[Monitoring of heparin in the treatment of deep venous thrombosis. An obsolete question?].

For over 25 years, it has been the rule to monitor heparin in this indication, mostly using the TCA (or APTT) test. The goal to be reached (APTT ratio), not yet definitely defined, results from multiplying an uncertain baseline value (control APTT) by a variable factor (> or = 1.5 control value), these values being, in turn, determined using different reagents not providing uniform responses. With time, it has become clear that it was difficult to maintain the successive APTTs' within the therapeutic range and moreover, that a biologically satisfying monitoring could not, by itself, prevents from complications or clinical failures. Other classical methods experienced the same shortcomings. Low molecular weight heparin fractions have been proved to be easier to administer, since there is no need for biological monitoring. Although persisting a still unresolved problem, heparin monitoring in this indication appears to be, to date, an obsolete situation and in the process of being circumvented.