A 62-year-old woman with a history of hypertension and type 2 diabetes presents to a tertiary care centre with acute onset substernal chest pain of 45 minutes duration. She is haemodynamically stable (BP 130/85, HR 92/min). A 12-lead ECG performed at 8 minutes shows ST elevation of 2.5 mm in leads V1–V4 with reciprocal ST depression in II, III, and aVF. Serum troponin I is 0.12 ng/mL. The centre has an active catheterisation laboratory with a door-to-balloon time of 65 minutes. What is the most appropriate next step in management?

Explanation

## Clinical Scenario Analysis This is an **anterior wall STEMI** (ST elevation in V1–V4 with reciprocal changes) presenting within the **PCI window (< 12 hours)** at a **PCI-capable facility** with **acceptable door-to-balloon time (65 minutes < 90 min target)**. ## STEMI Diagnosis Confirmed **Key Point:** The combination of: - Acute chest pain (45 min onset) - ST elevation ≥1 mm in contiguous precordial leads (V1–V4) - Elevated troponin (0.12 ng/mL, normal <0.04) - Reciprocal ST depression This meets **ESC/ACC criteria for STEMI** and requires **immediate reperfusion** [cite:Harrison 21e Ch 297]. ## Reperfusion Strategy Selection **High-Yield:** When PCI-capable centre is available AND door-to-balloon time is ≤90 minutes, **primary PCI is superior to fibrinolysis** (lower mortality, lower reinfarction, lower stroke) [cite:Harrison 21e Ch 297]. | Factor | Primary PCI | Fibrinolysis | |--------|-------------|---------------| | **Mortality reduction** | 25% vs. fibrinolysis | 30% vs. no reperfusion | | **Reinfarction rate** | 2–3% | 5–10% | | **Stroke risk** | <1% | 0.5–1% (but higher with SK) | | **Door-to-reperfusion time** | ≤90 min (door-to-balloon) | ≤30 min (door-to-needle) | | **Preferred if** | Available within 90 min | PCI unavailable or delayed >120 min | **Clinical Pearl:** This patient's door-to-balloon time of 65 minutes is **within the Class I recommendation**; therefore, primary PCI is the guideline-preferred reperfusion modality. ## Immediate Management Algorithm ```mermaid flowchart TD A["Anterior STEMI diagnosed<br/>ST elevation V1-V4<br/>Troponin elevated"]:::outcome --> B{"PCI-capable centre<br/>available?"}:::decision B -->|Yes| C{"Door-to-balloon<br/>≤90 min?"}:::decision B -->|No| D["Fibrinolysis<br/>within 30 min"]:::action C -->|Yes| E["Primary PCI<br/>without delay"]:::action C -->|No| F["Fibrinolysis<br/>+ early transfer"]:::action E --> G["Dual antiplatelet therapy<br/>Aspirin 300 mg<br/>Clopidogrel 600 mg"]:::action F --> G G --> H["Unfractionated heparin<br/>or bivalirudin"]:::action H --> I["Reperfusion achieved"]:::outcome ``` **Key Point:** Do NOT delay PCI for: - Stress testing (diagnostic, not therapeutic) - Observation period (time is myocardium) - Fibrinolysis (inferior to PCI in this scenario) ## Dual Antiplatelet Therapy (DAPT) for PCI | Agent | Dose | Route | Timing | |-------|------|-------|--------| | Aspirin | 300–325 mg | PO (chewed) | Immediately | | Clopidogrel | 600 mg loading | PO | Immediately (before catheterisation) | | Unfractionated heparin | 70–100 U/kg IV bolus | IV | At catheterisation lab | **Mnemonic: PCI PREP — "ABCDE"** - **A**spirin 300 mg immediately - **B**ivalirudin or heparin for anticoagulation - **C**lopidogrel 600 mg loading dose - **D**oor-to-balloon ≤90 min (this patient: 65 min ✓) - **E**mergency catheterisation without delay **Warning:** ~~Stress testing~~ is contraindicated in acute STEMI; it delays reperfusion and increases infarct size. ECG + troponin + clinical presentation are sufficient for diagnosis.