Bleeding and re-thrombosis in primary antiphospholipid syndrome on oral anticoagulation

Abstract

SummaryThe aimof this studay was to compare bleeding and re-thrombosis in primary antiphospholipid syndrome (PAPS), mitral valve replacement (MVR) and inherited thrombophilia (IT) at different oral anticoagulation intensities. It entailed a prospective 8-year follow-up on 67 patients with PAPS, 89 with IT and 24 with MVR. Anticardiolipin (aCL) antibodies detected by Elisa and lupus anticoagulant by clotting assays. At INR 2–3 minor bleeding rate was higher in MVR (33.3) than PAPS (10.9) and IT (4.2)(p<0.0001). At INR 3–4 minor bleeding rate was higher in PAPS (142) than IT (33.3) and MVR (5.8)(p<0.0001). At either INR major bleeding rate were not significantly different across the three groups, but in PAPS major and minor bleeding rates were superior at INR 3–4 than INR 2–3 (p=0.02 and p<0.0001). Re-thrombosis rate was higher in PAPS than IT at INR 2–3 (4.0 vs 0.35) (p=0.01) and at INR 3–4 (10.5 vs. nil). The hazard ratio for re-thrombosis between PAPS and IT was 13 (95% IC 1.6–102.2, p=0.015). By regression analysis, baseline IgG aCL titre (>80 GPL) (p=0.001) and male sex (p=0.03) independently predicted re-thrombosis. In conclusion, in PAPS, high intensity oral anticoagulation was not superior to conventional intensity in preventing re-thrombosis but was offset by greater bleeding rates. Male sex and elevated baseline IgG aCL predicted re-thrombosis in PAPS that is 13-fold more re-thrombogenic than IT.