Inhibition of the synthesis or activity of Factor X is the mechanism of action for many anticoagulants in use today. Warfarin, a synthetic derivative of coumarin, is the most widely used oral anticoagulant in the US. In some European countries, other coumarin derivatives (phenprocoumon and acenocoumarol) are used. These agents are vitamin K antagonists (VKA). Vitamin K is essential for the hepatic synthesis of Factors II (prothrombin), VII, IX and X.

Mirzayan et al. investigated the outcome of 49 patients who were identified retrospectively to have a SDH while receiving oral anticoagulation.

Most bleeding occurred while patients were within the recommended therapeutic window for oral anticoagulation. Mortality was 15%. The event-free survival probability was higher in the group of patients with reinstitution of phenprocoumon therapy than in the group without. Over a median follow-up of 32 months, thromboembolic events occurred in 4 of 23 patients without oral anticoagulation versus in none of 15 patients with phenprocoumon; hemorrhagic complications occurred in 1 in 23 versus 3 in 15 patients.

Reinstitution of oral anticoagulation with phenprocoumon after previous SDH appears to have an acceptable risk for hemorrhagic complications. Decision making might consider case-by-case differences. To establish specific guidelines, prospective large cohort studies are needed ¹⁾.

Administration of phenprocoumon and older age might increase the risk of poor outcome in patients with cSDH. Neither the administration of phenprocoumon nor antiplatelet drug influenced the recurrence rate of subdural hematoma in a patient cohort ²⁾.

Delayed traumatic intracerebral haemorrhage (DTICH) constitutes a serious complication of head injury, and several studies have set out to identify predisposing clinical variables and appropriate management strategies. Halatsch et al. report a distinct and particularly malignant course of DTICH associated with oral anticoagulant therapy ³⁾.