Abstract
Purpose: :
To assess the hemodynamic response of retinal arterioles and venules following an intravitreal injection of ranibizumab in neovascular age-related macular degeneration (AMD) patients and the influence of the number of prior injections on this response.
Methods: :
Fifteen patients with neovascular AMD were recruited and subsequently allocated into 2 groups depending upon the number of prior intravitreal ranibizumab injections; Group I comprised 7 patients who had undergone 3 or fewer prior injections (mean age 72.0, SD=8.8 years) and Group II comprised 8 patients who had undergone more than 3 prior injections (mean age 71.9, SD=7.4). Four non-neovascular patients (mean age 80.0, SD=2.8 years) were also included. Vessel diameter, centerline velocity and blood flow within two disc diameters of the optic nerve head along the superior temporal arteriole and venule were selected using the Canon Laser Blood Flowmeter (CLBF). Measurements were acquired in neovascular AMD patients immediately before a scheduled ranibizumab injection and immediately prior to the next monthly injection or assessment (Group I mean follow-up 37.7 days, SD=6.5; Group II mean follow-up 36.7 days, SD=7.1).
Results: :
At baseline, there were no differences in arteriolar diameter (one-way ANOVA, p=0.057) or retinal venule diameter (p=0.53) between the 3 groups. Neovascular AMD patients in Group I but not Group II experienced a significant decrease in retinal arteriolar diameter, velocity and flow at the monthly follow-up compared to baseline (paired t-test, p<0.05). No changes in the diameter, velocity or flow in the venule were observed in either group. At follow-up, there was still no difference in the retinal arteriolar diameter among the 3 groups of patients (one-way ANOVA, p=0.10).
Conclusions: :
Intravitreal ranibizumab treatment for neovascular AMD results in arteriolar vasoconstriction and a reduction in centerline velocity and blood flow in patients that have received 3 or less previous injections.
Keywords: age-related macular degeneration • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • vascular endothelial growth factor