[Retinal vein occlusion and resistance to activated protein C]

A new abnormality in the coagulation system, the resistance to activated protein C, has appeared among the numerous hereditary modifications which predispose patients to deep-vein thrombosis. The molecular 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.

The authors wished to search for this alteration of the haemostasis in 106 patients with retinal venous occlusion hospitalized in Centre Hospitalier National d'Ophthalmologie des Quinze-Vingts (Paris).

In our study of 106 patients presenting a retinal venous occlusion, the resistance to activated protein C was the most frequent coagulation abnormality found (4.71%), when compared with the other deficits of the inhibitors of the clotting system: protein S (2.80%), antithrombin III (0.94%) et protein C (0%).

The test of resistance to activated protein C should be recommanded in cases of retinal venous occlusion, particularly in the search for a cause of thrombosis in young patients or in recurrent thrombosis.