Sheathotomy BRVO. Is randomised prospective EuropeanMulitcenter Study necessary

Sandra Kunze, C. Mayer, H. H. Müller, P. Kroll (Marburg)

Branch retinal vein occlusion (BRVO) is a frequent cause of visual disturbance, almost half of the patients are 65 years of age or younger. Most of them suffer from a visual acuity of 0,4 or less.
The origin of BRVO is commonly localized at arteriovenous crossing sites. At this site both vessels share a common adventitial sheath. Arteriosclerotic changes and the resulting thickening of the arteria may compress the adjacent vein causing turbulent blood flow predisposing the AV-crossing for thrombosis and BRVO.
Due to missing successful therapeutical strategies Osterloh and Charles (1988) developed a new surgical procedure that involves decompression of the common sheath connecting the artery and vein at the crossing (adventitial sheathotomy of AV-crossing). Opremcak and Bruce (1999) described 10 of 15 cases with improved functional and morphological outcome. From August 1999 until February 2001 Mester and Dillinger performed a sheathotomy in 40 patients. They reported a significant increase of visual acuity compared to a group of patients only treated with isovolaemic haemodilution. However, the control group was not randomized, and isovolaemic haemodilution is not proven to be an internationally accepted standard.
Using the results of Mester and Dillinger as a pilot study we plan a randomized open study aiming to evaluate the therapeutic effect of AV-sheathotomy. Primary endpoint is the success rate. Success is defined as an improvement of at least 2 lines at the three months visit compared to the baseline visual acuity. The study is designed to detect an increase of approximately 20 % in the success rate with a power of 80 %. Thereby we expected a success rate of about 20 – 30% in the control group. Recruitment of 216 patients is necessary. Thus we require cooperation in a multicenter project to achieve this number of patients within a recruitment phase of about 1.5 years. Seven departments of ophthalmology in Germany and Spain will participate.


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