Evaluation of the hemostatic system in patients with arterial retinal occlusion.

Retinal arterial occlusion usually has an acute onset with damage of central or peripheral visual function. Pathogenesis is generally atherothrombotic or embolic. In this study we have evaluated hemostatic system parameters in acute phase and 3-6 months later in 13 patients (11 men and 2 women, age from 59 to 73 years) affected by acute retinal ischemia (central retinal arterial thrombosis, arterial branch thrombosis, embolism or retinal ischemia). Only one patient had a history of vascular accidents. Clinical manifestations, ophthalmoscopic finding and fluoroangiographic examination made diagnosis of retinal ischaemia. We measured in citrated plasma, by ELISA, prothrombin fragment 1+2 (F1+2), a quantitative index of prothrombin activation, thrombin-antithrombin complex (TAT), an index of circulating thrombin, and D-dimer, a cross-linked fibrin degradation product, in addition to routine hemostatic tests (activated PTT, prothrombin time, thrombin time, antithrombin III, fibronogen). The study of hemostasis was carried out at diagnosis, before any specific treatment, and then at least 1 month after the discontinuation of antithrombotic therapy. The results, outlined in the following table, indicate an accelerated activation of prothrombin to thrombin (high F1+2) and an increase in circulating thrombin (high TAT) in the acute phase, with subsequent normalization. Our findings provide evidence that increased thrombin generation may play a role in acute retinal ischemia; counteracting thrombin activity appears as a useful approach in the management of retinal occlusion.