Functional Assessment of fibrinolytic Resistance in whole Blood

Abstract

Venous thromboembolism represents a significant cause of Morbidity worldwide [1]. Korninger et al. [2] suggested that an impaired fibrinolytic response to venous occlusion May predispose to recurrent thrombosis. Various immunochemical and functional assays for the assessment of the components of the fibrinolytic pathway are available. The Main parameters determined are the tissue plasminogen activator (tPA), plasminogen and tissue plasminogen activator inhibitor I (PAI-1). Schulman et al. examined this hypothesis in a relatively large population [3]. He found that increased levels of tPA and PAI-1 correlated significantly with the development of recurrences, but concluded that the Measurements were of limited utility. A large cross-sectional study of venous thrombosis patients [4] came to a similar conclusion. In a recent study [5] the value of a comprehensive fibrinolytic screening in predicting recurrences was evaluated in 319 patients with a first episode of venous thrombosis. Assays were performed four weeks after the diagnosis of deep venous thrombosis while patients were receiving warfarin as well as one week after its discont inuation. No systematic differences in the levels of tPA antigen and functional PAl-1 or euglobulin lysis times were found between patients who did, or did not, suffer recurrent thrombosis. In a commentary to this article [6] Bauer comes to the conclusion that these classical fibrinolysis parameters are not useful in the assessment of the thrombophilia risk of patients with an initial episode of venous thrombosis.However the author also states that other mechanisms involved in the downregulation of fibrinolysis such as the thrombin activatable fibrinolysis inhibitor might be involved in the pathogenesis of thrombosis and that new assay systems of fibrinolysis might lead to an improved definition of the clinical implications of fibrinolysis abnormalities in patients with venous thrombosis.