Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com Original Paper Pathophysiol Haemost Thromb 2003/04;33:192–196 DOI: 10.1159/000081507 Acquired and Inherited Thrombophilic Factors and the Risk for Residual Venous Thrombosis Ivan Bank a Lidwine W. Tick c Barbara A. Hutten b Mark H.H. Kramer c Saskia Middeldorp a Harry R. Büller a Departments of a Vascular Medicine and b Clinical Epidemiology and Biostatistics, Academic Medical Center, University of Amsterdam, Amsterdam and c Department of Internal Medicine, Eemland Hospital, Amersfoort, The Netherlands inherited thrombophilia did not differ from patients with- out any thrombophilic abnormality with regard to resid- ual thrombotic mass [relative risk (RR) 1.3, 95% confi- dence interval (CI) 0.9–1.8], while acquired thrombophilic disorders increased the risk for residual thrombotic mass as compared to patients without any defect (RR 1.7, 95% CI 1.2–2.2). Although these results should be confirmed in a larger study, they might help us form hypotheses concerning why patients with thrombophilia are more prone to recurrent venous thromboembolic disease. Copyright © 2004 S. Karger AG, Basel Introduction Acquired and inherited thrombophilic factors are as- sociated with a tendency to develop venous thromboem- bolism (VTE). Although it is known that some (acquired) thrombophilic states, for example the antiphospholipid syndrome, malignancy and elevated clotting factor VIII:c (FVIII:c), as well as persistence of thrombotic obstruction, increase the risk for recurrence of VTE, little is known about the pathophysiological mechanisms caus- ing these recurrences [1–3] . Key Words Residual thrombosis  Location of thrombotic lesions  Deep venous thrombosis  Inherited thrombophilia  Acquired thrombophilia Abstract Acquired and inherited thrombophilic factors increase the risk for (recurrent) venous thrombotic disease. How- ever, little is known about the pathophysiological mech- anisms causing these recurrences, or the persistence of thrombosis despite adequate treatment. Because resid- ual thrombosis has been associated with a worse prog- nostic outcome, we performed an explorative study in order to investigate the prevalence of residual throm- botic lesions after anticoagulant treatment in patients with deep venous thrombosis. Thrombotic parameters as assessed by ultrasonography after a 12-week course of anticoagulants were used. Both thrombophilia in gen- eral and acquired thrombophilia in particular were found to be associated with the extent of residual thrombosis. Of the individual thrombophilic factors, protein C defi- ciency, prothrombin 20210A mutation, active malignant disease and lupus anticoagulant were associated with an increased risk of residual thrombotic mass. Patients with Received: February 25, 2004 Accepted after revision: June 22, 2004 Pathophysiology and Thrombosis of Haemostasis I. Bank Department of Vascular Medicine, Academic Medical Center F4-277, Meibergdreef 9 NL–1105 AZ, Amsterdam (The Netherlands) Tel. +31 20 5665976, Fax +31 20 6968833, E-Mail I.Bank@amc.uva.nl © 2004 S. Karger AG, Basel 1424–8832/04/0334–0191$21.00/0 Accessible online at: www.karger.com/pht