Incidence of delayed ipsilateral intraparenchymal hemorrhage after stent-assisted coiling of intracranial aneurysms in a high-volume single center

Delayed ipsilateral intraparenchymal hemorrhage (IPH) has been reported following technically successful treatment of intracranial aneurysms using flow-diverting stents in up to 8.5 % of patients. We report a similar, though less frequent phenomenon in the setting of stent-assisted coil embolization. Institutional review board approval was obtained. A retrospective analysis of a prospective neurointerventional procedure registry was performed to review all IPHs that occurred in aneurysm patients within 90 days of endovascular treatment performed between November 2002 and November 2014 at one institution. Age, sex, hypertension, dual antiplatelet therapy, and technical details of the procedure were recorded. A total of 1697 patients underwent endovascular treatment of an intracranial aneurysm without a flow diverter at our institution during the study period. Among these, 138 patients underwent stent-assisted coiling (8.1 %). Of these, three patients (2.2 %) suffered a delayed IPH within the vascular territory distal to the treated lesion (one woman, median age 60 years). Recently described in the setting of flow diversion, delayed ipsilateral IPH is not limited to flow-diverting stents. Though less frequent, a potential for this complication may exist following any intracranial stenting procedure, possibly related to hemorrhagic conversion of microembolic phenomena in the setting of dual antiplatelet or anticoagulation therapy.