Warfarin inhibits Vit K dependent synthesis of factors & proteins.
Vit K is necessary for the maturation of clotting factors II, VII, IX, X and protein C & S
So a drug that can inhibit the carboxylation of precursor proteins or in other words inhibit the maturation of the clotting factors will decrease the risk of thrombosis in this patient.
warfarin inhibits the synthesis of factors II, VII, IX, X, C, and S by blocking reduction of oxidized vitamin K. The enzyme Epoxide Reductase is inhibited by warfarin. The reduced (active) form of vit. K is a cofactor for gamma-glutamyl carboxylase.
Why not PGI2 by way of ASA? Especially given other answer choices of proteins C + S: doesn't warfarin also suppress these?