## Clinical Context This patient has acute ischaemic stroke secondary to atrial fibrillation and requires thrombolysis. The question tests knowledge of anticoagulation timing in the perioperative thrombolytic window. ## Key Management Principle **Key Point:** In acute ischaemic stroke treated with IV thrombolysis, anticoagulation should be deferred for 24 hours post-thrombolysis to minimize haemorrhagic transformation risk. After this window, anticoagulation is initiated based on stroke aetiology and haemorrhage risk. ## Rationale for Correct Answer Deferring anticoagulation for 24 hours post-thrombolysis is the standard of care because: 1. Thrombolytic agents (alteplase) already carry significant haemorrhagic transformation risk 2. Concurrent anticoagulation increases this risk exponentially 3. After 24 hours, the acute thrombolytic effect wanes and haemorrhage risk stabilizes 4. Warfarin (or DOAC) is then initiated for secondary stroke prevention in AF ## Why NOT the Other Options | Option | Problem | |--------|----------| | **Unfractionated heparin before thrombolysis** | Increases haemorrhagic transformation risk; heparin is contraindicated during acute thrombolysis | | **LMWH after thrombolysis** | LMWH is not preferred in acute stroke; unfractionated heparin (if anticoagulation needed within 24 hrs) is more reversible | | **DOAC with loading dose immediately** | DOACs are not loaded; they require 5–7 days to reach therapeutic levels; immediate loading is not a standard regimen | **High-Yield:** The 24-hour rule is a high-frequency exam topic. Remember: **thrombolysis + anticoagulation = haemorrhage**. Wait 24 hours, then anticoagulate. **Clinical Pearl:** If the patient had presented with haemorrhagic stroke instead, anticoagulation would be deferred even longer (7–10 days) and imaging repeated before initiation.
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