Risk of Recurrent Chronic Subdural Hematoma Associated with Early Warfarin Resumption: A Matched Cohort Study

Studies on resuming anticoagulation after burr-hole drainage for chronic subdural hematoma (CSDH) are limited. To evaluate the safety for early warfarin resumption after burr-hole drainage, we conducted a retrospective matched cohort study.

Between January 2008 and April 2015, 36 patients with warfarin-related unilateral CSDH and 151 patients with ordinary unilateral CSDH were enrolled in this study. Patients taking warfarin were managed homogeneously according to the study protocol, and the usual dosage of warfarin was resumed within 2 or 3 days of burr-hole drainage to reach a target international normalized ratio (INR) of 2.1. The primary outcome, defined as recurrent CSDH requiring repeated burr-hole drainage within 3 months of the initial surgery, was compared between the two groups.

The primary outcome was observed in 4 (11%) of the 36 patients taking warfarin and in 18 (12%) of the 151 ordinary patients. After propensity score matching, the primary outcome was observed in 3 of 33 patients (9%) in the matched warfarin cohort and 11 of 74 patients (15%) in the matched ordinary cohort. When the results were analyzed using the generalized estimating equation, no significant difference was observed in the rate of recurrent CSDH between the 2 groups (P = 0.411). In addition, we found that recurrent CSDH was not related to postoperative international normalized ratio levels (P = 0.332).

There was no definitive association between postoperative early warfarin resumption and the recurrence rate of CSDH. Patients with warfarin-related CSDH and a strong indication for anticoagulation can be managed by resuming warfarin within 3 days of burr-hole drainage.