Thromb Haemostasis
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Comparative Study Clinical Trial
Monitoring high-dose heparinization during cardiopulmonary by-pass--a comparison between prothrombinase-induced clotting time (PiCT) and two chromogenic anti-factor Xa activity assays.
Heparinization requires monitoring, but optimal methods for measuring the anticoagulant effects of heparin remain to be determined. We compared prothrombinase-induced clotting time (PiCT) and two chromogenic anti-factor Xa activity (anti-Xa) assays in monitoring high-dose heparinization during cardiopulmonary by-pass (CPB). Heparin effects were serially measured with PiCT and two anti-Xa assays in 100 patients. ⋯ In conclusion, in the challenging setting of CPB there is poor agreement between anti-Xa assays and PiCT. However, coagulation-based PiCT could provide an alternative to the chromogenic anti-Xa assays. Higher heparin levels during CPB were confirmed to associate with reduced transfusion requirements.
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The risk of stroke in atrial fibrillation (AF) needs to be assessed in each patient to determine the clinical and cost-effectiveness of thromboprophylaxis, with the aim of appropriate use of antithrombotic therapy. To achieve this, stroke risk factors in AF populations need to be identified and stroke risk stratification models have been devised on the basis of these risk factors. In this article, we firstly provide a systematic review of studies examining the attributable stroke risk of various clinical, demographic and echocardiographic patient characteristics in AF populations. ⋯ In patients at high risk of stroke, anticoagulation is cost effective, but not for those with a low risk of stroke. With the evidence available for stroke risk factors and the various alternative stroke risk stratification models, a review of these models in terms of the evidence on which they are devised and their performance in representative AF populations is important. The appropriate administration of thromboprophylaxis in AF patients would need to balance the risks and benefits of antithrombotic therapy with its cost-effectiveness.