What is the initial treatment plan for a patient presenting with unstable angina?

Initial Treatment Plan for Unstable Angina

Patients presenting with unstable angina require immediate hospitalization with continuous ECG monitoring, bed rest during active ischemia, antiplatelet therapy (aspirin plus clopidogrel), anticoagulation (preferably enoxaparin or fondaparinux), beta-blockers, nitrates for symptom control, and risk stratification to determine need for early invasive strategy versus conservative management. 1

Immediate General Care Measures

• Place patient on bed rest while ischemia is ongoing, but mobilize to chair and bedside commode when symptom-free to avoid inappropriate activity restriction 1
• Initiate continuous ECG monitoring immediately upon presentation, as sudden ventricular fibrillation is the major preventable cause of death in the early period 1
• Administer supplemental oxygen if arterial oxygen saturation (SaO2) falls below 90%, confirmed by pulse oximetry or direct measurement 1
• A short period of routine oxygen supplementation during initial stabilization is reasonable given safety concerns and potential for underrecognition of hypoxemia, even without documented hypoxemia 1

Antiplatelet Therapy (Mortality Reduction)

• Aspirin 75-325 mg should be administered immediately to all patients without contraindications 1

  • Doses of 75-150 mg daily and 160-325 mg daily show similar reduction in vascular events 1
  • After PCI, a lower dose of 75-162 mg daily is reasonable if bleeding risk is a concern 1

• Clopidogrel loading dose (300-600 mg) followed by 75 mg daily should be added to aspirin 1

  • Continue for 12 months in patients managed medically 1
  • If CABG is planned, stop clopidogrel approximately 5 days before surgery unless operation is urgent 1

Anticoagulation Therapy

Select one of the following anticoagulation strategies 1:

• Enoxaparin (preferred for conservative management): 1 mg/kg subcutaneously every 12 hours 1

  • Offers convenience of subcutaneous administration versus intravenous UFH 1
  • Lower risk of heparin-induced thrombocytopenia than UFH 1

• Fondaparinux: 2.5 mg subcutaneously once daily 1

  • Associated with less bleeding than enoxaparin in conservatively managed patients 1
  • Important caveat: If patient subsequently requires PCI, give additional UFH bolus (50-60 U/kg) as safety of fondaparinux alone during PCI is not well established 1

• Unfractionated heparin (UFH): Bolus 60 U/kg (maximum 4000 U) followed by infusion of 12 U/kg/hour, titrated to aPTT 1.5-2 times control 1

Anti-Ischemic Therapy

Nitrates (Symptom Control)

• Sublingual nitroglycerin (0.4 mg every 5 minutes for up to 3 doses) for immediate symptom relief 1
• Intravenous nitroglycerin for ongoing ischemia or hypertension: start at 5-10 mcg/min, titrate by 10 mcg/min every 3-5 minutes until symptoms resolve or blood pressure limits reached 1
• Transition to oral or topical long-acting nitrates once stabilized, with nitrate-free interval to avoid tolerance 1, 2

Beta-Blockers (Mortality Reduction)

• Oral beta-blockers should be started promptly in all patients without contraindications 1

  • Target heart rate 50-60 beats per minute 1
  • Contraindications include decompensated heart failure, shock, heart block, or severe reactive airway disease 1

• Alternatively, intravenous beta-blockers (such as metoprolol or esmolol) may be used initially, particularly if tachycardia or ongoing ischemia is present 1

  • Delay initiation if patient is hemodynamically unstable until stabilization of heart failure or shock is achieved 1

• Beta-blockers reduce cardiac events and mortality based on post-infarction data and should be strongly considered as initial therapy 1

Calcium Channel Blockers (Alternative)

• Use only if beta-blockers are contraindicated or not tolerated 1
• Non-dihydropyridine agents (verapamil or diltiazem) may be substituted, but not if left ventricular dysfunction is present 1
• Long-acting dihydropyridine calcium channel blockers may be added if angina or hypertension persists despite beta-blocker therapy 1
• Avoid short-acting dihydropyridines as they increase adverse cardiac events 1

Risk Stratification and Invasive Strategy Decision

High-Risk Features Requiring Early Invasive Strategy (Angiography Within 48 Hours)

Proceed with coronary angiography if any of the following are present 1:

• Recurrent ischemia (chest pain or dynamic ST-segment changes, particularly ST-depression or transient ST-elevation) 1
• Elevated troponin levels 1
• Hemodynamic instability during observation period 1
• Major arrhythmias (repetitive ventricular tachycardia, ventricular fibrillation) 1
• Early post-infarction unstable angina 1
• Diabetes mellitus 1

Glycoprotein IIb/IIIa Inhibitors

• Consider adding GP IIb/IIIa inhibitor (tirofiban, eptifibatide, or abciximab) in high-risk patients, particularly if early invasive strategy is planned 1, 3
• Start before angiography and continue for 12 hours (abciximab) or 24 hours (tirofiban, eptifibatide) after PCI if performed 1
• Tirofiban has demonstrated 32% risk reduction in composite endpoint of death, MI, and refractory ischemia at 7 days when added to heparin 3

Low-Risk Patients (Conservative Strategy)

For patients without high-risk features who are symptom-free during observation 1:

• Continue medical therapy with aspirin, clopidogrel, anticoagulation, beta-blockers, and nitrates as needed 1
• Perform non-invasive stress testing before discharge or within 72 hours to assess for inducible ischemia 1, 4
• Reserve angiography for those with positive stress test or recurrent symptoms 1

Additional Therapies for Mortality Reduction

Statins

• Initiate high-intensity statin therapy regardless of baseline LDL cholesterol level 1
• Statins reduce risk of adverse ischemic events in patients with established coronary artery disease 1

ACE Inhibitors

• Start ACE inhibitor if patient has anterior MI, persistent hypertension, left ventricular dysfunction, heart failure, or diabetes mellitus 1
• ACE inhibitors reduce cardiovascular death, MI, and stroke in patients with vascular disease 1
• Target blood pressure <130/80 mm Hg, but lower diastolic blood pressure slowly and avoid dropping below 60 mm Hg to prevent worsening myocardial ischemia 1

Common Pitfalls to Avoid

• Do not administer thrombolytic therapy to patients with unstable angina/NSTEMI without ST-segment elevation, as it is not beneficial and may be harmful 4
• Do not use dipyridamole as an antiplatelet agent, as it can enhance exercise-induced myocardial ischemia 1
• Avoid abrupt discontinuation of antiplatelet or anticoagulation therapy during hospitalization, as this increases risk of thrombotic events 1
• Do not delay beta-blocker therapy unless clear contraindications exist, as they are underutilized despite proven mortality benefit 1
• Remember to stop clopidogrel 5 days before CABG if surgery is planned and not urgent, to reduce bleeding risk 1