In a prospective double-blind trial, we treated 194 patients with acute venous thromboembolism with heparin or low molecular weight heparin (LMWH; Fragmin). To evaluate the most important prognostic factors for bleeding, the presenting clinical features of the patients, the patients' anticoagulant responses, and the doses of the drugs were analyzed using univariate and multivariate regression analyses. No significant differences in clinical risk factors associated with bleeding were observed between heparin and LMWH. The univariate analyses ranked the parameters in the following order of importance: World Health Organization (WHO) performance status, history of bleeding tendency, cardiopulmonary resuscitation, recent trauma or surgery, leukocyte counts, platelet counts, duration of symptoms, and body surface area. Patients with WHO grade 4 had an eightfold increase in risk of bleeding as compared with WHO grade 1. Assessment of the individual contribution of each variable using multivariate regression analysis showed that the WHO performance status was the most important independent factor predicting major bleeding. A history of a bleeding tendency, recent trauma or surgery, and body surface area were also independent risk factors. The risk of bleeding was influenced by two factors related to the treatment, the patient's anticoagulant response as measured with the anti-Xa assay and the dose of the drug expressed as U/24 h/m2. An increased risk of bleeding was only observed at mean anti-Xa levels greater than 0.8 U/mL for both drugs. Significantly more major bleedings occurred in patients treated with high doses of the drugs, an observation that was independent of the concomitant anti-Xa levels. It should be considered whether choosing an appropriate initial dose adapted to the patient's body surface area and clinical risk factors can improve the efficacy to safety ratio of heparin treatment.

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Our study demonstrates that reproducibility of measurements of IMT and arterial distensibility of the common carotid artery, by B-mode and M-mode ultrasonography respectively, is acceptable when used in large studies.

SummaryBackground: Clinical trials have been performed to compare with standard heparin a once or a twice daily regimen of low-molecular-weight heparin but no direct comparison has been done between these two low-molecular-weight heparin regimens in terms of efficacy and safety with a long-term clinical evaluation.Methods: Patients with proximal deep vein thrombosis, confirmed by venography were randomly assigned to either nadroparin (10,250 AXa IU/ml) twice daily or nadroparin (20,500 AXa IU/ml) once daily for at least 5 days. Regimens were adjusted to bodyweight. Oral anticoagulants were started on day 1 or 2 and continued for 3 months. Patients were followed up for 3 months. The composite outcome of venous thromboembolism and death possibly related to pulmonary embolism was the primary measure of efficacy. Major bleeding was the principal measure of safety. The study was designed to show equivalence between the two regimens.Results: Recurrent thromboembolic events or death possibly related to pulmonary embolism were reported in 13 patients in the once daily group (4.1%) and in 24 patients of the twice daily group (7.2%): (absolute difference 3.1% in favor of the once daily regimen; 95% confidence interval -6.6%, +0.5%). Major bleeding episodes during nadroparin treatment occurred in 4 (1.3%) and 4 patients (1.2%) in the once and twice daily groups, respectively.Conclusions: A nadroparin regimen of one injection per day is at least as effective and safe as the same total daily dose divided over two injections for the treatment of acute deep vein thrombosis.

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