The Effect of Intravitreal Injection of Bevacizumab on Retinal Circulation in Patients with Neovascular Macular Degeneration

Abstract

Purpose. Intravitreal (ITV) injection of anti-VEGFs like bevacizumab are widely used to treat neovascular AMD. However, VEGF is essential for biologic functions such as blood pressure regulation. Indeed, anti-VEGF intravenous administration is associated with hypertension. Therefore, the effect of ITV bevacizumab on retinal circulation was examined. Methods. Twenty-three patients with neovascular AMD treated with three repeat ITV injections of bevacizumab were recruited. Blood arteriolar diameter and flow measurements were performed with a bidirectional laser Doppler flowmeter at baseline, 1 week after the first injection, just before the second injection, and 5 weeks after the third injection. Scanning laser Doppler flowmetry was used to assess the effect of bevacizumab on tissue perfusion at the first and fourth visits. Results. Arteriolar diameter significantly decreased from 122.5 ± 14.5 μm to 118.9 ± 14.0 μm (P = 0.03) during the first week to reach a mean value of 117.2 ± 13.7 μm at the end of the study (P < 0.01). Arterial blood flow did not change significantly. Neuroretinal rim perfusion decreased from 181.1 ± 84.1 arbitrary flow units to 167.7 ± 76.5 arbitrary flow units, which was borderline significant (P = 0.06). No significant change was observed in the peripapillary retina. Conclusions. Arteriolar diameter decreased significantly after the first injection and persisted until the end of the study suggesting a long-term effect of bevacizumab on vascular tone. However, the blood flow change is not significant. A borderline significant decrease in neuroretinal rim perfusion was observed and suggests that the neuroretinal rim may be more sensitive than the peripapillary retina to the effects of bevacizumab.