Particles, Liquids, and Antiplatelets: Restarting Antiplatelets on Postintervention Day 3 or Later is Associated with Improved Outcomes After Particle Embolization.

Background And Objectives: Timing of restarting antiplatelet agents after middle meningeal artery embolization (MMAE) for chronic subdural hematoma (cSDH) is a topic of controversy. The aim of this study was to determine whether the timing of antiplatelet restart after MMAE for cSDH affects long-term radiographic and clinical outcomes.

Methods: A multi-institutional, retrospective cohort study was performed using data from 4 academic medical centers that performed MMAE for cSDH from 2018 to 2023. Patients were prescribed an antiplatelet agent before MMAE were included. Variables included demographics, comorbidities, timing of the procedure and antiplatelet restart, baseline modified Rankin Scale, initial size of SDH, and embolic material used. Outcomes were thickness of SDH at short-term (2 weeks) and long-term (6 weeks) follow-ups, need for unplanned surgical evacuation, and modified Rankin Scale at 90 days.

Results: Of 128 patients (78% male, median age 76 years [IQR 70-83]), 67 patients (52%) had their antiplatelet agent restarted postintervention. Patients who did not have their antiplatelet agent restarted experienced higher mortality (20% vs 5%, P = .038). Among patients with antiplatelet agent restarted postintervention, there was a significant correlation (R = -0.43, P = .025) between timing of antiplatelet restart and long-term SDH size change. Antiplatelet restart on postintervention day 3 or later was associated with improvement in long-term SDH thickness (β = -5.7 mm, s.e. 2.5, P = .034). This effect was observed in the particle-embolization subgroup (β = -8.3 mm, s.e. 3.2, P = .021), but not the liquid-embolization subgroup (β = 1.7 mm, s.e. 5.5, P = .773).

Conclusion: There was a higher rate of mortality and decreased functional independence among patients who did not have their antiplatelet agent restarted after MMAE for cSDH. Among patients who did have their antiplatelet restarted, a restart date of postintervention day 3 or later was associated with a significant decrease in long-term SDH size.