Impact of angiogenesis inhibitors on the postoperative course of Ahmed valve implantation in patients with neovascular glaucoma

Abstract

PURPOSE. To compare the course of the early postoperative period after Ahmed valve implantation in patients with neovascular glaucoma of diabetic and post-thrombotic genesis with and without anti-VEGF therapy.METHODS. This study included patients with refractory neovascular glaucoma of diabetic and post-thrombotic genesis who were indicated for Ahmed valve implantation. Some patients underwent intravitreal administration of ranibizumab 4–14 days prior to implantation. A total of 39 eyes from 39 patients were included in the study and divided into 2 groups: group 1 (n=20) — patients with refractory neovascular glaucoma of diabetic and post-thrombotic genesis with Ahmed valve implantation without prior anti-VEGF therapy; group 2 (n=19) — patients with refractory neo-vascular glaucoma of diabetic and post-thrombotic genesis with anti-VEGF therapy before Ahmed valve implantation. The following parameters were assessed: best corrected visual acuity (BCVA), intraocular pressure (IOP) before and after the intervention, and the course of the early post-operative period.RESULTS. In the group with prior intravitreal administration of ranibizumab, the incidence of hyphema was significantly reduced due to regression of the newly formed vessels. The study showed the best functional outcomes are achieved with the use of preparation therapy with anti-VEGF before Ahmed valve implantation: increase of corrected visual acuity by 34%, stabilization of initially elevated IOP by 100%. The baseline IOP of 29.9±6.6 mm Hg decreased to 9.7±3.6 mm Hg (p<0.05). The better visual results can be attributed to the reduced incidence of hyphema as a result of preoperative anti-VEGF therapy, which simplifies the surgical procedure. In addition, preoperative intravitreal injection of ranibizumab (IVI) improved best corrected visual acuity by relieving macular edema. Our study shows that the combination of Ahmed valve implantation and intravitreal injection of an anti-VEGF agent is successful in the early follow-up period, but fails to persist: an increase in IOP to almost 21 mm Hg was seen in both groups by the end of one-year follow-up, and visual acuity regressed in group 2.CONCLUSION. The use of anti-VEGF agent prior to Ahmed valve implantation provides better functional outcomes in the early postoperative period. Intravitreal administration of ranibizumab prior to Ahmed valve implantation minimizes the number of hemorrhagic complications in the early postoperative period and reduces the length of hospital stay. Within one year after surgery, patients experienced regression of visual acuity, as well as an increase in intraocular hypertension following the reactivation of iris neovascularization.