THE RESOLUTION OF DEEP VENOUS THROMBOSIS THAT OCCURS AFTER TOTAL JOINT ARTHROPLASTY - A STUDY OF THROMBI TREATED WITH ANTICOAGULATION AND OBSERVED BY REPEAT VENOUS ULTRASOUND SCANS

Thrombi found in the deep thigh veins of postoperative total hip or kn ee arthroplasty patients were followed prospectively by repeat venous ultrasonography to determine the efficacy and appropriate duration of anticoagulation therapy. Forty-four patients who had 47 proximal vein thrombi (femoral or popliteal) were treated with heparin or warfarin o r both. Thirteen patients had two or more and 34 had a single follow-u p venous ultrasound scan. The last follow-up scan was done at an avera ge of seven weeks after the thrombus was diagnosed. Thirty-four thromb i (72%) had lysed at that time. Twelve thrombi (26%) were smaller or u nchanged in size. One thrombus propagated and later embolized despite the use of heparin and warfarin. Forty-five percent (21 of 47) of the thrombi had lysed within six weeks of the initiation of anticoagulatio n therapy. The results of this study indicate that the standard durati on of anticoagulation therapy for postoperative proximal deep vein thr ombosis of three months may be excessively long for half of these pati ents. The use of follow-up venous ultrasound scanning to determine whe n it is appropriate to terminate anticoagulation therapy is a logical clinical management strategy.