TECHNIQUE OF LASER CHORIORETINAL ANASTOMOSIS CREATION IN CENTRAL RETINAL VEIN OCCLUSION AND SUCCESS RATE WITH A NEW PHOTOCOAGULATOR SYSTEM.

PURPOSE: To evaluate the success rate of laser chorioretinal anastomosis (L-CRA) creation with a new laser photocoagulator system capable of 5 watts (W) power in patients with central retinal vein occlusion (CRVO). METHODS: Patients with a treatment-naive CRVO were enrolled as part of an ongoing trial combining L-CRAs with anti-vascular endothelial growth factor treatment. RESULTS: Thirty-three patients were treated with an L-CRA developing in 29 (88%). Mean power was 2.7 W and mean time for development was 1.8 months. Each patient had two potential sites created. Eighteen patients developed 2 L-CRAs and the remaining 11 patients, one each. Of the 66 potential sites, successful L-CRAs developed at 47 sites (71%). Additional Nd:YAG laser applications were used in 39% of sites. Mean follow-up was 23 months and no significant complications were seen. CONCLUSION: An L-CRA as a means of permanently bypassing the obstruction to venous outflow in CRVO may become more relevant as not all patients respond well to intravitreal therapy. The limitation to this technique in the past has been lack of availability of a laser system with the power necessary to create the L-CRA. The success rate with the new system has improved to 88% representing a significant improvement over our original success rate of 33%.

The effect of central retinal venous pressure in patients with central retinal vein occlusion and a high mean area of nonperfusion.

PURPOSE: To evaluate the effect of central venous pressure (CVP) on visual outcomes and retinal ischemic consequences in patients with central retinal vein occlusion (CRVO). DESIGN: Prospective, single-center cohort study. PARTICIPANTS: Eighty-eight patients with CRVO and a high overall mean area (21.6 disc areas) of capillary nonperfusion (CNP) who were followed for 18 months before the availability of intravitreal therapy and who were offered standard care of the time. METHODS: Patients were evaluated at baseline and at 3, 8, and 18 months. At each study visit, measurements of CVP, best-corrected visual acuity (BCVA), area of CNP, retinal fluorescein transit time (FTT), and an evaluation for rubeosis iridis were performed. MAIN OUTCOME MEASURES: Evaluation of the effect of different levels of CVP on BCVA, retinal blood flow, and the development of retinal ischemia and rubeosis iridis. RESULTS: Mean BCVA was significantly higher in patients with lower CVP at all time points (P<0.0001). The area of CNP increased significantly with higher levels of CVP and progressed with time. The development of rubeosis iridis was significantly associated with CVP at all time points and was present in 5.6%, 27.9%, and 88.9% of those with low, moderate, and high CVP levels, respectively (P<0.0001), at the 18-month conclusion. Retinal blood flow as measured by FTT was reduced with higher levels of CVP. Spontaneous lowering of CVP had beneficial effects on BCVA, although this diminished with time. CONCLUSIONS: Eyes with increased CVP after more severe CRVO demonstrate significantly reduced vision, reduced retinal blood flow, a higher incidence of rubeosis iridis, and larger areas of CNP that correlate with the degree of CVP elevation.

Benefits of a Laser Chorioretinal Anastomosis Plus Ranibizumab vs Ranibizumab Alone for Central Retinal Vein Occlusion: 4-Year Results.

PURPOSE: To evaluate what clinical gains can be achieved over conventional treatment with ranibizumab alone for central retinal vein occlusion (CRVO) when causal pathology is additionally addressed successfully with a laser-induced chorio-retinal anastomosis (L-CRA). DESIGN: Two-year extension of prospective, randomized controlled clinical trial. METHODS: A total of 58 patients with macular edema secondary to CRVO were randomized 1:1 to receive either an L-CRA (n = 29) or sham procedure (n = 29) at baseline and then monthly intravitreal ranibizumab 0.5 mg. Outcomes (best corrected visual acuity [BCVA], central subfield thickness [CST], injection requirements) were monitored in the monthly pro re nata (PRN) ranibizumab phase from months 7 to 48. RESULTS: Injection requirements for patients with a functioning L-CRA (24 of 29) during the monthly PRN period from 7 to 24 months were a mean (95% CI) of 2.18 (1.57, 2.78) injections compared to 7.07 (6.08, 8.06) (P < .0001) for control (ranibizumab alone). These decreased further over the next 2 years to 0.29 (0.14, 0.61) compared to 2.20 (1.68, 2.88) (P < .001) for the third year and 0.25 (0.11, 0.56) and 1.84 (1.34, 2.54) for the fourth year (P < .001). Mean BCVA was statistically different at all follow-up time points from month 7 through month 48 for the group with the functioning L-CRA compared to the control monotherapy group. This improved to 14.06 letters at month 48 (P = .009). There was no difference in CST between any of the groups over the 48 months of follow-up. CONCLUSION: For CRVO patients, addressing causal pathology in addition to conventional therapy improves BCVA and reduces injection requirements.

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.

Functional benefits of a chorioretinal anastomosis at 2 years in eyes with a central retinal vein occlusion treated with ranibizumab compared with ranibizumab monotherapy.

OBJECTIVE: To evaluate the functional benefits (best corrected visual acuity (BCVA), central subfield thickness, injection loads, central venous pressure (CVP)) of a laser-induced chorioretinal anastomosis (L-CRA) in patients with central retinal vein occlusion (CRVO) treated with ranibizumab compared with ranibizumab monotherapy. METHODS AND ANALYSIS: This is a post-hoc analysis of the 2-year randomised ranibizumab plus L-CRA for CRVO trial. Twenty-four patients (82.5%) developed a functioning or successful L-CRA; outcome effects were monitored in the monthly as-needed ranibizumab phase from months 7 to 24 and compared with the ranibizumab monotherapy group (n=29). RESULTS: From months 7 to 24, the mean (95% CI) injection load for the functioning L-CRA group was 2.18 (1.57 to 2.78) compared with 7.07 (6.08 to 8.06) for the control group (p<0.0001). The mean BCVA was averaged across all timepoints between the control and functioning L-CRA groups (average difference=11.46 (3.16 to 19.75) letters, p=0.01). At 2 years, there was an 82.5% reduction in the odds of high CVP (greater or equal to central retinal artery diastolic pressure) for those with a successful L-CRA compared with controls (p<0.0001). CONCLUSION: For patients with CRVO, adding L-CRA as a causal-based treatment to conventional therapy reduced CVP and injection loads and offered improved BCVA.Trial registration number ACTRN12612000004864.

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.

Two-Year Efficacy of Ranibizumab Plus Laser-Induced Chorioretinal Anastomosis vs Ranibizumab Monotherapy for Central Retinal Vein Occlusion: A Randomized Clinical Trial.

Importance: Adding a laser-induced chorioretinal anastomosis (L-CRA) to current treatments for central retinal vein occlusion (CRVO) may improve outcomes and lessen therapy burdens. Objective: To determine the 2-year efficacy of intravitreal ranibizumab with an L-CRA vs ranibizumab alone for patients with macular edema caused by CRVO. Design, Setting, and Participants: In this randomized clinical trial conducted at a single university clinic from March 2012 to June 2015, 58 participants with macular edema caused by CRVO were randomized 1:1 to either an L-CRA or sham procedure at baseline. All participants received monthly intravitreal injections of ranibizumab, 0.5 mg. Data were analyzed from April 2017 to September 2017. Interventions: Random assignment to L-CRA plus monthly injections of intravitreal ranibizumab, 0.5 mg, (combination group; n = 29) or to a sham L-CRA procedure plus monthly injections of intravitreal ranibizumab, 0.5 mg, (ranibizumab alone group; n = 29) for 6 months. From month 7 to month 24, participants were evaluated monthly and received an injection of ranibizumab if a loss of 5 or more letters of best-corrected visual acuity (BCVA) on ETDRS chart from previous highest score occurred or if there was evidence of residual macular edema on optical coherence tomography. Main Outcomes and Measures: Mean number of injections from month 7 to month 24, change in BCVA, and change in central subfield thickness (CST). Results: Of the 58 included participants, 38 (66%) were men, and the mean (SD) age was 68.6 (11.8) years; participants had a mean (SD) BCVA of 57.09 (11.87) ETDRS letters (Snellen equivalent, 20/73) and a mean (SD) CST of 738.36 (175.54) µm. A successful L-CRA was created in 24 of 29 participants (83%) in the combination group. The mean number of injections from month 7 to month 24 was 3.2 (95% CI, 2.5-3.8) in the combination group and 7.1 (95% CI, 6.0-8.0) in the ranibizumab alone group. The ratio of the number of injections in the combination group compared with the ranibizumab alone group was 0.46 (95% CI, 0.36-0.61; P < .001). Mixed-effects regression modeling showed a difference in mean BCVA at 2 years between the combination and ranibizumab alone groups (combination, 70.3 letters [Snellen equivalent, 20/40]; ranibizumab alone, 61.6 letters [Snellen equivalent, 20/60]; difference, 8.8 letters; 95% CI, 0.2-17.3; P = .05). There was also a difference in CST at 2 years between the combination and ranibizumab alone groups (mean CST: combination, 303.6 µm; ranibizumab alone, 394.5 µm; difference, 90.9 µm; 95% CI, 24.3-157.5; P = .01). Four participants (14%) in the combination group required a vitrectomy for early macular traction or vitreous hemorrhage. Conclusions and Relevance: For macular edema caused by CRVO, an L-CRA significantly reduced the number of ranibizumab injections required. Trial Registration: anzctr.org.au Identifier: ACTRN12612000004864.

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.