DIAGNOSIS OF POSTOPERATIVE VENOUS THROMBOSIS WITH THE D-DIMER TEST

Purpose. The D-Dimer test has been shown to be highly sensitive for th e diagnosis of deep vein thrombosis (DVT) and pulmonary embolism. Two automatic quantitative tests giving a rapid response within 10 and 30 minutes have been recently marketed. In the postsurgery situation howe ver, the role of the D-Dimer test remains controversial and the optima l cutoff value remains open. The aim of this study was to determine th e cutoff value during the postoperative period. Patients and methods. One hundred three consecutive patients admitted to surgery were includ ed. In all patients, D-Dimer lest was performed every 2 or 4 days from admission to hospital discharge. The Vidas D-Dimer (Biomerieux, Marcy l'Etoile, France) and the STA Liatest D-DI (Diagnostica Stage, Asnier es, France) were performed in parallel in all cases. Results. Thirty-f ive patients were excluded because the follow-up period was too short. Results suggest that a D-Dimer value below 2 mu g/ml has a negative p redictive value of 100 %. A D-Dimer value over 4 mu g/ml would indicat e suspected deep vein thrombosis in half of the cases, even without cl inical signs. Dividing the patients into three groups according to the D-Dimer value; the two tests correlated poorly (r=0.36 and 0.57) in t he middle group (between 2 and 3 and between 3 and 4) and correctly fo r values below 2 or over 4 mu g/ml (r=0.83 and 0.78 respectively). Con clusion. These two optimum cutoff values (< 2 mu g/ml and > 4 mu g/ml) are useful for determining the need for further explorations for DVT. By limiting need for ultrasonography and contrast venography, the cos t-efficacy ratio for the detection of DVT during the postoperative per iod is greatly improved with the D-Dimer screening strategy.