Abstract
Purpose:
Pegaptanib has been shown to be an effective treatment in patients with diabetic macular edema (DME). In the original trial, however, patients with ischemia were excluded from the study. In this prospective, Phase IV, single-arm clinical trial, we have treated patients with ischemic DME.
Methods:
Ischemia was defined as a 30% increase in the area of the foveal avascular zone (FAZ) at 45 seconds on a fundus fluorescein angiogram (FFA). Participants were also required to have diffuse, foveal-involving DME with a central subfield thickness (CST) >300 microns on Heidelberg spectral domain optical coherence tomography. Five intravitreal Pegaptanib injections were given 6 weeks apart, with a final visit 6 weeks after the fifth injection. The primary study outcome was change in the size of the FAZ at 45 seconds on FFA. This was measured using Adobe Photoshop on a standardised image size. Secondary study outcomes were changes in best corrected visual acuity (BCVA) and CST over the 6 visits. Participants were subdivided into those with minimal/moderate ischemia (n=16, FAZ area <1000 pixels) and those with more severe ischemia (n=14, FAZ area >1000 pixels).
Results:
There were 30 participants. Mean age was 66.5 years (range 43-89 years) and the male:female ratio was 2:1. Three patients were unable to complete the full course of treatment: one due to a drop in BCVA of >30 letters, another due to bowel ischemia and another chose to discontinue treatment after 3 injections. The final results for these participants were carried forward for the purpose of this analysis. The overall mean FAZ area changed from 964 pixels at baseline to 987 pixels at Visit 6 (p=0.771). In the minimal/moderate ischemia group the mean FAZ area increased from 441 pixels at baseline to 538 pixels at Visit 6 (p=0.335). In the more ischemic group mean FAZ area decreased from 1562 pixels to 1500 pixels (p=0.624). Overall mean BCVA increased from 47.8 letters to 49.7 letters (p=0.476) and mean CST decreased from 491 microns to 451 microns (p=0.128). Analysis of the mean BCVA of those who completed the full course of treatment shows an increase from 49.2 letters at baseline to 53.9 letters at Visit 6 (p = 0.046).
Conclusions:
In our study intravitreal injection of Pegaptanib did not significantly alter the size of the FAZ in participants with varying degrees of ischemia and DME. In addition it did not lead to a statistically significant improvement in BCVA or CST.
Keywords: 499 diabetic retinopathy •
572 ischemia •
585 macula/fovea