Intracranial Hemorrhagic Events Associated with Flow Diversion Treatment: A Retrospective Analysis from a Single Academic Institution

Introduction: Intracranial hemorrhages are a highly concerning complication that can occur in the perioperative period of flow diversion (FD) treatment of cerebral aneurysms. The need for dual antiplatelet therapy post-placement heightens this risk. We aimed to characterize these complications and the factors influencing their occurrence.

Methods: A retrospective review of patients with intracranial aneurysms treated with F.D. from 2013 to 2023 at a single institution in the U.S. was conducted. Data on aneurysm characteristics, patient comorbidities, antiplatelet regimens, anticoagulation use, baseline functionality, and imaging features of the hemorrhages were collected for analysis. A univariate comparison was then developed to identify risk factors associated with intraparenchymal hemorrhages (IPHs).

Results: There were 622 patients harboring 788 aneurysms treated in 690 procedures during the study period. Within 7 months of follow-up, 15 intracranial hemorrhages were identified (2.2%): 2 acute subdural hematomas (SDH), 7 IPH, 1 intraventricular hemorrhage (IVH), and 5 subarachnoid hemorrhages (SAH), most of which presented within the first 24 hours after initial treatment. Patients experiencing hemorrhages exhibited lower rates of functional independence (mRS≤2) compared to those without hemorrhage (66.7% vs. 93.3%; p< 0.01). IPHs were slightly higher in patients receiving aspirin-ticagrelor (1.2%) compared to those on aspirin-clopidogrel (0.9%) or aspirin-prasugrel (0.0%). A univariate logistic regression model demonstrated an aneurysmal diameter ≥ 12 mm (OR=8.98; 95% CI= 1.98-16.03) and aneurysms with prior treatment (OR=7.20; 95% CI=1.59-32.60) as factors influencing IPHs after treatment. The incidence of hemorrhage decreased over the time interval of study.

Conclusion : Intracranial hemorrhages related to FD are rare but highly morbid complications. Treatments involving larger aneurysms and those with prior interventions are associated with a higher risk of IPHs.