Restarting Early Versus Later Anticoagulation for Chronic Subdural Hematoma With Atrial Fibrillation

Inclusion Criteria:

• Age ≥18 years.

• Patients with a symptomatic unilateral or bilateral CSDH requiring burr-holeevacuation with drainage (CSDH is predominantly hypodense or isodense on imaging [CT/MRI]; clinical symptoms attributable to the CSDH; patients with bilaterallyoperated CSDHs will be treated with the same protocol on both sides and analyzed asa single study participant).

• Patients that are on an oral anticoagulation medication due to permanent, persistentor paroxysmal spontaneous atrial fibrillation previously known

• Randomization done within 4 days of the surgery

Exclusion Criteria:

• Intraoperative or immediate postoperative hemorrhagic complication

• CSDH requiring surgical treatment other than burr-hole evacuation (e.g. craniotomy)

• Prior CSDH surgery within 12 months

• Cerebrospinal fluid shunt

• CSDH is in an arachnoid cyst

• If the operated hematoma is revealed to be a cerebrospinal fluid collection (hygroma)

• Conditions other than atrial fibrillation that require anticoagulation, includingtherapeutical dose of low molecular-weight heparin or heparin (for example,pulmonary embolism, deep vein thrombosis, hypercoagulability syndromes)

• Mechanical heart valve(s)

• Moderate or severe mitral stenosis (other valvular diseases and biological valvesare eligible)

• Contraindication to anticoagulation medication (for example bleeding disorder,documented high risk of fall [e.g. due to severe alcoholism], severethrombocytopenia, severe anemia)

• Concomitant use of antiplatelet medication

• Moderate to severe renal insufficiency (creatinine clearance <30 ml/min or ondialysis)

• Not a permanent resident in Finland (for Finnish patients) or not a permanentresident in Region Stockholm (for Swedish patients)