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-hole evacuation with drainage (CSDH is predominantly hypodense or isodense on imaging \[CT/MRI\]; clinical symptoms attributable to the CSDH; patients with bilaterally operated CSDHs will be treated with the same protocol on both sides and analyzed as a single study participant). * Patients that are on an oral anticoagulation medication due to permanent, persistent or 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, including therapeutical 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 valves are eligible) * Contraindication to anticoagulation medication (for example bleeding disorder, documented high risk of fall \[e.g. due to severe alcoholism\], severe thrombocytopenia, severe anemia) * Concomitant use of antiplatelet medication * Moderate to severe renal insufficiency (creatinine clearance \<30 ml/min or on dialysis) * Not a permanent resident in Finland (for Finnish patients) or not a permanent resident in Region Stockholm (for Swedish patients)