RETINAL VENOUS OCCLUSION AND RESISTANCE T O ACTIVATED PROTEIN-C

Background A new abnormality in the coagulation system, the resistance to activated protein C, has appeared among the numerous hereditary mo difications which predispose patients to deep-vein thrombosis. The mol ecular abnormality responsible for the resistance to activated protein C is due to a mutation of an amino acid in the 506 position (Arg --> Gln) at the level of the factor V, designated under the name of factor V Leiden. Methods The authors wished to seal ch for this alteration o f the haemostasis in 106 patients with retinal venous occlusion hospit alized in Centre Hospitalier National d'Ophtalmologie des Quinze-Vingt s (Paris). Results In our study of 106 patients presenting a retinal v enous occlusion, the resistance to activated protein C was the most fr equent coagulation abnormality found (4.71 %), when compared with othe r deficits of the inhibitors of the clotting system: protein S (2.80 % ), antithrombin III (0.94 %) et protein C (0 %). Conclusion The test o f resistance to activated protein C should be recommanded in cases of retinal venous occlusion, particularly in the search for a cause of th rombosis in young patients or in recurrent thrombosis.