Laboratory Monitoring of Heparin Therapy: Partial Thromboplastin Time or Anti-Xa Assay?

Lehman, Christopher M.; Frank, Elizabeth L.

doi:10.1309/lm9njgw2ziolphy6

Cited by 49 publications

(50 citation statements)

References 14 publications

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“…Options include weight-adjusted administration (as used in LMWH anticoagulation for venous thromboembolism [5]), fixed dose (as used for thromboprophylaxis [5]), and with or without monitoring using the anti-Xa activity assay as a surrogate of anticoagulation. Monitoring is used in some clinical settings, but has not become routine as its applicability at predicting clinical outcomes remains uncertain [6]. Much of the published data on LMWH (and UFH) has used clinical measures of coagulation or bleeding to assess efficacy and safety, or a single-point anti-Xa measurement to make the case for wider safe usage.…”

Section: Introductionmentioning

confidence: 99%

Anti-Xa Activity Supports Using a Simple Dosing Algorithm for Tinzaparin for Anticoagulation in Hemodialysis

et al. 2013

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Background: Unfractionated heparin has been traditionally used for anticoagulation during hemodialysis (HD), but more recently low-molecular-weight heparin (LMWH) is being used as an alternative. Anti-Xa activity can be measured as a surrogate of LMWH efficacy. We present 52 patients treated with tinzaparin anticoagulation on HD, confirming that fixed dosing is safe and efficacious with sound pharmacodynamic reason in relation to anti-Xa profiling. Methods: We undertook a prospective audit in a single dialysis unit. All patients were established on a simple anticoagulation protocol for at least 1 month prior to the audit. Blood anti-Xa activity was measured at time 0, 30, 60 and 120 min into and at the end of HD. Efficacy and safety data were collected on the study day and the two sessions before and after it. Results: Fifty-two patients were included in the efficacy and safety analysis with 43 patients undergoing anti-Xa analysis (9 sampling errors). Using current consensus (an end-HD anti-Xa activity of <0.4 IU/ml), our fixed-dose protocol resulted in satisfactory safety in all patients tested. Of 260 HD sessions, 10 (4%) had reduced tinzaparin efficacy. During 105 dialysis sessions (21 patients) using an arteriovenous fistula, 4 patients had one episode of minor bleeding and there were 6 episodes (2 patients) of post-needle-compression time greater than 15 min. Conclusion: Tinzaparin administered thrice weekly as a fixed dose has good efficacy and is well tolerated as an anticoagulant during HD when used according to our protocol.

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Section: Introductionmentioning

confidence: 99%

Anti-Xa Activity Supports Using a Simple Dosing Algorithm for Tinzaparin for Anticoagulation in Hemodialysis

et al. 2013

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“…Heparin levels were measured on the CA1500 using a chromogenic anti-Xa assay 12 . The anti-Xa assay is considered a more reliable measure of heparin activity than aPTT, especially at low heparin levels.…”

Section: Methodsmentioning

confidence: 99%

Chronic In Vivo Testing of the Penn State Infant Ventricular Assist Device

et al. 2012

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The Penn State Infant Ventricular Assist Device is a 12-14 ml stroke volume pneumatically actuated pump, with custom Björk-Shiley monostrut valves, developed under the National Heart, Lung, and Blood Institute (NHLBI) Pediatric Circulatory Support program. In this report we describe the 7 most recent chronic animal studies of the Infant VAD in the juvenile ovine model, with a mean body weight of 23.5 +/- 4.1 kg. The goal of 4-6 weeks survival was achieved in 5 of 7 studies, with support duration ranging from 5 to 41 days; mean 26.1 days. Anticoagulation was accomplished using unfractionated heparin, and study animals were divided into 2 protocol groups: the first based on a target activated partial thromboplastin time of 1.5 to 2 times normal, and a second group using a target thromboelastography R-time of 2 times normal. The second group required significantly less heparin, which was verified by barely detectable heparin activity (anti-Xa). In both groups, there was no evidence of thromboembolism except in one animal with a chronic infection and fever. Device thrombi were minimal, and were further reduced by introduction of the custom valve. These results are consistent with results of adult VAD testing in animals, and are encouraging given the extremely low levels of anticoagulation in the second group.

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“…Xa levels of 0.3-0.8 IU/mL normally correlate with an aPTT of 90-110 seconds [147]. Because the aPTT is dependent upon the reagents used, individual ranges must be established at each institution in accordance with the College of American Pathologists' recommendations [148]. Even within the same institution, individual patients on ECMO may have variations in their underlying coagulation system or treatment that impacts the correlations between heparin levels and their coagulation tests [126].…”

Section: Anti-xa Assaymentioning

confidence: 99%

ECMO Biocompatibility: Surface Coatings, Anticoagulation, and Coagulation Monitoring

Maul¹,

Massicotte²,

Wearden³

2016

Extracorporeal Membrane Oxygenation: Advances in Therapy

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The interaction between the patient and the ECMO (extracorporeal membrane oxygenation) circuit initiates a significant coagulation and inflammatory response due to the large surface area of foreign material contained within the circuit. This response can be blunted with the appropriate mix of biocompatible materials and anticoagulation therapy. The use of anticoagulants, in turn, requires appropriate laboratory testing to determine whether the patient is appropriately anticoagulated. Physicians must balance the risks of bleeding with the risks of thrombosis; the proper interpretation of these tests is often shrouded in mystery. It is the purpose of this chapter to help demystify the coagulation system, anticoagulants, biocompatible surfaces, and coagulation testing so that ECMO practitioners can make informed decisions about their patients and to spur coordinated efforts for future research to improve our understanding of these complex processes.

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Laboratory Monitoring of Heparin Therapy: Partial Thromboplastin Time or Anti-Xa Assay?

Cited by 49 publications

References 14 publications

Anti-Xa Activity Supports Using a Simple Dosing Algorithm for Tinzaparin for Anticoagulation in Hemodialysis

Anti-Xa Activity Supports Using a Simple Dosing Algorithm for Tinzaparin for Anticoagulation in Hemodialysis

Chronic In Vivo Testing of the Penn State Infant Ventricular Assist Device

ECMO Biocompatibility: Surface Coatings, Anticoagulation, and Coagulation Monitoring

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