title: Arterial and venous aneurysms associated with arteriovenous malformations.
abstract: OBJECTIVE
  To identify prioritization based on hemorrhagic risk and indications for treatment of arterial and venous aneurysms associated with arteriovenous malformation (AVM).
  
  
  METHODS
  From a global series of 400 consecutively treated AVMs, 34 patients (8.5%) with 45 arterial or venous aneurysms were extrapolated. These 45 lesions were classified as unrelated aneurysms (n = 5 cases; 11.%), flow-related aneurysms (n = 18 cases; 40%), and intranidal and postnidal venous aneurysms (n = 22; 49.%). The 18 flow-related aneurysms were further divided into remote (n = 6 cases) and adjacent (n = 12 cases) types. Of 45 aneurysms associated with AVMs, 15 were unruptured with a 5-year mean follow-up. Various possible risk indicators were considered and measured by univariate and multivariate analyses.
  
  
  RESULTS
  During the follow-up period, 1 of 15 unruptured aneurysms bled, and the patient died. A significantly different bleeding incidence was found between unrelated aneurysm and flow-related aneurysm types (P = 0.002). Bleeding was significantly less probable in flow-related remote aneurysm type than in venous and flow-related adjacent aneurysm types (P = 0.007). The location of the aneurysm was the only true risk factor for bleeding; the other parameters had no influence on bleeding.
  
  
  CONCLUSIONS
  In this series, different subtypes of aneurysms associated with AVMs had different clinical behaviors. The bleeding risk of the unrelated aneurysm and the flow-related remote aneurysm types should be considered almost the same as any other unruptured aneurysm. In other words, bleeding risk should be considered taking into account the parameters established by the International Study of Unruptured Intracranial Aneurysms (location, size, and morphology). Conversely, flow-related adjacent aneurysm and venous aneurysm types have significantly higher bleeding potentials.
authors.affiliation: Department of Neurosurgery, Niguarda Cà Granda Hospital, Milan, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: D'Aliberti
authors.affiliation: Department of Neurosurgery, Niguarda Cà Granda Hospital, Milan, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Talamonti
authors.affiliation: Department of Neurosurgery, Niguarda Cà Granda Hospital, Milan, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Cenzato
authors.affiliation: Department of Neurosurgery, Niguarda Cà Granda Hospital, Milan, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: La Camera
authors.affiliation: Department of Neurosurgery, Niguarda Cà Granda Hospital, Milan, Italy. Electronic address: albertodebernardi@hotmail.it.
authors.forename: Alberto
authors.initials: A
authors.lastname: Debernardi
authors.affiliation: Department of Neuroradiology, Niguarda Cà Granda Hospital, Milan, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Valvassori
authors.affiliation: Department of Neuroradiology, Niguarda Cà Granda Hospital, Milan, Italy.
authors.forename: Piano
authors.initials: P
authors.lastname: Mariangela
authors.affiliation: Department of Service of Bio-Statistics, Niguarda Cà Granda Hospital, Milan, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Nichelatti
mesh_terms: D000328:Adult; D000368:Aged; D002533:Cerebral Angiography; D002552:Cerebral Ventricles; D003131:Combined Modality Therapy / Q000379:methods; D004621:Embolization, Therapeutic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D002532:Intracranial Aneurysm / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D002538:Intracranial Arteriovenous Malformations / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D020300:Intracranial Hemorrhages / Q000000981:diagnostic imaging / Q000209:etiology* / Q000628:therapy*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery; D012189:Retrospective Studies; D012307:Risk Factors; D012640:Seizures / Q000209:etiology; D013345:Subarachnoid Hemorrhage / Q000209:etiology; D014057:Tomography, X-Ray Computed; D014696:Ventriculostomy
keywords: Cerebral aneurysms; Cerebral arteriovenous malformations; Embolization; Hematoma; Surgery