Introduction: The use of flow diverters (FDs) has shown promising results, particularly in the treatment of large or complex intracranial aneurysms. However, some complications can occur both during and after FD treatment, including delayed ipsilateral parenchymal hemorrhage (DIPH). The clinical presentation, etiopathogeny, and management of this complication are not well understood. We report a series of four patients with DIPH and discuss the potential mechanisms and modalities of treatment.
Methods: Four patients treated with FDs and presenting with DIPH were diagnosed in two different centers. Clinical and imaging data were reviewed before and after the procedure. Characteristics of the intraparenchymal hematomas, the modalities of treatment, and clinical course were analyzed.
Results: Intraparenchymal hemorrhage occurred 1 to 4 days after aneurysm treatment with FDs. All hemorrhages were situated in the ipsilateral hemisphere and were anatomically remote from the treated aneurysm. The four patients were treated with emergency surgery (hematoma evacuation). All patients had a favorable clinical outcome (mRS = 1) at midterm evaluation. Follow-up imaging showed good permeability of the FD in all subjects and complete aneurysm occlusion in all patients.
Conclusion: From the literature review, DIPH appears to be more frequent than delayed aneurysm rupture and may be a cause of increasing concern for the use of flow diverters. However, the mechanisms of DIPH are not completely understood. Surgical evacuation of the hematoma seems to be feasible with acceptable safety and good clinical outcomes.