Incidence of delayed bleeding in patients on antiplatelet therapy after mild traumatic brain injury: a systematic review and meta-analysis

Background: The scientific evidence regarding the risk of delayed intracranial bleeding (DB) after mild traumatic brain injury (MTBI) in patients administered an antiplatelet agent (APA) is scant and incomplete. In addition, no consensus exists on the utility of a routine repeated head computed tomography (CT) scan in these patients. Objective: The aim of this study was to evaluate the risk of DB after MTBI in patients administered an APA. Methods: A systematic review and meta-analysis of prospective and retrospective observational studies enrolling adult patients with MTBI administered an APA and who had a second CT scan performed or a clinical follow-up to detect any DB after a first negative head CT scan were conducted. The primary outcome was the risk of DB in MTBI patients administered an APA. The secondary outcome was the risk of clinically relevant DB (defined as any DB leading to neurosurgical intervention or death). Results: Sixteen studies comprising 2930 patients were included in this meta-analysis. The pooled absolute risk for DB was 0.77% (95% CI 0.23–1.52%), ranging from 0 to 4%, with substantial heterogeneity (I² = 61%). The pooled incidence of clinically relevant DB was 0.18%. The subgroup of patients on dual antiplatelet therapy (DAPT) had an increased DB risk, compared to the acetylsalicylic acid (ASA)-only patients (2.64% vs. 0.22%; p = 0.04). Conclusion: Our systematic review showed a very low risk of DB in MTBI patients on antiplatelet therapy. We believe that such a low rate of DB could not justify routine repeated CT scans in MTBI patients administered a single APA. We speculate that in the case of clinically stable patients, a repeated head CT scan could be useful for select high-risk patients and for patients on DAPT before discharge.