BEDSIDE MONITORING OF HEPARIN-THERAPY - COMPARISON OF ACTIVATED CLOTTING TIME TO ACTIVATED PARTIAL THROMBOPLASTIN TIME

Heparin anticoagulation is utilized during and after interventional ca rdiac catheterization procedures to reduce the risk of acute thromboti c coronary artery occlusion. The short half-life of heparin, the impor tance of maintaining therapeutic anticoagulation, and the time delay i nherent in the processing and retrieval of the activated partial throm boplastin time (aPTT) by the hospital laboratory has generated interes t in point-of-care heparin monitoring. The activated clotting time (AC T), the aPTT as assessed by both a new portable device, as well as the hospital laboratory, and heparin levels (H) were obtained from the sa me sample of blood in 100 patients receiving intravenous heparin. Ther e was an excellent correlation between the aPTT determined at the beds ide and by the hospital laboratory (r = .89). The ACT did not correlat e well with either the laboratory or bedside aPTT (r = .63, .68 respec tively). In the sub-therapeutic and therapeutic range, there was essen tially no correlation between ACT and H. Only ACT values > 225 sec wer e predictive of therapeutic or supra-therapeutic aPTTs. ACT values < 2 25 sec, however, were not useful in predicting degree of anticoagulati on. In situations in which the maintenance of therapeutic anticoagulat ion is critical as well as those in which the determination of lack of anticoagulation is required, the bedside determination of aPTT appear s to be a useful tool. (C) 1994 Wiley-Liss, Inc.