Intravitreal Bevacizumab and Triamcinolone Associated to Laser Photocoagulation for Diabetic Macular Edema(IBeTA)

Overview

Intravitreal triamcinolone has been effective for central macular thickness reduction and concomitant visual acuity improvement in patients with diabetic macular edema (DME). VEGF is a very effective inducer of permeability, being 50.000 times more potent than histamine, and may exert its effect on retinal vascular permeability by altering tight-junctions proteins, such as occluding and VE-cadherin. Based on these principles, there is a rationale for anti-VEGF agents treatment of increased retinal capillary permeability conditions, such as diabetic macular edema. Therefore, the purpose of this study is to evaluate the effects of intravitreal bevacizumab and intravitreal triamcinolone associated to laser photocoagulation for diabetic macular edema.

Macular edema is a leading cause of decreased visual acuity in patients with diabetic retinopathy1,2. Laser photocoagulation is the standard of care treatment for diabetic macular edema, based on ETDRS and recent clinical trials findings3,4. However, because visual acuity improvement post-laser is observed infrequently, and because of the frequent recurrence or persistence of DME (refractory DME) after appropriate laser treatment, particularly in eyes presenting with angiographically diffuse macular edema5-9, there is a need for alternative treatments for the management of DME. In addition, for some patients with significant cataract, precise visualization of posterior pole structures may not be possible, so that pharmacological therapy with intravitreal agents may be preferable over laser treatment. Recent studies have shown promising results of pharmacological therapies for Diabetic macular edema. Triamcinolone has shown similar results when compared to ranibizumab and deferred focal/grid LASER in pseudophakic eyes (DRCRnet, prompt versus deferred). Ranibizumab associated with deferred LASER or as monotherapy has also shown promising results (RISE and RIDE). However, there are several concerns regarding long-term intravitreal injections therapies that include economic feasibility for the public health system, risk of endophthalmitis and patient acceptability. For these reasons, the present study decided to check associations between LASER and drug therapy, in an attempt to improve focal/grid laser outcomes with reduced number of intravitreal injections.