Parent Artery Occlusion for Unruptured Cerebral Aneurysms: The Japanese Registry of Neuroendovascular Therapy (JR-NET) 1 and 2

Parent artery occlusion (PAO) is an alternative to surgical clipping or endovascular endosaccular coil embolization for the management of cerebral aneurysms. Most giant and fusiform aneurysms are not amenable to endosaccular coil embolization due to anatomical considerations, such as a broad-neck. However, majority of reports regarding the safety of PAO are based on case series involving a relatively small number of patients. In the present study, a total of 381 consecutive patients with unruptured cerebral aneurysms who were treated with PAO were extracted from the Japanese Registry of Neuroendovascular Therapy (JR-NET) 1 and JR-NET2 database, which are nationwide surveys conducted by the Japanese Society of Neuroendovascular Therapy. The mean age of the 381 patients was 58.1 years, and 59.3% were female. The aneurysmal location included the vertebral artery (42%) and the cavernous portion of internal carotid artery (32%). The aneurysm size and shape consisted of fusiform (45%), giant (25%), and large (22%). Symptomatic lesions were present in 59.8% of the population. Technical success was achieved in 98.4%. The 30-day morbidity and mortality rates were 3.1% and 1.0%, respectively. The most frequent procedure-related complication was ischemic stroke, which occurred in 12.9% (distal embolism, 6.0%; branch occlusion, 3.9%). The 30-day morbidity and mortality rates related to ischemic strokes were 2.1% and 0.3%, respectively. PAO for unruptured aneurysms is feasible with a high technical success rate. Peri-procedural management of ischemic stroke is the key to enhance the safety of this treatment option.