Changes of aqueous vascular endothelial growth factor and pigment epithelium-derived factor following intravitreal bevacizumab for macular oedema secondary to branch retinal vein occlusion

P>Background: To investigate sequential changes of aqueous vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF) in macular oedema secondary to branch retinal vein occlusion (BRVO) following intravitreal injection of bevacizumab (IVB). Methods: We recruited 10 healthy controls and 40 patients with BRVO. Aqueous levels of VEGF and PEDF were measured by ELISA at the time of IVB and 6 weeks later. Non-response to IVB was defined as showing persistent macular oedema based on reduction of central macular thickness by less than 20% from baseline measurements by optical coherence tomography and vision improvement by < 0.3 logMAR at 6 weeks after IVB. Fluorescein angiography was performed after resolution of foveal haemorrhage. We compared aqueous levels of VEGF and PEDF between responders and non-responders. Results: The aqueous levels of VEGF and PEDF were significantly higher in 16 non-responders than in 24 responders at baseline measurements (491 +/- 231 pg/mL vs. 250 +/- 112 pg/mL, P < 0.001; 32 +/- 4 ng/mL vs. 25 +/- 5 ng/mL, P < 0.001, respectively). Six weeks after IVB, the aqueous levels of VEGF and PEDF were still higher in non-responders than in responders (388 +/- 141 pg/mL vs. 104 +/- 40 pg/mL, P < 0.001; 30 +/- 8 ng/mL vs. 18 +/- 5 ng/mL, P < 0.001, respectively). Fluorescein angiography revealed that non-responders showed higher frequencies of macular ischaemia and ischaemic BRVO. Conclusions: Our results indicate that aqueous VEGF levels are associated with persistent macular oedema secondary to ischaemic BRVO following IVB.