A PROSPECTIVE RANDOMIZED COMPARISON OF THE ACCURACY OF COMPUTER-ASSISTED VERSUS GUSTO NOMOGRAM-DIRECTED HEPARIN-THERAPY

Failure to adequately anticoagulate the blood of patients receiving re combinant tissue plasminogen activator (TPA) leads to greater rates of rethrombosis. In a multicentered, randomized trial in 51 patients we compared the ability to achieve and maintain therapeutic anticoagulati on by use of computer-assisted heparin therapy or the GUSTO (Global Ut ilization of Streptokinase and TPA for Occluded Coronary Arteries) hep arin nomogram guidelines in patients with myocardial infarction treate d with recombinant TPA. Heparin therapy was initiated with either comp uter-generated starting doses or GUSTO guideline starting doses. Activ ated partial thromboplastin times were measured every 6 to 8 hours for the first 24 hours. The therapeutic range used in this trial was 1.5 to 2.5 times the patient's baseline activated partial thromboplastin t ime (APTT). Ninety-four percent of the AP?T ratios in the computer gro up were equal to or greater than 1.5 in the first 24 hours compared wi th 78% in the GUSTO group (p < 0.009). No significant difference in bl eeding was found (7.7% for GUSTO; 4.2% for computer). Incremental time -dependent changes in heparin dose were found (day 1, 1110 +/- 243 uni ts/hr, APTT ratio = 2.5 +/- 1.4; day 3, 1380 +/- 374 units/hr, APTT ra tio, 1.9 +/- 0.4). Computer-assisted heparin therapy TPA results in su perior anticoagulation accuracy compared with the GUSTO guidelines. In addition, the pharmacodynamic response to heparin changes in the 2 to 3 days after administration of TPA, leading to greater heparin requir ements.