What is the approach to managing Acute Coronary Syndrome (ACS)?

Approach to Acute Coronary Syndrome (ACS)

All patients with suspected ACS require immediate ECG within 10 minutes of presentation, continuous cardiac monitoring, high-sensitivity troponin measurement (with results available within 60 minutes), and dual antiplatelet therapy with aspirin plus a P2Y12 inhibitor initiated as soon as the diagnosis is confirmed. 1

Initial Assessment and Risk Stratification

Immediate Actions (First 10 Minutes)

• Obtain 12-lead ECG within 10 minutes to distinguish STEMI from non-ST-elevation ACS (NSTE-ACS) 1, 2
• Administer aspirin 150-300 mg loading dose immediately for all patients unless contraindicated 1, 3, 4
• Initiate continuous cardiac rhythm monitoring to detect life-threatening arrhythmias 1, 3
• Assess vital signs: systolic blood pressure, heart rate, oxygen saturation, and Killip classification 1

Laboratory Evaluation (Within 60 Minutes)

• High-sensitivity cardiac troponin (T or I) with results available within 60 minutes; repeat at 1-3 hours using validated 0h/1h or 0h/3h algorithms 1
• Complete blood count: hemoglobin, hematocrit, platelet count 1
• Renal function: serum creatinine and eGFR for medication dosing 1
• Blood glucose and INR (if on anticoagulation) 1
• Lipid profile should be assessed early if NSTE-ACS is confirmed 1

Echocardiography

• Perform echocardiography to evaluate left ventricular function, identify regional wall motion abnormalities, and exclude alternative diagnoses (pericarditis, aortic dissection, pulmonary embolism) 1, 3

Risk-Based Invasive Strategy Timing

Very High-Risk: Immediate Invasive Strategy (<2 Hours)

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

• Hemodynamic instability or cardiogenic shock
• Recurrent or ongoing chest pain refractory to medical treatment
• Life-threatening arrhythmias or cardiac arrest
• Mechanical complications of MI (valve rupture, ventricular septal defect)
• Acute heart failure with refractory angina or ST-segment deviation
• Recurrent dynamic ST- or T-wave changes, particularly with intermittent ST elevation

High-Risk: Early Invasive Strategy (<24 Hours)

Proceed to coronary angiography within 24 hours if any of the following are present: 1

• Rise or fall in cardiac troponin compatible with MI
• Dynamic ST- or T-wave changes (symptomatic or silent)
• GRACE score >140

Intermediate-Risk: Invasive Strategy (<72 Hours)

Proceed to coronary angiography within 72 hours if any of the following are present: 1

• Diabetes mellitus
• Renal insufficiency (eGFR <60 mL/min/1.73 m²)
• LVEF <40% or congestive heart failure
• Early post-infarction angina
• Recent PCI or prior CABG
• GRACE risk score >109 and <140

Immediate Medical Management

Dual Antiplatelet Therapy (DAPT)

Aspirin plus a P2Y12 inhibitor for 12 months unless contraindicated: 1, 5, 3

P2Y12 Inhibitor Selection:

• Ticagrelor (first choice): 180 mg loading dose, then 90 mg twice daily for moderate-to-high risk patients (elevated troponin), regardless of management strategy 1, 5
• Prasugrel: 60 mg loading dose, then 10 mg daily for patients proceeding to PCI with known coronary anatomy; contraindicated in patients with prior TIA/stroke; reduce to 5 mg daily if age ≥75 years or weight <60 kg 1, 5, 6
• Clopidogrel: 300-600 mg loading dose, then 75 mg daily only if ticagrelor or prasugrel cannot be used or if oral anticoagulation is required 1, 5

Critical caveat: Do not administer prasugrel before coronary anatomy is known 1, 6

Parenteral Anticoagulation

Initiate immediately with one of the following: 1, 5, 3, 4

• Fondaparinux 2.5 mg subcutaneously once daily (preferred for conservative management with best efficacy-safety profile) 5
• Enoxaparin (weight-adjusted dosing based on renal function) 5
• Unfractionated heparin (weight-adjusted IV bolus followed by continuous infusion, aPTT target 1.5-2.5 times control) 5
• Bivalirudin (for invasive strategy) 1, 3

Anti-Ischemic and Symptom Management

• Nitrates: Sublingual followed by IV for ongoing chest pain, uncontrolled hypertension, or heart failure 1, 5, 3
• Morphine: IV or subcutaneous for persistent severe chest pain or acute pulmonary congestion 1, 3, 4
• Beta-blockers: Initiate early for ongoing ischemic symptoms if no contraindications (heart failure, hypotension, bradycardia, heart block) 1, 5, 3
• Oxygen: Only if oxygen saturation <90% or respiratory distress 1

Immediate Secondary Prevention

• High-intensity statin therapy should be started immediately regardless of baseline cholesterol 1, 5, 3

Revascularization Strategy

STEMI Management

• Primary PCI within 120 minutes reduces mortality from 9% to 7% 2
• Fibrinolytic therapy (alteplase, reteplase, or tenecteplase) if PCI cannot be achieved within 120 minutes, followed by transfer for PCI within 24 hours 2, 4

NSTE-ACS Management

• Radial access is the standard approach for coronary angiography 1
• Drug-eluting stents (DES) are recommended over bare-metal stents for any PCI 1
• Revascularization strategy (ad hoc culprit lesion PCI, multivessel PCI, or CABG) should be based on clinical status, comorbidities, and disease severity (SYNTAX score) 1
• Emergency CABG is recommended if coronary anatomy is not amenable to PCI in cardiogenic shock 1

Special Populations

Elderly Patients (≥75 Years)

• Apply the same diagnostic and invasive strategies as younger patients 1, 5
• Reduce prasugrel dose to 5 mg daily if used (generally not recommended due to increased bleeding risk) 5, 6
• Adjust antithrombotic dosing based on renal function and bleeding risk 1, 5

Low Body Weight (<60 kg)

• Consider reducing prasugrel maintenance dose to 5 mg daily due to increased bleeding risk 6

Chronic Kidney Disease

• Apply the same diagnostic and therapeutic strategies with dose adjustments 1, 5
• Use low- or iso-osmolar contrast media at lowest possible volume 1, 5

Patients Requiring Oral Anticoagulation

• Triple therapy (aspirin + clopidogrel + oral anticoagulant) should be transitioned to dual therapy (oral anticoagulant + clopidogrel) after the acute phase (up to 1 week) 5

Long-Term Secondary Prevention (Post-Discharge)

• DAPT continuation: Aspirin plus P2Y12 inhibitor for 12 months, then aspirin monotherapy indefinitely 1, 5
• Beta-blockers: Especially if LVEF ≤40% 1, 3
• ACE inhibitors or ARBs: For LVEF ≤40%, heart failure, hypertension, or diabetes 1, 3
• Mineralocorticoid receptor antagonists (eplerenone): For LVEF ≤35% with heart failure or diabetes 3
• Cardiac rehabilitation enrollment is strongly recommended 1, 3
• Smoking cessation counseling 1, 7

Critical Pitfalls to Avoid

• Do not delay ECG beyond 10 minutes of presentation 1
• Do not give prasugrel before coronary anatomy is known or in patients with prior TIA/stroke 1, 6
• Do not discontinue DAPT prematurely, especially in the first few weeks after ACS, as this increases risk of subsequent cardiovascular events 6
• Do not routinely use IABP in cardiogenic shock without mechanical complications 1
• Do not perform routine immediate revascularization of non-culprit lesions in NSTE-ACS patients with multivessel disease presenting with cardiogenic shock 1
• Avoid hypoglycemia in diabetic patients 1