The Central Retinal Vein Bypass Study: a trial of laser-induced chorioretinal venous anastomosis for central retinal vein occlusion.

Abstract

PURPOSE:

To evaluate the effectiveness of a laser-induced chorioretinal venous anastomosis (L-CRA) as a treatment for nonischemic central retinal vein occlusion (CRVO).

DESIGN:

Prospective, randomized, controlled, multicenter clinical trial.

PARTICIPANTS:

A total of 113 consecutive patients with a nonischemic CRVO of >3 months' duration and visual acuity of < or =20/50.

METHODS:

Patients were randomized to L-CRA (58 patients) or conventional care (55 patients). They underwent standardized retinal photography, fluorescein angiography, and ophthalmic examinations, together with standardized assessments of best-corrected visual acuity, performed by masked visual acuity assessors using Early Treatment Diabetic Retinopathy Study protocols. Analysis was performed by intention-to-treat.

MAIN OUTCOME MEASURES:

The primary outcome measure was change in visual acuity at 18 months. Secondary outcomes were progression of retinal ischemia and rates of adverse events.

RESULTS:

A total of 53 control patients and 55 treatment patients completed the study. The 2 groups were comparable for age, age- and gender-adjusted mean visual acuity, and most other parameters. In the treated group of 55 patients, 42 (76.4%) developed an L-CRA. Over the 18-month follow-up period, treated eyes had an 8.3 letter mean improvement from baseline compared with control eyes (P = 0.03). Treated eyes that developed a functional L-CRA achieved an 11.7 letter mean improvement from baseline over the control group after 18 months (P = 0.004). Conversion to the ischemic CRVO category occurred in 20.8% of control eyes and in 9.6% of treated eyes overall (P = 0.33). Of the treated group who developed an L-CRA where the retinal ischemia was due to progression of the CRVO, 4.9% progressed to the ischemic category (P = 0.03). Neovascularization developed at the site of the L-CRA in 10 of 55 treated eyes (18.2%). Vitrectomy surgery was required by 5 of 55 treated eyes (9.1%) because of macular traction or nonresolving vitreous hemorrhage.

CONCLUSIONS:

Chorioretinal venous anastomosis was created in 76.4% of eyes with nonischemic CRVO in this study. Eyes that developed an anastomosis had a significant improvement (11.7 letters) in final visual acuity after 18 months, compared with eyes in the control group (P = 0.004). Complications were managed successfully with careful follow-up and early intervention.

• Authors: Ian L McAllister, Mark E Gillies, Lynne A Smithies, Elena Rochtchina, Colin A Harper, Mark D Daniell, Ian J Constable, Paul Mitchell
• Journal: Ophthalmology (Ophthalmology) Vol. 117 Issue 5 Pg. 954-65 (May 2010) ISSN: 1549-4713 [Electronic] United States
• PMID: 20163872 (Publication Type: Journal Article, Multicenter Study, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)
• Copyright: Copyright 2010 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Topics

• Adult
• Aged
• Aged, 80 and over
• Anastomosis, Surgical
• Choroid (blood supply)
• Female
• Fluorescein Angiography
• Follow-Up Studies
• Humans
• Laser Therapy
• Lasers, Solid-State
• Male
• Middle Aged
• Photography
• Prospective Studies
• Retinal Vein (surgery)
• Retinal Vein Occlusion (diagnosis, physiopathology, surgery)
• Treatment Outcome
• Visual Acuity (physiology)