title: Evaluation of arteriovenous crossing sheathotomy for branch retinal vein occlusion by fluorescein videoangiography and image analysis.
abstract: OBJECTIVE
  We quantitatively evaluated the effects of arteriovenous (A/V) crossing sheathotomy on retinal circulation in patients with branch retinal vein occlusion (BRVO) accompanied by macular edema.
  
  
  METHODS
  Interventional case series.
  
  
  METHODS
  In 18 consecutive patients (18 eyes) with BRVO accompanied by macular edema who underwent A/V crossing sheathotomy between August 1999 and April 2002, changes in retinal circulation after the surgery were evaluated by fluorescein videoangiography with a scanning laser ophthalmoscope and by image analysis using dye dilution technique. At a venule distal to the responsible A/V crossing site and a normal venule, the circulation time (T50) from the beginning of filling to 50% filling of the peak intensity was calculated. The time difference (DeltaT50) between T50 at the point on the affected venule and that at the point on the normal venule, which represents the filling delay at the venule distal to the A/V crossing site, was compared between before and early after the surgery.
  
  
  RESULTS
  The preoperative DeltaT50 was 1.36 +/- 1.15 seconds (mean +/- SD), and the postoperative DeltaT50 was 0.72 +/- 0.77 seconds (P =.035, paired t test). In 11 of the 18 eyes, DeltaT50 decreased by 20% or more after the surgery. In the other 7 eyes, DeltaT50 was unchanged or slightly increased after the surgery.
  
  
  CONCLUSIONS
  Although a randomized controlled study is needed to confirm the effectiveness of A/V crossing sheathotomy on visual function, this technique could be effective for improving the delay in perfusion in the affected venule.
authors.affiliation: Department of Ophthalmology, Kagawa University School of Medicine, 1750-1 Ikenobe, Miki-cho, Kagawa 761-0793, Japan.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Yamaji
authors.forename: Fumio
authors.initials: F
authors.lastname: Shiraga
authors.forename: Yozo
authors.initials: Y
authors.lastname: Tsuchida
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Hiroshoi
authors.initials: H
authors.lastname: Ohtsuki
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001165:Arteriovenous Malformations / Q000601:surgery*; D001783:Blood Flow Velocity; D003238:Connective Tissue / Q000601:surgery*; D019299:Decompression, Surgical; D005260:Female; D005451:Fluorescein Angiography; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007834:Lasers; D008269:Macular Edema / Q000209:etiology / Q000503:physiopathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D013508:Ophthalmologic Surgical Procedures; D009887:Ophthalmoscopy; D012039:Regional Blood Flow; D012161:Retinal Artery / Q000002:abnormalities*; D012169:Retinal Vein / Q000002:abnormalities*; D012170:Retinal Vein Occlusion / Q000150:complications / Q000503:physiopathology* / Q000601:surgery*; D014741:Video Recording; D014821:Vitrectomy