Macular Perfusion Determined by Fundus Fluorescein Angiography at the 4 Month Time Point in a Prospective Randomised Trial Comparing Intravitreal Bevacizumab With Laser Therapy in the Management of Diabetic Macular Oedema

Abstract

Purpose: : To assess macular perfusion with fundus fluorescein angiography (FFA) at the 4 month time point in a prospective randomised trial comparing intravitreal bevacizumab and laser therapy in patients with diabetic macular oedema.

Methods: : The design of this single centre study has been published previously. All enrolled patients had standard Wisconsin seven field fundus photographs and FFA at baseline and subsequently at 4 month intervals. Patients were excluded from the study if either the greatest linear dimension (GLD) of the foveal avascular zone (FAZ) was greater than 1000µm in diameter, or there was severe perifoveal capillary loss (ETDRS criteria) on FFA. The maintenance of the FAZ is a safety outcome in the study with patients being withdrawn from the study if between consecutive angiograms there is either a 3 step increase in perifoveal intercapillary space (or evidence of severe loss) or a 30% increase in the GLD of the FAZ. The FFAs of the bevacizumab (n=41) and the laser (n=39) groups have been reviewed by the Moorfields Reading Centre in a masked fashion to determine whether macular perfusion has been compromised in either treatment arm.

Results: : At baseline the mean GLD of the FAZ in the laser group was [ 701 + 290 µm ] and in the bevacizumab group was [ 735 + 275 µm ]. The baseline median perifoveal intercapillary distance was graded as moderate in both the laser group and in the bevacizumab arm.At the 4 month time point the mean GLD of the FAZ in the laser group was [ 679 + 215 µm ] and in the bevacizumab group was [ 681 + 237 µm ]. The 4 month median perifoveal intercapillary distance was graded as moderate in both the laser group and in the bevacizumab arm. To date no patients have been withdrawn from the study due to worsening macular ischaemia.

Conclusions: : At the 4 month time point there was no evidence of worsening macular ischaemia in either group. Our preliminary data is in contrast to previous clinical and laboratory studies suggesting an adverse effect of bevacizumab on macular perfusion.

Clinical Trial: : www.ISRCTN.org ISRCTN41984498

Keywords: diabetic retinopathy • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • vascular endothelial growth factor