ACS Case Management Flowchart
STEP 1: Immediate Assessment (Within 10 Minutes)
Obtain 12-lead ECG within 10 minutes of presentation to differentiate STEMI from NSTE-ACS 1, 2
ECG Interpretation Pathway:
ST-elevation ≥1mm in ≥2 contiguous leads → STEMI pathway 1
ST-depression, T-wave inversions, or non-specific changes → NSTE-ACS pathway 1
- Proceed to troponin measurement and risk stratification
ST-depression in V1-V3 → Consider posterior STEMI 1
- Obtain posterior lead ECG immediately
Concurrent Actions:
- Initiate continuous cardiac monitoring for arrhythmias 1, 2
- Establish IV access 1
- Assess vital signs: blood pressure, heart rate, oxygen saturation 1, 2
- Administer oxygen only if SpO2 <94%, signs of heart failure, or shock 1
STEP 2: Laboratory Assessment
Draw blood immediately for high-sensitivity cardiac troponin (hs-cTn) at presentation (0 hours) 1, 2
Troponin Protocol:
- Repeat hs-cTn at 1-2 hours if initial result non-diagnostic 1, 2
- Conventional troponin: Repeat at 3-6 hours if hs-cTn unavailable 1
- Troponin >99th percentile upper reference limit = Myocardial infarction 1, 2
Additional Laboratory Tests:
- Serum creatinine (for medication dosing) 1
- Hemoglobin, hematocrit, platelet count 1
- Blood glucose 1
- Lipid profile (if ACS confirmed) 1
- INR if patient on warfarin 1
STEP 3: Immediate Pharmacological Management
Antiplatelet Therapy (Start Immediately):
Aspirin 150-300mg loading dose orally (non-enteric) unless active GI bleeding or known aspirin allergy 1, 4, 2
Add P2Y12 inhibitor for dual antiplatelet therapy 4, 2:
- Ticagrelor 180mg loading dose (preferred) 4
- Prasugrel 60mg loading dose if proceeding to PCI, age <75 years, weight ≥60kg, no prior stroke/TIA 5
- Clopidogrel 300-600mg loading dose (alternative if above unavailable)
Anticoagulation:
Initiate parenteral anticoagulation immediately 2:
- Low molecular weight heparin (LMWH) (preferred) 1, 2
- Unfractionated heparin 70-100 units/kg IV bolus if proceeding to urgent angiography 4
- Continue until revascularization or hospital discharge 2
Anti-Ischemic Therapy:
- Sublingual or IV nitrates for ongoing chest pain 1, 2
- Beta-blockers (oral) unless contraindicated by hypotension, bradycardia, or acute heart failure 2
- Calcium channel blockers only if beta-blockers contraindicated 2
Additional Medications:
- High-intensity statin (atorvastatin 80mg or rosuvastatin 40mg) as early as possible 2
STEP 4: Risk Stratification for NSTE-ACS
Very High-Risk Features (Immediate Invasive Strategy <2 Hours) 1, 2:
- Hemodynamic instability or cardiogenic shock
- Recurrent or ongoing chest pain refractory to medical therapy
- Life-threatening arrhythmias or cardiac arrest
- Mechanical complications (acute mitral regurgitation, ventricular septal defect, free wall rupture)
- Acute heart failure
- Recurrent dynamic ST-segment or T-wave changes
Action: Immediate coronary angiography regardless of troponin or ECG findings 1, 2
High-Risk Features (Early Invasive Strategy <24 Hours) 1, 2:
- Rise/fall in troponin compatible with MI
- Dynamic ST-segment or T-wave changes (symptomatic or silent)
- GRACE score >140
Action: Coronary angiography within 24 hours 2
Intermediate-Risk Features (Invasive Strategy <72 Hours) 2:
- Diabetes mellitus
- Renal insufficiency (eGFR <60 mL/min/1.73m²)
- LVEF <40%
- Early post-infarction angina
- Prior PCI or CABG
- GRACE score 109-140
Action: Coronary angiography within 72 hours 2
TIMI Risk Score (Alternative Risk Tool) 1:
Calculate points for:
- Age ≥65 years (1 point)
- ≥3 CAD risk factors (1 point)
- Known CAD with stenosis ≥50% (1 point)
- Aspirin use in past 7 days (1 point)
- ≥2 anginal episodes in 24 hours (1 point)
- ST-deviation ≥0.5mm (1 point)
- Elevated cardiac markers (1 point)
Score 5-7: 26% risk of death/MI/urgent revascularization at 14 days (high risk) 1
STEP 5: Echocardiography
Perform urgent echocardiography for 1, 2:
- Hemodynamic instability
- Suspected mechanical complications
- Cardiogenic shock
- Acute heart failure
Echocardiography identifies:
- Regional wall motion abnormalities (confirms ischemia)
- LV systolic function
- Valvular complications
- Pericardial effusion
- Alternative diagnoses (aortic dissection, pulmonary embolism)
STEP 6: STEMI-Specific Reperfusion Strategy
Primary PCI (Preferred):
Goal: Door-to-balloon time ≤120 minutes 3
- Reduces mortality from 9% to 7% compared to no reperfusion 3
Fibrinolytic Therapy (If PCI Unavailable):
Administer if PCI cannot be achieved within 120 minutes 3:
- Age <75 years: Full-dose alteplase, reteplase, or tenecteplase 3
- Age ≥75 years: Half-dose tenecteplase 3
- Cost consideration: Streptokinase at full dose 3
- Transfer for PCI within 24 hours after fibrinolysis 3
Timing Considerations for NSTE-ACS:
- Do NOT administer prasugrel loading dose until coronary anatomy known 5
- Urgent CABG within 7 days of prasugrel increases bleeding risk substantially 5
STEP 7: Post-Acute Management
Secondary Prevention (All ACS Patients):
Dual antiplatelet therapy for 12 months 4, 2
- Aspirin 75-100mg daily + P2Y12 inhibitor
High-intensity statin indefinitely 2
ACE inhibitor or ARB if LV dysfunction (LVEF <40%), heart failure, hypertension, or diabetes 4
Beta-blocker for at least 1 year, especially if LV dysfunction 2
Lifestyle modifications: Smoking cessation, cardiac rehabilitation, dietary changes 6
Common Pitfalls to Avoid
- Delaying ECG beyond 10 minutes leads to missed diagnosis and treatment delays 2
- Waiting for troponin before starting antiplatelet therapy in high-risk patients delays critical treatment 2
- Missing atypical presentations: 40% of men and 48% of women present without chest pain 3
- Administering prasugrel to patients with prior stroke/TIA is contraindicated due to increased ICH risk 5
- Routine oxygen administration in normoxemic patients provides no benefit 1
- Premature discontinuation of DAPT in first weeks post-ACS increases CV event risk 5
- Failing to dose-adjust anticoagulation for renal function increases bleeding risk 1