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.