Activated partial thromboplastin time (aPTT) monitoring to achieve therapeutic anticoagulation before and after introducing a nomogram for adjunctiveheparin treatment with thrombolytic therapy for acute myocardial infarction

In patients with acute myocardial infarction (AMI) receiving thrombolytic t herapy and i.v. unfractionated heparin, anticoagulant levels are frequently outside the target range. We evaluated the effects on anticoagulant levels before (group A) and after (group B) the introduction of a heparin nomogra m in consecutive AMI-patients, receiving thrombolytic therapy and adjunctiv e heparin treatment. The target activated partial thromboplastin time (aPTT ) was defined as 60-90 s. During the first 72 h after admission, the total number of aPTTs within the target range and the time taken to achieve the r ange were compared. The incidence of bleeding complications was assessed. G roup A consisted of 56 and group B of 55 patients. The number of patients w ithin the target range at 72 h (44 versus 51; chi(2) = 4.51; P = 0.034) was significantly higher in group B. No difference was found between total aPT Ts within the target range (26% in group A versus 30% in group B; P = ns). Bleeding complications were slightly less in group B (7 versus in group A v ersus 2 patients in group B; P = ns). We concluded that the introduction of a nomogram resulted in significantly more patients with aPTTs within the t arget range. However, a substantial number of aPTTs before and after introd uction of the nomogram were outside the target range. Moreover, this retros pective study shows that previously acquired prospective data (which showed st marked improvement of anticoagulation using a heparin nomogram) are not necessarily reproduced in the real life clinical setting. (C) 1998 Elsevie r Science Ireland Ltd. All rights reserved.