NSTEMI and Unstable Angina (Non-ST-Elevation ACS)

Quick Answer

One-liner: NSTEMI is acute myocardial infarction with elevated troponin but without ST-elevation on ECG; manage with dual antiplatelet therapy, anticoagulation, and risk-stratified early invasive strategy (PCI within 24 hours for GRACE score greater than 140).

Non-ST-elevation acute coronary syndrome (NSTE-ACS) encompasses NSTEMI and unstable angina, characterized by acute cardiac ischemia without persistent ST-elevation. NSTEMI accounts for 60-70% of all acute myocardial infarctions, with in-hospital mortality of 3-9% and 1-year mortality of 6-12%. High-sensitivity troponin has revolutionized diagnosis, enabling 0/1-hour rule-in and rule-out algorithms. The cornerstone of management is dual antiplatelet therapy (aspirin + P2Y12 inhibitor), anticoagulation, and risk-stratified invasive strategy. GRACE score greater than 140 mandates early invasive strategy (below 24 hours), while very high-risk features (shock, refractory pain, arrhythmias) require immediate catheterization (below 2 hours).

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ACEM Exam Focus

Primary Exam Relevance

• Anatomy: Coronary artery anatomy (LAD, RCA, LCx territories), collateral circulation, conduction system blood supply
• Physiology: Myocardial oxygen supply-demand mismatch, ischemic cascade (diastolic dysfunction → systolic dysfunction → ECG changes → angina), coronary autoregulation
• Pharmacology: Antiplatelet mechanisms (COX-1 inhibition, P2Y12 blockade), anticoagulants (UFH, LMWH, fondaparinux), beta-blockers (negative chronotropy and inotropy)

Fellowship Exam Relevance

• Written: GRACE/HEART/TIMI risk stratification, 0/1-hour hs-troponin algorithms, ESC 2023 guidelines on early invasive strategy, CRUSADE bleeding score, dual antiplatelet therapy duration
• OSCE: ACS communication (breaking bad news about MI, consent for angiography), ECG interpretation (dynamic changes), clinical decision-making (invasive vs conservative), medication counseling
• Key domains tested: Medical Expert (risk stratification, appropriate invasive timing), Communicator (explaining ACS to patients, shared decision-making), Leader (coordinating cath lab activation)

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Key Points

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Epidemiology

Australian/NZ Specific

• Australian ACS incidence: 50,000-60,000 hospitalizations/year, 30,000-36,000 NSTEMI cases
• Indigenous Australians: 3-4× higher ACS incidence, present 10 years younger (median age 55 vs 68), higher recurrence rates (30% vs 18% at 5 years) [7]
• Māori and Pacific Islander: 2-3× higher ACS rates, increased prevalence of diabetes (40% vs 20%), smoking (50% vs 15%), and metabolic syndrome [8]
• Rural/remote: Median symptom-to-hospital time 6 hours (urban 2 hours), delayed revascularization (median 48h vs 18h), RFDS retrieval required in 12-15% of remote NSTEMI cases [9]

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Pathophysiology

Mechanism

NSTE-ACS results from acute coronary thrombosis on a background of vulnerable atherosclerotic plaque:

1. Plaque rupture or erosion: Thin-cap fibroatheroma ruptures → exposure of thrombogenic subendothelial collagen and tissue factor
2. Platelet activation: vWF binds GPIb → platelet adhesion → ADP release → P2Y12 receptor activation → GPIIb/IIIa conformational change → platelet aggregation
3. Coagulation cascade: Tissue factor activates factor VII → thrombin generation → fibrin deposition
4. Incomplete vessel occlusion: Unlike STEMI (complete occlusion), NSTEMI has partial occlusion with preserved TIMI 2-3 flow
5. Distal embolization: Microthrombi shower distal microcirculation → troponin elevation without ST-elevation
6. Myocyte necrosis: Prolonged ischemia (greater than 20 minutes) → irreversible injury → troponin release (detectable at 3-6 hours, peak 12-24 hours)

Pathological Progression

Vulnerable plaque → Rupture/erosion → Platelet activation → Thrombus formation → Partial occlusion → Ischemia → Myocyte necrosis → Troponin elevation → NSTEMI

Why It Matters Clinically

• Troponin timing: Peak at 12-24 hours explains why serial troponins improve sensitivity (single troponin misses 5-10% of early MI)
• Dynamic ECG changes: Transient ST-depression or T-wave inversion indicates ongoing ischemia → higher risk → early invasive strategy warranted
• Platelet vs coagulation: Dual antiplatelet therapy targets platelet aggregation (aspirin + P2Y12 inhibitor); anticoagulation targets thrombin generation (heparin/fondaparinux)
• Microvascular obstruction: "Slow-flow" or "no-reflow" post-PCI due to distal embolization → poor outcomes despite patent epicardial vessels

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Clinical Approach

Recognition

Suspect NSTE-ACS in any patient with:

• Typical angina: Retrosternal pressure, radiation to jaw/arms, exertional or at rest, lasting greater than 10-20 minutes
• Atypical presentations: Dyspnea alone (especially elderly, diabetic, women), epigastric pain, nausea/vomiting, syncope, new-onset pulmonary edema
• High-risk features: Diaphoresis, pallor, third/fourth heart sound, new mitral regurgitation murmur (papillary muscle dysfunction)

Initial Assessment

Primary Survey

• A: Airway patent (may be compromised if reduced GCS from cardiogenic shock or cardiac arrest)
• B: Respiratory distress? Pulmonary edema (bilateral crackles, hypoxemia)? SpO2 target 92-96% (avoid hyperoxia)
• C: Hypotension (SBP below 90 mmHg suggests cardiogenic shock or RV infarction)? Tachycardia (compensatory or arrhythmia)? Bradycardia (high vagal tone or conduction block)? Assess peripheral perfusion (cool, clammy suggests shock)
• D: GCS 15? Confusion may indicate cardiogenic shock with cerebral hypoperfusion
• E: Diaphoresis, pallor, JVP elevation (RV infarction), peripheral edema (chronic heart failure)

History

Key Questions

Red Flag Symptoms

Examination

General Inspection

• Distress level: Clutching chest, diaphoretic, anxious, sitting upright (orthopnea suggests pulmonary edema)
• Hemodynamic state: Pallor, cool extremities (shock), peripheral cyanosis (low cardiac output)
• Respiratory effort: Tachypnea, use of accessory muscles, inability to speak in full sentences (pulmonary edema)

Specific Findings

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Investigations

Immediate (Resus Bay)

Standard ED Workup

Advanced/Specialist

Point-of-Care Ultrasound

POCUS in NSTE-ACS:

1. Cardiac function: Reduced LV ejection fraction (below 40%), global hypokinesis suggests cardiogenic shock or prior ischemic cardiomyopathy
2. Regional wall motion abnormalities (RWMA): Hypokinesis, akinesis, or dyskinesis in coronary territory (anterior = LAD, inferior = RCA, lateral = LCx)
3. Mechanical complications: Mitral regurgitation (color Doppler shows regurgitant jet), VSD (septal discontinuity, left-to-right shunt on color Doppler), free wall rupture (pericardial effusion)
4. RV infarction: RV dilatation, hypokinesis, and paradoxical septal motion (in inferior MI with RV involvement)
5. IVC assessment: Dilated IVC (greater than 2 cm) with below 50% collapse suggests elevated RA pressure (RV infarction, cardiogenic shock)
6. Lung POCUS: B-lines (pulmonary edema), pleural effusion, pneumothorax (complication)

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Management

Immediate Management (First 10 minutes)

1. **Oxygen**: Only if SpO2 below 92%. Target SpO2 92-96%. Avoid hyperoxia (may worsen myocardial injury) [10]
2. **Aspirin 300 mg**: Chewed or dispersed PO (rapid absorption). If unable to swallow, 300 mg PR
3. **P2Y12 inhibitor loading**:
   - Prasugrel 60 mg PO (if PCI planned, age below 75, weight ≥60 kg, no prior stroke/TIA) [11]
   - Ticagrelor 180 mg PO (if conservative strategy or coronary anatomy unknown) [12]
   - Clopidogrel 600 mg PO (if prasugrel/ticagrelor contraindicated or high bleeding risk)
4. **Anticoagulation**:
   - UFH 70 U/kg IV bolus (max 5,000 U), then 12-15 U/kg/h infusion (target APTT 60-80 sec)
   - OR Enoxaparin 1 mg/kg SC BD (if eGFR greater than 30 mL/min; 1 mg/kg OD if eGFR 15-30)
   - OR Fondaparinux 2.5 mg SC daily (if eGFR ≥20 mL/min, bleeding risk high) [13]
5. **Glyceryl trinitrate (GTN) 0.4-0.8 mg sublingual**: Repeat every 5 min × 3 if pain persists (contraindicated if SBP below 90 mmHg, RV infarction, PDE5 inhibitor use within 24-48h)
6. **Morphine 2.5-5 mg IV**: If pain persists despite GTN. Caution: may reduce P2Y12 inhibitor absorption and increase mortality [14]
7. **Beta-blocker (metoprolol 25-50 mg PO)**: Only if no contraindications (heart failure, hypotension, bradycardia, asthma/COPD). Avoid IV beta-blockers in ED (increased cardiogenic shock risk)
8. **High-intensity statin (atorvastatin 80 mg PO)**: Immediate loading reduces recurrent ischemic events [15]
9. **Anti-emetic (metoclopramide 10 mg IV or ondansetron 4 mg IV)**: If nausea/vomiting
10. **12-lead ECG monitoring**: Continuous ECG to detect ST-segment changes, arrhythmias

Resuscitation (if applicable)

Airway

• Indications for intubation: Cardiac arrest, cardiogenic shock with respiratory failure, reduced GCS (below 8), inability to protect airway
• Approach: Rapid sequence intubation (ketamine 1-2 mg/kg + rocuronium 1 mg/kg). Avoid propofol (myocardial depression, hypotension). Post-intubation: lung-protective ventilation (TV 6-8 mL/kg, PEEP 5-8 cmH2O), target SpO2 92-96%, avoid hyperventilation (hypocapnia causes coronary vasoconstriction)

Breathing

• Oxygenation targets: SpO2 92-96%. PaO2 60-80 mmHg. Avoid hyperoxia (PaO2 greater than 100 mmHg increases oxidative stress and infarct size) [16]
• Ventilation targets: Avoid hyperventilation. Target PaCO2 35-45 mmHg. Permissive hypercapnia (PaCO2 45-50 mmHg) acceptable if pH greater than 7.25
• NIV for pulmonary edema: CPAP 5-10 cmH2O reduces preload and afterload, improves oxygenation, reduces intubation rate (30% → 15%) [17]

Circulation

• Haemodynamic targets:
  • SBP 100-140 mmHg (avoid hypotension below 90 mmHg and hypertension greater than 180 mmHg)
  • MAP greater than 65 mmHg (ensure coronary perfusion pressure)
  • HR 60-100 bpm (optimize myocardial oxygen demand)
• Hypotension management:
  • "RV infarction (inferior MI + ST-elevation in V4R): Avoid nitrates and diuretics. Fluid resuscitation (500 mL NS bolus, reassess). If persistent hypotension: inotropes (dobutamine 5-10 mcg/kg/min) [18]"
  • "Cardiogenic shock (LV failure): Consider inotropes (dobutamine, adrenaline) or mechanical circulatory support (intra-aortic balloon pump, ECMO). Urgent cath lab activation"
• Hypertension management (SBP greater than 180 mmHg): GTN infusion 10-200 mcg/min IV (titrate to SBP 140-160 mmHg). Avoid excessive BP reduction (reduces coronary perfusion)

Medications

Paediatric Dosing

Ongoing Management

Risk Stratification

Use GRACE Score 2.0 (gold standard for NSTEMI risk stratification) [20]:

• Variables: Age, heart rate, SBP, creatinine, Killip class, cardiac arrest, ST-deviation, elevated biomarkers
• Interpretation:
  • "Low risk (below 109): 6-month mortality below 3%. Consider selective invasive strategy (below 72h) or conservative strategy"
  • "Intermediate risk (109-140): 6-month mortality 3-8%. Early invasive strategy (below 24h) preferred"
  • "High risk (greater than 140): 6-month mortality greater than 8%. Early invasive strategy (below 24h) mandatory"

HEART Score (ED triage tool, not for NSTEMI management) [21]:

• Variables: History, ECG, Age, Risk factors, Troponin
• Interpretation:
  • 0-3: Low risk (0.9-1.7% MACE). Safe for early discharge with outpatient follow-up
  • 4-6: Intermediate risk (12-17% MACE). Admit for serial troponins, stress test, or invasive strategy
  • 7-10: High risk (50-65% MACE). Admit for invasive strategy

CRUSADE Bleeding Score (assess bleeding risk) [22]:

• Variables: Baseline Hct, creatinine, heart rate, sex, CHF, prior vascular disease, diabetes, SBP
• Interpretation:
  • "Very low (below 20): 3% bleeding risk"
  • "Low (21-30): 5% bleeding risk"
  • "Moderate (31-40): 9% bleeding risk"
  • "High (41-50): 12% bleeding risk"
  • "Very high (greater than 50): 20% bleeding risk"
• Implication: If very high bleeding risk, consider fondaparinux (lowest bleeding risk), avoid prasugrel, consider radial PCI approach (reduces bleeding 30-50%)

Invasive Strategy Timing

Definitive Care

• Percutaneous coronary intervention (PCI): Preferred revascularization strategy for NSTEMI. Radial access preferred (reduces bleeding 30-50% vs femoral). Drug-eluting stents (DES) preferred over bare-metal stents. Bivalirudin vs UFH: similar efficacy, bivalirudin may reduce bleeding in high-risk patients
• Coronary artery bypass grafting (CABG): Indications: left main disease, 3-vessel disease with reduced LVEF (below 40%), diabetes + multi-vessel disease, failed PCI. Timing: semi-urgent (within 1-7 days after stabilization)
• Conservative strategy: Medical therapy alone if: low-risk (GRACE below 109), patient refusal, severe comorbidities, limited life expectancy, no angina after stabilization

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Disposition

Admission Criteria

• All NSTEMI patients require admission (troponin-positive)
• Unstable angina (troponin-negative): Admit if high-risk features (dynamic ECG changes, HEART score ≥4, recurrent pain, hemodynamic instability)
• Telemetry/CCU: Continuous ECG monitoring for 24-48 hours (arrhythmia detection, ischemia monitoring)

ICU/CCU Criteria

• Cardiogenic shock (SBP below 90 mmHg, signs of hypoperfusion)
• Acute heart failure with pulmonary edema (requiring NIV or intubation)
• Life-threatening arrhythmias (VT, VF, complete heart block requiring temporary pacing)
• Mechanical complications (acute MR, VSD, free wall rupture)
• Post-cardiac arrest
• Hemodynamic instability requiring inotropes or mechanical circulatory support

Discharge Criteria

NSTEMI patients should NOT be discharged from ED. Minimum 24-48 hour observation required. Safe discharge criteria (post-admission) include:

• Pain-free for greater than 24 hours
• No hemodynamic instability
• No arrhythmias on telemetry
• Revascularization completed (PCI or planned CABG)
• Optimized medical therapy (DAPT, statin, beta-blocker, ACE inhibitor)
• LVEF assessed (echo)
• Patient education completed (cardiac rehabilitation referral, lifestyle modification, medication adherence)

Red flags to return:

• Recurrent chest pain or pressure
• Severe dyspnea
• Syncope or pre-syncope
• Palpitations
• Uncontrolled bleeding (if on DAPT)

Follow-up

• Cardiology outpatient review: Within 1-2 weeks post-discharge
• Cardiac rehabilitation: Commence within 2-4 weeks (reduces mortality 20-30%, improves quality of life)
• Repeat echocardiography: At 6-8 weeks if LVEF below 40% (assess for ICD candidacy - primary prevention if EF below 35% at 3 months post-MI)
• GP letter: Detail diagnosis, revascularization performed, medications (emphasize DAPT duration: 12 months minimum), risk factor modification targets (LDL below 1.4 mmol/L, BP below 130/80 mmHg, smoking cessation, diabetes control HbA1c below 7%)
• Specialist referral: Heart failure clinic if LVEF below 40%, electrophysiology if arrhythmias, cardiac surgery if CABG planned

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Special Populations

Paediatric Considerations

NSTEMI is rare in children (below 1% of ACS cases). Consider alternate diagnoses:

• Kawasaki disease with coronary aneurysms: Fever, rash, conjunctivitis, strawberry tongue, coronary artery thrombosis
• Familial hypercholesterolemia: Premature CAD, tendon xanthomas, corneal arcus, family history
• Congenital coronary anomalies: Anomalous coronary artery origin, sudden cardiac death during exertion
• Cocaine use: Adolescents with drug use, coronary vasospasm
• Management: Pediatric cardiology consultation mandatory. DAPT dosing: aspirin 5 mg/kg (max 300 mg), UFH 75 U/kg bolus + 20 U/kg/h infusion

Pregnancy

ACS in pregnancy is rare (1 in 10,000-20,000 pregnancies) but increasing. Peak risk: third trimester and postpartum.

• Etiology: Spontaneous coronary artery dissection (SCAD, 40%), atherosclerosis (30%), coronary thrombosis (20%), vasospasm (10%)
• Diagnostic challenges: Atypical symptoms common (dyspnea, fatigue). Troponin normal in pregnancy. ECG may show non-specific changes
• Radiation risk: Angiography safe with below 0.5 mGy fetal exposure (use radial approach, minimize fluoroscopy time, abdominal shielding)
• Medications:
  • "Safe: Aspirin (low-dose, below 100 mg/day), UFH, beta-blockers (labetalol, metoprolol), GTN, morphine"
  • "Avoid: ACE inhibitors (teratogenic), statins (teratogenic), prasugrel/ticagrelor (limited data - clopidogrel preferred)"
• Revascularization: PCI preferred over CABG. Avoid fibrinolytics (placental abruption, maternal hemorrhage). For SCAD: conservative management preferred (80% heal spontaneously); PCI if hemodynamically unstable
• Delivery: Vaginal delivery preferred (lower risk). Cesarean section if obstetric indications. Maintain DAPT throughout (regional anesthesia contraindicated)

Elderly (≥75 years)

• Higher mortality: In-hospital mortality 15% (vs 3% in below 65 years). Increased bleeding risk (2-3×)
• Atypical presentation: Dyspnea alone (40%), confusion (15%), falls, syncope. Silent MI more common (20-30%)
• Bleeding risk: CRUSADE score often greater than 50. Consider: radial PCI approach, fondaparinux (lowest bleeding), avoid prasugrel (age ≥75 contraindication), consider de-escalation to clopidogrel after acute phase
• Invasive strategy: Age alone should NOT exclude invasive strategy. If GRACE greater than 140 and acceptable surgical risk, early invasive improves outcomes (After Eighty trial: 40% vs 61% MACE at 1.5 years with invasive vs conservative) [26]
• Medication adjustments: Reduce prasugrel to 5 mg if age ≥75 (if used), dose-adjust anticoagulation for renal function (common CKD), avoid morphine (delirium risk)
• Frailty assessment: Clinical Frailty Scale (CFS) greater than 6 suggests limited benefit from invasive strategy. Shared decision-making with patient and family

Indigenous Health

Important Note: Aboriginal, Torres Strait Islander, and Māori considerations:

• Health disparities:
  • "Incidence: 3-4× higher ACS rates, present 10 years younger (median age 55 vs 68 years)"
  • "Mortality: 2× higher in-hospital mortality (6% vs 3%), 2.5× higher 1-year mortality (15% vs 6%) [27]"
  • "Recurrent events: 30% vs 18% at 5 years"
  • "Risk factors: Higher prevalence of smoking (50% vs 15%), diabetes (40% vs 20%), renal disease (20% vs 5%), rheumatic heart disease [28]"
• Cultural safety considerations:
  • Use of Aboriginal Liaison Officers and Māori Cultural Support Workers
  • Family-centered care (whānau in Māori culture) - involve extended family in decision-making
  • "Communication style: Allow time for questions, avoid medical jargon, use teach-back method"
  • "Discharge planning: Ensure culturally safe cardiac rehabilitation programs, address transport barriers (long distances in remote areas), link with Aboriginal Medical Services or Māori health providers"
• Interpreter and liaison services: Use accredited interpreters for language barriers (Aboriginal English, Torres Strait Creole, te reo Māori). Avoid family members as interpreters
• Barriers to revascularization: Geographic isolation (median distance to PCI center 450 km), cultural factors (reluctance to leave community/country), financial barriers (accommodation, travel costs), fear of mainstream health system (historical trauma)
• Interventions to improve outcomes: Culturally tailored cardiac rehabilitation (47% attendance vs 15% standard programs), Aboriginal Health Practitioner follow-up (reduces 30-day readmission 25% → 12%), telemedicine for remote medication reviews

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Pitfalls & Pearls

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Viva Practice

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OSCE Scenarios

Station 1: NSTEMI History and Risk Stratification

Format: History/Communication Time: 11 minutes Setting: ED cubicle

Candidate Instructions:

A 58-year-old man has presented to the Emergency Department with chest discomfort. Take a focused history, assess his risk of acute coronary syndrome, and explain your immediate management plan to the patient.

Examiner Instructions: Patient has presented with 2 hours of central chest pressure, 7/10 severity, associated with dyspnea and nausea. He has risk factors: hypertension, hypercholesterolemia, smoking (30 pack-years), family history (father MI at age 52). Pain started at rest, not relieved by GTN spray given by paramedics. No previous cardiac history.

Vital signs: HR 92 bpm, BP 165/95 mmHg, SpO2 96% RA, RR 18/min, GCS 15.

Progression: If candidate asks about ECG, inform them it shows 2 mm ST-depression in V4-V6 and leads I, aVL. If asked about troponin, it is elevated at 550 ng/L (normal below 14 ng/L).

Patient is anxious, worried about dying like his father. Wants to know: "Am I having a heart attack? Will I die? Do I need surgery?"

Actor/Patient Brief: You are a 58-year-old accountant who developed sudden chest pressure 2 hours ago while watching TV. It feels like "an elephant sitting on my chest," 7/10 severity, radiating to your left shoulder. You also feel short of breath and nauseous. The ambulance gave you a spray under your tongue (GTN) but it didn't help.

You are very anxious because your father died of a heart attack at age 52. You are worried you will die too. You smoke 1 pack/day for 30 years, take tablets for blood pressure and cholesterol (but don't always remember to take them). You want to know if you're having a heart attack, if you will die, and if you need heart surgery.

Answer questions honestly. Express anxiety about dying. Ask about prognosis and treatment.

Marking Criteria:

Expected Standard:

• Pass: ≥8/14
• Key discriminators: Candidates who score highly will identify high-risk features (rest angina, prolonged duration, ST-depression, elevated troponin), calculate GRACE score (or mention it), and confidently explain early invasive strategy. Failing candidates often miss risk factor assessment, fail to address patient anxiety, or provide vague management plans.

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Station 2: NSTEMI Communication - Consent for Coronary Angiography

Format: Communication Time: 11 minutes Setting: ED relatives room

Candidate Instructions:

You are an emergency registrar. A 65-year-old woman has been diagnosed with NSTEMI (heart attack without ST-elevation on ECG). The cardiology team has arranged an urgent coronary angiogram tomorrow morning. Explain the diagnosis, procedure, risks, and benefits to the patient and obtain consent for the angiogram.

Examiner Instructions: Patient is a 65-year-old woman with NSTEMI (troponin 420 ng/L, ST-depression in lateral leads, GRACE score 152). She has hypertension and type 2 diabetes. She is stable, pain-free after aspirin, ticagrelor, and GTN infusion.

Cardiology has arranged early invasive strategy (angiogram at 8 AM tomorrow, below 24 hours from presentation).

Patient is anxious about the procedure. She has never had surgery or invasive procedures before. She wants to know: "What is an angiogram? Is it dangerous? What if they find something? Can't I just take tablets instead?"

Candidate must: explain NSTEMI diagnosis, explain angiogram procedure (including possibility of PCI/stenting), discuss risks (bleeding, contrast reaction, stroke, MI, kidney injury, death), discuss benefits (reduced recurrent MI and death), address concerns, obtain informed consent.

Actor/Patient Brief: You are a 65-year-old retired teacher who has been told you have a "heart attack" but you don't fully understand what that means. The doctors have explained you need a "test" tomorrow morning but you're very anxious because you've never had surgery or any invasive procedures.

You have questions:

• "What exactly is an angiogram? Will I be asleep?"
• "Is it dangerous? Could I die?"
• "What if they find something? Will they fix it during the procedure?"
• "Can't I just take tablets and avoid the procedure?"
• "How long is the recovery?"

You are willing to proceed if the doctor explains things clearly and addresses your concerns. If the doctor rushes, uses too much jargon, or doesn't address your anxiety, you become more hesitant.

Marking Criteria:

Expected Standard:

• Pass: ≥8/14
• Key discriminators: High-scoring candidates explain the procedure in lay terms (avoid "percutaneous coronary intervention," use "angiogram and possible stent"), balance risks and benefits clearly, and empathetically address patient anxiety. Failing candidates use excessive jargon, rush through risks, or fail to explain why the procedure is recommended (high-risk score).

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Station 3: NSTEMI Management - Critical Deterioration

Format: Resuscitation Time: 11 minutes Setting: ED resuscitation bay

Candidate Instructions:

You are the emergency registrar managing a 60-year-old man with confirmed NSTEMI (troponin 650 ng/L, ST-depression in anterior leads). He has received aspirin, ticagrelor, enoxaparin, and GTN infusion 30 minutes ago. The nurse calls you urgently - the patient has developed sudden chest pain, dyspnea, and hypotension. Lead the resuscitation and make appropriate management decisions.

Examiner Instructions: Patient has developed cardiogenic shock 30 minutes after initial NSTEMI management.

Initial vital signs (when candidate arrives): HR 118 bpm, BP 78/45 mmHg, SpO2 85% RA, RR 32/min, GCS 14 (confused), cold/clammy skin.

Progression:

1. If candidate requests repeat ECG: Shows new 3 mm ST-depression in V2-V6, no STEMI
2. If candidate requests bedside echo: Reveals severe global hypokinesis, LVEF 20%, no mechanical complications (MR, VSD)
3. If candidate starts oxygen: SpO2 improves to 90-92% on 15 L/min non-rebreather
4. If candidate starts CPAP: SpO2 improves to 94%
5. If candidate starts inotropes (dobutamine or adrenaline): BP improves to 95/55 mmHg, HR 105 bpm
6. If candidate activates cath lab: Interventional cardiology available in 20 minutes

Expected actions:

• ABCDE approach
• High-flow oxygen → CPAP if not improving
• IV access, fluid restriction (avoid bolus due to pulmonary edema)
• Inotropic support (dobutamine 5-10 mcg/kg/min)
• Stop GTN infusion (worsening hypotension)
• Immediate cath lab activation (cardiogenic shock is Class I indication for immediate PCI below 2h)
• Consider mechanical circulatory support (IABP, Impella, ECMO)
• Notify ICU (post-procedure destination)

Nurse role (played by examiner or assistant):

• Provides vital signs when asked
• Can perform tasks (IV access, draw bloods, connect monitoring, prepare medications, call cardiology/ICU)
• Prompts if candidate misses critical actions: "Doctor, the blood pressure is still 78 mmHg, should we do anything else?" (if inotropes not started)

Marking Criteria:

Expected Standard:

• Pass: ≥8/14
• Key discriminators: Recognizing cardiogenic shock early, avoiding fluid bolus (common mistake - worsens pulmonary edema), initiating inotropes promptly, and activating cath lab immediately. Failing candidates often delay cath lab activation, give fluid bolus, or fail to recognize cardiogenic shock.

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SAQ Practice

Question 1 (8 marks)

Stem: A 55-year-old man presents to the Emergency Department with 90 minutes of central chest pressure (7/10) radiating to the left arm. He has a history of hypertension and smoking. ECG shows 2.5 mm ST-depression in leads V4-V6, I, and aVL. High-sensitivity troponin I at 0 hours is 320 ng/L (normal below 14 ng/L).

Question: Outline your immediate Emergency Department management (first 30 minutes). (8 marks)

Model Answer:

• Aspirin 300 mg PO chewed or dispersed (immediate antiplatelet therapy, irreversible COX-1 inhibition) (1 mark)
• P2Y12 inhibitor loading: Ticagrelor 180 mg PO OR Prasugrel 60 mg PO (if PCI planned, age below 75, weight ≥60 kg, no prior stroke) (1 mark)
• Anticoagulation: UFH 70 U/kg IV bolus (max 5,000 U) then 12-15 U/kg/h infusion (target APTT 60-80 sec) OR Enoxaparin 1 mg/kg SC BD (1 mark)
• Glyceryl trinitrate (GTN) 0.4-0.8 mg sublingual, repeat every 5 min × 3 if pain persists (contraindicated if SBP below 90 mmHg or RV infarction) (1 mark)
• High-intensity statin: Atorvastatin 80 mg PO loading dose (1 mark)
• Oxygen only if SpO2 below 92% (avoid hyperoxia; target SpO2 92-96%) (0.5 mark)
• Morphine 2.5-5 mg IV PRN if pain persists despite GTN (use sparingly due to P2Y12 absorption concerns and potential mortality increase) (0.5 mark)
• Risk stratification: Calculate GRACE score (likely greater than 140 based on age, ECG changes, elevated troponin) → indicates early invasive strategy below 24h (1 mark)
• Activate cardiology: Urgent cardiology consultation for early invasive strategy (coronary angiography within 24 hours) (1 mark)

Examiner Notes:

• Accept: Clopidogrel 600 mg if prasugrel/ticagrelor contraindicated (0.5 marks), fondaparinux 2.5 mg SC (0.5 marks)
• Accept: Beta-blocker (metoprolol 25-50 mg PO) if no contraindications (0.5 marks bonus, but not required for full marks)
• Do not accept: IV beta-blockers (increased shock risk per COMMIT trial), routine oxygen therapy, fibrinolysis (not indicated in NSTEMI)

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Question 2 (6 marks)

Stem: A 68-year-old woman with NSTEMI has a GRACE score of 158. The cardiology team is planning coronary angiography.

Question: List THREE indications for immediate (below 2 hours) coronary angiography in NSTEMI and THREE indications for early (below 24 hours) angiography. (6 marks)

Model Answer:

Immediate (below 2 hours) indications:

• Cardiogenic shock (SBP below 90 mmHg with signs of end-organ hypoperfusion) (1 mark)
• Refractory or recurrent chest pain despite optimal medical therapy (1 mark)
• Life-threatening arrhythmias (VT, VF, complete heart block) (1 mark)

Accept: Acute heart failure with pulmonary edema (0.5 marks), mechanical complications (acute MR, VSD) (0.5 marks), dynamic ST-segment changes including transient ST-elevation (0.5 marks)

Early (below 24 hours) indications:

• GRACE score greater than 140 (high risk, 6-month mortality greater than 8%) (1 mark)
• Dynamic ECG changes (ST-depression, T-wave inversion) with elevated troponin (1 mark)
• Confirmed NSTEMI with high-risk features (diabetes, CKD, prior MI, LVEF below 40%) (1 mark)

Accept: Transient ST-elevation that resolves (0.5 marks), early post-infarction angina (0.5 marks)

Examiner Notes:

• Do not accept: "Abnormal ECG" (too vague, must specify ST-depression or dynamic changes), "Elevated troponin" alone (all NSTEMI have elevated troponin, need additional high-risk feature)

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Question 3 (8 marks)

Stem: You are choosing between prasugrel and ticagrelor for a 62-year-old man with NSTEMI planned for early invasive strategy (angiography within 24 hours). He weighs 75 kg, has no history of stroke, and has an eGFR of 55 mL/min.

Question: a) State the loading and maintenance doses for prasugrel and ticagrelor. (2 marks)
b) Compare the evidence for prasugrel vs ticagrelor in NSTEMI (name ONE key trial for each). (2 marks)
c) List FOUR contraindications to prasugrel. (2 marks)
d) When should prasugrel be administered in NSTEMI planned for invasive strategy? (2 marks)

Model Answer:

a) Dosing:

• Prasugrel: 60 mg PO loading, then 10 mg PO daily (1 mark)
• Ticagrelor: 180 mg PO loading, then 90 mg PO BD (twice daily) (1 mark)

b) Evidence:

• Prasugrel: TRITON-TIMI 38 (prasugrel vs clopidogrel, 9.9% vs 12.1% MACE) OR ISAR-REACT 5 (prasugrel vs ticagrelor, 6.9% vs 9.3% MACE, prasugrel superior) (1 mark)
• Ticagrelor: PLATO trial (ticagrelor vs clopidogrel, 9.8% vs 11.7% MACE) (1 mark)

c) Contraindications to prasugrel (FOUR of the following):

• Age ≥75 years (0.5 mark)
• Weight below 60 kg (0.5 mark)
• Prior stroke or TIA (transient ischemic attack) (0.5 mark)
• Active pathological bleeding (0.5 mark)

Accept: Severe hepatic impairment (0.5 marks), history of intracranial hemorrhage (0.5 marks)

d) Timing of prasugrel administration:

• In the catheterization laboratory AFTER coronary anatomy is confirmed (not pre-treatment in ED) (1 mark)
• Rationale: ACCOAST trial showed pre-treatment with prasugrel increased bleeding without reducing ischemic events. Wait until PCI is confirmed and patient has no contraindications (no prior stroke identified, suitable coronary anatomy) (1 mark)

Examiner Notes:

• Accept: "After angiography," "At time of PCI," "In cath lab" (1 mark)
• Do not accept: "Immediately in ED" (incorrect, this is pre-treatment which increases bleeding), "With aspirin" (too vague, doesn't specify timing)

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Question 4 (6 marks)

Stem: A 58-year-old Aboriginal man with NSTEMI requires transfer from a remote Northern Territory ED to a tertiary center 600 km away via RFDS (Royal Flying Doctor Service). The flight will take 4 hours round-trip.

Question: a) List THREE specific health disparities affecting Aboriginal and Torres Strait Islander peoples with acute coronary syndrome. (3 marks)
b) Outline THREE strategies to improve outcomes for this patient population. (3 marks)

Model Answer:

a) Health disparities:

• Higher incidence: 3-4× higher ACS rates compared to non-Indigenous Australians (1 mark)
• Younger age of presentation: Median age 55 years vs 68 years (present 10-13 years younger) (1 mark)
• Higher mortality: 2× higher in-hospital mortality (6% vs 3%), 2.5× higher 1-year mortality (15% vs 6%) (1 mark)

Accept: Higher recurrent event rate (30% vs 18% at 5 years) (1 mark), higher prevalence of risk factors - smoking (50% vs 15%), diabetes (40% vs 20%), CKD (20% vs 5%), rheumatic heart disease (1 mark), delayed presentation (median 6h vs 2h symptom-to-hospital time) (1 mark), lower revascularization rates (40% vs 65% receive PCI) (1 mark)

b) Strategies to improve outcomes:

• Aboriginal Liaison Officers/Health Practitioners: Cultural mediation, improve communication, address cultural safety, coordinate follow-up with Aboriginal Medical Services, reduce 30-day readmission (25% → 12%) (1 mark)
• Culturally tailored cardiac rehabilitation: Programs designed for Aboriginal and Torres Strait Islander peoples, community-based, address transport barriers, incorporate cultural activities (attendance 47% vs 15% standard programs) (1 mark)
• Telemedicine and remote medication reviews: Telehealth follow-up for medication adherence, reduce need for travel, link with remote health clinics, RFDS-coordinated outreach services (1 mark)

Accept: Early RFDS retrieval protocols (reduce delay to revascularization) (1 mark), partnership with Aboriginal Medical Services for discharge planning and follow-up (1 mark), address social determinants of health (housing, food security, financial support for medications/travel) (1 mark), family-centered care (involve whānau/extended family in decision-making and education) (1 mark)

Examiner Notes:

• Do not accept: "Better education" (too vague, must specify culturally tailored), "More resources" (too vague, must specify intervention type)

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Australian Guidelines

ARC/ANZCOR

• ANZCOR Guideline 11.7: Acute Coronary Syndromes (2023 update)
  • "Key points: "
    • Aspirin 300 mg loading, then 100 mg daily (Class I, LOE A)
    • P2Y12 inhibitor (prasugrel, ticagrelor, or clopidogrel) in addition to aspirin (Class I, LOE A)
    • Anticoagulation with UFH, LMWH, or fondaparinux (Class I, LOE A)
    • Early invasive strategy (below 24h) for high-risk NSTEMI (GRACE greater than 140) (Class I, LOE A)
    • Immediate invasive strategy (below 2h) for very high-risk features (shock, refractory pain, arrhythmias) (Class I, LOE B)
• Key differences from ESC 2023/AHA 2023:
  • ANZCOR emphasizes radial access for PCI (reduces bleeding, Class IIa vs ESC Class I)
  • ANZCOR supports fondaparinux as preferred anticoagulant if bleeding risk high (aligned with ESC)
  • ANZCOR includes specific guidance on remote/retrieval medicine (RFDS protocols, fibrinolysis if PCI greater than 120 min in evolved STEMI)

Therapeutic Guidelines

• Therapeutic Guidelines: Cardiovascular (Version 7, 2023)
  • "Antiplatelet therapy: Aspirin 300 mg loading + ticagrelor 180 mg loading (preferred over clopidogrel). Prasugrel reserved for PCI patients without contraindications."
  • "Anticoagulation: Enoxaparin 1 mg/kg BD (preferred over UFH for ease of use). Dose-reduce to 1 mg/kg OD if eGFR 15-30 mL/min. Fondaparinux 2.5 mg daily if high bleeding risk."
  • "Statin: Atorvastatin 80 mg loading, then 40-80 mg daily (target LDL below 1.4 mmol/L)"
  • "Beta-blocker: Metoprolol 25-50 mg PO BD (only after stabilization, avoid if heart failure, hypotension, bradycardia, asthma/COPD)"
  • "ACE inhibitor: Ramipril 2.5 mg PO, titrate to 10 mg daily (if LVEF below 40%, heart failure, anterior MI, diabetes)"
  • "Duration of DAPT: Minimum 12 months post-ACS (Class I). Consider de-escalation to clopidogrel monotherapy after 12 months if high bleeding risk."

PBS (Pharmaceutical Benefits Scheme) Considerations

• Ticagrelor (Brilinta®): PBS-listed for ACS (authority required for initial prescription, GP can continue after specialist initiation). Cost: ~$40/month with concession card, ~$150/month without.
• Prasugrel (Effient®): PBS-listed for ACS undergoing PCI. Requires specialist prescription. Cost similar to ticagrelor.
• Clopidogrel (Plavix®, generics): PBS-listed, no authority required. Cost: ~$6/month with concession, ~$20/month without (much cheaper than ticagrelor/prasugrel).
• Atorvastatin (Lipitor®, generics): PBS-listed for cardiovascular disease prevention. Cost: ~$6/month with concession.

State-Specific

• NSW Health: ACS Clinical Pathway (2023) - mandates GRACE score calculation, early invasive strategy if GRACE greater than 140, 24/7 primary PCI network across 14 centers
• Victorian Cardiac Clinical Network: STEMI/NSTEMI protocols align with ESC 2023, emphasis on regional retrieval (MICA paramedics can activate cath lab pre-hospital)
• Queensland Health: Remote ACS management protocol (RFDS activation criteria, fibrinolysis if evolved STEMI greater than 120 min from PCI)

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Remote/Rural Considerations

Pre-Hospital

• Paramedic assessment: 12-lead ECG (pre-hospital STEMI activation if ST-elevation develops), aspirin 300 mg PO, GTN 0.4-0.8 mg SL, IV access, oxygen if SpO2 below 92%
• Pre-hospital notification: For STEMI, paramedics activate cath lab directly (bypass ED). For NSTEMI, ED assessment first (GRACE score, troponin) before cath lab activation.
• Extended Care Paramedics (ECP) / MICA: In some states (VIC, SA), advanced paramedics can administer additional medications (morphine, antiemetics, heparin), interpret 12-lead ECGs (identify posterior MI, RV infarction), and make retrieval decisions.

Resource-Limited Setting

• Remote ED capabilities:
  • ECG interpretation (12-lead + posterior/right-sided leads)
  • Point-of-care troponin (qualitative or semi-quantitative, may not have high-sensitivity troponin)
  • Basic medications (aspirin, clopidogrel, UFH, GTN, morphine, atorvastatin)
  • Limited availability of newer P2Y12 inhibitors (prasugrel/ticagrelor may not be stocked - use clopidogrel)
  • No on-site cardiology, ICU, or PCI capability
• Modified approach when resources limited:
  • Use clopidogrel 600 mg if ticagrelor/prasugrel unavailable
  • UFH preferred over enoxaparin (easier to reverse if bleeding complication during transfer)
  • Stabilize before transfer (pain control, oxygen, hemodynamic stability)
  • Telemedicine consultation with tertiary center cardiologist (discuss GRACE score, retrieval urgency)

Retrieval

• Criteria for RFDS retrieval:
  • "Immediate (below 2h): Cardiogenic shock, refractory pain, life-threatening arrhythmias, hemodynamic instability"
  • "Urgent (below 6h): GRACE greater than 140, dynamic ECG changes, confirmed high-risk NSTEMI"
  • "Semi-urgent (below 24h): GRACE 109-140, stable NSTEMI, no very high-risk features"
• RFDS capabilities:
  • Advanced life support (intubation, mechanical ventilation, inotropes, temporary pacing)
  • Point-of-care testing (troponin, BSL, iSTAT)
  • Fibrinolysis capability (tenecteplase for STEMI if evolved during transfer and PCI greater than 120 min)
  • Cardiac monitoring (12-lead ECG, defibrillation)
  • "Medical crew: RFDS doctor + critical care flight nurse"
• Coordination:
  • "Remote ED activates RFDS via 1800 number (NSW: 1800 222 182, NT: 1800 626 628, QLD: 1300 362 111)"
  • "Notify receiving tertiary center cardiology (handover: age, GRACE score, troponin, ECG, medications given, ETA)"
  • Arrange cath lab booking (if high-risk, book for arrival + 1-2h to allow stabilization)
  • Family accommodation (RFDS may fund one accompanying relative, Aboriginal Medical Services provide support)

Telemedicine

• Remote consultation approach:
  • "ECG transmission: Email or telehealth platform (send 12-lead ECG as PDF, include clinical context)"
  • "Video consultation: Discuss patient with tertiary cardiologist, review ECG together, calculate GRACE score, decide invasive strategy timing"
  • "Decision support: Tertiary cardiologist provides guidance on: P2Y12 inhibitor choice, anticoagulation dosing, retrieval urgency, cath lab booking"
• Post-discharge telemedicine:
  • Remote medication reviews (ensure DAPT adherence, statin adherence, monitor for bleeding)
  • Cardiac rehabilitation via telehealth (exercise prescription, risk factor modification, psychological support)
  • Follow-up echocardiography (arrange portable echo via RFDS or visiting cardiologist)

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Medication Interactions and Contraindications

P2Y12 Inhibitor Interactions

Prasugrel

Pharmacology: Thienopyridine prodrug requiring CYP3A4 and CYP2B6 hepatic metabolism to active metabolite. Irreversible P2Y12 receptor antagonist.

Drug interactions:

• CYP3A4 inhibitors (ketoconazole, clarithromycin, grapefruit juice): Minimal effect (prodrug already has low bioavailability, metabolism occurs via multiple pathways)
• CYP3A4 inducers (rifampicin, phenytoin, carbamazepine): May reduce active metabolite levels, but clinical significance unclear
• Proton pump inhibitors (PPIs): No significant interaction (unlike clopidogrel)
• Warfarin/NOACs: Increased bleeding risk. If combination required, reduce DOAC dose (e.g., rivaroxaban 15 mg daily instead of 20 mg)
• NSAIDs: Avoid if possible (GI bleeding risk 3-4×). Use paracetamol for analgesia

Contraindications (absolute):

• Active pathological bleeding
• Prior stroke or TIA (any time)
• Age ≥75 years (relative - can use 5 mg maintenance dose if high-risk and no alternatives)
• Weight below 60 kg (relative - can use 5 mg maintenance dose)
• Severe hepatic impairment (Child-Pugh C)

Caution (relative contraindications):

• Recent surgery or trauma (below 7 days)
• Thrombocytopenia (below 100 × 10⁹/L)
• Anemia (Hb below 100 g/L)
• CKD (eGFR below 30 mL/min - increased bleeding risk, no dose adjustment but monitor closely)

Ticagrelor

Pharmacology: Cyclopentyltriazolopyrimidine. Direct-acting, reversible P2Y12 antagonist (no prodrug metabolism required). Active metabolite AR-C124910XX contributes 30-40% of antiplatelet effect.

Drug interactions:

• CYP3A4 inhibitors (ketoconazole, clarithromycin, diltiazem, verapamil, ritonavir): CONTRAINDICATED - increase ticagrelor levels 2-3×, severe bleeding risk
• CYP3A4 inducers (rifampicin, phenytoin, carbamazepine, St John's wort): CONTRAINDICATED - reduce ticagrelor levels 80%, loss of efficacy
• Simvastatin/lovastatin: Limit to 40 mg daily (ticagrelor inhibits CYP3A4, increases statin levels, myopathy risk)
• Digoxin: Increase digoxin levels 50% (ticagrelor inhibits P-glycoprotein). Monitor digoxin levels, reduce dose if needed
• Warfarin/NOACs: Increased bleeding risk. Avoid triple therapy if possible
• Morphine: Delays ticagrelor absorption (gastric stasis). Peak concentration reduced 25%, delayed by 1-2 hours. Use sparingly

Contraindications (absolute):

• Active pathological bleeding
• History of intracranial hemorrhage
• Severe hepatic impairment (Child-Pugh C)
• Concomitant strong CYP3A4 inhibitors or inducers

Caution:

• Bradycardia (3-5% incidence of sinus pauses greater than 3 sec, usually transient)
• Dyspnea (15% incidence, usually mild, resolves spontaneously)
• CKD (no dose adjustment needed, but increased bleeding risk)
• Elderly (no dose adjustment, but increased bleeding risk)

Anticoagulation Interactions

Unfractionated Heparin (UFH)

Monitoring: APTT target 60-80 sec (1.5-2.5× control). Check APTT at 6h, 12h, 24h, then daily. Adjust infusion rate by ±2 units/kg/h.

Drug interactions:

• Antiplatelet agents: Synergistic bleeding risk (expected in ACS)
• NSAIDs: Avoid (bleeding risk)
• Thrombolytics: Avoid in NSTEMI (no indication)

Complications:

• Heparin-induced thrombocytopenia (HIT): 1-5% incidence. Platelets drop greater than 50% on day 5-10. Paradoxical thrombosis risk (DVT, PE, arterial thrombosis). If suspected: STOP all heparin immediately, check HIT antibodies (anti-PF4), switch to bivalirudin or fondaparinux, consult hematology
• Over-anticoagulation: If APTT greater than 120 sec and no bleeding, stop infusion for 1 hour, recheck APTT, restart at reduced rate. If active bleeding, stop heparin, give protamine 1 mg per 100 units of heparin received in last 2 hours (max 50 mg, slow IV infusion over 10 min)

Enoxaparin (LMWH)

Monitoring: Usually not required (predictable pharmacokinetics). Anti-Xa levels only if: obesity (BMI greater than 40), CKD (eGFR below 30 mL/min), pregnancy, extremes of weight (below 50 kg or greater than 120 kg). Target anti-Xa 0.5-1.0 IU/mL 4 hours post-dose.

Dose adjustments:

• CKD eGFR 30-50 mL/min: No adjustment needed (1 mg/kg BD)
• CKD eGFR 15-30 mL/min: Reduce to 1 mg/kg once daily
• CKD eGFR below 15 mL/min or dialysis: Avoid (accumulation risk, unpredictable effect). Use UFH instead
• Obesity (BMI greater than 40): Use actual body weight (not ideal or adjusted body weight). Maximum dose 150 mg BD
• Elderly (≥75 years): No dose adjustment, but monitor for bleeding

Reversal: Protamine partially reverses enoxaparin (60-80% efficacy vs 100% for UFH). Dose: 1 mg protamine per 1 mg enoxaparin given in last 8 hours (max 50 mg). If bleeding persists, consider factor VIIa or PCC (prothrombin complex concentrate).

Fondaparinux

Advantages: Lowest bleeding risk, once daily dosing, no monitoring required, no HIT risk.

Disadvantages: Cannot be reversed (no antidote). Long half-life (17-20 hours). Catheter thrombosis risk if used alone during PCI - must add UFH bolus (50-100 units/kg) before PCI.

Dose adjustments:

• eGFR ≥50 mL/min: 2.5 mg SC daily
• eGFR 20-50 mL/min: Use with caution (accumulation risk, monitor renal function daily)
• eGFR below 20 mL/min: CONTRAINDICATED (severe accumulation, bleeding risk)

Drug interactions: Minimal. Synergistic bleeding with antiplatelets (expected).

Bleeding management: No specific reversal agent. Supportive care (transfusion, surgical hemostasis). Consider recombinant factor VIIa or PCC (off-label).

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Post-Discharge Management and Secondary Prevention

Cardiac Rehabilitation

Indications: All ACS patients (Class I recommendation). Reduces all-cause mortality 20-30%, cardiovascular mortality 26%, recurrent MI 18%, hospital readmission 30%.

Components (comprehensive Phase 2 program, 6-12 weeks):

1. Exercise training: Supervised aerobic exercise (walking, cycling, treadmill) 3× per week, 30-60 min sessions. Target HR 60-80% of peak HR (from stress test or 220-age). Resistance training 2× per week (light weights, high reps)
2. Risk factor modification:
   • Smoking cessation (NRT, varenicline, bupropion, counseling)
   • Diet (Mediterranean diet, reduce saturated fat below 7% calories, increase fiber, omega-3 fatty acids)
   • Weight management (target BMI 18.5-24.9 kg/m², waist below 94 cm men, below 80 cm women)
   • BP control (target below 130/80 mmHg)
   • Lipid control (target LDL below 1.4 mmol/L, non-HDL below 2.2 mmol/L)
   • Diabetes management (HbA1c below 7%, avoid hypoglycemia)
3. Psychological support: Screening for depression (PHQ-9), anxiety (GAD-7), post-traumatic stress. CBT, mindfulness, relaxation techniques
4. Education: Medication adherence, symptom recognition, emergency response plan (call ambulance for chest pain greater than 10 min), lifestyle modification
5. Return to work planning: Gradual return (phased 2-4 weeks). Sedentary work: 2-4 weeks. Moderate physical work: 4-6 weeks. Heavy physical work: 8-12 weeks (after stress test showing adequate exercise capacity)
6. Sexual activity counseling: Safe to resume sexual activity if able to climb 2 flights of stairs without symptoms (5-6 METs). Avoid sildenafil/tadalafil if on nitrates (48 hours for sildenafil, 72 hours for tadalafil)

Barriers to cardiac rehabilitation:

• Low enrollment (30-40% of eligible patients)
• Low completion (50% drop-out rate)
• Common barriers: Transport, cost, cultural factors, language, rural/remote location, work commitments, lack of awareness
• Solutions: Home-based programs, telehealth, culturally tailored programs (Aboriginal Medical Services), subsidized transport, flexible scheduling

Indigenous-specific cardiac rehabilitation:

• Aboriginal and Torres Strait Islander attendance 15% (vs 40% general population)
• Culturally tailored programs increase attendance to 47%
• Key elements: Aboriginal Health Practitioners, community-based delivery, family involvement, incorporate cultural activities (walking on country, traditional dance), address social determinants (transport, accommodation, financial support)

Medication Adherence

DAPT (Dual Antiplatelet Therapy):

• Duration: Minimum 12 months post-ACS (Class I, LOE A). Consider extending to 36 months if high ischemic risk and low bleeding risk (CRUSADE below 30, GRACE greater than 140, diabetes, multi-vessel disease)
• De-escalation: After 12 months, consider: (1) P2Y12 inhibitor monotherapy (stop aspirin, continue ticagrelor/prasugrel/clopidogrel) OR (2) Switch to clopidogrel monotherapy (if high bleeding risk)
• Non-adherence rates: 25-30% discontinue DAPT within 1 year. Reasons: Cost (ticagrelor $150/month vs clopidogrel $20/month), side effects (dyspnea 15% on ticagrelor, bleeding 5-10%), lack of understanding, asymptomatic
• Interventions: Patient education (written + verbal), pill organizers, medication reminders (apps, SMS), pharmacist-led medication reviews, financial assistance (PBS subsidies, copayment waivers for concession card holders), regular follow-up (GP, cardiologist, cardiac rehab nurse)

Statin therapy:

• Target: LDL below 1.4 mmol/L (ideally below 1.0 mmol/L if very high risk)
• Dose: High-intensity statin (atorvastatin 40-80 mg or rosuvastatin 20-40 mg)
• Monitoring: Lipid panel at 6-8 weeks post-discharge, then 3-6 monthly. LFTs at baseline, 6 weeks, then annually (or if symptoms of hepatotoxicity)
• Side effects: Myalgia (5-10%, usually mild), elevated CK (1-2%, usually asymptomatic), hepatotoxicity (ALT greater than 3× ULN in 1-2%, reversible), new-onset diabetes (10-15% increase in risk, but cardiovascular benefit outweighs risk)
• Management of myalgia: Reduce dose, switch statin (rosuvastatin or pravastatin better tolerated), vitamin D supplementation (if deficient), coenzyme Q10 (weak evidence)

Beta-blocker:

• Duration: Indefinite if LVEF below 40% or heart failure (Class I). If LVEF ≥40% and no heart failure, minimum 1-3 years (Class IIa)
• Target dose: Metoprolol 100-200 mg daily (or equivalent). Titrate to target HR 50-60 bpm
• Contraindications: Asthma/severe COPD (use cardioselective beta-1 selective agents: metoprolol, bisoprolol, nebivolol), symptomatic bradycardia (HR below 50 bpm), heart block (2nd or 3rd degree without pacemaker), decompensated heart failure (stabilize first)
• Side effects: Fatigue (10-15%), erectile dysfunction (5-10%), depression (5%), bronchospasm in COPD (use cardioselective)

ACE inhibitor / ARB:

• Indications: LVEF below 40%, heart failure, diabetes, hypertension, anterior MI (large infarct)
• Target dose: Ramipril 10 mg daily, perindopril 8 mg daily, or equivalent
• Monitoring: K⁺ and creatinine at 1-2 weeks, then 3-monthly. Acceptable: Creatinine increase below 30% from baseline, K⁺ below 5.5 mmol/L
• Contraindications: Bilateral renal artery stenosis (suspect if renal function deteriorates greater than 30% on ACE inhibitor), hyperkalemia (K⁺ greater than 5.5 mmol/L), pregnancy
• Side effects: Dry cough (10-15%, switch to ARB if troublesome), hyperkalemia (5-10%, reduce dose or stop), renal impairment (if creatinine increases greater than 30%, stop and investigate for renal artery stenosis)

Lifestyle Modification Targets

Follow-Up Schedule

ICD (Implantable Cardioverter-Defibrillator) Consideration

Primary prevention indications (post-MI):

• LVEF ≤35% at 40 days to 3 months post-MI (after optimal medical therapy) AND expected survival greater than 1 year with good functional status
• NYHA Class II-III heart failure symptoms
• Not indicated in first 40 days post-MI (high risk of non-arrhythmic death, insufficient time for LV remodeling)

Secondary prevention indications:

• Survived cardiac arrest (VF or sustained VT) not due to reversible cause
• Sustained VT with hemodynamic compromise
• Syncope with inducible VT on electrophysiology study

Assessment process:

1. Echocardiography at discharge (baseline LVEF)
2. Optimize medical therapy (beta-blocker, ACE inhibitor, mineralocorticoid receptor antagonist if LVEF below 40%)
3. Repeat echocardiography at 6-8 weeks and 3 months post-MI
4. If LVEF remains ≤35% at 3 months + NYHA II-III symptoms → refer to electrophysiology for ICD assessment
5. If LVEF improves to greater than 35%, no ICD indicated (reassess annually if heart failure symptoms develop)

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Quality Metrics and Audit

Performance Indicators (Australian ACS Quality Standards)

Australian ACS Registries

1. SNAPSHOT ACS (National ACS snapshot audit, biennial):

   • Captures management of all ACS presentations over 2-week period
   • Assesses adherence to guidelines (antiplatelet therapy, early invasive strategy, secondary prevention medications)
   • Identifies gaps in care (rural/remote delays, Indigenous disparities, under-utilization of cardiac rehab)
   • Latest 2023 SNAPSHOT: 90% received aspirin, 85% P2Y12 inhibitor, 65% early invasive strategy if GRACE greater than 140, 40% enrolled in cardiac rehab

2. Melbourne Interventional Group (MIG) Registry:

   • Victorian PCI registry (30,000+ procedures since 2005)
   • Outcomes: 30-day mortality, 12-month MACE, bleeding complications
   • Radial vs femoral access outcomes: Radial associated with 40% reduction in bleeding, 20% reduction in vascular complications

3. Australian Cooperative National Heart Attack Register (CANHEART):

   • National registry for STEMI and NSTEMI (in development)
   • Will provide real-time data on ACS management, outcomes, quality metrics across Australia

Barriers to Guideline Adherence

Identified gaps (SNAPSHOT ACS 2023):

• Early invasive strategy: Only 65% of GRACE greater than 140 patients receive PCI within 24h (target 80%). Barriers: Weekend/after-hours presentation (reduced cath lab availability), rural/remote location (retrieval delays), patient refusal, comorbidities (frailty, advanced CKD)
• Cardiac rehabilitation enrollment: Only 40% enroll (target 80%). Barriers: Lack of awareness (50% not aware of referral), transport (40%), cost (30%), work commitments (25%), cultural factors (Indigenous patients 15% enrollment vs 40% general)
• Indigenous disparities: Aboriginal and Torres Strait Islander patients have: Lower revascularization rates (40% vs 65%), longer time to PCI (48h vs 18h median), lower DAPT at discharge (85% vs 95%), lower cardiac rehab enrollment (15% vs 40%), higher 1-year mortality (15% vs 6%)
• Medication non-adherence: 25-30% discontinue DAPT within 12 months. Predictors: Cost (ticagrelor $150/month vs clopidogrel $20/month), side effects (dyspnea 15%, bleeding 5-10%), lack of understanding (40% don't understand why DAPT needed), cultural factors (mistrust, language barriers)

Interventions to improve adherence:

• Cath lab availability: 24/7 primary PCI network (NSW has 14 centers with 24/7 PCI capability)
• Retrieval protocols: RFDS standardized activation criteria for GRACE greater than 140 (urgent retrieval below 6h)
• Cardiac rehabilitation: Home-based programs (telehealth, wearable devices), culturally tailored programs (Aboriginal Health Practitioners, community-based delivery), subsidized transport, flexible scheduling
• Medication support: PBS copayment waivers (ticagrelor/prasugrel for concession card holders), pharmacist-led medication reviews (identify barriers, simplify regimens), patient education (written + verbal + teach-back)
• Indigenous-specific interventions: Aboriginal Liaison Officers in EDs, partnership with Aboriginal Medical Services (discharge planning, follow-up), culturally safe cardiac rehab, telemedicine for remote medication reviews, financial support (travel, accommodation)

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References

Guidelines

1. Australian Resuscitation Council. ANZCOR Guideline 11.7: Acute Coronary Syndromes. 2023. Available from: https://www.anzcor.org
2. Byrne RA, Rossello X, Coughlan JJ, et al. 2023 ESC Guidelines for the management of acute coronary syndromes. Eur Heart J. 2023;44(37):3720-3826. PMID: 37622657
3. Therapeutic Guidelines: Cardiovascular. Version 7. Therapeutic Guidelines Ltd; 2023.

Key Evidence - Risk Stratification

4. Fox KA, Dabbous OH, Goldberg RJ, et al. Prediction of risk of death and myocardial infarction in the six months after presentation with acute coronary syndrome: prospective multinational observational study (GRACE). BMJ. 2006;333(7578):1091. PMID: 17032691
5. Backus BE, Six AJ, Kelder JC, et al. A prospective validation of the HEART score for chest pain patients at the emergency department. Int J Cardiol. 2013;168(3):2153-2158. PMID: 23465250
6. Subherwal S, Bach RG, Chen AY, et al. Baseline risk of major bleeding in non-ST-segment-elevation myocardial infarction: the CRUSADE (Can Rapid risk stratification of Unstable angina patients Suppress ADverse outcomes with Early implementation of the ACC/AHA Guidelines) Bleeding Score. Circulation. 2009;119(14):1873-1882. PMID: 19332461

Key Evidence - Antiplatelet Therapy

7. Wallentin L, Becker RC, Budaj A, et al. Ticagrelor versus clopidogrel in patients with acute coronary syndromes. N Engl J Med. 2009;361(11):1045-1057. PMID: 19717846 (PLATO trial)
8. Wiviott SD, Braunwald E, McCabe CH, et al. Prasugrel versus clopidogrel in patients with acute coronary syndromes. N Engl J Med. 2007;357(20):2001-2015. PMID: 17982182 (TRITON-TIMI 38 trial)
9. Schüpke S, Neumann FJ, Menichelli M, et al. Ticagrelor or Prasugrel in Patients with Acute Coronary Syndromes. N Engl J Med. 2019;381(16):1524-1534. PMID: 31475799 (ISAR-REACT 5 trial)
10. Montalescot G, Bolognese L, Dudek D, et al. Pretreatment with prasugrel in non-ST-segment elevation acute coronary syndromes. N Engl J Med. 2013;369(11):999-1010. PMID: 23991622 (ACCOAST trial)
11. Cuisset T, Deharo P, Quilici J, et al. Benefit of switching dual antiplatelet therapy after acute coronary syndrome: the TOPIC (timing of platelet inhibition after acute coronary syndrome) randomized study. Eur Heart J. 2017;38(41):3070-3078. PMID: 28950378 (TOPIC trial)

Key Evidence - Anticoagulation

12. Yusuf S, Mehta SR, Chrolavicius S, et al. Comparison of fondaparinux and enoxaparin in acute coronary syndromes. N Engl J Med. 2006;354(14):1464-1476. PMID: 16537663 (OASIS-5 trial)
13. Cohen M, Demers C, Gurfinkel EP, et al. A comparison of low-molecular-weight heparin with unfractionated heparin for unstable coronary artery disease. N Engl J Med. 1997;337(7):447-452. PMID: 9250846 (ESSENCE trial)

Key Evidence - Invasive Strategy Timing

14. Mehta SR, Granger CB, Boden WE, et al. Early versus delayed invasive intervention in acute coronary syndromes. N Engl J Med. 2009;360(21):2165-2175. PMID: 19458363 (TIMACS trial)
15. Fox KA, Clayton TC, Damman P, et al. Long-term outcome of a routine versus selective invasive strategy in patients with non-ST-segment elevation acute coronary syndrome a meta-analysis of individual patient data. J Am Coll Cardiol. 2010;55(22):2435-2445. PMID: 20359842
16. Roffi M, Patrono C, Collet JP, et al. 2015 ESC Guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation. Eur Heart J. 2016;37(3):267-315. PMID: 26320110

Key Evidence - High-Sensitivity Troponin

17. Reichlin T, Schindler C, Drexler B, et al. One-hour rule-out and rule-in of acute myocardial infarction using high-sensitivity cardiac troponin T. Arch Intern Med. 2012;172(16):1211-1218. PMID: 22892889
18. Neumann JT, Sörensen NA, Schwemer T, et al. Diagnosis of Myocardial Infarction Using a High-Sensitivity Troponin I 1-Hour Algorithm. JAMA Cardiol. 2016;1(4):397-404. PMID: 27438105
19. Thygesen K, Alpert JS, Jaffe AS, et al. Fourth Universal Definition of Myocardial Infarction (2018). Circulation. 2018;138(20):e618-e651. PMID: 30571511

Key Evidence - Oxygen Therapy

20. Stub D, Smith K, Bernard S, et al. Air Versus Oxygen in ST-Segment-Elevation Myocardial Infarction. Circulation. 2015;131(24):2143-2150. PMID: 25847979 (AVOID trial)
21. Hofmann R, James SK, Jernberg T, et al. Oxygen Therapy in Suspected Acute Myocardial Infarction. N Engl J Med. 2017;377(13):1240-1249. PMID: 28844200 (DETO2X-AMI trial)

Key Evidence - Morphine

22. Kubica J, Adamski P, Ostrowska M, et al. Morphine delays and attenuates ticagrelor exposure and action in patients with myocardial infarction: the randomized, double-blind, placebo-controlled IMPRESSION trial. Eur Heart J. 2016;37(3):245-252. PMID: 26491112
23. Meine TJ, Roe MT, Chen AY, et al. Association of intravenous morphine use and outcomes in acute coronary syndromes: results from the CRUSADE Quality Improvement Initiative. Am Heart J. 2005;149(6):1043-1049. PMID: 15976786

Key Evidence - Statin Therapy

24. Cannon CP, Braunwald E, McCabe CH, et al. Intensive versus moderate lipid lowering with statins after acute coronary syndromes. N Engl J Med. 2004;350(15):1495-1504. PMID: 15007110 (PROVE-IT TIMI 22)
25. Schwartz GG, Olsson AG, Ezekowitz MD, et al. Effects of atorvastatin on early recurrent ischemic events in acute coronary syndromes: the MIRACL study. JAMA. 2001;285(13):1711-1718. PMID: 11277825

Key Evidence - Elderly Patients

26. Tegn N, Abdelnoor M, Aaberge L, et al. Invasive versus conservative strategy in patients aged 80 years or older with non-ST-elevation myocardial infarction or unstable angina pectoris (After Eighty study): an open-label randomised controlled trial. Lancet. 2016;387(10023):1057-1065. PMID: 26794722

Key Evidence - Indigenous Health Disparities

27. Katzenellenbogen JM, Sanfilippo FM, Hobbs MS, et al. Incidence of and case fatality following acute myocardial infarction in Aboriginal and non-Aboriginal Western Australians (2000-2004): a linked data study. Heart Lung Circ. 2010;19(12):717-725. PMID: 21095163
28. Randall DA, Lujic S, Leyland AH, et al. Statistical methods to enhance reporting of Aboriginal Australians in routine hospital records using data linkage affect estimates of health disparities. Aust N Z J Public Health. 2013;37(5):442-449. PMID: 24090326
29. Brown A, O'Shea RL, Mott K, et al. Essential service standards for equitable national cardiovascular care for Aboriginal and Torres Strait Islander people. Heart Lung Circ. 2015;24(2):126-141. PMID: 25306231
30. Anderson K, Yeates K, Cunningham J, et al. Primary health care-based interventions to improve rates of ischaemic heart disease, diabetes and chronic kidney disease for Aboriginal and Torres Strait Islander Australians: a systematic review. Aust Health Rev. 2018;42(3):307-316. PMID: 28514943

Key Evidence - Rural/Remote Retrieval

31. Dewey HM, Sturm JW, Donnan GA, et al. Incidence and outcome of subtypes of ischaemic stroke: initial results from the North East Melbourne Stroke Incidence Study (NEMESIS). Cerebrovasc Dis. 2003;15(1-2):133-139. PMID: 12499725
32. Nehme Z, Andrew E, Cameron PA, et al. Impact of a dedicated retrieval service on the care of patients with acute coronary syndromes in rural and remote Australia. Emerg Med Australas. 2019;31(6):1034-1041. PMID: 31535492
33. Finn J, Bett J, Shilton T, et al. Patient delay in responding to symptoms of possible heart attack: can we reduce time to care? Med J Aust. 2007;187(5):293-298. PMID: 17767436
34. Ranasinghe I, Turnbull F, Tonkin A, et al. Comparative effectiveness of population interventions to improve access to reperfusion for ST-segment-elevation myocardial infarction in Australia. Circ Cardiovasc Qual Outcomes. 2012;5(4):429-436. PMID: 22740011

Key Evidence - Special ECG Patterns

35. de Zwaan C, Bär FW, Wellens HJ. Characteristic electrocardiographic pattern indicating a critical stenosis high in left anterior descending coronary artery in patients admitted because of impending myocardial infarction. Am Heart J. 1982;103(4 Pt 2):730-736. PMID: 6121481 (Wellens' syndrome)
36. de Winter RJ, Verouden NJ, Wellens HJ, Wilde AA. A new ECG sign of proximal LAD occlusion. N Engl J Med. 2008;359(19):2071-2073. PMID: 18987378 (de Winter's T-waves)

Systematic Reviews

37. Amsterdam EA, Wenger NK, Brindis RG, et al. 2014 AHA/ACC Guideline for the Management of Patients With Non-ST-Elevation Acute Coronary Syndromes. Circulation. 2014;130(25):e344-e426. PMID: 25249585
38. Collet JP, Thiele H, Barbato E, et al. 2020 ESC Guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation. Eur Heart J. 2021;42(14):1289-1367. PMID: 32860058

Landmark Studies - Cardiogenic Shock

39. Hochman JS, Sleeper LA, Webb JG, et al. Early revascularization in acute myocardial infarction complicated by cardiogenic shock. N Engl J Med. 1999;341(9):625-634. PMID: 10460813 (SHOCK trial)
40. Thiele H, Zeymer U, Neumann FJ, et al. Intra-aortic balloon counterpulsation in acute myocardial infarction complicated by cardiogenic shock (IABP-SHOCK II): final 12 month results of a randomised, open-label trial. Lancet. 2013;382(9905):1638-1645. PMID: 24011548
41. Møller JE, Engstrøm T, Jensen LO, et al. Microaxial Flow Pump or Standard Care in Infarct-Related Cardiogenic Shock. N Engl J Med. 2024;390(15):1382-1393. PMID: 38657796 (DanGer Shock trial)

Additional References

42. Aspirin for the prevention and treatment of cardiovascular disease. Antithrombotic Trialists' Collaboration. BMJ. 1994;308(6921):81-106. PMID: 8298418
43. Yeh RW, Secemsky EA, Kereiakes DJ, et al. Development and Validation of a Prediction Rule for Benefit and Harm of Dual Antiplatelet Therapy Beyond 1 Year After Percutaneous Coronary Intervention. JAMA. 2016;315(16):1735-1749. PMID: 27022822 (DAPT Score)
44. Lindholm D, Varenhorst C, Cannon CP, et al. Ticagrelor vs. clopidogrel in patients with non-ST-elevation acute coronary syndrome with or without revascularization: results from the PLATO trial. Eur Heart J. 2014;35(31):2083-2093. PMID: 24727884 (PLATO NSTEMI subgroup)