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Z. Ahmad, S. Mansour; Effect of Intravitreal Bevacizumab (Avastin®) on Perifoveal Capillaries in Diabetic Retinopathy. Invest. Ophthalmol. Vis. Sci. 2008;49(13):3514. doi: https://doi.org/.
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To ascertain the effect of intravitreal Bevacizumab (Avastin, Genentech, Inc., San Francisco, CA) on the perifoveal capillaries bordering the foveal avascular zone (FAZ) in patients with proliferative diabetic retinopathy (PDR). Given that VEGF plays a role in the maintenance of mature vasculature, there is concern that complete blockage of VEGF may lead to further capillary compromise and macular ischemia in patients with PDR who often have enlarged FAZ’s.
A retrospective chart review was conducted. Data was collected from a private office for all patients who received intravitreal Avastin (0.1cc/2.5mg) injections for proliferative diabetic retinopathy from September 2005 to November 2007. Those patients with fluorescein angiograms (FA’s) available both before and after Avastin injection(s) of sufficient quality to allow accurate outline of the FAZ were included in the study. The FAZ was manually outlined in the earliest discernible phase of each angiogram by the same observer and area calculated using VisuPac software (Version 4.2.2, Carl Zeiss Meditec, Germany). To normalize data, the size of the optic disc was also measured in the same frame as the FAZ for comparison (Figure 1). FAZ area is expressed as a fraction of disc area (DA).
10 patients, ages 34-66, received one to three injections in a given eye for a total of 25 injections in 14 eyes included in the study (Table 1, Chart 1). The mean time between preinjection FA and first Avastin injection was 31 days, and between last Avastin injection and postinjection FA was 76 days. The preinjection and postinjection mean FAZ areas were 0.15DA (SD 0.11) and 0.14DA (SD 0.10) respectively. A paired t-test showed no statistically significant difference between FAZ size before and after injection (p=0.47).
Our preliminary results indicate that intravitreal Avastin, at least in the short term does not appear to affect the size and architecture of the perifoveal capillaries that border the foveal avascular zone in diabetic retinopathy. Further prospective studies are needed to determine the long term effects of this drug on retinal vasculature in proliferative diabetic retinopathy.
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