title: Acute serious rebleeding after angiographically successful coil embolization of ruptured cerebral aneurysms.
abstract: OBJECTIVE
  The present study investigated the incidence of acute rebleeding after successful coil embolization of a ruptured cerebral aneurysm, including clinical outcomes, and possible mechanisms of the events other than coil compaction and/or incomplete embolization.
  
  
  METHODS
  This study included 591 consecutive patients who presented with aneurysmal subarachnoid hemorrhage, were treated with coil embolization, and whose post-procedural angiography revealed successful embolization. Data were collected retrospectively from six patients who showed acute rebleeding despite that angiographically successful coil embolization was achieved. All clinical, radiological data and intraoperative videos were reviewed to identify causative factors which could have contributed to the occurrence of rebleeding.
  
  
  RESULTS
  Incidence of acute rebleeding after successful coil embolization of ruptured cerebral aneurysm was 1.0% (6/591). In all of these six patients, complete angiographic occlusion was achieved except in one case where a small residual neck was intentionally left to avoid compromise of the parent artery. Four of the six patients showed poor clinical courses, either died or recovered with severe disability. Whenever possible, we performed an immediate craniotomy for exploration and additional clipping. Based on intraoperative findings, we hypothesized that uneven distribution of the coil masses and spontaneous resolution of thrombus among the strands of coil (inter-coil-loop thrombolysis) could be possible mechanisms of rebleeding.
  
  
  CONCLUSIONS
  Acute rebleeding is extremely rare, but is possible as a complication of coil embolization of a ruptured cerebral aneurysm even when a case is angiographically successful. The higher degree of morbidity and mortality is a major concern. Therefore, further investigation to discover risk factors and causative mechanisms for such a complication is sorely needed.
authors.affiliation: Department of Neurosurgery, Daegu-Gyeongbuk Cardiocerebrovascular Center, Kyungpook National University, Daegu, Republic of Korea.
authors.forename: Dong-Hun
authors.initials: DH
authors.lastname: Kang
authors.forename: Yong-Sun
authors.initials: YS
authors.lastname: Kim
authors.forename: Seung-Kug
authors.initials: SK
authors.lastname: Baik
authors.forename: Seong-Hyun
authors.initials: SH
authors.lastname: Park
authors.forename: Jaechan
authors.initials: J
authors.lastname: Park
authors.forename: In-Suk
authors.initials: IS
authors.lastname: Hamm
mesh_terms: D000328:Adult; D000368:Aged; D015984:Causality; D004621:Embolization, Therapeutic / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging / Q000473:pathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods; D019106:Postoperative Hemorrhage / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology*; D019736:Prostheses and Implants / Q000009:adverse effects; D011475:Prosthesis Failure; D019919:Prosthesis Implantation / Q000009:adverse effects / Q000379:methods; D011859:Radiography; D012008:Recurrence; D012086:Reoperation; D012189:Retrospective Studies; D018570:Risk Assessment; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy*; D016896:Treatment Outcome; D014656:Vascular Surgical Procedures / Q000379:methods