Aspirin in Surgically Treated Chronic Subdural Hematoma: A Randomized Placebo Controlled Trial

Introduction: Discontinuation of low-dose acetylsalicylic acid (ASA) during the perioperative phase of chronic subdural hematoma (cSDH) may reduce recurrence rates from 25-33% to 7-10%. However, the efficacy and safety of discontinuing ASA in this patient population remain unclear.

Methods: We performed an investigator-initiated, placebo-controlled trial at six national sites· Participants were randomized 1:1 to receive either continuous ASA or placebo for 12 day. Both assessors and participants were blinded to the treatment arms. The primary endpoint was the recurrence of cSDH necessitating reoperation within 6 months. Secondary outcomes included cardiovascular and thromboembolic events, as well as mortality. An intention-to-treat analysis was performed, calculating risk differences using inverse probability of censoring weights (IPCW) to account for missing outcomes.

Results: Out of 155 participants, 78 were assigned to continuous ASA and 77 to placebo. A primary outcome event occurred in 10.3% of the ASA group and 9.1% of the placebo group. When weighted using IPCW, these rates were 13.9% for the ASA group and 9.5% for the placebo group (weighted risk difference 4.4%; 95% CI, -7.2 to 15.9; p=0.558). The incidence of cardiovascular events indicating ASA treatment was 0.02% per person half-year in the ASA group and 0.06% in the placebo group (HR 0.24 [95% CI, 0.03 to 2.12]. Other intracranial bleeding events showed an incidence of 0.10% per person half-year in the ASA group and 0.08% in the placebo group (HR 1.16 [95% CI, 0.36 to 3.82]). All-cause mortality occurred at rates of 0.06% per person half-year in the ASA group and 0.03% in the placebo group (HR 1.92 [95% CI, 0.35 to 10.51].

Conclusion : Discontinuous ASA treatment did not appear to reduce recurrence rate of surgically treated cSDH within six months. Notably, recurrence risk estimates for continuous ASA treatment in our trial are distinctly lower than previously reported.
(Funded by the Swiss National Science Foundation and others; SECA ClinicalTrials.gov number NCT03120182)