Multicenter study of the European Assessment Group for Lysis in the Eye (EAGLE) for the treatment of central retinal artery occlusion: design issues and implications. EAGLE Study report no. 1

Background: The natural course of central retinal artery occlusion (CRAO) often leads to legal blindness in the affected eye. To date, none of the conservative therapies had proven effective in retrospective studies. In 1991, a new minimally invasive therapy was started in patients with an acute CRAO. This therapy, namely, local intra-arterial fibrinolysis, is comparable to the minimally invasive therapy in patients with an acute ischemic stroke. In pilot studies, it showed promising results in comparison with conservative treatments. The efficacy of this method is now being investigated in a randomized multicenter study. Methods: The European Assessment Group for Lysis in the Eye (EAGLE) started a prospective and randomized multicenter study in 2002 to evaluate therapeutic efficacy. Inclusion criteria are age between 18 and 75 years and a CRAO not older than 20 h with a visual acuity less than 0.32. The most important exclusion criteria are branch retinal artery occlusion (BRAO), cilioretinal arteries supplying the macula, and serious general disease. After randomization the patient is treated by conservative or local intra-arterial lysis therapy. The conservative regime included bulbus massage, lowering intraocular pressure with topical beta-blocker and acetazolamide, acetylsalicylic acid, heparin, and-depending on the hematocrit-isovolemic hemodilution. In case of local intra-arterial fibrinolysis, a maximum of 50 mg rtPA is injected into the ophthalmic artery by the neuroradiologist. During the following 5 days, all patients are treated with heparin. Primary study end point is visual acuity 1 month after therapy in comparison with visual acuity before therapy. The calculated sample size is 100 patients per subtrial (a total of 200 patients). The study was started in June 2002. To April 2005, 47 patients were included. Conclusions: The EAGLE Study is the first randomized prospective clinical trial to compare conservative medical treatment and local intra-arterial fibrinolysis in patients with CRAO. The results of this study should enable ophthalmologists and neuroradiologists to improve the therapy of patients with acute CRAO. To April 2005, treatment is only justified in randomized multicenter studies because of the limited therapeutical visual outcome. We welcome new study centers to join.