How should an adult with an acute ischemic stroke and known atrial fibrillation be managed acutely and for secondary prevention?

Management of Acute Ischemic Stroke with Atrial Fibrillation

For adults with acute ischemic stroke and known atrial fibrillation, prioritize immediate reperfusion therapy if eligible, initiate cardiac monitoring for 24 hours, and restart anticoagulation using a severity-based timing algorithm: 1 day for TIA, 3 days for mild stroke (NIHSS <8), 6 days for moderate stroke (NIHSS 8-15), and 12 days for severe stroke (NIHSS ≥16). 1, 2

Acute Phase Management (First 24 Hours)

Immediate Assessment and Imaging

• Perform emergent non-contrast CT or MRI within 10 minutes of ED arrival to exclude hemorrhage before any antithrombotic therapy 3, 1
• Obtain 12-lead ECG to confirm atrial fibrillation, though this should not delay CT imaging or thrombolysis decisions 3
• Establish IV access and obtain baseline labs including complete blood count, coagulation studies (PT/INR, aPTT), and blood glucose 3

Reperfusion Therapy Decisions

• For patients presenting within 3 hours: Administer IV alteplase (rtPA) if eligible, regardless of atrial fibrillation status 1, 2
• For patients presenting 3-4.5 hours: Consider IV alteplase based on eligibility criteria 1
• Critical contraindication: Do NOT give thrombolysis if INR >1.7 on warfarin or if on therapeutic oral anticoagulation 1, 2
• For large vessel occlusion: Proceed with endovascular thrombectomy within 6 hours, even in anticoagulated patients 1, 2

Blood Pressure Management

• If eligible for thrombolysis: Lower BP to <185/110 mmHg before rtPA and maintain <180/105 mmHg for 24 hours post-treatment using labetalol 10-20 mg IV or nicardipine 5 mg/hr IV 3
• If NOT eligible for thrombolysis: Avoid routine BP lowering unless systolic >220 mmHg or diastolic >120 mmHg; then reduce by only 15% (not more than 25%) over 24 hours 3
• Rapid BP reduction worsens outcomes—each 10% decline increases unfavorable outcomes by 89% 3

Cardiac Monitoring

• Institute continuous cardiac monitoring for at least 24 hours to detect life-threatening arrhythmias and confirm atrial fibrillation 3
• Extend monitoring beyond 24 hours with Holter or event-loop recording if paroxysmal AF is suspected 3, 2
• Do NOT treat hemodynamically stable arrhythmias acutely unless they compromise cerebral perfusion 3

Aspirin for Non-Thrombolysis Candidates

• Administer aspirin 160-325 mg for patients NOT receiving thrombolysis 1
• Hold aspirin for 24 hours after thrombolysis 1

Anticoagulation Timing for Secondary Prevention

The most critical decision is WHEN to restart anticoagulation, not whether to restart it. The European Society of Cardiology provides the definitive algorithm based on stroke severity 1, 2:

Severity-Based Timing Algorithm

Stroke Severity	NIHSS Score	Start Anticoagulation
TIA	N/A	Day 1
Mild	<8	Day 3
Moderate	8-15	Day 6
Severe	≥16	Day 12

1, 2

This timing balances recurrent stroke risk (7.6% at 90 days) against hemorrhagic transformation risk (3.6% symptomatic cerebral bleeding at 90 days). 4 The RAF study demonstrated that initiating anticoagulation 4-14 days post-stroke reduced combined outcomes by 47% compared to earlier or later initiation (HR 0.53,95% CI 0.30-0.93) 4

Critical Timing Contraindications

• Absolute contraindication: Do NOT anticoagulate within 24 hours of IV thrombolysis 5
• Days 2-7: Highest hemorrhagic transformation risk—limit therapeutic anticoagulation to mild strokes or life-threatening PE 5
• Beyond 2 weeks: Hemorrhagic transformation risk markedly declines, making anticoagulation generally safe 5

Anticoagulation Selection

First-Line Options

• Direct oral anticoagulants (DOACs): Preferred for non-valvular atrial fibrillation 1, 2, 6
• Warfarin: Target INR 2.0-3.0 (mean 2.5) for non-valvular AF 1, 2
• Mechanical prosthetic valves: Warfarin is mandatory (target INR 2.0-3.0) 1

Evidence for DOAC Superiority

The RAF study showed patients treated with oral anticoagulants alone had 7% outcome events versus 16.8% with low molecular weight heparin alone and 12.3% with LMWH bridging to oral anticoagulants (p=0.003) 4. Therefore, avoid LMWH bridging—start oral anticoagulants directly at the appropriate time. 4

If Anticoagulation Contraindicated

• Use aspirin 325 mg daily or clopidogrel 75 mg daily 2
• Consider left atrial appendage closure for patients intolerant of anticoagulation 7

Prevention of Acute Complications

Venous Thromboembolism Prophylaxis

• For immobilized patients: Administer prophylactic enoxaparin 40 mg daily or intermittent pneumatic compression devices 1, 5
• Do NOT use: Elastic compression stockings—they are ineffective 1
• If therapeutic PE develops: The mortality risk from untreated PE (up to 50%) exceeds hemorrhagic transformation risk in mild-moderate strokes, supporting therapeutic anticoagulation 5

Swallowing Assessment

• Screen swallowing within 24 hours using a validated tool before administering oral medications 3
• Keep patient NPO until screening completed 3

Monitoring for Deterioration

• Perform serial neurological examinations—25% of patients deteriorate post-admission 3
• Obtain immediate repeat imaging if any neurological worsening occurs 5

Common Pitfalls and How to Avoid Them

Pitfall 1: Starting Anticoagulation Too Early

Problem: 35% of AF patients who stroke are already on anticoagulation, often with suboptimal INR 8. Starting too early increases hemorrhagic transformation risk without preventing early recurrence 2.

Solution: Strictly follow the NIHSS-based timing algorithm—resist pressure to anticoagulate immediately 1, 2

Pitfall 2: Using LMWH Bridging

Problem: LMWH bridging increases bleeding without reducing recurrence 4.

Solution: Start oral anticoagulants directly at the appropriate time without heparin bridging 4

Pitfall 3: Aggressive Blood Pressure Lowering

Problem: Each 20 mmHg drop in BP increases early deterioration, poor outcomes, and death 3.

Solution: Tolerate elevated BP unless thrombolysis candidate or extreme elevation (>220/120 mmHg) 3

Pitfall 4: Delaying Thrombolysis for ECG

Problem: ECG delays time-sensitive reperfusion therapy 3.

Solution: Obtain ECG after CT and thrombolysis decision—it can wait 3

Risk Stratification for Recurrence

High-risk features predicting 90-day events include 4:

• High CHA2DS2-VASc score
• High NIHSS at presentation
• Large ischemic lesion on imaging
• Type of anticoagulant used

These factors should inform closer monitoring but should NOT alter the timing algorithm, which is based on hemorrhagic transformation risk, not recurrence risk. 4