Abstract
Purpose: :
There is growing interest in the treatment of diabetic macular edema (DME) with VEGF inhibitors, including bevacizumab (Avastin) and ranibizumab (Lucentis). It has been found that certain OCT subtypes of DME are more likely to respond favorably to focal laser photocoagulation or to intravitreal triamcinolone (IVTA). This study examines the response of OCT subtypes of DME to VEGF inhibition with Avastin.
Methods: :
A retrospective chart review was performed on all patients receiving Avastin for DME at a single vitreoretinal practice. Patients were included only if their primary diagnosis was DME, posttreatment OCT was performed within 3-8 weeks of injection, and no other treatment was given concurrent with Avastin therapy (e.g. Avastin plus focal laser). Patients previously treated with another modality were included if the treatment preceded the date of Avastin injection by at least 3 months. The pretreatment OCT was used to classify each patient’s DME as predominantly cystic (CME), diffuse retinal thickening (DRT), or predominantly tractional (ERM/VMT). The primary outcome measures were change in central subfield thickness (CST) and change in logMAR visual acuity (VA).
Results: :
Analysis was performed on 41 injections in 19 eyes (9 with NPDR and 10 with PDR) of 16 patients. All eyes had received prior focal laser, IVTA, or both. Overall, the mean change in VA was +0.03 (95% confidence interval -0.04 to +0.10, p = 0.70, 2-tailed student’s t-test). The mean change in CST was -12.4 µm (95% CI -40.0 µm to +15.1 µm, p = 0.60). For CME, the mean change in VA was +0.03 (95% CI -0.08 to +0.14, p = 0.77). The mean change in CST was -22.9 µm (95% CI -79.9 µm to +35.3 µm, p = 0.47). For DRT, the mean change in VA was -0.05 (95% CI -0.13 to +0.03, p = 0.71). The mean change in CST was +3.0 µm (95% CI -25.0 µm to +31.2 µm, p = 0.92). For ERM/VMT, the mean change in VA was +0.22 (95% CI +0.06 to +0.38, p = 0.15). The mean change in CST was -37.0 µm (95% CI -122.9 µm to +48.6 µm, p = 0.52).
Conclusions: :
In this subgroup of patients with previously treated, refractory DME, there was no statistically significant difference in VA or CST after treatment with Avastin. Stratification of the patients by OCT subtype of DME did not significantly alter the outcome data, although there was a trend toward visual decline in the group with ERM/VMT.
Keywords: diabetic retinopathy • edema • imaging/image analysis: clinical