Summary

The aimof this studay was to compare bleeding and re-thrombosisin primary antiphospholipid syndrome (PAPS), mitral valvereplacement (MVR) and inherited thrombophilia (IT) at differentoral anticoagulation intensities. It entailed a prospective 8-yearfollow-up on 67 patients with PAPS,89 with IT and 24 with MVR.Anticardiolipin (aCL) antibodies detected by Elisa and lupusanticoagulant by clotting assays.At INR 2–3 minor bleeding ratewas 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 inPAPS (142) than IT (33.3) and MVR (5.8)(p<0.0001). At eitherINR major bleeding rate were not significantly different acrossthe 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 (4.0vs 0.35) (p=0.01) and at INR 3–4 (10.5 vs. nil).The hazard ratiofor re-thrombosis between PAPS and IT was 13 (95% IC1.6–102.2, p=0.015). By regression analysis, baseline IgG aCLtitre (>80 GPL) (p=0.001) and male sex (p=0.03) independentlypredicted re-thrombosis. In conclusion, in PAPS, high intensityoral anticoagulation was not superior to conventional intensityin preventing re-thrombosis but was offset by greater bleedingrates. Male sex and elevated baseline IgG aCL predicted rethrombosisin PAPS that is 13-fold more re-thrombogenic thanIT.