Acute branch occlusion after Pipeline embolization of intracranial aneurysms.

Flow-diverters are used in the treatment of large and complex intracranial aneurysms. One major concern with this concept is the potential for compromise of side branches and perforators covered by the device. We describe three patients treated with the Pipeline embolization device (PED; ev3 Endovascular, Plymouth, MN, USA) who developed immediate compromise of flow into an eloquent side branch covered by the device. Three patients, two with giant posterior circulation aneurysms and one with recurrence of a previously clipped and subsequently coiled middle cerebral artery aneurysm, were each treated by placement of a single PED. Shortly after placement of the devices, despite adequate antiplatelet and anticoagulation regimens, partial or complete occlusion of a major side branch occurred. In all three patients, the occlusion was promptly reversed with intra-arterial administration of abciximab with no clinical sequelae. These cases are concerning because branch occlusion occurred even in the setting of patients appropriately premedicated with dual antiplatelet therapy and in whom genetic testing suggested clopidogrel responsiveness. Close monitoring of patients treated with these devices is critical to establish the frequency of this and other unanticipated complications.