title: Survival analysis of risk factors for major recurrence of intracranial aneurysms after coiling.
abstract: BACKGROUND
  Recurrence after intracranial aneurysm coiling is a highly prevalent outcome, yet to be understood. We investigated clinical, radiological and procedural factors associated with major recurrence of coiled intracranial aneurysms.
  
  
  METHODS
  We retrospectively analyzed prospectively collected coiling data (2003-12). We recorded characteristics of aneurysms, patients and interventional techniques, pre-discharge and angiographic follow-up occlusion. The Raymond-Roy classification was used; major recurrence was a change from class I or II to class III, increase in class III remnant, and any recurrence requiring any type of retreatment. Identification of risk factors associated with major recurrence used univariate Cox Proportional Hazards Model followed by multivariate regression analysis of covariates with P<0.1.
  
  
  RESULTS
  A total of 467 aneurysms were treated in 435 patients: 283(65%) harboring acutely ruptured aneurysms, 44(10.1%) patients died before discharge and 33(7.6%) were lost to follow-up. A total of 1367 angiographic follow-up studies (range: 1-108 months, Median [interquartile ranges (IQR)]: 37[14-62]) was performed in 384(82.2%) aneurysms. The major recurrence rate was 98(21%) after 6(3.5-22.5) months. Multivariate analysis (358 patients with 384 aneurysms) revealed the risk factors for major recurrence: age>65 y (hazard ratio (HR): 1.61; P=0.04), male sex (HR: 2.13; P<0.01), hypercholesterolemia (HR: 1.65; P=0.03), neck size ≥4 mm (HR: 1.79; P=0.01), dome size ≥7 mm (HR: 2.44; P<0.01), non-stent-assisted coiling (HR: 2.87; P=0.01), and baseline class III (HR: 2.18; P<0.01).
  
  
  CONCLUSIONS
  Approximately one fifth of the intracranial aneurysms resulted in major recurrence. Modifiable factors for major recurrence were choice of stent-assisted technique and confirmation of adequate baseline occlusion (Class I/II) in the first coiling procedure.
authors: 1Department of Medical Imaging,The Ottawa Hospital;University of Ottawa.Ottawa,ON,Canada.
authors: Marlise P
authors: MP
authors: dos Santos
authors: 1Department of Medical Imaging,The Ottawa Hospital;University of Ottawa.Ottawa,ON,Canada.
authors: Armin
authors: A
authors: Sabri
authors: 2Department of Neurology,The Ottawa Hospital;University of Ottawa.Ottawa,ON,Canada.
authors: Dar
authors: D
authors: Dowlatshahi
authors: 1Department of Medical Imaging,The Ottawa Hospital;University of Ottawa.Ottawa,ON,Canada.
authors: Ali Muraback
authors: AM
authors: Bakkai
authors: 1Department of Medical Imaging,The Ottawa Hospital;University of Ottawa.Ottawa,ON,Canada.
authors: Abed
authors: A
authors: Elallegy
authors: 3Department of Neurosurgery(HL),The Ottawa Hospital;University of Ottawa.Ottawa,ON,Canada.
authors: Howard
authors: H
authors: Lesiuk
authors: 1Department of Medical Imaging,The Ottawa Hospital;University of Ottawa.Ottawa,ON,Canada.
authors: Cheemun
authors: C
authors: Lum
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002533:Cerebral Angiography; D057510:Endovascular Procedures / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002532:Intracranial Aneurysm / Q000453:epidemiology / Q000401:mortality / Q000601:surgery; D008297:Male; D011183:Postoperative Complications / Q000453:epidemiology; D016016:Proportional Hazards Models; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D015607:Stents / Q000009:adverse effects*; D016019:Survival Analysis; D016896:Treatment Outcome
keywords: survival analysis