 4.
Work Up of Unstable Angina
- Many patients suspected of having unstable angina can be discharged home after adequate initial evaluation, while further outpatient evaluation may be scheduled for up to 72 hours after initial presentation for patients with clinical symptoms of unstable angina judged at initial evaluation to be at low risk for complications 5.
- Patients with acute ischemic heart disease judged to be at intermediate or high risk of complications should be hospitalized for careful monitoring of their clinical course 5.
- Assessment of prognosis by noninvasive testing often aids selection of appropriate therapy, and coronary angiography is appropriate for patients judged to be at high risk for cardiac complications or death based on their clinical course or results of noninvasive testing 5.
Management and Follow-Up
- The discharge care plan should include continued monitoring of symptoms; appropriate drug therapy, including aspirin; risk-factor modification; and counseling 5.
- Coronary artery bypass surgery should be recommended for almost all patients with left main disease and many patients with three-vessel disease, especially those with left ventricular dysfunction 5.