Factors promoting success and influencing complications in laser-induced central vein bypass.

PURPOSE: 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. DESIGN: Interventional cohort study. PARTICIPANTS: 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. MAIN OUTCOME MEASURES: 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. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

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

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.

Randomized controlled trial of intravitreal ranibizumab versus standard grid laser for macular edema following branch retinal vein occlusion.

PURPOSE: To assess the efficacy of intravitreal 0.5 mg ranibizumab for the treatment of center-involving macular edema secondary to branch retinal vein occlusion (BRVO) over 1 year compared with standard-of-care grid laser. DESIGN: A prospective randomized controlled clinical trial. METHODS: A total of 36 patients with vision loss in 1 eye attributable to macular edema following BRVO were recruited from 5 institutions. Patients were randomized 1:1 to a treatment group that received 6 monthly injections of 0.5 mg ranibizumab and thereafter monthly as needed based on best-corrected visual acuity (BCVA) and central foveal thickness (CFT) assessments on optical coherence tomography scans, or a standard-of-care group that received monthly sham injections for the 1-year duration of the study. Grid laser was administered at 13 and 25 weeks in both groups if criteria for laser treatment were met. Main outcome measures included mean change in BCVA in Early Treatment Diabetic Retinopathy Study (ETDRS) letter scores from baseline to month 12. Secondary outcomes included anatomic outcomes and the percentage of patients requiring grid laser in both groups. RESULTS: Mean BCVA change from baseline was significantly greater in the treatment compared with the standard-of-care group at 12 months (12.5 ETDRS letters vs -1.6 ETDRS letters, P = .032). The mean CFT was significantly reduced in the treatment compared with standard-of-care group (361.7 µm vs 175.6 µm, P = .025). At 13 and 25 weeks, more patients in the standard-of-care group (68.4%, 50.0%) received grid laser than in the treatment group (6.7%, 8.3%). No new ocular or systemic adverse events were observed. CONCLUSIONS: Compared with standard grid laser, intravitreal ranibizumab provided significant and sustained benefits in visual acuity gain and anatomic improvement in eyes with macular edema secondary to BRVO.