[Treatment of deep venous thromboses with heparin. Therapeutic management and biological monitoring].

Heparin may be administered either prophylactically (to prevent postoperative thromboembolic complications) or therapeutically (when thrombosis has occurred) and the dosages are very different. In addition, low molecular weight heparins are now available, and usually reserved only for prevention of thrombosis. The biological monitoring of these different therapies has evolved, and in addition to the classical tests like the recalcified plasma clotting time or the APTT, it is now possible to use more specific tests like the amidolytic activity of anti-IIa or anti-Xa. None of the simple tests alone is satisfactory for the verification of the efficacy of the treatment on a formed thrombosis or for detecting patients at high risk of haemorrhage. At this present state of our knowledge, the association of two of the preceding tests is recommended as any discrepancy could lead to the detection of an associated, unrecognised abnormality such as a circulating anticoagulant factor or thrombocytopaenia. The monitoring of classical prophylactic treatment generally only requires a very limited monitoring.