Role of antithrombotic therapy in the risk of hematoma recurrence and thromboembolism after chronic subdural hematoma evacuation: a population-based consecutive cohort study

OBJECTIVE: To establish the risk of recurrence in patients with chronic subdural hematoma (cSDH) on antithrombotic treatment (AT, i.e., antiplatelets and anticoagulants). Secondary end points were perioperative morbidity and mortality between groups (AT vs. no-AT group) and exploration if timing of resumption of AT treatment (i.e., prophylactic early vs. late resumption) influenced the occurrence of thromboembolism and hematoma recurrence. MATERIALS: In a population-based consecutive cohort, we conducted a retrospective review of 763 patients undergoing primary burr hole procedures for cSDH between January 1, 2005, and December 31, 2010, at the Karolinska University Hospital, Stockholm, Sweden. Early AT resumption was ≤30 days and late >30 days after the procedure. RESULTS: A total of 308/763 (40.4%) cSDH patients were on AT treatment at the time of diagnosis. There was no difference in cSDH recurrence within 3 months (11.0% vs. 12.0%, p = 0.69) nor was there any difference in perioperative mortality (4.0% vs. 2.0%, p = 0.16) between those using AT compared to those who were not. However, perioperative morbidity was more common in the AT group compared to no-AT group (10.7% vs. 5.1%, p = 0.003). Comparing early vs. late AT resumption, there was no difference with respect to recurrence (7.0% vs. 13.9%, p = 0.08), but more thromboembolism in the late AT resumption group (2.0% vs. 7.0%, p < 0.01). CONCLUSION: In clinical practice, cSDH patients on AT therapy at the time of diagnosis have similar recurrence rates and mortality compared to those without AT therapy, but with higher morbidity. Early resumption was not associated with more recurrence, but with lower thromboembolic frequency. Early AT resumption seems favorable, and a prospective RCT is needed.