Monitoring heparin effect in patients at risk of DV thrombosis

ABSTRACT

This work was designed to find out the optimal investigation [s] for monitoring heparin therapy. 50 patients, 25 males and 25 females, suffering from various cardiopulmonary diseases having or at risk of deep venous thrombosis admitted to ICU of Ain Shams University hospitals were treated with intermittent [4 hourly] I.V. heparin therapy. Blood samples were withdrawn before, 1, 2, 3 and 4 hours after heparin injections and the samples were analysed for ACT, APTT, IT and factor X[a] assay as well as protamine sulphate titration for heparin level and in vitro estimation of heparin level in plasma by APTT and IT. We found that ACT is the most practical and reliable test for monitoring heparin effect as it correlated significantly with heparin level using protamine titration test. It is especially useful when APTT and TT were paralyzed. On the other hand, factor X[a] assay is very unreliable as it measures mainly the anti-X[a] activity of heparin without the antithrombin effect. It was also found that therapeutic levels 3 hours after heparin injection were not significantly different from pre - injection levels denoting increase risk of thrombosis. Thus intermittent schedule for heparin injection is unreliable method of anticoagulation in patients at risk of D.V.T, pulmonary, or coronary embolism