title: In-Pipeline Stenosis: Incidence, Predictors, and Clinical Outcomes.
abstract: BACKGROUND
  The Pipeline Embolization Device is a widely utilized flow diverter in the treatment of intracranial aneurysms.
  
  
  OBJECTIVE
  To assess the incidence, clinical significance, predictors, and outcomes of in-Pipeline stenosis (IPS).
  
  
  METHODS
  Angiographic studies in 139 patients treated between 2011 and 2013 were independently reviewed by 2 authors for the presence of IPS. Multivariable logistic regression analysis was conducted to determine predictors of IPS.
  
  
  RESULTS
  A total of 21 (15.8%) patients demonstrated some degree of IPS during the follow-up period at a mean time point of 6.7 months (range, 3-24 months). The stenosis was mild (<50%) in 11 patients, moderate (50%-75%) in 5, and severe (>75%) in 6. None were symptomatic or required further intervention. Sixteen of these 22 patients (73%) had IPS detected within 6 months. IPS was noted in 7.6% (1/13) of patients with posterior circulation aneurysms vs 16.7% (21/126) of those with anterior circulation aneurysms (P = .03). The rate of IPS was 60% (3/5) in patients who did not receive aspirin vs only 14.2% (19/134) in those who received aspirin (P = .02). In multivariable analysis, no aspirin therapy (odds ratio, 10.0; 95% confidence interval, 1.4-67.7; P = .02) and internal carotid artery aneurysm location (odds ratio, 3.1; 95% confidence interval, 1.1-8.8; P = .03) were strong independent predictors of IPS.
  
  
  CONCLUSIONS
  IPS is a common, early, and mostly benign complication. Patients with internal carotid artery aneurysms are more likely to develop IPS. Aspirin plays a key role in preventing IPS. The results of this study further support the safety of flow diverters.
  
  
  BACKGROUND
  IPS, in-Pipeline stenosisPED, Pipeline Embolization Device.
authors.affiliation: *Department of Neurosurgery, Thomas Jefferson University and Jefferson Hospital for Neuroscience, Philadelphia, Pennsylvania; ‡Department of Neurosurgery, University of Iowa, Iowa City, Iowa.
authors.forename: Nohra
authors.initials: N
authors.lastname: Chalouhi
authors.forename: Adam
authors.initials: A
authors.lastname: Polifka
authors.forename: Badih
authors.initials: B
authors.lastname: Daou
authors.forename: David
authors.initials: D
authors.lastname: Kung
authors.forename: Guilherme
authors.initials: G
authors.lastname: Barros
authors.forename: Stavropula
authors.initials: S
authors.lastname: Tjoumakaris
authors.forename: L Fernando
authors.initials: LF
authors.lastname: Gonzalez
authors.forename: Robert M
authors.initials: RM
authors.lastname: Starke
authors.forename: David
authors.initials: D
authors.lastname: Hasan
authors.forename: Brendan
authors.initials: B
authors.lastname: Judy
authors.forename: Robert H
authors.initials: RH
authors.lastname: Rosenwasser
authors.forename: Pascal
authors.initials: P
authors.lastname: Jabbour
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001241:Aspirin / Q000627:therapeutic use; D002533:Cerebral Angiography; D015331:Cohort Studies; D004621:Embolization, Therapeutic / Q000009:adverse effects* / Q000295:instrumentation*; D005260:Female; D006083:Graft Occlusion, Vascular / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy; D006801:Humans; D015994:Incidence; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D012449:Safety; D055815:Young Adult
chemical_list: D010975:Platelet Aggregation Inhibitors; D001241:Aspirin