Angiographic warning of hemorrhagic transformation after stent retriever thrombectomy procedure.

This study reports cerebral angiographic findings observed after stent retriever thrombectomy that is suggestive of a higher risk of hemorrhagic transformation (HT). A woman aged 65-75 presented with a right middle cerebral artery syndrome confirmed by non-contrast CT brain scan. Endovascular revascularization using the Solitaire device was placed across the thromboembolic occlusion and thromboembolectomy was performed. Angiography showed complete recanalization of the left internal carotid artery, anterior and middle cerebral artery branches. Twelve hours following the procedure the patient had a hemorrhagic conversion of the ischemic infarct with significant mass effect causing herniation. Despite surgical intervention (hemicraniectomy) the patient died. The angiographic features following revascularization of the vessels distal to the occlusion showed subtle dilations which were visualized at the branch points of the vessels. This may be a warning sign of increased risk of HT.