Sustained prothrombotic profile after hip replacement surgery: the influence of prolonged prophylaxis with dalteparin.

In a randomized trial on the effect of dalteparin for 5 weeks after HRS we evaluated hemostatic variables in plasma sampled before and 1, 6 and 35 days postoperatively. In 218 patients we found that prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin complexes (TAT), d-dimer and fibrinogen were significantly higher on day 35 as compared with baseline values in the placebo group (P < 0.001 for all). The same pattern was found in the dalteparin group, but with significantly lower values for F1 + 2, TAT and d-dimer. In patients in the placebo group with venographically proven deep vein thrombosis (DVT) on day 35 (33%), significantly higher values were found for F1 + 2, TAT and d-dimer than in patients without DVT. Patients in the highest quartile of d-dimer (>2850 ng mL-1) had an odds ratio for the presence of DVT of 24.0 when compared with patients in the lowest quartile (<1625 ng mL-1). It is concluded that a substantial hypercoagulability is sustained until day 35 after HRS, significantly reduced with prolonged administration of dalteparin.