An autopsy report of basilar artery aneurysm flow diversion complicated by postoperative day 3 hemorrhage from vessel rupture.

A middle-aged patient presented with posterior circulation symptoms attributable to a large eccentric basilar trunk aneurysm. The planned treatment was flow diversion with loose coil packing which was successfully performed using a Pipeline Flex device deployed from the basilar to the left posterior cerebral artery. The complete procedure including live biplane fluoroscopy was digitally recorded. The patient had symptomatic improvement postoperatively and was discharged on day 1. The patient suffered a cardiac arrest on postoperative day 3 secondary to massive intraventricular and subarachnoid hemorrhage. An aneurysm rupture was suspected; however, postmortem examination showed an intact aneurysm sac. The hemorrhage was attributed to a small focal rent in the distal basilar artery next to an atheromatous plaque. The Pipeline device was visible through the rent. This is an autopsy report documenting an injury to the parent artery and not the aneurysm as a source of fatal delayed subarachnoid hemorrhage following flow diversion.