Postoperative Versus Preoperative Initiation of Deep-Vein Thrombosis Prophylaxis with a Low-Molecular-Weight Heparin (Nadroparin) in Elective Hip Replacement

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Abstract
The aim of this multicenter, randomized, dou ble-blind study performed in patients undergoing elective hip surgery was to compare the efficacy and safety of prophylaxis with low-molecular-weight heparin (LMWH) (Nadroparin, 7,500 anti-Xa IC units for the first 3 days and 10,000 from the fourth day on, s.c. o.i.d.) begun in one group shortly after surgery and in the other 12 h before operation, as is usually recommended. Preopera tive administration (drug or placebo) was the only differ ence between the two groups. Deep vein thrombosis (DVT) was detected by bilateral venography 10-15 days after surgery. The study investigated 179 patients (55 men), 40-80 years old, in seven Italian orthopedic cen ters. In 131 patients efficacy analysis was possible be cause of adequate bilateral venography. All 179 patients were evaluated for bleeding complications. The preva lence of thrombotic complications was similar in the two groups. Proximal DVT was found in 8.4% of patients (10.8% and 6.1% in the preop and postop groups, respec tively ; difference not statistically significant). Distal DVT was recorded in 30.5% of patients (30.8% and 30.3% in the pre- and postop groups, respectively). DVTs were more common in patients ≥65 years old (54.2% versus 28.4%, p < 0.05); no significant differences were detected in terms of other characteristics. No significant differ ences were recorded in the number or type of bleeding complications: major (nonfatal) bleeding episodes were reported in five patients (2.8%, two and three in the pre- and postop groups); minor bleeding was noted in 25 (13.9%, 14 and 11 in the pre- and postop groups). In con clusion, the present study suggests that a LMWH regi men started postoperatively is no less effective in pre venting DVT in elective hip replacement than the classi cal regimen started preoperatively. Surprisingly, postoperative commencement offered no significant ad vantage in terms of bleeding complications.