LOW-MOLECULAR-WEIGHT HEPARINS IN THE INITIAL TREATMENT OF DEEP-VEIN THROMBOSIS

All major trials to-date provide strong evidence that, for the initial treatment of DVT, adjusted-dose LMWHs are at least as effective and s afe as unfractionated heparin (UFH). When compared with UFH, LMWHs ach ieved better thrombus lysis and had less bleeding complications (21-91 % risk reduction) and mortality (51% reduction). They also reduced the incidence of recurrent DVT and PE at 90 days follow-up while there wa s no need for monitoring. Despite these exciting findings however long -term evaluation of mortality rate, recurrent venous thromboembolism, blood monitoring tests efficacy and thrombus propagation/reduction are open issues. Furthermore, venous haemodynamics have never been tested . There is an ongoing Canadian study today, aiming to determine LMWHs effectiveness in reducing death, recurrent venous thromboembolism and haemorrhagic complications; it is obvious however that further studies are needed. We must determine if a prologned use of LMWHs (i.e. 90 da ys) is more effective in preventing the post-thrombotic sequelae, redu cing also the incidence of haemorrhagic complications; we also need to know the nature of the haematological changes that develop and the re lationship between these changes and the recurrence rate; and finally, we must identify effective blood tests to monitor this treatment.