DIAGNOSTIC-VALUE OF COMPRESSION ULTRASONOGRAPHY AND FIBRINOGEN-RELATED PARAMETERS FOR THE DETECTION OF POSTOPERATIVE DEEP-VEIN THROMBOSIS FOLLOWING ELECTIVE HIP-REPLACEMENT - A PILOT-STUDY

To determine their ability to diagnose postoperative deep vein thrombo sis (DVT) D-dimer - by three methods -, fibrinogen degradation product s (FgDP) and fibrinogen levels were measured in 68 consecutive patient s before elective surgery for hip replacement and on postoperative day 1, 3, 6, and 10. All patients received prophylaxis and underwent comp ression real-time B-mode ultrasonography (C-US) on postoperative day 5 and 9, and bilateral ascending venography on day 10. Twenty-two out o f 68 patients developed asymptomatic postoperative DVT, which was limi ted to the calf veins in 14 and involved the proximal veins in 8 patie nts. C-US was negative in all patients on day 5. On day 9, C-US sensit ivity and specificity for proximal DVT were 63% (95% confidence interv al: 26%-90%) and 98% (89%-100%) respectively. Postoperative changes in the laboratory parameters evaluated were not different in patients wi th or without DVT until day 10. On day 10, mean D-dimer, FgDP and fibr inogen levels were significantly higher in patients with DVT than in t hose without DVT (p values between 0.006 and 0.032), but only D-dimer was higher with DVT involving two or more venous segments than with th rombosis involving one venous segment only (p <0.05). Stepwise logisti c regression analysis identified D-dimer and fibrinogen on day 10 as p redictors of postoperative DVT. In a receiver operator curve and after weighing for the coefficients generated by logistic regression analys is, the combination of-a latex photometric immuno-assay and of PT-deri ved fibrinogen yielded - at a cut-off value of 7.0 a sensitivity of 10 0% (73%-100%) and a specificity of 58% (39%-75%) for DVT, with a negat ive predictive value of 100% (78%-100%), a positive predictive value o f 52% (32%-71%) and an overall accuracy of 71% (55%-83%). These result s suggest that two simple, fast and reproducible tests may permit the identification of patients at low risk of having postoperative DVT and that a combination of sensitive laboratory assays and of the highly s pecific C-US may select patients requiring anticoagulant treatment. Ef ficacy and cost-effectiveness of this approach should be evaluated in large clinical management studies.