Assessment of the role of thrombin activatable fibrinolysis inhibitor in retinal vein occlusion.

PURPOSE: To determine whether elevated levels of thrombin activatable fibrinolysis inhibitor (TAFI) may contribute to thrombotic risk for patients with retinal vein occlusion (RVO) and to investigate the possible correlations between TAFI activity level and other conventional risk factors.

METHODS: Ninety patients with RVO (cases), except those receiving medication affecting the study parameters, those undergoing a surgical procedure within the last week, and those with kidney and/or liver failure, were enrolled in the study. The control group included similar patients matched for age and sex. After written informed consent was obtained, parameters including TAFI activity levels, conventional risk factors, results of routine hematological examination, and factor V Leiden and prothrombin G20210A mutations were evaluated by analysis of blood samples obtained after an 8-hour fast.

RESULTS: Although TAFI activity levels were slightly elevated in cases (190.5 +/- 43.8) compared with controls (183.9 +/- 41.8), the difference was not statistically significant (P = 0.36). According to evaluation of TAFI activity in subgroups (>200%, 150-200%, and 0-150%), 36.7% with central RVO, 40.0% with branch RVO, and 30% of controls were found to have TAFI activity of >200% (P = 0.83). TAFI activity levels did not correlate with age, sex, demographics, clinical status, and hematological variables. Finally, in stepwise regression analysis, TAFIa (carboxypeptidase U) activity was not found to be an important risk factor for RVO.

CONCLUSION: On the basis of these data, TAFI activity was not found to be a new risk factor for either type of RVO. However, further larger studies may better identify the exact role of TAFI in the pathogenesis of RVO.