Summary
The 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.
Keywords
Antiphospholipid - anticardiolipin - lupus anticoagulant - warfarin - thrombosis