2.3 Management of acute coronary syndrome

Approach to investigating suspected ACS

1. Initial clinical assessment

   • Symptoms: Chest pain (central, pressure-like), radiating to arm/jaw, dyspnoea, nausea

   • Risk factors: Age, smoking, hypertension, hyperlipidaemia, diabetes, Family history (FHx)

2. ECG

   • Perform within 10 minutes of presentation

   • Repeat every 5-10 mins if initial ECG is non-diagnostic but suspicion remains high

3. Cardiac Enzymes

• High-sensitivity Troponin-T (hs-TnT)

  • Gold standard blood test for detecting myocardial injury (e.g. in a heart attack / myocardial infarction).

  • Troponin is a protein released from damaged heart muscle cells.

  • Positive results mean myocardial injury

• Negative result at 2 hours post-onset

  • If symptoms began ≥2 hours ago, and troponin is negative,
    repeat test at 3 hours (from initial test) to catch delayed elevation.

• Symptoms began <2 hours ago

  • Troponin may not be elevated yet.

  • In very early presenters (<2 hours), a repeat test at 6–8 hours post-onset is often needed to safely rule out MI.

• Why do we test for troponin

  • Troponin rises 1–3 hours after myocardial injury

  • Peaks at ~24 hours

  • Stays elevated for up to 2 weeks

4. Risk stratification tools

   • These are clinical prediction tools used to estimate a patient's risk of death or major cardiac events, guiding how aggressively to treat.

   • GRACE Score (Global Registry of Acute Coronary Events)

     • Purpose: Predicts in-hospital and 6-month mortality in ACS (NSTEMI, STEMI, UA).

     • More accurate and widely used in hospital settings.

     • Variables include:

       • Age

       • Heart rate

       • Systolic BP

       • Creatinine

       • Killip class (heart failure severity)

       • Cardiac arrest at admission

       • ST deviation

       • Elevated cardiac markers

     • High GRACE score = high mortality → more urgent intervention

   • TIMI Score (Thrombolysis In Myocardial Infarction)

     • Purpose: Estimates 14-day risk of death, MI, or urgent revascularisation in unstable angina / NSTEMI.

     • Simpler, used in ED settings.

     • Each factor scores 1 point (max 7):

       1. Age ≥65

       2. ≥3 risk factors for CAD

       3. Prior coronary stenosis ≥50%

       4. ST deviation on ECG

       5. ≥2 angina episodes in 24h

       6. Aspirin use in past 7 days

       7. Elevated cardiac markers

     • Score ≥3 = moderate to high risk

5. Echocardiography

   • Use if ECG/troponin inconclusive, or to assess regional wall motion abnormality or complications

Importance of early intervention

• Every 30 min delay results in a 1-year increased mortality risk by 7.5%

• Goal: 

  1. Percutaneous Coronary Intervention (PCI) – GOLD STANDARD

     • Also called primary angioplasty

     • Goal:
       Door-to-balloon time ≤ 90 minutes

       • "Door" = when patient arrives at hospital

       • "Balloon" = inflation of balloon in the blocked coronary artery

     • Why? Best long-term outcomes, lower risk of bleeding/stroke

  2. Thrombolysis (Fibrinolytic Therapy) – If PCI Unavailable

     • Administer clot-busting drugs (e.g. tPA, tenecteplase)

     • Goal:
       Door-to-needle time ≤ 30 minutes

     • Used when: PCI can’t be done within 120 minutes (e.g. rural/remote settings)

• Repurfusion saves lives

  • Mortality benefit from thrombolysis/PCL greatest in first 2 hours (also known as the “golden hour”)

  • Primary PCI > Thrombolysis for efficacy and reduced re-infarction.

Principles of ACS management

ECG monitoring & coronary artery correlation

• STEMI criteria: ST elevation in ≥ 2 contiguous leads

  • V2–V3: ≥2 mm (men) or ≥1.5 mm (women)

  • Other leads: ≥1 mm

  • New LBBB = STEMI equivalent

Serum troponin

• Detects myocardial injury

• High sensitivity and specificity

• Key to differentiating NSTEMI from unstable angina

Angiography

• STEMI: Immediate PCI

• NSTEMI/UA: Urgent angiography within 24h (earlier if unstable)

Complications to prevent & monitor

• LV failure: pulmonary oedema, cardiogenic shock

• Arrhythmias: VT/VF, AV block, AF

• Mechanical: papillary muscle rupture, VSD, tamponade

• Pericarditis

• LV thrombus

Therapeutic strategies & goals

Non-pharmacological

• Lifestyle: smoking cessation, weight loss, BP control, diabetes management

• Cardiac rehabilitation: physical, psychological, education

• No driving: for 2 weeks post-MI

• GP + Cardiologist: follow-up

Pharmacological

• Immediate ACS therapy

  • Aspirin 300 mg

  • Ticagrelor 180 mg loading (or prasugrel/clopidogrel)

  • Heparin (UFH or LMWH)

  • Sublingual GTN (IV GTN if persistent pain)

  • Morphine (for pain)

  • Beta-blocker (if not bradycardic/hypotensive)

  • Oxygen if SpO2 < 90%

• Reperfusion

  • Primary PCI: preferred within 12h onset

  • Thrombolysis: if PCI not available; follow with early angiography (within 3–24 h)

• Post-PCI care

  • Dual antiplatelet therapy (DAPT): Aspirin + P2Y12 inhibitor (Ticagrelor, Clopidogrel, Prasugrel)

  • Statins: Start high-intensity statin (e.g. Atorvastatin 80 mg)

  • ACE inhibitors

  • Beta-blockers

  • Eplerenone/Spironolactone: If EF < 40%

  • Colchicine: anti-inflammatory (select cases)

Secondary prevention targets