Update on low molecular weight heparins at the beginning of third millennium. Focus on reviparin.

BACKGROUND: This review provides an outline of the main pharmacological and clinical features of low molecular weight heparins (LMWHs) and a wider description of reviparin. The basic pharmacological properties of LMWHs are compared with those of unfractionated heparin, showing clear advantages of the former, mainly as for pharmacokinetic profile. DESIGN: Consequently LMWHs are characterized by a more predictable behaviour. A key issue is the lack of "bioequivalence": LMWHs are in fact distinct chemical entities, with typical pharmacological and clinical profile for each agent. Therefore, they are not reciprocally interchangeable. The efficacy and safety of reviparin, a second generation LMWH, has been evaluated in many clinical trials as both thrombosis prevention and treatment. Reviparin use is documented in general and orthopaedic surgery. In patients undergoing abdominal surgery reviparin resulted more effective and better tolerated than unfractionated heparin (UFH). In total hip replacement patients, reviparin compared favourably with enoxaparin, showing the same efficacy but better safety. In patients who undergone total hip replacement, also the long-term, out of hospital prevention of deep vein thrombosis (DVT) has been proven. CONCLUSIONS: The comparison with acenocoumarol demonstrated that reviparin was more effective in preventing DVT recurrences and far better tolerated than oral anticoagulant treatment. Reviparin was also effective and well tolerated in immobilised patients following leg injury with plaster casts or braces applications. Positive results were also obtained in the treatment of venous thromboembolism in well-designed studies on large patient populations. In this indication reviparin compared favourably with iv UFH. As for the use in cardiology patient, reviparin is at present the only approved LMWH for the prevention of acute thrombotic events in patients undergoing percutaneous transluminal coronary angioplasty.

Peripheral blood abnormalities in Alzheimer disease: evidence for early endothelial dysfunction.

Clinical and epidemiologic studies demonstrate that vascular risk factors may be involved in Alzheimer disease (AD). To evaluate whether vascular abnormalities are an early feature of AD, several parameters of coagulation and fibrinolysis were assessed. Thirty patients with mild AD and 30 age-matched control subjects entered the study. All subjects performed a standardized clinical and laboratory protocol. Persons with vascular risk factors and systemic diseases were excluded. AD patients present significant increased levels of thrombomodulin (p < 0.0001) and sE-selectin (p < 0.03). In contrast, no difference was found between the two diagnostic groups in the levels of beta-thromboglobulin, prothrombin fragment 1+2, fibrinogen, and von Willebrand factor. No other association but diagnosis was found with thrombomodulin and sE-selectin. These findings suggest that endothelial dysfunction is an early event in AD patients.