title: Fetal-type posterior cerebral artery: the pitfall of parent artery occlusion for ruptured P₂ segment and distal aneurysms.
abstract: OBJECTIVE
  P2 segment and distal aneurysms are rare lesions of the cerebrovascular system. The efficacy and safety of endovascular occlusion for these types of aneurysms remain controversial. The aim of this study was to reveal risk factors for endovascular parent artery occlusion of ruptured P2 segment and distal aneurysms.
  
  
  METHODS
  Between March 2010 and November 2012, 812 patients with a ruptured intracranial aneurysm were admitted to the authors' hospital. Among them, 11 patients presented with P2 segment and distal posterior cerebral artery (PCA) aneurysms. These patients were subjected to endovascular treatment. Periprocedural data and clinical and angiographic records were studied retrospectively.
  
  
  RESULTS
  Of the patients with a ruptured PCA aneurysm, 2 of them underwent selective aneurismal coiling, and the remaining patients were treated with simultaneous occlusion of the parent artery. Patients with an adult-type PCA (n = 6), treated with either selective coiling or simultaneous parent artery occlusion, had no serious neurological deficits on follow-up. Four patients with a fetal-type PCA that was also occluded intraoperatively exhibited newly developed permanent paralysis and hemianopsia. However, 1 patient with a fetal-type PCA aneurysm that was selectively coiled recovered without complications. No recanalization was observed in any of the treated aneurysms.
  
  
  CONCLUSIONS
  Endovascular occlusion of an aneurysm and its parent artery is a safe and effective method for managing adult-type P2 segment and distal aneurysms. However, the authors' clinical data suggest that this method is of high risk for patients with fetal-type PCA aneurysms.
authors.affiliation: Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province;
authors.forename: Jing
authors.initials: J
authors.lastname: Xu
authors.affiliation: Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province;
authors.forename: Liang
authors.initials: L
authors.lastname: Xu
authors.affiliation: Department of Vascular and Endovascular Surgery, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, People's Republic of China.
authors.forename: Ziheng
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province;
authors.forename: Xianyi
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province;
authors.forename: Jun
authors.initials: J
authors.lastname: Yu
authors.affiliation: Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province;
authors.forename: Jianmin
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000368:Aged; D017542:Aneurysm, Ruptured / Q000150:complications / Q000628:therapy*; D004621:Embolization, Therapeutic / Q000379:methods*; D057510:Endovascular Procedures; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
keywords: BOT = balloon occlusion test; CTA = CT angiography; DSA = digital subtraction angiography; GOS = Glasgow Outcome Scale; HH = Hunt and Hess; ICA = internal carotid artery; ICH = intracerebral hematoma; IVH = intraventricular hemorrhage; MRA = MR angiography; PAO = parent artery occlusion; PCA = posterior cerebral artery; PCoA = posterior communicating artery; SAH = subarachnoid hemorrhage; aneurysm; coiling; fetal-type; parent artery occlusion; posterior cerebral artery; spontaneous subarachnoid hemorrhage; vascular disorders