title: Venous flow rearrangement after treatment of cerebral arteriovenous malformations: a novel approach to evaluate the risks of treatment.
abstract: OBJECTIVE
  This study aims to identify the angiographic parameters that could help predict the risks of hyperemic complications (HCs) in the treatment of cerebral arteriovenous malformations (AVMs).
  
  
  METHODS
  The charts and the pre- and post-treatment angiographies of 400 consecutively treated patients with cerebral AVMs were retrospectively reviewed. Several parameters were analyzed: grade, size, drainage depth, number of the "recruited veins" (veins coming from the brain and joining the main AVM drainage), and "venous times" (the times of visualization of the nidus and the main drainage, of the "recruited veins," and finally of the normal cerebral veins). On this basis, two groups were identified: group 1, consisting of 309 patients (77.3%) with normal/subnormal venous times, and group 2, consisting of 91 patients (22.7%) with altered venous times and venous engorgement. Finally, the weight of the various parameters was measured by univariate and multivariate analyses.
  
  
  RESULTS
  An overall number of 245 patients (61.2%) achieved favorable outcomes. HCs occurred in a total of 28 patients (7%): No patient belonged to group 1, so that these adverse effects were reported in 30.7% of group 2 patients. The presence of deep drainage and the number of recruited veins resulted in statistically significantly different impacts on the risk of the different grades.
  
  
  CONCLUSIONS
  The statistical analysis allowed the identification of three different risk scores, which were named Nig-scores (Niguarda scores). Nig-score 0 means no risk of HCs and concerns patients without altered venous times; Nig-score 1 represents patients with intermediate risk, that is, with moderately altered venous times and few recruited veins; Nig-score 2 indicates high risk of HCs and refers to patients with markedly altered venous times.
authors: Department of Neurosurgery, Niguarda CA' Granda Hospital, Milan, Italy.
authors: Giuseppe
authors: G
authors: D'Aliberti
authors: Department of Neurosurgery, Niguarda CA' Granda Hospital, Milan, Italy. Electronic address: g.talamonti@yahoo.it.
authors: Giuseppe
authors: G
authors: Talamonti
authors: Department of Neurosurgery, Niguarda CA' Granda Hospital, Milan, Italy.
authors: Maurizio
authors: M
authors: Piparo
authors: Department of Neurosurgery, Niguarda CA' Granda Hospital, Milan, Italy.
authors: Alberto
authors: A
authors: Debernardi
authors: Department of Neurosurgery, Niguarda CA' Granda Hospital, Milan, Italy.
authors: Samis
authors: S
authors: Zella
authors: Department of Neuroradiology, Niguarda CA' Granda Hospital, Milan, Italy.
authors: Edoardo
authors: E
authors: Boccardi
authors: Department of Neuroradiology, Niguarda CA' Granda Hospital, Milan, Italy.
authors: Luca
authors: L
authors: Valvassori
authors: Service of Bio-Statistics, Niguarda CA' Granda Hospital, Milan, Italy.
authors: Michele
authors: M
authors: Nichelatti
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D002533:Cerebral Angiography; D002543:Cerebral Hemorrhage / Q000150:complications / Q000601:surgery; D002548:Cerebral Revascularization / Q000379:methods*; D002550:Cerebral Veins / Q000473:pathology* / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology; D002648:Child; D004322:Drainage; D004621:Embolization, Therapeutic; D005260:Female; D006801:Humans; D006940:Hyperemia / Q000209:etiology / Q000503:physiopathology; D002538:Intracranial Arteriovenous Malformations / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000503:physiopathology / Q000628:therapy; D012189:Retrospective Studies; D012306:Risk; D012640:Seizures / Q000209:etiology / Q000601:surgery; D016896:Treatment Outcome; D055815:Young Adult
keywords: Cerebral arteriovenous malformations; Embolization; Hematoma; Hyperemia; Seizures; Surgery; Surgery complications