A cross sectional study of antiphospholipid-protein antibodies in patientswith venous thromboembolism

Objective: To look for an association between venous thromboembolism (VTE) and antiphospholipid antibodies (aPL) in patients without Systemic Lupus Er ythematosus (SLE) when implementing, beside conventional assays, new tests for aPL screening directed towards purified proteic targets. Methods: We co nducted a cross-sectional, hospital-based study of consecutive unselected o utpatients. We compared VTE+ patients to VTE- among 398 consecutive unselec ted outpatients referred for clinical suspicion of VTE. To detect aPL, the following ELISAs were performed : 1) a conventional standardized ELISA 2) a n improved APA assay, 3) an anti-Beta2GPI ELISA, 4) an a-mi-Annexin V ELISA , 5) an anti-Prothrombin ELISA. We sought an association between VTE and aP L through a quantitative (t-test) and a qualitative comparison (chi-square test, according to the cut-off values set as the 95th percentile of aPL dis tribution). First we conducted an analysis of all patients. Then we stratif ied them into 2 subgroups, with or without a wellknown risk factor for VTE (prolonged immobilization > 72h, surgery or trauma within the past three mo nths, current malignancy). Results: 61% of patients were classified as VTE- positive. Before stratification, we did not find any significant associatio n between the VTE status and aPL. However, after stratification, in the sub group without risk factors for VTE, the frequency of positive values as re( yards the anti Prothrombin antibodies detection was significantly higher in VTE+ patients (p = 0,04). Conclusion: The presence of anti Prothrombin ant ibodies mi-ht be an independent risk factor of VTE. However systematic scre ening for aPL in non SLE patients referred for VTE suspicion at the time of the thrombo-embolic event has little clinical relevance.