Risk factors associated with Ahmed valve implant dysfunction in patients with neovascular glaucoma during the first postoperative year

Abstract

AbstractBackgroundThe current surgical management of Neovascular Glaucoma (NVG) is with the placement of the Ahmed Valve. However, up to 70% fail and the factors associated with this failure are unknown. Recognizing the factors associated with dysfunction will help to identify patients prone to failure promptly to establish prompt management and improve visual and functional prognosis.ObjectiveTo determine the risk factors associated with Ahmed valve dysfunction in patients with NVG during the first year after surgery.PopulationPatients diagnosed with VNG who have undergone Ahmed valve implantation in the Glaucoma - APEC service, during the 2013 to 2019 period.Methodsambispective cohort. Patients with NVG defined as the Presence of neovessels in the iris or angle of the anterior chamber were included, those who had a history of implantation of a drainage device, and patients with a diagnosis of glaucoma in the terminal phase, worse visual acuity of perception were excluded. of light. The research unit was eyes subjected to Ahmed valve implantation. The demographic characteristics of the patients were evaluated, as well as the characteristics of the eyes.The primary outcome and the secondary outcomes were adverse events, visual acuity, and final intraocular pressure. An unadjusted Cox proportional hazards model was used to determine risk factors such as Hazzard ratios (HR). Those significant factors were included in a Cox proportional hazards model to adjust for the main confounding variables.Results174 eyes were included. Baseline intraocular pressure (IOP) was 46.03 (±11.8) mmHG. Baseline VA in LogMAR was 1.52(0.89-2.3). Risk factors were: Age <50 years with HR 1.54(95% CI 1.04-2.30); HB1Ac >8% HR 1.71 (95% CI 1.12-2.60) and presence hypertensive phase HR 3.13 (95% CI 1.57-6.23). The multivariate model was adjusted for the following variables, baseline IOP less than 40mmHg HR 1.60 (95% CI 1.04-2.47); HB1Ac >8% HR 1.80 (95% CI 1.16-2.78); FP7 valve type HR 1.75(95% CI 1.04-2.94) and presence of hypertensive phase HR 3.24 (95% CI 1.60-6.59).ConclusionBasal IOP less than 40mmHg, HB1Ac >8%, type of FP7 valve, surgery performed by a resident, lack of photocoagulation after implantation, and the presence of a hypertensive phase are the independent risk factors for implant valvular dysfunction.