Abstract
Purpose: :
The aim is to investigate the short-term effect of a single intravitreal bevacizumab, ranibizumab or pegaptanib sodium injection on the retinal arteriolar caliber in minipigs.
Methods: :
Eight eyes received an intravitreal injection: bevacizumab 1,25mg (n=3), ranibizumab 0,5mg (n=4) and pegaptanib sodium 0,3mg (n=1). The diameter of the retinal arterioles was measured in vivo with a Retinal Vessel Analyzer (RVA) every 15 minutes for 2 hours.
Results: :
For the bevacizumab group, mean retinal arteriolar diameter was 198.9μm at baseline, 190.6μm after 30min, 183.5μm after 45min, 169.9μm after 1h, 182.2μm after 1h and 30min and 169.6μm after 2h. For the ranibizumab group, mean retinal arteriolar diameter was 191.16μm at baseline, 176.5μm after 30min, 169.5μm after 45min, 167.7μm after 1h, 162.5μm after 1h and 30min and 163.4μm after 2h. The eye that received pegaptanib sodium showed no modification of the arteriolar diameter. There was no significant change in MAP during the follow-up period (p > 0.05).
Conclusions: :
After the injection of bevacizumab statistical significant vasoconstriction was reached 1h after injection (p< 0.01) and persisted until the end of the measurements (2h). Ranibizumab injection induces a transient vasoconstriction of the retinal arterioles. Statistical significant (p < 0.05) arteriolar vasoconstriction is reached only 45min following the injection. Preliminary results after pegaptanib sodium injection revealed no vasomotor effect of the substance. The results suggest that intravitreal injection of anti VEGF induces retinal vasoconstriction. Further studies with a larger number of subjects would be helpful in establishing more clearly the effect of intravitreal anti-vascular endothelial growth factor treatment on retinal vessel diameters.
Keywords: retina • growth factors/growth factor receptors • blood supply