Abstract
Purpose: :
To study the effect of intravitreal (IVT) ranibizumab on the retinal arteriolar diameter in patients with neovascular age-related macular degeneration (AMD).
Methods: :
Eleven eyes of eleven patients with previously untreated neovascular AMD were included. All eyes had three monthly IVT injections of ranibizumab and then as needed based on visual acuity and optical coherence tomography (OCT) crtiteria. The diameter of the retinal arterioles was measured in vivo with a Retinal Vessel Analyzer (RVA) before the first IVT injection, 7 and 30 days after the first, the second and the third injection, and at month 12 of follow-up. Primary endpoints were changes in retinal arteriolar diameter, and mean arterial blood pressure (MAP). Secondary endpoints were changes in best-corrected visual acuity (BCVA) and central retinal thickness following IVT ranibizumab.
Results: :
A significant vasoconstriction of the retinal arterioles was observed following each one of the first three IVT injections of ranibizumab. Thirty days following the first, second and third injection, there was a mean decrease of 8.1 ± 3.2 %, 11.5 ± 4.4 % and 17.6 ± 7.4 % respectively of the retinal arteriolar diameter (n=11) compared to baseline (p < 0.01). At month 12, the vasoconstriction was still present with a mean decrease of 19 ± 8 % of the retinal arteriolar diameter (n=10) compared to baseline (p<0.01). Mean number of IVT ranibizumab injections was 5 ± 2. There was no correlation between the number of injections and % diameter decrease at month 12 (r = 0.54, p > 0.1). There was no significant change in MAP during the period of follow-up (p > 0.05). At month 12, mean BCVA improved by 4.3 ± 7.2 ETDRS letters and central retinal thickness decreased by 110 ± 117 µm (p < 0.05).
Conclusions: :
These results suggest that IVT ranibizumab induces sustained retinal arteriolar vasoconstriction in patients with neovascular AMD. Further studies with larger sample sizes are needed to confirm these results as well as potential adverse effects on the retinal circulation in patients with neovascular AMD and with retinal vascular diseases.
Keywords: age-related macular degeneration • clinical (human) or epidemiologic studies: outcomes/complications • retina