FREQUENCY OF PULMONARY-EMBOLISM IN PATIENTS WHO HAVE ILIOFEMORAL DEEP-VEIN THROMBOSIS AND ARE TREATED WITH ONCE-DAILY OR TWICE-DAILY LOW-MOLECULAR-WEIGHT HEPARIN

Purpose: The purpose of this study was to compare the efficacy and saf ety of treating mobile iliofemoral patients with deep venous thrombosi s (DVT) with subcutaneous low-molecular-weight heparin (dalteparin sod ium) either 200 IU/kg once-daily (group I) or 100 IU/kg twice-daily (g roup 2). Methods: Consecutive patients with suspected iliofemoral DVT diagnosed by duplex ultrasonography and verified by radionuclide venog raphy were randomized to one of the two low-molecular-weight heparin ( LMWH) regimens. Perfusion and when necessary ventilation scans were pe rformed for diagnosis of pulmonary emboli (PE) in all patients immedia tely after admission and were repeated after approximately 10 days, wh ereupon oral anticoagulation was started unless contraindicated. Minim al and maximal anti-factor Xa activity was measured after 2 to 3 days of therapy. All patients were kept mobile with compression bandages. T he primary end point was reduction in frequency of PE as assessed on t he second lung scan. Results: A total of 140 patients with confirmed D VT were randomized, 76 to group 1 and 64 to group 2. The two groups we re comparable in their baseline clinical characteristics. In the initi al lung scans 36 (47.4%) patients in group I and 29 (45.3%) patients i n group 2 had objectively verified PE, but only 11 (14.5%) and 8 (12.5 %) patients, respectively, had symptoms. After dalteparin treatment PE disappeared in two patients in group 1, but in two other cases new PE s occurred, (NS). In group 2 a resolution of PEs was observed in eight patients, whereas only one new PE could be detected This change refle cts the efficacy of therapy as defined by resolution of existing PEs a nd by the occurrence of new PEs and is statistically significant accor ding to Me Nemar's chi(2) test with the exact binomial method pair pro cedure (p < 0.05). Symptomatic PE was reduced from 14.5% to 5.3% in gr oup 1 (96% to CI for the difference, -1.5% to +17.3%) and from 12.5% t o 1.6% in group 2 (95% CI for the difference 0.7% to 18%, p < 0.05). T here was one single fatal PE, one serious and three minor bleeding epi sodes in group 1, and one minor bleeding episode in group 2 (95% CI fo r the difference: -3.6% to +8.1%). Conclusions: Treatment of ambulant iliofemoral patients with DVT with 100 IU/kg dalteparin twice-daily ap pears to be more safe and effective than 200 IU/kg given once-daily. B ed rest is not necessary for treating mobile patients.