Heparin half-life and sensitivity in normal subjects and in patients affected by deep vein thrombosis.

In some patients affected with deep vein thrombosis (DVT) it is necessary to administer large doses of heparin to achieve proper anticoagulation. To investigate the clinical relevance of this phenomenon, we studied the heparin half-life and the heparin sensitivity after a bolus IV injection of 60 i.u. kg-1 in seven healthy volunteers and eight DVT patients investigated on day 1 or 2 and again between day 10 and 20 of the heparin therapy. The heparin half-life, the in vitro and ex vivo heparin sensitivity, were comparable in the healthy volunteers and in the patients at both times of investigation. However, there were large interindividual variations in the controls and in the patients, not correlated to the levels of any coagulation factors. Thus, the heparin hyperconsumption phenomenon occasionally observed in a given patient reflected individual characteristics and was no value in the diagnosis of DVT.