[Effects of thromboprophylaxis duration on coagulation indicators after total hip replacement]

To compare the effects of short-term and long-term thromboprophylaxis after total hip replacement on coagulation indicators in plasma sampled before and 1, 7 and 35 days post-operation.

A total of 40 patients scheduled for elective total hip replacement were randomly assigned into the short-term (n = 20) or long-term (n = 20) thromboprophylaxis groups on oral rivaroxaban 10 mg once daily for 7 or 35 days. The primary efficacy hemostatic variables included thrombin-antithrombin complexes (TAT), prothrombin fragment 1+2 (F1t2), D-dimer and fibrinogen (Fib) preoperatively and at Days 1, 7 and 35 postoperatively. And ultrasonography was performed on all patients preoperatively and at days 7 and 35 postoperatively to exclude deep vein thrombosis of lower extremities.

None of them had deep vein thrombosis (DVT) of lower extremities. Among them, TAT, F1+2, D-dimer and Fib post-operation were higher than those preoperative baseline values. TAT and D-dimer peaked at day 1 postoperatively while the peaks of F1+2 and Fib appeared at day 7 postoperatively. At Day 35 post-operation, the levels of TAT and F1+2 in the long-term thromboprophylaxis group were significantly lower than those of the short-term thromboprophylaxis group (P < 0.05).

The status of hypercoagulability may sustain at least 35 days after total hip replacement. Though not completely eliminated, it can still be reduced by prolonged thromboprophylaxis. However, according to ultrasonography, the effects of short-term and long-term thromboprophylaxis on the incidence rate of DVT remain to be further explored.