Risk for developing primary events. Relation between prothrombin F1+2 plasma levels and the risk of developing primary end points during the first 6 months (thin line) and from 6 months to the end of follow-up (thick line). The 2 curves have similar shapes, but the lowest risk for developing primary events was observed in conjunction with prothrombin F1+2 plasma levels of between 1.0 and 1.7 nM in the first 6 months, and between 1.9 and 2.5 nM from 6 months to the end of follow-up.