A low-molecular-weight heparinoid compared with unfractionated heparin in the prevention of deep vein thrombosis in patients with acute ischemic stroke. A randomized, double-blind study. Prophylaxis of deep venous thrombosis with a low-molecular-weight heparin (Kabi 2165/Fragmin) in stroke patients. [Prevention of deep venous thrombosis of the leg by a very low molecular weight heparin fraction (CY 222) in patients with hemiplegia following cerebral infarction: a randomized pilot study (30 patients)]. Low-dose subcutaneous heparin in the prevention of deep-vein thrombosis and pulmonary emboli following acute stroke. Subcutaneous low-molecular-weight heparin compared with continuous intravenous heparin in the treatment of proximal-vein thrombosis. Low-molecular-weight heparin in the treatment of patients with venous thromboembolism. The Columbus Investigators. A double-blind and randomized placebo-controlled trial of low molecular weight heparin once daily to prevent deep-vein thrombosis in acute ischemic stroke. A randomised trial of subcutaneous low molecular weight heparin (CY 216) compared with intravenous unfractionated heparin in the treatment of deep vein thrombosis. A collaborative European multicentre study. Low molecular weight heparin and prevention of postoperative thrombosis in abdominal surgery.
To compare the relative safety and efficacy of a low-molecular-weight heparinoid (ORG 10172) with unfractionated heparin in the prevention of deep vein thrombosis in patients with acute ischemic stroke.
                Double-blind randomized trial.
                Seven Canadian university-affiliated hospitals.
                Eighty-seven patients with acute ischemic stroke resulting in lower-limb paresis.
                Patients received either low-molecular-weight heparinoid, 750 anti-factor Xa units twice daily, or unfractionated heparin, 5000 units subcutaneously twice daily. Treatment was continued for 14 days or until hospital discharge if sooner.
                Deep vein thrombosis was diagnosed using 125I-labeled fibrinogen leg scanning and impedance plethysmography. Venography was indicated if either test was positive. Overt hemorrhage, major or minor, was assessed clinically.
                Venous thrombosis occurred in four patients (9%) given low-molecular-weight heparinoid and in 13 patients (31%) given heparin (relative risk reduction, 71%; 95% CI, 16% to 93%. The corresponding rates for proximal vein thrombosis were 4% and 12%, respectively (relative risk reduction, 63%; P greater than 0.2). The incidence of hemorrhage was 2% in both groups.
                Low-molecular-weight heparinoid, given in a fixed dose of 750 anti-factor Xa units subcutaneously twice daily, is more effective than subcutaneous low-dose heparin for the prevention of deep vein thrombosis in patients with acute ischemic stroke. In a group of 60 patients in the acute phase of an ischemic stroke the assumption that low-molecular-weight heparin Kabi 2165 in the dose of 2 X 2,500 anti-Xa units s.c. could prevent thromboembolic complications was tested using a double-blind, placebo-controlled, randomized trial design. Thirty patients were allocated to each group. Both treatment groups were comparable with regard to neurological status and general condition. In the Kabi 2165 group there were 6 cases of deep venous thrombosis (DVT) compared to 15 in the placebo group (p = 0.05). In the placebo group there were 4 deaths during the trial versus 9 in the Kabi-2165-treated group (NS). Cerebral bleeding complicated 2 cases in the placebo group versus 4 in the Kabi 2165 group (NS). These results indicate that in ischemic stroke patients Kabi 2165 2 X 2,500 anti-Xa units s.c./24 h reduces the frequency of DVT. Because of the small number of patients it is impossible to evaluate the safety. The effectiveness and safety of a very low molecular weight heparin fraction were evaluated in the prevention of deep-vein thrombosis in patients confined to bed due to hemiplegia consecutive to a recent cerebral infarction. CY 222 was administered within 48 hours of the stroke by one single daily subcutaneous injection of 0.6 ml (= 15,000 U AXa IC) during 14 days. This randomized pilot study involved 30 patients. The effects of CY 222 were assessed in a group of 15 patients compared with a control group of 15 untreated patients. No deep-vein thrombosis was detected by the labelled fibrinogen test in the treated group, as against 12 patients in the control group. Six patients (3 in each group) died during the study. One case of lethal pulmonary embolism was observed and confirmed at autopsy in the control group. In the remaining 5 patients, no systematic autopsy which would have asserted the absence of pulmonary embolism or drug-induced haemorrhage was performed. Numerous standard laboratory tests confirmed that CY 222 was well tolerated. Venous thrombo-embolism is a major and often unrecognized cause of morbidity and mortality in patients after acute strokes. Three hundred and five elderly patients were randomly allocated to either control (161) or treatment (144) with 5000 units calcium heparin subcutaneously 8-hourly for two weeks. A reduction in deep-vein thrombosis rate from 72.7% in the control group to 22.2% in treatment patients was achieved. In patients who died (84), post-mortem examination to look for pulmonary emboli was performed in 71. Comparison between treated and untreated patients showed significantly fewer deaths and pulmonary emboli in the treated group. Most of the beneficial effect on mortality was seen in patients with lighter strokes. When patients with pulmonary emboli at post-mortem were excluded, there was no significant difference in the death rate in treatment (17) and control (14) groups. At post-mortem, 9.9% of the strokes were haemorrhagic (4 in the treatment and 3 in the control group). Low-dose calcium heparin given subcutaneously following acute stroke reduced the number of deep-vein thromboses, pulmonary emboli and deaths without increasing the number of haemorrhagic strokes in this study. Low-molecular-weight heparin has a high bioavailability and a prolonged half-life in comparison with conventional unfractionated heparin. Limited data are available for low-molecular-weight heparin as compared with unfractionated heparin for the treatment of deep-vein thrombosis.
                In a multicenter, double-blind clinical trial, we compared fixed-dose subcutaneous low-molecular-weight heparin given once daily with adjusted-dose intravenous heparin given by continuous infusion for the initial treatment of patients with proximal-vein thrombosis, using objective documentation of clinical outcomes.
                Six of 213 patients who received low-molecular-weight heparin (2.8 percent) and 15 of 219 patients who received intravenous heparin (6.9 percent) had new episodes of venous thromboembolism (P = 0.07; 95 percent confidence interval for the difference, 0.02 percent to 8.1 percent). Major bleeding associated with initial therapy occurred in 1 patient receiving low-molecular-weight heparin (0.5 percent) and in 11 patients receiving intravenous heparin (5.0 percent), a reduction in risk of 91 percent (P = 0.006). This apparent protection against major bleeding was lost during long-term therapy. Minor hemorrhagic complications were infrequent. Ten patients receiving low-molecular-weight heparin (4.7 percent) died, as compared with 21 patients receiving intravenous heparin (9.6 percent), a risk reduction of 51 percent (P = 0.049).
                Low-molecular-weight heparin is at least as effective and as safe as classic intravenous heparin therapy under the conditions of this study and more convenient to administer. The simplified therapy provided by low-molecular-weight heparin may allow patients with uncomplicated proximal deep-vein thrombosis to be cared for in an outpatient setting. Low-molecular-weight heparin is known to be safe and effective for the initial treatment of patients with proximal deep-vein thrombosis. However, its application to pulmonary embolism or previous episodes of thromboembolism has not been studied.
                We randomly assigned 1021 patients with symptomatic venous thromboembolism to fixed-dose, subcutaneous low-molecular-weight heparin (reviparin sodium) or adjusted-dose, intravenous unfractionated heparin. Oral anticoagulant therapy with a coumarin derivative was started concomitantly and continued for 12 weeks. Approximately one third of the patients had associated pulmonary embolism. The outcome events studied over the 12 weeks were symptomatic recurrent venous thromboembolism, major bleeding, and death. We sought to determine whether low-molecular-weight heparin is at least equivalent to unfractionated heparin in patients with venous thromboembolism.
                Twenty-seven of the 510 patients assigned to low-molecular-weight heparin (5.3 percent) had recurrent thromboembolic events, as compared with 25 of the 511 patients assigned to unfractionated heparin (4.9 percent). The difference of 0.4 percentage point indicates that the two therapies have equivalent value according to our predetermined definition of equivalence. Sixteen patients assigned to low-molecular-weight heparin (3.1 percent) and 12 patients assigned to unfractionated heparin (2.3 percent) had episodes of major bleeding (P= 0.63), and the mortality rates in the two groups were 7.1 percent and 7.6 percent, respectively (P=0.89).
                Fixed-dose, subcutaneous low-molecular-weight heparin is as effective and safe as adjusted-dose, intravenous unfractionated heparin for the initial management of venous thromboembolism, regardless of whether the patient has pulmonary embolism or a history of venous thromboembolism. The effect of LMW heparin (Kabi 2165, Fragmin) was compared with placebo for the prevention of DVT in 103 patients with acute ischemic stroke using a prospective, double-blind, randomized trial design. Treatment was started within 72 hours, and LMW heparin was administered subcutaneously once daily according to body weight classes, which corresponded to about 55 to 65 Factor-Xa inhibitory U/kg, for 14 days, or until discharge from the hospital, if earlier. All patients underwent thrombosis surveillance with unilateral venography of the paretic limb. Evaluation of venography could be performed in 42 of 52 patients randomized to LMW heparin and in 50 of 51 patients randomized to placebo. The frequency of DVT was 15 of 42 patients or 36% (95% confidence interval 22 to 52%) in the LMW heparin group and 17 of 50 patients or 34% (21 to 49%) in the placebo group. The frequency of proximal thrombi was 5 of 42 (12%) and 8 of 50 (16%), respectively. There was one fatal pulmonary embolism in the placebo group. The mortality rate (28 days follow-up) was 5 of 52 in the LMW heparin group and 1 of 51 in the placebo group (p = 0.24). None of the deaths was related to treatment. No major hemorrhagic complications were observed. The mean Factor Xa inhibitory activity levels at peak concentration were 0.34 U/ml on day 2 and 0.42 U/ml on day 12 (p = 0.02). We conclude that LMW heparin in the dose range studied did not provide efficient prophylaxis against DVT in patients with acute ischemic stroke. The standard treatment of deep vein thrombosis is given by continuous intravenous infusion of unfractionated heparin. This entails hospitalisation, nursing care, immobility and repeated laboratory tests (e.g. activated partial thromboplastin time [APTT], platelet count). In addition approximately 10% of patients suffer major haemorrhages. The potential advantages of a low molecular weight heparin (CY 216) given subcutaneously were explored in a randomised trial with blind quantitative evaluation of venograms. The study included 166 patients and both "therapeutic efficacy" and "intention to-treat" analyses showed that subcutaneous CY 216 in fixed doses based only on body weight was more effective on the Arnesen and Marder phlebographic scores than continuous i.v. standard heparin with daily dose adjustment according to results of coagulation tests. There was no increase in the risks of pulmonary embolism, haemorrhage or clot extension. In a prospective, double-blind, randomized multicenter trial the efficacy and safety of low molecular weight heparin and unfractionated heparin were compared for the prevention of postoperative deep vein thrombosis in patients undergoing abdominal surgery. Six hundred and seventy-three patients were randomly allocated to the two prophylaxis groups; 20 of these, however, did not undergo surgery and did not receive any prophylaxis. Of the remaining 653 patients 323 received one subcutaneous injection of 3,000 anti-Xa units of low molecular weight heparin and 330 received subcutaneously 5,000 U heparin three times a day. Treatment was initiated 2 h preoperatively and continued for 7 to 10 days. The occurrence of DVT was determined by the 125I-labelled fibrinogen uptake test and phlebography. Venous thrombosis was diagnosed in 24 of 323 patients (7.4%) treated with low molecular weight heparin and in 26 of 330 patients (7.9%) treated with low-dose heparin. DVT of proximal veins was detected in four patients of the low molecular weight heparin group and in three patients of the low-dose heparin group. During the observation period three pulmonary emboli - one fatal and two non-fatal - occurred in patients receiving prophylaxis with low-dose heparin. No pulmonary embolism was found in patients treated with low molecular weight heparin. Both prophylactic schemes were well tolerated. Intra- and postoperative blood loss, incidence of wound hematoma, frequency and volume of intra- and postoperative blood transfusion were similar in both groups with a slight advantage for the low molecular weight heparin group.(ABSTRACT TRUNCATED AT 250 WORDS)
Since the last version of this review none of the three new relevant studies with 2397 participants have provided additional information to change the conclusions. Treatment with a low-molecular-weight heparin or heparinoid after acute ischaemic stroke appears to decrease the occurrence of deep vein thrombosis compared with standard unfractionated heparin, but there are too few data to provide reliable information on their effects on other important outcomes, including death and intracranial haemorrhage.