ANTIPHOSPHOLIPID ANTIBODIES AND VENOUS THROMBOEMBOLISM

The clinical relevance of antiphospholipid antibodies (APLA) in patien ts without systemic lupus erythematosus who have venous thromboembolis m (VTE) is unknown. Limited evidence suggests that there is an associa tion between the presence of APLA and both initial and recurrent episo des of VTE and that patients with APLA and VTE are resistant to warfar in therapy, Unselected patients with a first episode of clinically sus pected deep vein thrombosis or pulmonary embolism were evaluated with objective tests for VTE and with laboratory tests for APLA; the latter included tests for the lupus anticoagulant (LA) and anticardiolipin a ntibodies (ACLA), Patients with VTE were treated with anticoagulant th erapy and observed during and after discontinuation of anticoagulants for symptomatic recurrence of VTE. There was a strong association betw een LA and VTE (odds ratio, 9.4; 95% confidence interval [CI], 2.1 to 46.2) and 9 of 65 (14%; 95% CI, 7% to 25%) patients with VTE had LA. T here was no association between the presence of ACLA and VTE (odds rat io, 0.7; 95%CI, 0.3 to 1.7) because of the high frequency of positive ACLA assays in patients without VTE, None of the 16 patients with VTE and APLA developed recurrent VTE while receiving warfarin therapy, The re was no difference in rates of recurrent VTE in patients with or wit hout APLA after anticoagulant therapy was discontinued, The strong ass ociation between LA and VTE suggests that testing for LA in patients w ith VTE is useful, The measurement of ACLA in patients with VTE has no clinical usefulness because the results are abnormal in a high propor tion of patients without VTE, Although the presence of APLA in patient s with VIE was not associated with resistance to a conventional intens ity of warfarin or an increased risk of recurrent VTE after discontinu ation of warfarin, a larger study should address these issues in a sub group of patients with VTE and LA. (C) 1995 by The American Society of Hematology.