Risk factors associated with thrombosis in patients with antiphospholipid antibodies

Objective. To define risk factors associated with thrombosis in patients wi th antiphospholipid antibodies (aPL). Methods. Ninety-rune patients with aPL. most of whom had prior thrombosis, were evaluated for the presence of acquired and inherited thrombophilic sta tes. Genomic testing was performed for factor V-R506Q, 3' prothrombin (PTG) and methylene tetrahydrofolate reductase (MTHFR) polymorphisms. Clinical r ecords were reviewed for the presence of acquired risk factors (RF) for thr ombosis and events associated with aPL. Univariate statistical analysis was performed using Fisher's exact testing. A neural network statistical model was also used to identify which thrombophilic risk factors were most impor tant in development of arterial and venous thrombosis. Results. For arterial thrombosis. hypertension, tobacco use, hyperlipidemia , and diabetes mellitus were the most important predictors of thrombosis. B y contrast. tobacco use, the 3' PTG and factor V-R506Q polymorphisms, and p revious cardiac surgery were the most important predictors of venous thromb osis. Conclusion. In this hypothesis-generating retrospective study, acquired ris k factors were most important in arterial thrombosis. while the presence of factor V-R506Q and 3' PTG polymorphisms were more important in the develop ment of venous thrombosis. These findings are being validated in an ongoing , prospective study.