Abstract
Purpose:
To adopt a new grading scale (SAVE protocol) based on morphologic characteristics in spectral domain optical coherence tomography (SDOCT) and fluorescein angiography (FA) for the follow up of patients treated with intravitreal injections for diabetic macular edema (DME).
Methods:
Monthly acquired OCT scans and quarterly acquired FAs obtained during the study period of 12 months in 3 prospective clinical trials of the diabetic retinopathy research group (DRRG) Vienna were graded in regard to morphologic characteristics. The grading protocol abbreviated “SAVE” evaluates the presence of subretinal fluid (“S”), the edema expansion in the ETDRS grid (area, “A”), vitreo-retinal abnormalities (“V”), as well as the source of leakage (edema type, “E”).
Results:
586 OCTs and 247 FAs of 50 patients (mean age 61 (±10,2) yrs, 22 female) receiving treatment for center involving DME were evaluated: 20 patients received three initial injections with 2,5mg bevacizumab followed by monthly PRN treatment, 20 patients received initially 8mg triamcinolone intravitreally followed by quarterly PRN treatment, and 10 patients received a loading dose of three injections with 0,5mg ranibizumab followed by monthly PRN treatment. Treatment response was similar in all treatment groups showing early resolution of subretinal fluid and dissolving macular edema from initially 509(±125) microns at the center subfield to 325(±105) microns after 12 months. At baseline retinal thickening was prevalent in 7 ETDRS subfields and regressed to 3 subfields at month 12. Vitreomacular abnormalities were present in 11 patients, in 3 cases they were not visible at baseline but only became apparent after regression of CME. In FA primarily focal or primarily diffuse edema pattern were graded in 22 and 28 patients respectively, with ischemic areas detected in 42 subjects.
Conclusions:
SD OCT and FA provide more information than currently used for DME classification or treatment algorithms. The SAVE grading scale defines the basic characteristics of DME in a detailed, but evident approach that can be easily integrated in daily clinical practice. Future studies are needed to evaluate treatment decisions based on the SAVE protocol.
Keywords: 499 diabetic retinopathy •
550 imaging/image analysis: clinical