Management of Acute Coronary Syndrome
Acute coronary syndrome (ACS) requires immediate risk stratification and treatment based on ECG findings, troponin levels, and clinical presentation, with an early invasive strategy recommended for high-risk patients to reduce mortality and improve outcomes.
Definition and Classification
Acute coronary syndrome refers to a spectrum of conditions resulting from reduced blood flow to the heart muscle, including:
- ST-segment elevation myocardial infarction (STEMI)
- Non-ST-segment elevation myocardial infarction (NSTEMI)
- Unstable angina (UA)
Initial Assessment and Diagnosis
Immediate Steps (First 10 Minutes)
- Obtain 12-lead ECG within 10 minutes of first medical contact 1, 2
- Assess vital signs and perform targeted physical examination
- Initiate cardiac monitoring
- Classify the patient into one of four categories:
- STEMI
- NSTE-ACS with ongoing ischemia/hemodynamic instability
- NSTE-ACS without ongoing ischemia/hemodynamic instability
- ACS unlikely
Laboratory Assessment
- Draw blood for high-sensitivity cardiac troponin (repeat at 1-3 hours) 1, 2
- Complete blood count, renal function, electrolytes, glucose
- Lipid profile (early during admission)
Risk Stratification
- Use GRACE score (score >140 indicates high risk) 2
- Assess for high-risk features:
- Recurrent/persistent chest pain
- Dynamic ECG changes
- Elevated troponin levels
- Hemodynamic instability
- Major arrhythmias
- Diabetes mellitus
- Left ventricular dysfunction
Treatment Strategy
Antiplatelet Therapy
Anticoagulation
- Choose one of the following:
- Unfractionated heparin
- Low molecular weight heparin (enoxaparin)
- Fondaparinux (requires additional UFH during PCI)
- Bivalirudin (during PCI)
Invasive Management
Immediate invasive strategy (<2 hours): For patients with:
Early invasive strategy (<24 hours): For high-risk patients with:
Delayed invasive strategy (24-72 hours): For intermediate-risk patients
Revascularization Approach
- For single-vessel disease: PCI of culprit lesion 2
- For left main or triple-vessel disease: CABG generally preferred 2
- For double-vessel disease: Either PCI or CABG based on anatomy and comorbidities 2
Medical Therapy
Acute Phase
- Nitrates for persistent chest pain (sublingual or IV) 1, 2
- Beta-blockers within 24 hours if no contraindications 2
- Oxygen therapy only if saturation <90% 2
- Morphine reserved for severe persistent pain 2
Secondary Prevention
- High-intensity statin therapy started as early as possible 2
- ACE inhibitors for patients with LV dysfunction, heart failure, hypertension, or diabetes 2
- Dual antiplatelet therapy for 12 months after PCI 2
Special Considerations
Prasugrel Precautions 3
- Not recommended for patients ≥75 years (except high-risk patients with diabetes or prior MI)
- Avoid in patients with history of stroke or TIA
- Consider lower maintenance dose (5mg) for patients <60kg
- Discontinue at least 7 days before CABG when possible
Common Pitfalls to Avoid
- Delaying ECG beyond 10 minutes of first medical contact
- Missing dynamic ECG changes in patients with normal initial ECG
- Failing to repeat troponin measurements at appropriate intervals
- Administering oxygen to patients with normal oxygen saturation
- Delaying invasive management in high-risk patients
- Overlooking secondary prevention measures
Follow-up Care
- Schedule follow-up appointments:
- 1-2 weeks for high-risk patients
- 2-6 weeks for low-risk patients or after revascularization 2
- Provide patient education about symptoms requiring emergency care
- Ensure medication adherence and risk factor modification
By following this evidence-based approach to ACS management, clinicians can significantly reduce mortality and improve outcomes for patients presenting with this life-threatening condition.