Clinical monitoring of hirudin and direct thrombin inhibitors
Narrative review published in Seminars in thrombosis and hemostasis (2001)
Abstract
In addition to heparin, the standard medication for prophylaxis and therapy of thromboembolism, several other substances have been developed and tested for clinical use with the aim of decreasing or eliminating side effects. Most of all, hirudin, a direct antithrombin (AT), has proved to be effective. To define the therapeutic range and to avoid underdosage or overdosage, clinical monitoring is necessary. For monitoring of hirudin, thrombin time (TT) is not suited because of the missing linearity of the standard curve. Activated partial thromboplastin time (aPTT) can be used only in the lower hirudin level range, where the standard curve is quite linear. However, high and toxic hirudin levels cannot be determined using aPTT. Another drawback is a high variation in single measurements and in the normal value of patients. Methods using chromogenic substrates are suited for determination of hirudin in plasma but cannot be used at bedside. Especially for monitoring of hirudin, the ecarin clotting time (ECT) was developed. The standard curve is linear over the entire concentration range. There are no influences by other coagulation parameters or anticoagulants. For both acute clinical situations and long-term monitoring, this method capable of point-of-care therapy (POCT) will be the method of choice.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Summary
This article reviews methods for monitoring hirudin anticoagulation, concluding that ecarin clotting time is most suitable due to its linear standard curve, lack of interference, and point-of-care availability.
Context
This review article examined laboratory methods for clinical monitoring of hirudin—a direct antithrombin (AT)—comparing the suitability of thrombin time, activated partial thromboplastin time (aPTT), chromogenic substrate assays, and ecarin clotting time (ECT) for defining therapeutic ranges and avoiding under- or overdosage. Hirudin is a clinically used anticoagulant, and the abstract identifies ECT as offering a linear standard curve across the entire concentration range with no influence from other coagulation parameters, making it the method of choice for point-of-care therapy monitoring. The review addresses pharmacological anticoagulation monitoring and does not involve leeches, leech therapy, or the salivary secretome.
Citation
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