Comparison of Two Doses of Intravitreal Bevacizumab as Primary Treatment for Macular Edema Secondary to Retinal Vein Occlusions: Results of the Pan American Collaborative Retina Study Group (PACORES) at 24 Months

Abstract

Purpose: : To compare the 24 month visual and anatomic outcomes after injecting two different doses of intravitreal bevacizumab as primary treatment in patients with macular edema secondary to branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO).

Methods: : An interventional, retrospective, multicenter study of 149 eyes (63 eyes with BRVO and 86 eyes with CRVO) with macular edema secondary to retinal vein occlusion that were treated primarily with at least one intravitreal injection of 2 different doses of bevacizumab. The main outcome measures were the central 1 mm macular thickness (CMT) and the change of best corrected visual acuity (BCVA) at 24 months.

Results: : All 149 patients completed at least 24 months of follow-up. At the 24 month follow-up, the logMAR BCVA improved in the BRVO 1.25 mg group 0.38 ± 0.63 units vs 0.64 ± 0.60 units for the BRVO 2.5 mg group (p=0.2950); in the CRVO 1.25 mg group the logMAR BCVA improved 0.35 ± 0.57 units vs 0.17 ± 0.68 units for the CRVO 2.5 mg group (p=0.5001). The CMT improved from 453 ± 140 µm to 244 ± 125 µm in the BRVO 1.25 mg group vs 444 ± 175 µm to 234 ± 80 µm in the BRVO 2.5 mg group (p=0.6415); the CMT in the CRVO 1.25 mg group improved from 635 ± 324 µm to 264 ± 160 µm vs 528 ± µm to 293 ± 137 µm in the CRVO 2.5 mg group (p=0.8290). There were no cases of endophthalmitis, 1 case of uveitis was reported. Systemic adverse events included 1 death, 2 myocardial infarctions and 3 cerebrovascular accidents. The average number of injections were 7.2 for the CRVO 1.25 mg group vs 8.1 for the CRVO 2.5 mg group (p=0.4492) and 4.2 for the BRVO 1.25 mg group vs 5.4 for the BRVO 2.5 mg group (p=0.2721).

Conclusions: : There were no statistically significant differences between the two dose groups with regard to the number of injections, CMT and change in visual acuity. Intravitreal bevacizumab at doses up to 2.5 mg appears to be effective in improving visual acuity and reducing CMT in macular edema secondary to retinal vein occlusions.

Keywords: vascular occlusion/vascular occlusive disease • vascular endothelial growth factor • edema