Laboratory Monitoring of Parenteral Direct Thrombin Inhibitors
Review published in Seminars in Thrombosis and Hemostasis (2017)
Abstract
Argatroban and bivalirudin are parenteral direct inhibitors of the activity of thrombin, but, unlike heparin, can inhibit both soluble as well as clot-bound thrombin. These agents do not require antithrombin as a cofactor for activity. The parenteral direct thrombin inhibitors (DTIs) can be used in a variety of settings, including heparin-induced thrombocytopenia (HIT) or an allergy to heparin, and patients requiring anticoagulation for an invasive cardiovascular intervention. Both agents have a relatively short half-life in patients without organ system failure and are typically administered by continuous infusion. Argatroban is primarily eliminated by the liver, while bivalirudin is removed by a combination of proteolytic cleavage by thrombin and renal clearance mechanisms. Several laboratory tests are available for monitoring the anticoagulant effects of the DTIs: the activated partial thromboplastin time (aPTT) and the activated clotting time (ACT) are the most commonly used assays, but on occasion, the thrombin time may be useful. Other coagulation assays such as the dilute thrombin time (dTT), chromogenic anti-IIa assays, and the ecarin clotting time (ECT) can be used. The intensity of anticoagulation with DTIs depends on the indication for use. For patients with HIT, the target aPTT is 1.5 to 3.0 and 1.5 to 2.5 times the patient's baseline value for argatroban and bivalirudin, respectively. DTI anticoagulation used during percutaneous coronary intervention can be measured using ACT. Both DTIs may cause an elevation in the international normalized ratio depending on their plasma concentration. This article will review the use of parenteral DTIs and related laboratory assays for assessing the anticoagulant effect of these drugs.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Summary
Review of laboratory monitoring approaches for the parenteral direct thrombin inhibitors argatroban and bivalirudin (aPTT, ACT, thrombin time, ecarin clotting time, chromogenic anti-IIa); discusses indication-specific target ranges.
Why This Matters for Hirudotherapy
This review details laboratory monitoring for parenteral direct thrombin inhibitors, focusing on argatroban and bivalirudin in settings such as HIT, heparin allergy, and invasive cardiovascular intervention. It explains that these agents inhibit both soluble and clot-bound thrombin without antithrombin as a cofactor, and discusses aPTT, ACT, dilute thrombin time, chromogenic anti-IIa, and ecarin clotting assays. Bivalirudin (formerly Hirulog) is a synthetic peptide anticoagulant designed partly on the C-terminal sequence of hirudin, the anticoagulant of the medicinal leech (Maraganore et al., 1990); this paper studies the drug, not leech therapy. The paper concerns pharmaceutical laboratory assays, and no actual leech use is described.
Citation
Reference (Vancouver style)
Van Cott EM, Roberts AJ, Dager WE. Laboratory Monitoring of Parenteral Direct Thrombin Inhibitors. Semin Thromb Hemost. 2017;43(3):270-276. doi:10.1055/s-0036-1597297. PMID: 28052306
Bibliographic details (authors, volume, pages, DOI) are taken from the PubMed record.
Added to ASH library: May 27, 2026 · Site last updated: June 18, 2026