Use of a Standardized Heparin Nomogram to Achieve Therapeutic Anticoagulation After Thrombolytic Therapy in Myocardial Infarction

Abstract

The use of a heparin nomogram provided improved anticoagulation in patients treated with thrombolytic therapy for myocardial infarction. Weight- and age-adjusted heparin dosing may provide further improvement in anticoagulation with heparin therapy. Our findings support the need for frequent monitoring of the activated partial thromboplastin time and for a standardized approach to adjusting the heparin dosage.

Automated Heparin-Delivery System to Control Activated Partial Thromboplastin Time

“…[1][2][3] If aPTT values are too low, recurrent thrombotic events are more common. [1][2][3] Accordingly, numerous attempts to improve control of the anticoagulation level with heparin, including the use of standardized nomograms, 5 weight-adjusted dosing, 6 bedside aPTT monitoring, 4 and all 3 together, 9 have failed to make a major improvement (Figure 4). Only 30% to 35% of patients were in the target 30-second range a full 24 hours after titration of heparin in TIMI 9B 8 and in a randomized trial of both bedside monitoring and weight-adjusted heparin dosing.…”

“…Because of the complex pharmacokinetics and pharmacodynamics of heparin, wide patient variability in anticoagulant response, and time delays between obtaining the blood sample and reporting aPTT results, 4 it is difficult to establish and maintain the therapeutic level of anticoagulation for each patient. Despite numerous efforts to improve the delivery of heparin, including heparin administration nomograms, 5 use of bedside aPTT devices, 4 and use of weight-adjusted 6 and computer-based algorithms, 7 recent trials have achieved only 30% to 35% of aPTTs that were within a 30-second target range. 8,9 In an attempt to improve heparin control, we developed and tested a prototype of the AutoHep system, which automatically acquires a venous blood sample, performs an aPTT measurement, and adjusts the heparin infusion rate to achieve an operator-selected aPTT target.…”

State-of-the-Art Review : Monitoring of High-Dose Intravenous Heparin Therapy—A Contribution to the Safety of Heparin Monitoring

“…high-dose UHF therapy has gained importance, for instance, in the therapy of thromboembolic events ( 11,13), in coronary stenting (3), and after thrombolytic therapy in myocardial infarction (14). With patients with thromboembolic events, it is known that the anticoagulant response to UFH varies between individuals (2).…”

“…Maintaining a plasma heparin assay between 0.2 and 0.4 U/ml by protamin titration or 0.3 and 0.7 U/ml by the antifactor Xa assay is now recommended ( 10,12). The claim for high-dose, wellcontrolled UFH therapy is raised not only in the therapy of thromboembolic events ( 11,13) but also, for example, in the therapy after thrombolysis in myocardial infarction for prevention of reocclusion of the reopened vessel (14) and after coronary stenting in preventing acute and subacute stent thrombosis (3).…”

A Bayesian Formulation of the Kalman Filter Applied to the Estimation of Individual Pharmacokinetic Parameters

“…The appropriate therapeutic range depends on the condition being treated. For example, following myocardial infarction, a recommended therapeutic range is 1.5 to 2.5 times the baseline APTT (6,8). Again, useful results may be obtained with as few as one or two APTT results.…”