Preoperative identification of patients at high risk of deep venous thrombosis despite prophylaxis in total hip replacement.

Clinical and laboratory variables were measured on the day before operation in 111 patients who underwent total hip replacement prophylactically treated with acetylsalicylic acid or heparin-dihydroergotamine. Postoperative deep vein thrombosis (DVT) was detected in 16 patients by ascending venography. Stepwise logistic discriminant analysis was used to identify DVT predicting factors. Three such factors, fibrinogen degradation products (FDP), plasminogen activator inhibitor (PA-inhibitor) and tissue type plasminogen activator (t-PA), were found to be significantly associated with DVT and were used to construct a predictive index. The predictive index, I = -2.09 + 0.46 (FDP) + 1.39 (PA-inhibitor) -0.24 (t-PA), was 100% sensitive and 95% specific in the prediction of DVT. This index would allow for identification of those patients in whom routine prophylaxis would be sufficient and for selecting those in whom more effective prophylactic regimens would be necessary.