What is the management approach for a patient presenting with cardiac ischemia?

Management of Cardiac Ischemia

The optimal management of cardiac ischemia requires a dual approach focused on immediate relief of ischemia and prevention of serious adverse outcomes (death or myocardial infarction), achieved through anti-ischemic therapy, antithrombotic therapy, ongoing risk stratification, and appropriate use of invasive procedures. 1

Initial Assessment and Monitoring

• Continuous ECG monitoring with defibrillator capacity should be initiated immediately in all patients with suspected cardiac ischemia 1
• Bed/chair rest with continuous ECG monitoring is recommended for all patients with unstable angina/non-ST-elevation myocardial infarction (UA/NSTEMI) during the early hospital phase 1
• Supplemental oxygen should be administered only to patients with arterial saturation <90%, respiratory distress, or other high-risk features for hypoxemia 1
• Patients at intermediate or high risk for adverse outcomes should be admitted to a critical care environment with ready access to emergency interventions 1

Immediate Pharmacological Management

Anti-ischemic Therapy

• Nitrates:

  • Patients with ongoing ischemic discomfort should receive sublingual nitroglycerin (0.4 mg) every 5 minutes for a total of 3 doses, after which assessment should be made about the need for intravenous nitroglycerin 1
  • Intravenous nitroglycerin is indicated in the first 48 hours for treatment of persistent ischemia, heart failure, or hypertension 1
  • Nitrates should NOT be administered to patients with systolic blood pressure <90 mmHg, severe bradycardia (<50 beats/min), tachycardia (>100 beats/min) without heart failure, or right ventricular infarction 1
  • Nitrates should NOT be given to patients who have used phosphodiesterase inhibitors for erectile dysfunction within 24 hours (sildenafil) or 48 hours (tadalafil) 1

• Beta-blockers:

  • Oral beta-blocker therapy should be initiated within the first 24 hours unless contraindicated 1
  • Contraindications include signs of heart failure, evidence of low-output state, increased risk for cardiogenic shock, or other relative contraindications (PR interval >0.24s, second or third degree heart block, active asthma) 1
  • Intravenous beta-blockers should be avoided in patients with risk factors for cardiogenic shock 1

• Calcium Channel Blockers:

  • Non-dihydropyridine calcium channel blockers (verapamil or diltiazem) should be given as initial therapy in patients with continuing ischemia when beta-blockers are contraindicated 1
  • Immediate-release dihydropyridine calcium channel blockers may be considered with adequate beta blockade for ongoing ischemic symptoms or hypertension 1
  • Immediate-release dihydropyridine calcium channel blockers should NOT be administered in the absence of a beta-blocker 1

Antithrombotic Therapy

• Antiplatelet Therapy:

  • Aspirin (162-325 mg non-enteric formulation, orally or chewed) should be administered immediately 1
  • A potent P2Y12 inhibitor (prasugrel or ticagrelor), or clopidogrel if these are unavailable, should be administered before or at the time of PCI 1, 2
  • Clopidogrel (300-600 mg loading dose followed by 75 mg daily) in combination with aspirin has been shown to reduce cardiovascular death, MI, or stroke by 20% compared to aspirin alone 3

• Anticoagulation:

  • Anticoagulation should be administered until revascularization or for the duration of hospital stay 1, 2
  • Options include unfractionated heparin, enoxaparin, bivalirudin, or fondaparinux 1
  • Intravenous ACE inhibitors should NOT be given within the first 24 hours due to increased risk of hypotension 1

Invasive vs. Conservative Strategy

• Early Invasive Strategy (diagnostic angiography with intent to perform revascularization) is indicated for:

  • Patients with refractory angina or hemodynamic/electrical instability 1
  • Initially stabilized patients with elevated risk for clinical events 1
  • High-risk patients (GRACE score >140) benefit most from early intervention (within 24 hours) 1

• Conservative Strategy (selective invasive approach) may be considered for initially stabilized patients who are not at high risk 1

Special Considerations

• ST-Elevation Myocardial Infarction (STEMI):

  • Primary PCI is the preferred reperfusion strategy when performed by an experienced team within 120 minutes of STEMI diagnosis 1, 2
  • If primary PCI cannot be performed in a timely manner, fibrinolytic therapy should be administered within 12 hours of symptom onset 1
  • Transfer to a PCI-capable center following fibrinolysis is indicated in all patients immediately after fibrinolysis 1

• Cardiogenic Shock:

  • Emergency angiography and PCI are recommended in patients with heart failure/shock 1

Long-term Management

• Dual antiplatelet therapy (DAPT) with aspirin plus a P2Y12 inhibitor should be maintained for 12 months 2
• Beta-blockers should be continued in patients with heart failure and/or reduced left ventricular ejection fraction 2
• ACE inhibitors should be started within 24 hours in patients with heart failure, LV systolic dysfunction, diabetes, or anterior infarct 2
• High-intensity statin therapy should be initiated as early as possible 2
• NSAIDs (except for aspirin) should NOT be administered during hospitalization due to increased risks of mortality, reinfarction, hypertension, heart failure, and myocardial rupture 1

Common Pitfalls and Caveats

• Failure to recognize atypical presentations, particularly in women, elderly, and diabetic patients, can lead to missed diagnoses 2, 4
• Women under 55 years old, non-white patients, and those presenting with shortness of breath as their chief symptom are at higher risk for inappropriate discharge 4
• Normal or non-diagnostic ECGs do not rule out acute cardiac ischemia and are associated with higher rates of missed diagnoses 4
• Immediate-release dihydropyridine calcium channel blockers without concomitant beta-blockers can worsen outcomes due to reflex tachycardia 1, 5
• The combination of different anti-ischemic medications (nitrates, beta-blockers, calcium channel blockers) may provide greater reduction in myocardial oxygen demand than monotherapy 5