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Amin A, Kartashov A, Ngai W, Steele K, Rosenthal N. Effectiveness, safety, and costs of thromboprophylaxis with enoxaparin or unfractionated heparin in inpatients with obesity. Front Cardiovasc Med 2023; 10:1163684. [PMID: 37396589 PMCID: PMC10313352 DOI: 10.3389/fcvm.2023.1163684] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Accepted: 05/08/2023] [Indexed: 07/04/2023] Open
Abstract
Background Obesity is a frequent and significant risk factor for venous thromboembolism (VTE) among hospitalized adults. Pharmacologic thromboprophylaxis can help prevent VTE, but real-world effectiveness, safety, and costs among inpatients with obesity are unknown. Objective This study aims to compare clinical and economic outcomes among adult medical inpatients with obesity who received thromboprophylaxis with enoxaparin or unfractionated heparin (UFH). Methods A retrospective cohort study was performed using the PINC AI™ Healthcare Database, which covers more than 850 hospitals in the United States. Patients included were ≥18 years old, had a primary or secondary discharge diagnosis of obesity [International Classification of Diseases (ICD)-9 diagnosis codes 278.01, 278.02, and 278.03; ICD-10 diagnosis codes E66.0x, E66.1, E66.2, E66.8, and E66.9], received ≥1 thromboprophylactic dose of enoxaparin (≤40 mg/day) or UFH (≤15,000 IU/day) during the index hospitalization, stayed ≥6 days in the hospital, and were discharged between 01 January 2010, and 30 September 2016. We excluded surgical patients, patients with pre-existing VTE, and those who received higher (treatment-level) doses or multiple types of anticoagulants. Multivariable regression models were constructed to compare enoxaparin with UFH based on the incidence of VTE, pulmonary embolism (PE)---------related mortality, overall in-hospital mortality, major bleeding, treatment costs, and total hospitalization costs during the index hospitalization and the 90 days after index discharge (readmission period). Results Among 67,193 inpatients who met the selection criteria, 44,367 (66%) and 22,826 (34%) received enoxaparin and UFH, respectively, during their index hospitalization. Demographic, visit-related, clinical, and hospital characteristics differed significantly between groups. Enoxaparin during index hospitalization was associated with 29%, 73%, 30%, and 39% decreases in the adjusted odds of VTE, PE-related mortality, in-hospital mortality, and major bleeding, respectively, compared with UFH (all p < 0.002). Compared with UFH, enoxaparin was associated with significantly lower total hospitalization costs during the index hospitalization and readmission periods. Conclusions Among adult inpatients with obesity, primary thromboprophylaxis with enoxaparin compared with UFH was associated with significantly lower risks of in-hospital VTE, major bleeding, PE-related mortality, overall in-hospital mortality, and hospitalization costs.
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Affiliation(s)
- Alpesh Amin
- Department of Medicine, University of California at Irvine, Irvine, CA, United States
| | - Alex Kartashov
- PINC AI™ Applied Sciences, Premier Inc., Charlotte, NC, United States
| | | | | | - Ning Rosenthal
- PINC AI™ Applied Sciences, Premier Inc., Charlotte, NC, United States
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2
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Amiral J, Amiral C, Dunois C. Optimization of Heparin Monitoring with Anti-FXa Assays and the Impact of Dextran Sulfate for Measuring All Drug Activity. Biomedicines 2021; 9:700. [PMID: 34205548 PMCID: PMC8235539 DOI: 10.3390/biomedicines9060700] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 06/08/2021] [Accepted: 06/16/2021] [Indexed: 11/22/2022] Open
Abstract
Heparins, unfractionated or low molecular weight, are permanently in the spotlight of both clinical indications and laboratory monitoring. An accurate drug dosage is necessary for an efficient and safe therapy. The one-stage kinetic anti-FXa assays are the most widely and universally used with full automation for large series, without needing exogenous antithrombin. The WHO International Standards are available for UFH and LMWH, but external quality assessment surveys still report a high inter-assay variability. This heterogeneity results from the following: assay formulation, designed without or with dextran sulfate to measure all heparin in blood circulation; calibrators for testing UFH or LMWH with the same curve; and automation parameters. In this study, various factors which impact heparin measurements are reviewed, and we share our experience to optimize assays for testing all heparin anticoagulant activities in plasma. Evidence is provided on the usefulness of low molecular weight dextran sulfate to completely mobilize all of the drug present in blood circulation. Other key factors concern the adjustment of assay conditions to obtain fully superimposable calibration curves for UFH and LMWH, calibrators' formulations, and automation parameters. In this study, we illustrate the performances of different anti-FXa assays used for testing heparin on UFH or LMWH treated patients' plasmas and obtained using citrate or CTAD anticoagulants. Comparable results are obtained only when the CTAD anticoagulant is used. Using citrate as an anticoagulant, UFH is underestimated in the absence of dextran sulfate. Heparin calibrators, adjustment of automation parameters, and data treatment contribute to other smaller differences.
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Affiliation(s)
| | - Cédric Amiral
- HYPHEN BioMed, 95000 Neuville sur Oise, France; (C.A.); (C.D.)
| | - Claire Dunois
- HYPHEN BioMed, 95000 Neuville sur Oise, France; (C.A.); (C.D.)
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3
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Williams-Norwood T, Caswell M, Milner B, Vescera JC, Prymicz K, Ciszak AG, Ingle C, Lacey C, Stavrou EX. Design and Implementation of an Anti-Factor Xa Heparin Monitoring Protocol. AACN Adv Crit Care 2020; 31:129-137. [PMID: 32526007 DOI: 10.4037/aacnacc2020132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
BACKGROUND The VA Northeast Ohio Healthcare System introduced a new nurse-driven anti-factor Xa (anti-Xa) protocol for monitoring unfractionated heparin to replace the previous activated partial thromboplastin time protocol. OBJECTIVE To design, implement, and evaluate the efficacy of the anti-Xa monitoring protocol. METHODS An interdisciplinary team of providers collaborated to develop and implement a nurse-driven, facility-wide anti-factor Xa protocol for monitoring unfractionated heparin therapy. The effectiveness of this protocol was evaluated by retrospective analysis. RESULTS We reviewed 100 medical records for compliance with the new anti-Xa monitoring protocol. We then evaluated 178 patients whose anticoagulation was monitored with the anti-Xa assay to determine the time to therapeutic range. We found that 80% of patients receiving the anti-Xa protocol achieved therapeutic anticoagulation within 24 hours, as compared with 54% of patients receiving the activated partial thromboplastin time protocol (P < .001). Protocol conversion also yielded a decrease in blood draws, dose adjustments, and potential calculation errors. CONCLUSIONS Monitoring intravenous heparin therapy with the anti-Xa assay rather than activated partial thromboplastin time resulted in a shorter time to therapeutic anticoagulation, longer maintenance of therapeutic levels, and fewer laboratory tests and heparin dosage changes. We believe the current practice of monitoring heparin treatment with activated partial thromboplastin time assays should be reexamined.
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Affiliation(s)
- Tanya Williams-Norwood
- Tanya Williams-Norwood is a Clinical Nurse Specialist; Barbara Milner is a Clinical Nurse Specialist; Joseph C. Vescera is Associate Chief of Inpatient Pharmacy; Amy G. Ciszak is Clinical Applications Coordinator, Informatics and Analytics; Carol Ingle is Clinical Pharmacy Manager of the Anticoagulation Clinic; Christopher Lacey is Associate Chief, Clinical Pharmacy Service; VA Northeast Ohio Healthcare System, Cleveland, Ohio
| | - Megan Caswell
- Megan Caswell is Board-Certified Pharmacotherapy Specialist, Internal Medicine, Cleveland Clinic Foundation, Cleveland, Ohio
| | - Barbara Milner
- Tanya Williams-Norwood is a Clinical Nurse Specialist; Barbara Milner is a Clinical Nurse Specialist; Joseph C. Vescera is Associate Chief of Inpatient Pharmacy; Amy G. Ciszak is Clinical Applications Coordinator, Informatics and Analytics; Carol Ingle is Clinical Pharmacy Manager of the Anticoagulation Clinic; Christopher Lacey is Associate Chief, Clinical Pharmacy Service; VA Northeast Ohio Healthcare System, Cleveland, Ohio
| | - Joseph C Vescera
- Tanya Williams-Norwood is a Clinical Nurse Specialist; Barbara Milner is a Clinical Nurse Specialist; Joseph C. Vescera is Associate Chief of Inpatient Pharmacy; Amy G. Ciszak is Clinical Applications Coordinator, Informatics and Analytics; Carol Ingle is Clinical Pharmacy Manager of the Anticoagulation Clinic; Christopher Lacey is Associate Chief, Clinical Pharmacy Service; VA Northeast Ohio Healthcare System, Cleveland, Ohio
| | - Kelly Prymicz
- Kelly Prymicz is Consultant, Chelko Consulting Group, Westlake, Ohio
| | - Amy G Ciszak
- Tanya Williams-Norwood is a Clinical Nurse Specialist; Barbara Milner is a Clinical Nurse Specialist; Joseph C. Vescera is Associate Chief of Inpatient Pharmacy; Amy G. Ciszak is Clinical Applications Coordinator, Informatics and Analytics; Carol Ingle is Clinical Pharmacy Manager of the Anticoagulation Clinic; Christopher Lacey is Associate Chief, Clinical Pharmacy Service; VA Northeast Ohio Healthcare System, Cleveland, Ohio
| | - Carol Ingle
- Tanya Williams-Norwood is a Clinical Nurse Specialist; Barbara Milner is a Clinical Nurse Specialist; Joseph C. Vescera is Associate Chief of Inpatient Pharmacy; Amy G. Ciszak is Clinical Applications Coordinator, Informatics and Analytics; Carol Ingle is Clinical Pharmacy Manager of the Anticoagulation Clinic; Christopher Lacey is Associate Chief, Clinical Pharmacy Service; VA Northeast Ohio Healthcare System, Cleveland, Ohio
| | - Christopher Lacey
- Tanya Williams-Norwood is a Clinical Nurse Specialist; Barbara Milner is a Clinical Nurse Specialist; Joseph C. Vescera is Associate Chief of Inpatient Pharmacy; Amy G. Ciszak is Clinical Applications Coordinator, Informatics and Analytics; Carol Ingle is Clinical Pharmacy Manager of the Anticoagulation Clinic; Christopher Lacey is Associate Chief, Clinical Pharmacy Service; VA Northeast Ohio Healthcare System, Cleveland, Ohio
| | - Evi X Stavrou
- Evi X. Stavrou is Staff Physician and Medical Director of Anticoagulation Clinic, VA Northeast Ohio Healthcare System; Oscar D. Ratnoff Professor in Medicine and Hematology; Assistant Professor in the Department of Medicine at Case Western Reserve University School of Medicine, 10701 East Blvd, Cleveland, OH, 44106
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4
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Patel JP, Byrne RA, Patel RK, Arya R. Progress in the monitoring of direct oral anticoagulant therapy. Br J Haematol 2019; 184:912-924. [DOI: 10.1111/bjh.15756] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Jignesh P. Patel
- Department of Haematological Medicine; King's Thrombosis Centre; King's College Hospital Foundation NHS Trust; London UK
- Institute of Pharmaceutical Science; King's College London; London UK
| | - Rosalind A. Byrne
- Department of Haematological Medicine; King's Thrombosis Centre; King's College Hospital Foundation NHS Trust; London UK
| | - Raj K. Patel
- Department of Haematological Medicine; King's Thrombosis Centre; King's College Hospital Foundation NHS Trust; London UK
| | - Roopen Arya
- Department of Haematological Medicine; King's Thrombosis Centre; King's College Hospital Foundation NHS Trust; London UK
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Välimäki S, Beyeh NK, Linko V, Ras RHA, Kostiainen MA. A supramolecular host-guest complex for heparin binding and sensing. NANOSCALE 2018; 10:14022-14030. [PMID: 29995039 DOI: 10.1039/c8nr03132k] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Heparin is an anionic polysaccharide widely used in clinics as an anticoagulant. However, heparin usage requires an antidote and sensors for safe operation during and after surgeries. In this study, a host-guest complex capable of selective heparin binding and sensing is presented. Heparin binding affinity was studied in solution with a variety of polycationic macrocyclic hosts, a pillar[5]arene and multiple resorcin[4]arenes, by dynamic light scattering, dye displacement assay, isothermal titration calorimetry, and anti-Xa assay. The measurements reveal the significant importance of multivalency in electrostatic host-heparin binding in competitive, application-relevant media. Additionally, to monitor the heparin concentration, a host-guest indicator displacement assay was performed by following the free and bound state of the methyl orange dye in UV-Vis spectroscopic experiments. Furthermore, this colorimetric sensing based on the tertiary host-guest-heparin supramolecular assembly was utilized in the construction of a calibration curve in a range of blood plasma concentrations.
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Affiliation(s)
- Salla Välimäki
- Department of Bioproducts and Biosystems, Aalto University, P.O. Box 16100, FI-00076 Aalto, Espoo, Finland
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Bürki S, Brand B, Escher R, Wuillemin WA, Nagler M. Accuracy, reproducibility and costs of different laboratory assays for the monitoring of unfractionated heparin in clinical practice: a prospective evaluation study and survey among Swiss institutions. BMJ Open 2018; 8:e022943. [PMID: 29886450 PMCID: PMC6009553 DOI: 10.1136/bmjopen-2018-022943] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
OBJECTIVES To investigate the accuracy, reproducibility and costs of different laboratory assays for the monitoring of unfractionated heparin (UFH) in clinical practice and to study test utilisation in Switzerland. DESIGN Prospective evaluation study and survey among Swiss hospitals and laboratories. SETTING Secondary care hospital in rural Switzerland (evaluation study); all Swiss hospitals and laboratories (survey). PARTICIPANTS All consecutive patients, monitored for treatment with UFH during two time periods, were included (May to July 2014 and January to February 2015; n=254). OUTCOME MEASURES Results of activated partial thromboplastin time (aPTT), thrombin time (TT), prothrombinase-induced clotting time (PiCT) and anti-Xa activity with respect to UFH concentration RESULTS: Spearman's correlation coefficient (rs) with regard to anti-Xa activity was 0.68 (95% CI 0.60 to 0.75) for aPTT, 0.79 (0.69 to 0.86) for TT and 0.94 (0.93 to 0.95) for PiCT. The correlation (rs) between anti-Xa activity and heparin concentration as determined by spiking plasma samples was 1.0 (1.0 to 1.0). The coefficient of variation was at most 5% for PiCT and anti-Xa activity (within-run as well as day-to-day variability). The total costs per test in Swiss Francs (SFr) were SFr23.40 for aPTT, SFr33.30 for TT, SFr15.70 for PiCT and SFr24.15 for anti-Xa activity. The various tests were employed in Swiss institutions with the following frequencies: aPTT 53.2%, TT 21.6%, anti-Xa activity 7.2%, PiCT 1.4%; 16.6% of hospitals performed more than one test. CONCLUSIONS The accuracy and reproducibility of PiCT and anti-Xa activity for monitoring of UFH was superior, and analytical costs were equivalent to or lower than aPTT and TT.
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Affiliation(s)
- Susanne Bürki
- Department of Haematology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Béatrice Brand
- Department of Medicine, Spital Emmental, Burgdorf, Switzerland
| | - Robert Escher
- Department of Medicine, Spital Emmental, Burgdorf, Switzerland
| | - Walter A Wuillemin
- Division of Haematology and Central Haematology Laboratory, Luzerner Kantonsspital, Lucerne, Switzerland
| | - Michael Nagler
- Department of Haematology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Department for BioMedical Research, University of Bern, Bern, Switzerland
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7
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Francoia JP, Pascal R, Vial L. Monitoring clinical levels of heparin in human blood samples with an indicator-displacement assay. Chem Commun (Camb) 2015; 51:1953-6. [PMID: 25531454 DOI: 10.1039/c4cc08563a] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We report that a "tree-like" polymer of lysine is able to form a multi-ligand complex with a fluorescently labelled peptide, leading to the almost complete extinction of the optical signal that can be restored upon the introduction of heparin. This simple system allows, for the first time, the turn-ON fluorescent sensing of the anticoagulant in human blood at clinically relevant levels.
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Affiliation(s)
- Jean-Patrick Francoia
- Institut des Biomolécules Max Mousseron, UMR 5247 CNRS - Université de Montpellier, Place Eugène Bataillon, cc 1706, 34296 Montpellier cedex 5, France.
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8
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Egan G, Ensom MHH. Measuring anti-factor xa activity to monitor low-molecular-weight heparin in obesity: a critical review. Can J Hosp Pharm 2015; 68:33-47. [PMID: 25762818 PMCID: PMC4350497 DOI: 10.4212/cjhp.v68i1.1423] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
BACKGROUND The choice of whether to monitor anti-factor Xa (anti-Xa) activity in patients who are obese and who are receiving low-molecular-weight heparin (LMWH) therapy is controversial. To the authors' knowledge, no systematic review of monitoring of anti-Xa activity in such patients has been published to date. OBJECTIVE To systematically ascertain the utility of monitoring anti-Xa concentrations for LMWH therapy in obese patients. DATA SOURCES MEDLINE (1946 to September 2014), the Cochrane Database of Systematic Reviews, Embase (1974 to September 2014), PubMed (1947 to September 2014), International Pharmaceutical Abstracts (1970 to September 2014), and Scopus were searched using the terms obesity, morbid obesity, thrombosis, venous thrombosis, embolism, venous thromboembolism, pulmonary embolism, low-molecular weight heparin, enoxaparin, dalteparin, tinzaparin, anti-factor Xa, anti-factor Xa monitoring, anti-factor Xa activity, and anti-factor Xa assay. The reference lists of retrieved articles were also reviewed. STUDY SELECTION AND DATA EXTRACTION English-language studies describing obese patients treated with LMWH or reporting anti-Xa activity were reviewed using a 9-step decision-making algorithm to determine whether monitoring of LMWH therapy by means of anti-Xa activity in obesity is warranted. Studies published in abstract form were excluded. DATA SYNTHESIS The analysis showed that anti-Xa concentrations are not strongly associated with thrombosis or hemorrhage. In clinical studies of LMWH for thromboprophylaxis in bariatric surgery, orthopedic surgery, general surgery, and medical patients, and for treatment of venous thrombo embolism and acute coronary syndrome, anti-Xa activity can be predicted from dose of LMWH and total body weight; no difference in clinical outcome was found between obese and non-obese participants. CONCLUSIONS Routinely determining anti-Xa concentrations in obese patients to monitor the clinical effectiveness of LMWH is not warranted on the basis of the current evidence. Circumstances where measurement of anti-Xa concentration may help in clinical decision-making in either obese or non-obese patients would be cases where elimination of LMWH is impaired or there is an unexpected clinical response, as well as to confirm compliance with therapy or to identify deviation from predicted pharmacokinetics.
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Affiliation(s)
- Gregory Egan
- BScPharm, ACPR, PharmD, is a Clinical Pharmacy Specialist in Neurology, Vancouver General Hospital, Vancouver, British Columbia
| | - Mary H H Ensom
- BS(Pharm), PharmD, FASHP, FCCP, FCSHP, FCAHS, is a Professor in the Faculty of Pharmaceutical Sciences and Distinguished University Scholar, The University of British Columbia, and a Clinical Pharmacy Specialist, Children's and Women's Health Centre of British Columbia, Vancouver, British Columbia. She is also the Editor of the CJHP
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9
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Kitchen S, Gray E, Mackie I, Baglin T, Makris M. Measurement of non-Coumarin anticoagulants and their effects on tests of Haemostasis: Guidance from the British Committee for Standards in Haematology. Br J Haematol 2014; 166:830-41. [DOI: 10.1111/bjh.12975] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Steve Kitchen
- Sheffield Haemophilia and Thrombosis Centre; Sheffield Teaching Hospitals NHS Trust; Sheffield UK
| | - Elaine Gray
- Haemostasis section; Biotherapeutics Group; National Institute for Biological Standards and Control; Potters Bar UK
| | - Ian Mackie
- Haemostasis Research Unit; Department of Haematology; University College London; London UK
| | - Trevor Baglin
- Department of Haematology; Addenbrooke's Hospital; Cambridge UK
| | - Mike Makris
- Sheffield Haemophilia and Thrombosis Centre; Sheffield Teaching Hospitals NHS Trust; Sheffield UK
- Department of Cardiovascular Science; University of Sheffield; Sheffield UK
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10
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Liu H, Song P, Wei R, Li K, Tong A. A facile, sensitive and selective fluorescent probe for heparin based on aggregation-induced emission. Talanta 2014; 118:348-52. [DOI: 10.1016/j.talanta.2013.09.055] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 09/24/2013] [Accepted: 09/28/2013] [Indexed: 01/20/2023]
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Wool GD, Lu CM. Pathology consultation on anticoagulation monitoring: factor X-related assays. Am J Clin Pathol 2013; 140:623-34. [PMID: 24124140 DOI: 10.1309/ajcpr3jtok7nkdbj] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
OBJECTIVES To review various anticoagulation therapies and related laboratory monitoring issues, with a focus on factor X-related chromogenic assays. METHODS A case-based approach is used to review pertinent published literatures and product inserts of anticoagulation drugs and to look back on clinical use of factor X-related chromogenic assays. RESULTS The number of anticoagulants available to clinicians has increased greatly in the past decade. Whether and how these anticoagulants should be monitored are areas of uncertainty for clinicians, which can lead to misuse of laboratory assays and suboptimal patient management. Factor X-related assays are of particular concern because of the similar and often confusing test names. Based on a common clinical case scenario and literature review regarding anticoagulant monitoring, an up-to-date discussion and review of the various factor X-related assays are provided, focusing on the differences in test designs and clinical utilities between the chromogenic anti-Xa and chromogenic factor X activity assays. CONCLUSIONS Anticoagulation therapy and related laboratory monitoring are rapidly evolving areas of clinical practices. A good knowledge of relevant laboratory assays and their clinical applications is necessary to help optimize patient care.
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Affiliation(s)
- Geoffrey D. Wool
- Department of Laboratory Medicine, University of California San Francisco and Laboratory Medicine Service, Veterans Affairs Medical Center, San Francisco, CA
| | - Chuanyi M. Lu
- Department of Laboratory Medicine, University of California San Francisco and Laboratory Medicine Service, Veterans Affairs Medical Center, San Francisco, CA
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Abstract
The anti-factor Xa (anti-Xa) assay is a functional assay that facilitates the measurement of antithrombin (AT)-catalyzed inhibition of factor Xa by unfractionated heparin (UFH) and direct inhibition of factor Xa by low-molecular-weight heparin (LMWH) (Kitchen, Br J Haematol 111:397-406, 2000; Walenga et al., Semin Thromb Hemost 11:17-25, 1985; Levine et al., Arch Intern Med 154:49-56, 1994; Barrowcliffe et al., J Pharm Biomed Anal 7:217-226, 1989; Triplett, Ther Drug Monit 1:173-197, 1979; Nelson, Clin Lab Sci 12:359-364, 1999; Laffan and Manning, Dacie and Lewis: practical haematology, Churchill Livingstone, London, pp 465-479, 2001; Olson et al., Arch Pathol Lab Med 122:782-798, 1998). Whilst automated methods for the determination of the abilities of UFH and LMWH to inhibit factor Xa have been available since the 1970s, their cost was viewed to prohibit their broad use in the clinical management of UFH and LMWH until relatively recently. The anti-Xa assay can also be used to guide the determination of therapeutic APTT ranges in the clinical management of UFH (Hirsh and Raschke, Chest 126:188S-203S, 2004). As a result, the anti-Xa assay is commonly viewed as a heparin assay, despite the fact that it actually provides a measure of UFH effect as opposed to a measure of UFH concentration.
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Affiliation(s)
- Fiona Newall
- Department of Clinical Haematology, The Royal Children's Hospital, Melbourne, Australia
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13
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Abstract
Protamine titration is the gold standard method for the measurement of unfractionated heparin (UFH) concentration in plasma. Protamine titration produces reliable and reproducible results; however it is -generally not considered a convenient assay for current clinical management of UFH as it is not readily automated (Olson et al. Arch Pathol Lab Med 122(9):782-798, 1998). Early clinical trials of UFH therapy determined that a heparin concentration of 0.2-0.4 U/ml by protamine titration correlated to an APTT of 1.5-2.5 times higher compared to baseline values produced desirable UFH safety and efficacy outcomes (Hull et al. N Engl J Med 315(18):1109-1114, 1986; Hull et al. N Engl J Med 322:1260-1264, 1990; Turpie et al. N Engl J Med 320:352-357, 1989; Brill-Edwards et al. Ann Intern Med 119(2):104-109, 1993; Hull Int Angiol 14(1):32-34, 1995). Such studies paved the way to the current view that it is no longer ideal to manage UFH based solely upon a 1.5-2.5 times prolongation of the "normal" APTT. Most advisory bodies recommend therapeutic APTTs be determined by correlating APTT results with therapeutic UFH levels as measured by anti-Xa assay (0.35-0.7 U/ml) or protamine titration (0.2-0.4 U/ml) (Hirsh and Raschke. Chest 126(3):188S-203S, 2004) (see Note 1). The concentration of UFH in a sample is measured by determining the amount of protamine required to return the thrombin clotting time (TCT) test (prolonged by UFH) to a pre-UFH level (Laffan and Manning. Dacie and Lewis: practical haematology. Churchill Livingstone: London, 2001).
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Affiliation(s)
- Fiona Newall
- Department of Clinical Haematology, The Royal Children's Hospital, Melbourne, Australia
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14
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Harris LF, Rainey P, Castro-López V, O'Donnell JS, Killard AJ. A microfluidic anti-Factor Xa assay device for point of care monitoring of anticoagulation therapy. Analyst 2013; 138:4769-76. [DOI: 10.1039/c3an00401e] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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15
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Gouin-Thibaut I, Martin-Toutain I, Peynaud-Debayle E, Marion S, Napol P, Alhenc-Gelas M. Monitoring unfractionated heparin with APTT: A French collaborative study comparing sensitivity to heparin of 15 APTT reagents. Thromb Res 2012; 129:666-7. [DOI: 10.1016/j.thromres.2011.11.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 11/09/2011] [Accepted: 11/09/2011] [Indexed: 11/29/2022]
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16
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Comparison of the anticoagulant response of a novel fluorogenic anti-FXa assay with two commercial anti-FXa chromogenic assays. Thromb Res 2011; 128:e166-70. [DOI: 10.1016/j.thromres.2011.08.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 07/22/2011] [Accepted: 08/02/2011] [Indexed: 10/17/2022]
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17
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Comparison of a fluorogenic anti-FXa assay with a central laboratory chromogenic anti-FXa assay for measuring LMWH activity in patient plasmas. Thromb Res 2011; 128:e125-9. [DOI: 10.1016/j.thromres.2011.07.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 07/04/2011] [Accepted: 07/11/2011] [Indexed: 11/17/2022]
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18
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Castro-López V, Harris LF, O’Donnell JS, Killard AJ. Quantification of unfractionated heparin in human plasma and whole blood by means of novel fluorogenic anti-FXa assays. J Pharm Biomed Anal 2011; 56:992-7. [DOI: 10.1016/j.jpba.2011.07.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2011] [Revised: 07/20/2011] [Accepted: 07/21/2011] [Indexed: 11/24/2022]
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Prolonged activated prothromboplastin time and breed specific variation in haemostatic analytes in healthy adult Bernese Mountain dogs. Vet J 2011; 190:150-3. [DOI: 10.1016/j.tvjl.2010.09.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 08/09/2010] [Accepted: 09/20/2010] [Indexed: 11/17/2022]
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Krishnaswamy A, Lincoff AM, Cannon CP. Bleeding complications of unfractionated heparin. Expert Opin Drug Saf 2010; 10:77-84. [DOI: 10.1517/14740338.2011.521150] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Kitchen S, Preston FE, Jennings I, Kitchen DP, Woods TAL, Walker I. Interlaboratory agreement in the monitoring of unfractionated heparin using the anti-factor Xa-correlated activated partial thromboplastin time: a rebuttal. J Thromb Haemost 2009; 7:2157-8; author reply 2178-9. [PMID: 19765209 DOI: 10.1111/j.1538-7836.2009.03616.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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NEWALL F, JOHNSTON L, IGNJATOVIC V, SUMMERHAYES R, MONAGLE P. Refinement and feasibility testing of a manual micro-method for protamine titration. Int J Lab Hematol 2009; 31:457-61. [DOI: 10.1111/j.1751-553x.2008.01055.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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van Veen JJ, Laidlaw S, Swanevelder J, Harvey N, Watson C, Kitchen S, Makris M. Contact factor deficiencies and cardiopulmonary bypass surgery: detection of the defect and monitoring of heparin. Eur J Haematol 2009; 82:208-12. [DOI: 10.1111/j.1600-0609.2008.01191.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Newall F, Johnston L, Ignjatovic V, Monagle P. Unfractionated heparin therapy in infants and children. Pediatrics 2009; 123:e510-8. [PMID: 19221154 DOI: 10.1542/peds.2008-2052] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Unfractionated heparin is frequently used in tertiary pediatric centers for the prophylaxis and treatment of thromboembolic disease. Recent evidence suggests that the clinical outcomes of unfractionated heparin therapy in children are poor, as determined by target-range achievement and adverse-event rates. These reports of poor outcomes may be related to an age-dependent mechanism of action of unfractionated heparin. Furthermore, several published studies have indicated that unfractionated heparin-monitoring assays currently in clinical use have significant limitations that likely affect the safety and efficacy of anticoagulant management. This review summarizes the growing body of evidence suggesting that pediatric-specific recommendations for unfractionated heparin therapy management are required to improve clinical outcomes related to this commonly prescribed medication.
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Affiliation(s)
- Fiona Newall
- MN, BSci, Royal Children's Hospital, Clinical Haematology Department, 9th Floor, Main Building, Flemington Road, Parkville, Victoria 3052, Australia.
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Dinwoodey DL, Ansell JE. Heparins, Low-Molecular-Weight Heparins, and Pentasaccharides: Use in the Older Patient. Cardiol Clin 2008; 26:145-55, v. [DOI: 10.1016/j.ccl.2007.12.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Wang S, Chang YT. Discovery of heparin chemosensors through diversity oriented fluorescence library approach. Chem Commun (Camb) 2008:1173-5. [DOI: 10.1039/b717058k] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Voke J, Keidan J, Pavord S, Spencer NH, Hunt BJ. The management of antenatal venous thromboembolism in the UK and Ireland: a prospective multicentre observational survey. Br J Haematol 2007; 139:545-58. [DOI: 10.1111/j.1365-2141.2007.06826.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Bluestein D, Brantley C, Barnes-Eley M, Gravenstein S, Basta S. Measuring international normalized ratios in long-term care: a comparison of commercial laboratory and point-of-care device results. J Am Med Dir Assoc 2007; 8:404-8. [PMID: 17619039 DOI: 10.1016/j.jamda.2007.02.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2007] [Revised: 02/20/2007] [Indexed: 11/27/2022]
Abstract
OBJECTIVES Point-of-care (POC) anticoagulation testing devices can potentially improve warfarin therapeutics in long-term care; however, there is variable accuracy reported for these devices and scant data when used in older adults. Accordingly, we undertook this study to determine the accuracy of a POC device (Hemosense INratio) in long-term care settings and examine factors associated with discrepant results. DESIGN Case series. SETTING Two, demographically comparable continuing-care retirement communities in the Southeastern United States. PARTICIPANTS Long-term (nursing home and assisted living) residents with atrial fibrillation, venous thromboembolism, or prior cerebrovascular accident (16 at site 1; 8 at site 2). MEASUREMENTS INR results calculated by the Hemosense device were compared with those determined by venipuncture-collected samples run in commercial laboratories. Patient demographic and clinical data were collected, as was performance by tester. RESULTS Correlation varied between sites and, at site 1, between testers. Accuracy at site 1 was comparable to published reports for 2 of the 3 testers, with rather disconcerting discrepancy rates of 17.8% and 23.1%. However, correlation for the third tester was much better, with only a 7% discrepancy rate based on clinician rating of Hemosense-Reference lab differences. Correlation at site 2 was considerably worse than site 1, to the point that the Hemosense could not be safely adopted. CONCLUSION POC devices may not be appropriate for commercial laboratory tests substitution without prior performance evaluation. Running POC INRs concurrent with laboratory-determined INRS can determine test reliability. Timing of Hemosense testing in relation to when laboratory INRs were drawn is one likely explanation for our results, although user differences may also contribute significantly. Further research in larger, more diverse populations, using a variety of POC devices, and with direct comparison of older and younger patients is needed.
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Affiliation(s)
- Daniel Bluestein
- Department of Family and Community Medicine, Eastern Virginia Medical School, Norfolk, VA 23507, USA.
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Affiliation(s)
- Jimena C Sauceda
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
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Ignjatovic V, Summerhayes R, Gan A, Than J, Chan A, Cochrane A, Bennett M, Horton S, Shann F, Lane G, Ross-Smith M, Monagle P. Monitoring Unfractionated Heparin (UFH) therapy: Which Anti Factor Xa assay is appropriate? Thromb Res 2007; 120:347-51. [PMID: 17118432 DOI: 10.1016/j.thromres.2006.10.006] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Revised: 10/09/2006] [Accepted: 10/10/2006] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Anti-Factor Xa (Anti-Xa) assays specifically determine the anticoagulant activity of UFH by measuring the ability of heparin-bound Antithrombin (AT) to inhibit a single enzyme, Factor Xa (FXa). Recent improvements in the automation, cost-effectiveness and accessibility of the assay to clinicians, have resulted in the Anti-Xa assay becoming a part of daily clinical practice in many institutions. OBJECTIVES We hypothesized that different Anti-Xa assays have different applicability for use in clinical settings, depending on the amount of UFH administered. This was investigated in a tertiary paediatric institution. MATERIALS AND METHODS Samples were collected from children receiving Low-dose of UFH of at least 10 IU/kg/h, with or without a previous bolus of up to 25 IU/kg/h, within the previous 6 h in the PICU and HDU. High-dose UFH population consisted of children undergoing Cardiac Catheterization (CC), who received a bolus of UFH of 100 IU/kg body weight, 30 min prior to sampling. RESULTS AND CONCLUSIONS The Anti-Xa activity for a given dose of UFH was found to vary significantly based on the Anti-Xa assay and the population being monitored. Our study suggests that the MODIFIED COMATIC Anti-Xa assay provides the best physiological measure of the UFH effect in children, as it does not introduce sources of error, such as exogenous AT, which may increase the measured ant Factor Xa activity, nor Dextran Sulphate which can displace plasma protein bound heparin and once again leading to falsely elevated assay results. Further studies that include assessment of clinical outcomes are required to confirm the applicability of use of this particular assay in monitoring UFH therapy.
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Affiliation(s)
- Vera Ignjatovic
- Department of Clinical Haematology, Royal Children's Hospital, Melbourne, Australia.
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Milović NM, Behr JR, Godin M, Hou CSJ, Payer KR, Chandrasekaran A, Russo PR, Sasisekharan R, Manalis SR. Monitoring of heparin and its low-molecular-weight analogs by silicon field effect. Proc Natl Acad Sci U S A 2006; 103:13374-9. [PMID: 16938875 PMCID: PMC1569171 DOI: 10.1073/pnas.0604471103] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2006] [Indexed: 11/18/2022] Open
Abstract
Heparin is a highly sulfated glycosaminoglycan that is used as an important clinical anticoagulant. Monitoring and control of the heparin level in a patient's blood during and after surgery is essential, but current clinical methods are limited to indirect and off-line assays. We have developed a silicon field-effect sensor for direct detection of heparin by its intrinsic negative charge. The sensor consists of a simple microfabricated electrolyte-insulator-silicon structure encapsulated within microfluidic channels. As heparin-specific surface probes the clinical heparin antagonist protamine or the physiological partner antithrombin III were used. The dose-response curves in 10% PBS revealed a detection limit of 0.001 units/ml, which is orders of magnitude lower than clinically relevant concentrations. We also detected heparin-based drugs such as the low-molecular-weight heparin enoxaparin (Lovenox) and the synthetic pentasaccharide heparin analog fondaparinux (Arixtra), which cannot be monitored by the existing near-patient clinical methods. We demonstrated the specificity of the antithrombin III functionalized sensor for the physiologically active pentasaccharide sequence. As a validation, we showed correlation of our measurements to those from a colorimetric assay for heparin-mediated anti-Xa activity. These results demonstrate that silicon field-effect sensors could be used in the clinic for routine monitoring and maintenance of therapeutic levels of heparin and heparin-based drugs and in the laboratory for quantitation of total amount and specific epitopes of heparin and other glycosaminoglycans.
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Affiliation(s)
| | | | - Michel Godin
- *Biological Engineering Division, Departments of
| | | | - Kristofor R. Payer
- Microsystems Technology Laboratories, Massachusetts Institute of Technology, Cambridge, MA 02139
| | | | | | | | - Scott R. Manalis
- *Biological Engineering Division, Departments of
- Electrical Engineering and Computer Science and
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Abstract
Elderly patients require special consideration when administered anticoagulants because of age-related alterations in renal function, protein binding, and increased bleeding risk. Unfractionated heparin can be used in most patients but difficulties with dosing and monitoring often lead to inadequate anticoagulation. Low-molecular-weight heparin has more predictable pharmacokinetics than conventional heparin, but requires dose adjustments in renal impairment and obesity. Fondaparinux is a synthetic pentasaccharide that is being used increasingly for both treatment and prophylaxis of venous thromboembolism. The immune-mediated form of heparin-induced thrombocytopenia is a syndrome with thrombocytopenia or thrombosis in the setting of heparin use. Heparin-induced thrombocytopenia must be identified early, and treated with argatroban or lepirudin to avoid life-threatening complications.
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Affiliation(s)
- Danya L Dinwoodey
- Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
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Stief TW. Inhibition of Intrinsic Thrombin Generation. Drug Target Insights 2006. [DOI: 10.1177/117739280600100003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Thomas W. Stief
- Department of Clinical Chemistry, University Hospital Giessen & Marburg, Germany
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Favaloro EJ, Bonar R, Aboud M, Low J, Sioufi J, Wheeler M, Lloyd J, Street A, Marsden K. How useful is the monitoring of (low molecular weight) heparin therapy by anti-Xa assay? A laboratory perspective. ACTA ACUST UNITED AC 2005; 11:157-62. [PMID: 16174600 DOI: 10.1532/lh96.05028] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have conducted a series of laboratory-based surveys to assess variability in assay results utilized to monitor heparin anticoagulant therapy. These surveys involved laboratories participating in the Haematology component of the Royal College of Pathologists of Australasia Quality Assurance Program (RCPA QAP). Thirty five of 646 laboratories that were sent a preliminary questionnaire indicated that they performed anti-Xa assays and these laboratories were sent a panel of four plasma samples. These plasma samples contained respectively: (i) no added heparin, (ii) low molecular weight heparin (LMWH), enoxaparin, added to a level of approximately .5 U/mL, (iii) unfractionated heparin added to a level of approximately .5 U/mL, and (iv) LMWH added to a level of approximately 1.0 U/mL. Tests to be performed were the activated partial thromboplastin time (APTT), the thrombin time (TT), fibrinogen, and anti-Xa. As expected, returned results for APTT and TT showed some elevation in heparinized samples while fibrinogen assays were not affected. Anti-Xa assays yielded the following results (median [range]): (i) .01 [0-.11], (ii) .43 [.33-.80], (iii) .23 [.10-.49], and (iv) .90 [.60-1.30]. Thus, although median values were close to those anticipated, there was a wide variation in returned results. In a repeat exercise a few months later laboratories were also asked about their therapeutic ranges (TRs) and provided with an additional vial of LMWH-spiked (1.0 U/mL) plasma labeled as 'heparin-standard' to be used as an assay calibrant. TRs varied substantially between laboratories, from low ranges of .2-.4 to high ranges of .8-1.2. Anti-Xa assay results were similar to those of the first survey: (median [range]): (a) repeat testing: (i) .02 [0-.28], (ii) .47 [.34-.80], (iii) .25 [.14-.58], (iv) .95 [.65-1.31]; (b) repeat testing using survey provided 'heparin-standard': (i) .02 [0-.24], (ii) .55 [.4-.83], (iii) .28 [.10-.63], (iv) 1.00 [.9-1.16]. Thus using the provided 'heparin-standard' yielded lower variability in results for LMWH. In conclusion, the high variability of anti-Xa assay results coupled with the widely variable TRs suggests that therapeutic heparin monitoring is poorly standardized, and this raises some concerns over the clinical value of such monitoring.
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Affiliation(s)
- Emmanuel J Favaloro
- Department of Haematology and RCPA Quality Assurance Program (QAP), Institute of Clinical Pathology and Medical Research (ICPMR), Westmead Hospital, NSW, Australia.
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Wright AT, Zhong Z, Anslyn EV. A Functional Assay for Heparin in Serum Using a Designed Synthetic Receptor. Angew Chem Int Ed Engl 2005; 44:5679-82. [PMID: 16086350 DOI: 10.1002/anie.200501437] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Aaron T Wright
- Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX 78712, USA
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37
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Wright AT, Zhong Z, Anslyn EV. A Functional Assay for Heparin in Serum Using a Designed Synthetic Receptor. Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200501437] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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38
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Favaloro EJ, Bonar R, Sioufi J, Wheeler M, Low J, Aboud M, Lloyd J, Street A, Marsden K. An international survey of current practice in the laboratory assessment of anticoagulant therapy with heparin. Pathology 2005; 37:234-8. [PMID: 16175898 DOI: 10.1080/00313020500098900] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
AIMS We conducted a survey of laboratory practice for assessment of heparin anticoagulant therapy by participants of the Royal College of Pathologists of Australasia Quality Assurance Program (RCPA QAP). METHODS A questionnaire was sent to 646 laboratories enrolled in the Haematology component of the QAP, requesting details of tests used for monitoring heparin therapy. RESULTS Seventy laboratories (10.8%) returned results that indicated that they performed laboratory monitoring of heparin therapy. Most laboratories (69/70 = 98.6%) use the activated partial thromboplastin time (APTT) to monitor unfractionated heparin, with eight (11.4%) also using the APTT for monitoring low molecular weight (LMW) heparin. Five (7.1%) laboratories use the thrombin time (TT) test to help monitor heparin therapy and 37 (52.9%) laboratories use an anti-Xa assay to monitor heparin (either LMW or unfractionated). Normal reference ranges (NRR) for APTT differed considerably between laboratories, even those using the same reagent. Therapeutic ranges (TR) also differed considerably between laboratories, for both APTT and the anti-Xa assay. Laboratory differences in NRR and TR using the same reagents could only be partly explained by the use of different instrumentation. CONCLUSIONS There is a large variation in current laboratory practice relating to monitoring of heparin anticoagulant therapy. This finding is similar to that of a similar survey conducted by the RCPA QAP almost a decade ago. This study suggests that better standardisation is still required for laboratory monitoring of heparin therapy.
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Affiliation(s)
- Emmanuel J Favaloro
- Department of Haematology and Royal College of Pathologists of Australasia Quality Assurance Program, Institute of Clinical Pathology and Medical Research, Westmead Hospital, Westmead, New South Wales, Australia.
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Abstract
Although the use of low-molecular-weight heparins for treatment of acute coronary syndromes (ACS) has increased in recent years, unfractionated heparin (UFH) remains the drug of choice for many patients and institutions. One reason is that this agent is safe for patients with renal dysfunction as well as those who undergo percutaneous coronary intervention or coronary artery bypass graft. The use of UFH is complicated by the increased risk of bleeding due to concurrent administration of numerous antiplatelet drugs in most patients with ACS, the limited data regarding ideal therapeutic range, and the wide variability of patient response. Knowledge regarding the optimal therapeutic range and how to achieve it efficiently may enable clinicians to improve clinical outcomes in patients with ACS. We reviewed and analyzed the available evidence to clarify how to best manage UFH therapy in patients with ACS. Current data support the use of a lower and narrower therapeutic range for patients with ACS than the range that is used for venous thromboembolism. Many factors in addition to weight affect patient response to UFH, including age, sex, diabetes mellitus, smoking status, and obesity.
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Affiliation(s)
- Omar Badawi
- Department of Pharmacy Practice and Science, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201, USA.
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Dreier JP, Lurtzing F, Kappmeier M, Bohner G, Klingebiel R, Leistner S, Einhaupl KM, Schielke E, Valdueza JM. Delayed Occlusion after Internal Carotid Artery Dissection under Heparin. Cerebrovasc Dis 2004; 18:296-303. [PMID: 15331876 DOI: 10.1159/000080355] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2003] [Accepted: 04/07/2004] [Indexed: 11/19/2022] Open
Abstract
Internal carotid artery dissection (ICAD) is a frequent etiology of stroke in the young. Immediate anticoagulation with unfractionated heparin is the most frequent treatment. A theoretical side effect of unfractionated heparin is an increase in the intramural hematoma resulting in hemodynamic cerebral infarction. We studied 20 patients with ICAD. All patients were immediately treated with unfractionated heparin. Activated partial thromboplastin time (aPTT) ratios were measured twice daily. We prospectively monitored the course of ICAD with repeated ultrasound in hospital. Unexpectedly, delayed ICA occlusion was noted in 5 patients under treatment. One of these developed a watershed infarct. We then analyzed the aPTT ratios over the first 6 days after diagnosis. Patients with delayed occlusion had significantly higher aPTT ratios (2.6 +/- 0.4 vs. 2.0 +/- 0.5, p < 0.05). Within the limits of a partially retrospective design, our study seems to support the notion that unfractionated heparin can increase the intramural hematoma. Our findings further justify a randomized clinical trial to resolve the anticoagulant/antiplatelet debate.
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Affiliation(s)
- Jens P Dreier
- Department of Neurology, Campus Mitte, Charité University of Medicine Berlin, Berlin, Germany.
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41
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Abstract
Adequate initial anticoagulant therapy of deep venous thrombosis (DVT) is required to prevent thrombus growth and pulmonary embolism (PE). Intravenous unfractionated heparin (UFH) is being replaced by low-molecular-weight heparin (LMWH) as the anticoagulant of choice for initial treatment of venous thromboembolism (VTE). Both agents are relatively safe and effective when used to treat VTE, with LMWH suitable for outpatient therapy because of improved bioavailability and more predictable anticoagulant response. Serious potential complications of heparin therapy, such as heparin-induced thrombocytopenia (HIT) and osteoporosis, seem less common with LMWH. The potential for fetal harm and changes in maternal physiology complicate the treatment of VTE during pregnancy. Although systemic thrombolysis is used in patients with massive PE and in some patients with proximal DVT, controversy persists with respect to appropriate patient selection for this intervention.
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Affiliation(s)
- Simon J McRae
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
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42
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Gosselin RC, King JH, Janatpour KA, Dager WE, Larkin EC, Owings JT. Variability of Plasma Anti-Xa Activities with Different Lots of Enoxaparin. Ann Pharmacother 2004; 38:563-8. [PMID: 14982983 DOI: 10.1345/aph.1d245] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Previous studies have indicated the variability of anti-Xa activity in different sources of heparin and the variability of different methods used for measuring anti-Xa activity. Manufacturers of low-molecular-weight heparins (LMWHs) determine each lot's anti-Xa activity against the World Health Organization standard, but little information is known about anti-Xa activity variation between lots of LMWH and the impact on reported anti-Xa activity in patient samples. OBJECTIVE To determine the variation of plasma anti-Xa activity in patients receiving enoxaparin when different lots of enoxaparin are used for test calibration. METHODS We obtained 7 lots of enoxaparin containing approximately 10 000 IU/mL and one lot containing approximately 15 000 IU/mL of anti-Xa activity. For each lot, a 2.0 anti-Xa IU/mL dilution was prepared and a calibration curve performed using a chromogenic method. To test the variation in reported results between the different calibration lots, 20 patient samples were tested. Nineteen patients receiving enoxaparin and one patient not receiving enoxaparin (negative control) were tested in a blinded fashion, and the changes in light absorbance recorded. Anti-Xa activity results from tested plasmas were then extrapolated from each enoxaparin lot calibration curve. RESULTS Using Student's paired t-test, there were statistically significant differences between the plasma anti-Xa activities generated from the various enoxaparin lots. In the range of 0.5–1.0 IU/mL of anti-Xa activity, 3 (4.2%) samples had a >0.2 IU/mL difference (maximum difference 0.33 IU/mL) in anti-Xa activity between 2 lots of enoxaparin. For samples that had supratherapeutic anti-Xa activities (1.0–1.5 IU/mL anti-Xa activity), there was a wider variation (>0.2 IU/mL) in anti-Xa activity, which may have resulted in a dosing change. CONCLUSIONS The statistical differences in plasma anti-Xa activities noted between enoxaparin lots are not clinically significant. However, anti-Xa activities in the upper therapeutic and supratherapeutic ranges (>1.0 IU/mL of anti-Xa activity) resulted in a deviation of >0.3 IU/mL in reported anti-Xa activity, which may result in dosing changes.
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Affiliation(s)
- Robert C Gosselin
- Department of Pathology, University of California Davis Medical Center, Sacramento, CA 95817-2201, USA
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43
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Rao GG, Crook M, Tillyer ML. Pathology tests: is the time for demand management ripe at last? J Clin Pathol 2003; 56:243-8. [PMID: 12663633 PMCID: PMC1769923 DOI: 10.1136/jcp.56.4.243] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/29/2002] [Indexed: 11/04/2022]
Abstract
With the ever increasing demands for pathology testing within the National Health Service there is a need to manage the demand for these tests. This review discusses strategies for the demand management of requests made by clinicians in the disciplines of biochemistry, haematology, and microbiology. The various approaches that have been used to manage demand will be described, along with specific clinical strategies for demand management.
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Affiliation(s)
- G Gopal Rao
- Department of Microbiology, University Hospital Lewisham, London SE13 6LH, UK.
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44
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Reiss RA, Haas CE, Griffis DL, Porter B, Tara MA. Point-of-care versus laboratory monitoring of patients receiving different anticoagulant therapies. Pharmacotherapy 2002; 22:677-85. [PMID: 12066958 DOI: 10.1592/phco.22.9.677.34060] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
STUDY OBJECTIVE To compare point-of-care and standard hospital laboratory assays for monitoring patients receiving single or combination anticoagulant regimens. DESIGN Prospective analysis. SETTING Nursing units and clinics at a large, community hospital. PATIENTS One hundred fifty patients receiving anticoagulants for cardiac, vascular, orthopedic, or cancer indications. Thirty patients were enrolled into each treatment group: warfarin, enoxaparin, heparin, warfarin plus enoxaparin, and warfarin plus heparin. INTERVENTION Capillary and venous blood samples were collected once in each patient for simultaneous measurement of international normalized ratio (INR) and activated partial thromboplastin time (aPTT) by both assays. MEASUREMENTS AND MAIN RESULTS Mean differences in paired INR and paired aPTT by point-of-care and standard assays were small, but 95% confidence intervals were wide. The INR differences were greater for the warfarin plus heparin group than for the warfarin group or warfarin plus enoxaparin group; clinical decision agreement was 47% for warfarin plus heparin, 73% for warfarin, and 93% for warfarin plus enoxaparin. The aPTT difference was greater for the warfarin plus heparin than for the heparin group; however, clinical decision agreement, 67% and 70%, respectively, was similar. CONCLUSIONS Point-of-care methods showed limited agreement with standard hospital laboratory assays of coagulation for all treatment groups. For INR values, significantly greater disagreement was noted between the assay methods for the warfarin plus heparin group compared with the warfarin group, but the agreement was similar for the warfarin and warfarin plus enoxaparin groups. Our data indicate that the point-of-care assays should not be considered interchangeable with standard laboratory assays.
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Affiliation(s)
- Robert A Reiss
- Department of Pharmacy Services, ViaHealth-Rochester General Hospital, New York, USA
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