Timing of Warfarin Resumption After Subdural Hematoma with Stable Repeat Scans
For patients with subdural hematoma (SDH) and stable repeat scans, warfarin (Coumadin) should be restarted no earlier than 7-10 days after the initial hemorrhage, and only if there is a high risk of thromboembolism. 1
Risk Stratification Approach
The decision to restart warfarin after SDH requires careful consideration of both thrombotic and hemorrhagic risks:
High Thrombotic Risk Patients
- Mechanical heart valves
- Atrial fibrillation with CHA₂DS₂-VASc score ≥4
- Recent venous thromboembolism
- Left ventricular or left atrial thrombus
- History of thromboembolism with prior anticoagulation interruption 2
For these high-risk patients:
- Wait at least 7-10 days after SDH onset 1
- Confirm SDH stability or significant reduction on follow-up imaging
- Consider bridging with heparin initially 2
Moderate Thrombotic Risk Patients
- Wait 4-8 weeks after SDH onset
- Ensure complete SDH resolution on imaging
- Consider antiplatelet therapy instead of full anticoagulation 2
Low Thrombotic Risk Patients
- Consider permanent discontinuation of warfarin
- Switch to antiplatelet therapy if needed for other indications 2
Monitoring Requirements Before Resumption
Before restarting warfarin:
- Obtain follow-up imaging at 2-4 weeks to confirm SDH stability or resolution
- Perform weekly neurological assessments during the first month
- If resuming warfarin, maintain INR at the lower end of the therapeutic range 2
Important Considerations and Pitfalls
Location of SDH
Lobar SDHs may have a higher risk of recurrence with anticoagulation resumption compared to deep SDHs. A decision analysis showed that elderly patients with lobar hemorrhages had worse outcomes with warfarin continuation 1.
Age and Comorbidities
- Elderly patients (≥75 years) have increased risk of SDH recurrence 3
- Chronic kidney disease increases bleeding risk and warrants longer anticoagulation-free periods (at least 4 weeks) 2
SDH Characteristics
- Larger SDH (≥25mm) is associated with higher recurrence risk 3
- Residual SDH significantly increases rebleeding risk (up to 41.2% with residual SDH, and 62.5% with large residual SDH) 4
Evidence on Recurrence and Thromboembolic Risk
Studies show varying outcomes regarding anticoagulation resumption:
In patients with high thromboembolic risk, early warfarin resumption (3 days after surgery) showed a 15.8% SDH recurrence rate, which is comparable to the recurrence rate of ordinary SDHs 3
A systematic review found that patients restarted on anticoagulation had an 11.1% recurrence rate versus 22.2% in those not restarted on anticoagulation. Thromboembolic events occurred in 2.2% of those restarted versus none in the control group 5
Most recurrences and thromboembolic events occurred within the first 4 weeks after initial surgical evacuation 5
Alternative Approaches
For patients with both high bleeding and thrombotic risks, consider:
- Middle meningeal artery embolization as an adjunct therapy before anticoagulation resumption 6
- Left atrial appendage closure for patients with atrial fibrillation 2
Conclusion
The timing of warfarin resumption after SDH requires balancing thromboembolic and rebleeding risks. For patients with high thrombotic risk, resumption at 7-10 days may be reasonable if repeat scans show stability. For others, waiting 4-8 weeks or until complete resolution is safer, especially in elderly patients or those with large or residual SDHs.