title: The Pipeline Embolization Device: learning curve and predictors of complications and aneurysm obliteration.
abstract: BACKGROUND
  The Pipeline Embolization Device (PED) has emerged as a promising treatment for intracranial aneurysms.
  
  
  OBJECTIVE
  To assess the safety and efficacy of the PED, to analyze the effect of operator experience on the complication rate, and to identify predictors of complications and obliteration.
  
  
  METHODS
  A total of 109 patients with 120 aneurysms were treated with PED at our institution. The patient population was divided into 3 consecutive equal groups to assess whether overall and major complication rates decreased over time: group 1, patients 1 through 37; group 2, patients 38 through 73; and group 3, patients 74 through 109.
  
  
  RESULTS
  The number of PEDs used was 1.40 per aneurysm. Symptomatic and major procedure-related complications occurred in 11% and 3.7% of patients, respectively. The rate of complications decreased from 16.2% in group 1 to 5.6% in group 3, and the rate of major complications fell dramatically from 10.8% in group 1 to 0% in groups 2 and 3 (P < .05). Procedure time significantly decreased over time (P = .04). In multivariate analysis, previously treated aneurysms were predictive of procedural complications (P = .02). At the latest follow-up, 65.8% of aneurysms were completely occluded, 9.6% were nearly completely occluded, and 24.6% were incompletely occluded. In multivariate analysis, fusiform aneurysms (P = .05) and shorter angiographic follow-up (P = .03) were negative predictors of aneurysm obliteration.
  
  
  CONCLUSIONS
  PED therapy may have an acceptable safety-efficacy profile. The risk of complications appears to decrease dramatically with physician experience, supporting the existence of a learning curve. Patients with previously treated aneurysms have higher complication rates, whereas fusiform aneurysms achieve lower obliteration rates.
authors.affiliation: Department of Neurosurgery, Thomas Jefferson University and Jefferson Hospital for Neuroscience, Philadelphia, Pennsylvania, USA. pascal.jabbour@jefferson.edu
authors.forename: Pascal
authors.initials: P
authors.lastname: Jabbour
authors.forename: Nohra
authors.initials: N
authors.lastname: Chalouhi
authors.forename: Stavropoula
authors.initials: S
authors.lastname: Tjoumakaris
authors.forename: L Fernando
authors.initials: LF
authors.lastname: Gonzalez
authors.forename: Aaron S
authors.initials: AS
authors.lastname: Dumont
authors.forename: Ciro
authors.initials: C
authors.lastname: Randazzo
authors.forename: Robert M
authors.initials: RM
authors.lastname: Starke
authors.forename: David
authors.initials: D
authors.lastname: Hasan
authors.forename: Rohan
authors.initials: R
authors.lastname: Chitale
authors.forename: Saurabh
authors.initials: S
authors.lastname: Singhal
authors.forename: Lea A
authors.initials: LA
authors.lastname: Moukarzel
authors.forename: Robert
authors.initials: R
authors.lastname: Rosenwasser
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001807:Blood Vessel Prosthesis / Q000706:statistics & numerical data*; D015897:Comorbidity; D004621:Embolization, Therapeutic / Q000295:instrumentation* / Q000706:statistics & numerical data*; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000175:diagnosis / Q000453:epidemiology* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010414:Pennsylvania / Q000453:epidemiology; D011183:Postoperative Complications / Q000453:epidemiology*; D015995:Prevalence; D020127:Recovery of Function; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome; D055815:Young Adult