Impact of Early Resumption of Oral Anticoagulation on Recurrence After Surgery for Chronic Subdural Hematoma in Patients With Atrial Fibrillation: A Target Trial Emulation

ABSTRACT Purpose Clinicians treating patients with atrial fibrillation (AF) on oral anticoagulants who undergo surgery for chronic subdural hematoma (CSDH) face a dilemma: while early postoperative resumption of anticoagulation is necessary to prevent embolism, it may increase the risk of CSDH recurrence. To date, however, no study has evaluated this question while adequately addressing common biases in observational studies. Here, we assessed this issue using target trial emulation framework. Methods We identified patients undergoing initial CSDH surgery who had received anticoagulation for AF preoperatively from two hospital‐based administrative databases (2014–2022). We compared two treatment strategies: resumption of anticoagulation within 14 days postoperatively versus no resumption during this period. Using a three‐step method of cloning, censoring, and weighting, we estimated the risk of CSDH recurrence, along with the risk ratio and risk difference at postoperative day 90. Results 291 CSDH patients with AF were eligible, of whom 29 (10.0%) underwent CSDH reoperation. The weighted estimated 90‐day reoperation risk was 11.7% (95% confidence interval [CI], 6.0 to 14.3) for resuming anticoagulation within 14 days postoperatively and 9.4% (95% CI, 4.1 to 12.8) for not resuming within 14 days, corresponding to a risk ratio of 1.20 (95% CI, 0.67 to 2.36) and risk difference of 1.9% (95% CI, −4.0 to 6.6). Conclusions 90‐day risk of CSDH recurrence may not differ between early and non‐early resumption of anticoagulation, although early resumption could modestly accelerate recurrence. Allowing for the imprecision of the estimates, these findings provide important insights for clinical decision‐making regarding anticoagulation resumption.