![]() 21ĪCT is determined predominantly by the anti-IIa activity of the anticoagulant. 6 Activity can be monitored by ACT or aPTT. 20 Argatroban is licensed for treatment and prevention of HIT-associated thrombosis and for anticoagulation during PCI when heparin is contraindicated because of a recent history of HIT. 6Īrgatroban is a competitive thrombin inhibitor. 13, 15 ⇓ ⇓ ⇓– 19 Bivalirudin is licensed as an alternative to heparin in patients with HIT who require PCI. ![]() 13, 14 Several trials have suggested its superiority over UFH (alone or in combination with GP IIb/IIIa inhibitors) during PCI in reducing the risk of bleeding complications. The binding of bivalirudin to the active site of thrombin is transient. In the United States, lepirudin is licensed for the treatment of thrombosis complicating HIT.īivalirudin is a synthetic hirudin analog with a half-life of 25 minutes. 12 Lepirudin has 2 important side effects: 1) the formation of antibodies against hirudin, which occurs in up to 40% of patients and can prolong the plasma half-life of lepirudin, resulting in drug accumulation and 2) anaphylaxis, which can occur if patients with antibodies are re-exposed to the drug. Lepirudin is a recombinant form of hirudin. It directly and irreversibly binds with thrombin. Hirudin was the first direct thrombin inhibitor to be used clinically. Currently available LMWHs in the United States include enoxaparin, tinzaparin, and dalteparin. Hemonox device International Technidyne, Edison, New Jersey) 10 and the Enox test (measured by the Cascade device Helena Laboratories, Beaumont, Texas) 11 have been developed to monitor the anticoagulant effect of LMWH. More recently, POC tests such as Hemonox clotting time (measured by the Hemochron Jr. 9 LMWH activity can be measured by chromogenic anti-Xa. 6 Recently, the safety and efficacy of IV LMWH anticoagulation for patients undergoing PCI has been demonstrated. 8 Therefore, LMWHs have more predictable pharmacokinetic and pharmacodynamic properties and a lower risk of side effects. 7 LMWHs cause less platelet activation and exhibit less binding to cells and plasma proteins compared with UFH. However, they have a much smaller effect on factor IIa and are thus relatively factor Xa−specific. 6 LMWHs exert their anticoagulant properties by activating AT. LMWHs are produced by depolymerization of heparin. It can be divided into 3 pathways: the extrinsic pathway (tissue factor and factor VIIa), which is the primary activator of the cascade the intrinsic pathway (factors XIIa, XIa, IXa, and VIIIa), which amplifies the cascade and the common pathway (factor Xa, factor Va, and thrombin), which generates thrombin and fibrin. 1, 2 The coagulation cascade ( Fig 1) consists of a sequential conversion of a series of proenzymes, or inactive precursor proteins (zymogens) to active enzymes, resulting in the formation of thrombus. Multiple studies have demonstrated accelerated platelet activation during coronary and cerebral angioplasty. Thromboembolism ensues from activation of platelets and the coagulation cascade and is a major source of complications during endovascular procedures. ĭownload a CMS fact sheet about the final rule.ABBREVIATIONS: ACT activated clotting time Anti-Xa quantitative chromogenic heparin assay aPTT activated partial thromboplastin time AT antithrombin CI confidence interval GP IIb/IIIa glycoprotein IIb/IIIa Hemonox-CT Hemonox clotting time HIT heparin-induced thrombocytopenia HMT Heparin Management Test IV intravenous LMWH low-molecular-weight heparin MI myocardial infarction OR odds ratio PCI percutaneous coronary intervention POC point of care UFH unfractionated heparin Read the CLIA PT final rule in the Federal Register. The regulations related to laboratories performing tests of moderate and high complexity testing that also perform waived testing and voluntarily enroll in PT for the waived tests (§§ 493.20 and 493.25) are effective on August 10, 2022, 30 days after the publication date of the final rule in the Federal Register. The delayed effective date also gives laboratories time to subscribe to PT for the new analytes or microbiology tests. The delayed effective date reflects the timeframe that CMS and CDC believe PT programs will need to produce the PT samples to meet the revised regulations and incorporate any updates to PT reporting requirements.The revisions to PT requirements related to addition and deletion of analytes or microbiology tests and updates to the criteria for acceptable performance and administrative processes for PT programs (§§ 493.2 and 493.801 through 493.959) are effective on July 11, 2024, two years after the publication date of the final rule in the Federal Register.
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