title: Factors promoting success and influencing complications in laser-induced central vein bypass.
abstract: OBJECTIVE
  To evaluate the factors influencing the successful creation of a laser-induced chorioretinal venous anastomosis (L-CRA) and those involved in the development of complications.
  
  
  METHODS
  Interventional cohort study.
  
  
  METHODS
  Fifty-five patients with a nonischemic central retinal vein occlusion (CRVO) who were randomized to receive an L-CRA from the total of 108 who completed the follow-up period of the Central Vein Bypass Study.
  
  
  METHODS
  Patients who were randomized to L-CRA were followed up for an 18-month period. They were stratified in 2 sets of 2 cohorts: those who did or did not demonstrate an L-CRA and those who did or did not demonstrate neovascular complications at the site of the L-CRA. Subgroup analysis was performed to determine what factors influenced the creation of an L-CRA and the development of complications at each individual laser site.
  
  
  METHODS
  Identification of systemic and local ocular factors associated with increased success rates of L-CRA creation and those involved with an increased risk of neovascular complications.
  
  
  RESULTS
  Younger age (P = 0.03), better baseline visual acuity (P = 0.04), and the absence of hypertension (P = 0.001) were systemic features associated with an increased chance of demonstrating a successful L-CRA at each site, whereas sex and duration of the CRVO were not. The position of the L-CRA site did not influence the outcome; however, evidence of rupture of the vein wall at the time of the attempt was associated with a higher chance of success (P = 0.008). Increased risk of neovascularization, which occurred at 12 sites in 10 eyes, was associated with higher central venous pressure before treatment (P = 0.03), prolonged fluorescein transit time (P = 0.0001), and the presence of some capillary nonperfusion (P = 0.01).
  
  
  CONCLUSIONS
  Younger age, better baseline visual acuity, and the absence of hypertension were associated with an improved success rate, as was evidence of rupture of the vein wall. High baseline central venous pressure, prolonged fluorescein transit time, and the presence of any retinal ischemia were associated with a higher incidence of neovascular complications.
  
  
  BACKGROUND
  Proprietary or commercial disclosure may be found after the references.
authors.affiliation: Centre for Ophthalmology and Visual Science, Lions Eye Institute, The University of Western Australia, Perth, Australia. ianmcallister@lei.org.au
authors.forename: Ian L
authors.initials: IL
authors.lastname: McAllister
authors.forename: Mark E
authors.initials: ME
authors.lastname: Gillies
authors.forename: Lynne A
authors.initials: LA
authors.lastname: Smithies
authors.forename: Elena
authors.initials: E
authors.lastname: Rochtchina
authors.forename: Colin A
authors.initials: CA
authors.lastname: Harper
authors.forename: Mark D
authors.initials: MD
authors.lastname: Daniell
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Constable
authors.forename: Paul
authors.initials: P
authors.lastname: Mitchell
mesh_terms: D000368:Aged; D000714:Anastomosis, Surgical; D002829:Choroid / Q000098:blood supply*; D015331:Cohort Studies; D005260:Female; D005451:Fluorescein Angiography; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D007431:Intraoperative Complications; D053685:Laser Therapy; D054018:Lasers, Excimer; D008297:Male; D011183:Postoperative Complications; D011446:Prospective Studies; D012169:Retinal Vein / Q000601:surgery*; D012170:Retinal Vein Occlusion / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D012307:Risk Factors; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology