Prothrombin fragment 1+2 in urine as an indicator of sustained coagulation activation after total hip arthroplasty

Purpose: Prothrombin fragment 1 + 2 measured in spot urine (uF1 + 2) is an indicator of thrombin generation. We examined whether measured levels of uF1 + 2 can be used to differentiate between patients who do and do not acquire sustained coagulation activation after total hip arthroplasty (THA). Methods: We performed two separate studies in patients undergoing THA. Study 1 was a prospective pilot study aiming to roughly estimate the extent of pre- and postoperative fluctuations in the uF1 + 2 concentration. Study 2 was a larger prospective cohort study aiming to verify the findings of Study 1 and to examine the association between the uF1 + 2 concentrations and risk of vascular thrombotic complications (VTC) or death. Finally, we sought to define a cut-off concentration value that could be used to identify patients with a sustained uF1 + 2 elevation after the first postoperative week. The urine samples were analysed by ELISA. In both studies thromboprophylaxis was used for at least 7 days after the operation. Results: The operative trauma resulted in elevation of the uF1 + 2 level in all patients compared with the preoperative level and levels in the healthy volunteers. Ten out of 113 patients (8.8%) in the second study suffered VTC or death, assumed to be caused by a coagulation problem. Analysis of variance revealed the following statistically significant associations: pre- vs. postoperative tog uF1 + 2 Levels (P