Fibrinolytic parameters in patients undergoing total hip replacement: relationship with the development of asymptomatic deep vein thrombosis and diagnostic usefulness of venous occlusion.

Background and Objective. It has been suggested that impaired fibrinolytic activity contributes to deep vein thrombosis in orthopedic surgery. Studying the fibrinolytic system following venous occlusion has been proposed as a good method of detecting the risk of this postoperative complication. The objective of this work was to verify whether venous occlusion represents a reliable method of detecting an impaired fibrinolytic response after total hip replacement. Methods. Thirty-two consecutive patients undergoing total hip replacement were studied. Citrated blood samples were taken from each patient the day before surgery and on postoperative days 1, 3, and 7, before and after venous occlusion, in order to evaluate plasma levels of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI-1). All patients underwent bilateral phlebography 10 days after surgery. Results. Seven out of 32 patients (21.9%) developed deep venous thrombosis (DVT) according to the venographic test. After surgery, an increase in t-PA antigen levels was detected both in patients who developed DVT and in those who did not, with a significant increase on the first and seventh days after surgery only in the non-DVT group. After 10-min venous occlusion, t-PA antigen levels increased at all postoperative recordings in both groups of patients, but most significantly on days 1 and 7 after surgery. PAI-1 antigen plasma levels, when measured before venous occlusion, increased only in non-DVT patients on the seventh postoperative day. After venous occlusion, a difference was found between the two groups only postoperatively on day 7 with regard to PAI-1 levels. Interpretation and Conclusions. According to our results, no impaired fibrinolytic response was found in DVT patients. In addition, venous stasis seems to give no further information with respect to basal values in the early detection of postoperative thromboembolic complications in orthopedic patients.