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Mehic D, Assinger A, Gebhart J. Utility of Global Hemostatic Assays in Patients with Bleeding Disorders of Unknown Cause. Hamostaseologie 2024. [PMID: 38950624 DOI: 10.1055/a-2330-9112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/03/2024] Open
Abstract
Bleeding disorder of unknown cause (BDUC) is a diagnosis of exclusion after exhaustive evaluation of plasmatic coagulation and platelet function. This review explores the utility of global hemostatic assays as confirmatory tests and in elucidating the pathophysiology of BDUC. Unlike traditional hemostatic tests that focus on coagulation factors, global assays are conducted both in plasma and also whole blood. These assays provide a more comprehensive understanding of the cell-based model of coagulation, aid in the identification of plasmatic factor abnormalities that may reduce hemostatic capacity, and allow for the assessment of impaired platelet-endothelial interactions under shear stress, as well as hyperfibrinolytic states. While clinical tests such as skin bleeding time and global assays such as PFA-100 exhibit limited diagnostic capacity, the role of viscoelastic testing in identifying hemostatic dysfunction in patients with BDUC remains unclear. Thrombin generation assays have shown variable results in BDUC patients; some studies demonstrate differences compared with healthy controls or reference values, whereas others question its clinical utility. Fibrinolysis assessment in vitro remains challenging, with studies employing euglobulin clot lysis time, plasma clot lysis time, and fluorogenic plasmin generation yielding inconclusive or conflicting results. Notably, recent studies suggest that microfluidic analysis unveils shear-dependent platelet function defects in BDUC patients, undetected by conventional platelet function assays. Overall, global assays might be helpful for exploring underlying hemostatic impairments, when conventional hemostatic laboratory tests yield no results. However, due to limited data and/or discrepant results, further research is needed to evaluate the utility of global assays as screening tools.
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Affiliation(s)
- Dino Mehic
- Clinical Division of Hematology and Hemostaseology, Department of Medicine I, Medical University of Vienna, Vienna, Austria
| | - Alice Assinger
- Institute of Vascular Biology and Thrombosis Research, Centre of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Johanna Gebhart
- Clinical Division of Hematology and Hemostaseology, Department of Medicine I, Medical University of Vienna, Vienna, Austria
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Bavinck AP, Heerde WV, Schols SEM. Point-of-Care Testing in Patients with Hereditary Disorders of Primary Hemostasis: A Narrative Review. Semin Thromb Hemost 2024. [PMID: 38950596 DOI: 10.1055/s-0044-1787976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/03/2024]
Abstract
Inherited disorders of primary hemostasis, such as von Willebrand disease and congenital platelet disorders, can cause extensive, typically mucocutaneous bleeding. Assays to diagnose and monitor these disorders, such as von Willebrand factor activity assays and light transmission aggregometry, are performed in specialized hemostasis laboratories but are commonly not available in local hospitals. Due to the complexity and relative scarcity of these conventional assays, point-of-care tests (POCT) might be an attractive alternative in patients with hereditary bleeding disorders. POCTs, such as thromboelastography, are increasingly used to assess hemostasis in patients with acquired hemostatic defects, aiding clinical decision-making in critical situations, such as during surgery or childbirth. In comparison, the use of these assays in patients with hereditary hemostasis defects remains relatively unexplored. This review aims to give an overview of point-of-care hemostasis tests in patients with hereditary disorders of primary hemostasis. A summary of the literature reporting on the performance of currently available and experimental POCTs in these disorders is given, and the potential utility of the assays in various use scenarios is discussed. Altogether, the studies included in this review reveal that several POCTs are capable of identifying and monitoring severe defects in the primary hemostasis, while a POCT that can reliably detect milder defects of primary hemostasis is currently lacking. A better understanding of the strengths and limitations of POCTs in assessing hereditary defects of primary hemostasis is needed, after which these tests may become available for clinical practice, potentially targeting a large group of patients with milder defects of primary hemostasis.
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Affiliation(s)
- Aernoud P Bavinck
- Department of Hematology, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Waander van Heerde
- Department of Hematology, Radboud University Medical Centre, Hemophilia Treatment Centre Nijmegen-Eindhoven-Maastricht, Nijmegen, The Netherlands
| | - Saskia E M Schols
- Department of Hematology, Radboud University Medical Centre, Hemophilia Treatment Centre Nijmegen-Eindhoven-Maastricht, Nijmegen, The Netherlands
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Favaloro EJ. Description of an In Vitro Platelet Function Analyzer (PFA-100/PFA-200) 30 Years in the Making. Semin Thromb Hemost 2024; 50:320-324. [PMID: 37903565 DOI: 10.1055/s-0043-1776325] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2023]
Affiliation(s)
- Emmanuel J Favaloro
- Department of Haematology, Sydney Centres for Thrombosis and Haemostasis, Institute of Clinical Pathology and Medical Research, Westmead Hospital, Westmead, New South Wales, Australia
- School of Dentistry and Medical Sciences, Faculty of Science and Health, Charles Sturt University, Wagga Wagga, New South Wales, Australia
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Westmead Hospital, Westmead, New South Wales, Australia
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4
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Favaloro EJ. Evolution of Hemostasis Testing: A Personal Reflection Covering over 40 Years of History. Semin Thromb Hemost 2024; 50:8-25. [PMID: 36731486 DOI: 10.1055/s-0043-1761487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
There is no certainty in change, other than change is certain. As Seminars in Thrombosis and Hemostasis celebrates 50 years of publication, I felt it appropriate to reflect on my own 40-year plus scientific career. My career in the thrombosis and hemostasis field did not start until 1987, but the subsequent 35 years reflected a period of significant change in associated disease diagnostics. I started in the Westmead Hospital "coagulation laboratory" when staff were still performing manual clotting tests, using stopwatches, pipettes, test tubes, and a water bath, which we transported to the hospital outpatient department to run our weekly warfarin clinic. Several hemostasis instruments have come and gone, including the Coag-A-Mate X2, the ACL-300R, the MDA-180, the BCS XP, and several StaR Evolution analyzers. Some instruments remain, including the PFA-100, PFA-200, the AggRAM, the CS-5100, an AcuStar, a Hydrasys gel system, and two ACL-TOP 750s. We still have a water bath, but this is primarily used to defrost frozen samples, and manual clotting tests are only used to teach visiting medical students. We have migrated across several methodologies in the 45-year history of the local laboratory. Laurel gel rockets, used for several assays in the 1980s, were replaced with enzyme-linked immunosorbent assay assays and most assays were eventually placed on automated instruments. Radio-isotopic assays, used in the 1980s, were replaced by an alternate safer method or else abandoned. Test numbers have increased markedly over time. The approximately 31,000 hemostasis assays performed at the Westmead-based laboratory in 1983 had become approximately 200,000 in 2022, a sixfold increase. Some 90,000 prothrombin times and activated partial thromboplastic times are now performed at this laboratory per year. Thrombophilia assays were added to the test repertoires over time, as were the tests to measure several anticoagulant drugs, most recently the direct oral anticoagulants. I hope my personal history, reflecting on the changes in hemostasis testing over my career to date in the field, is found to be of interest to the readership, and I hope they forgive any inaccuracies I have introduced in this reflection of the past.
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Affiliation(s)
- Emmanuel J Favaloro
- Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), Sydney Centres for Thrombosis and Haemostasis, NSW Health Pathology, Westmead Hospital, Westmead, NSW Australia
- School of Dentistry and Medical Sciences, Faculty of Science and Health, Charles Sturt University, Wagga Wagga, New South Wales, Australia
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Westmead Hospital, Westmead, New South Wales, Australia
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Lu C, Zhang Y. Gastrointestinal bleeding during the transcatheter aortic valve replacement perioperative period: A Review. Medicine (Baltimore) 2022; 101:e31953. [PMID: 36482568 PMCID: PMC9726417 DOI: 10.1097/md.0000000000031953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
With the aging of the population, the incidence of senile degenerative valvular heart disease is expected to increase. Transcatheter aortic valve replacement (TAVR) has been used for patients at lower surgical risk with symptomatic severe aortic valve stenosis. Because of the improvements in TAVR technology and increasing experience of the operators, TAVR is regarded as a safe and feasible procedure. Bleeding events during the TAVR perioperative period, especially gastrointestinal (GI) bleeding, have been proven to be related to the long-term prognosis and mortality. Elderly patients with valvular heart disease are susceptible to GI bleeding because of their use of antithrombotic drugs, physical damage of coagulation factors, and GI angiodysplasia. Frequent GI bleeding and low levels of preoperative hemoglobin increase the risk of TAVR, especially for elderly patients. Because of these risks, which are easily overlooked, we should focus more attention on the perioperative management of TAVR. Reasonable screening tools, including blood examinations, risk evaluation scales, and endoscopy, are beneficial to the prevention of complications that can occur during the perioperative period. Additionally, medical therapy can safely help patients at high-risk for bleeding patients throughout the perioperative period. This study aimed to characterize the pathology of TAVR patients and discuss treatment strategies for GI bleeding during the perioperative period.
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Affiliation(s)
- Chuan Lu
- From the Second Hospital of Dalian Medicial University, Shahekou District, Dalian City, China
| | - Yue Zhang
- From the Second Hospital of Dalian Medicial University, Shahekou District, Dalian City, China
- * Correspondence: Yue Zhang, From the Second Hospital of Dalian Medicial University, 467 Zhongshan Road, Shahekou District, Dalian city, China (e-mail: )
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Favaloro EJ, Pasalic L. Laboratory Diagnosis of von Willebrand Disease (VWD): Geographical Perspectives. Semin Thromb Hemost 2022; 48:750-766. [PMID: 36055264 DOI: 10.1055/s-0042-1754331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
von Willebrand disease (VWD) is reportedly the most common inherited bleeding disorder, and can also arise as an acquired (von Willebrand) syndrome (AVWS). The hemostasis laboratory plays a key role in the diagnosis or exclusion of VWD/AVWS, which may otherwise be suspected due to the patient's clinical (bleeding) history. VWD/AVWS arise from deficiency and/or defects in the adhesive plasma protein, von Willebrand factor (VWF). VWF undertakes various roles within hemostasis, but principally acts within primary hemostasis to anchor platelets to sites of vascular damage, thereby facilitating thrombus formation to arrest bleeding. The diagnosis or exclusion of VWD/AVWS requires laboratory testing for both VWF level and activity, with the latter potentially comprising several of a potential plethora of different assays. Complete diagnosis of VWD also requires the differentiation of VWD type, with six types comprising the current classification (i.e., qualitative [types 2A, 2B, 2M, 2N VWD] vs. quantitative [types 1 and 3 VWD] deficiency/defects). Although appropriate diagnosis and type classification hold important therapeutic consequences, these remain problematic and sometimes elusive for some laboratories to achieve. This report reviews the laboratory aided diagnosis or exclusion of VWD from a geographic perspective, and focuses on the disparities of approaches and methods in different regions of the world. This is primarily done from the perspective of data available from published reports related to external quality assessment (or proficiency testing) from different geographic localities. Moreover, differences in approaches between laboratories may arise due to differential adherence of particular guidelines, as well as regulatory aspects and predominance of local manufacturers and suppliers.
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Affiliation(s)
- Emmanuel J Favaloro
- Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, North South Wales, Australia.,Sydney Centres for Thrombosis and Haemostasis, Westmead, North South Wales, Australia.,Faculty of Science and Health, Charles Sturt University, Wagga Wagga, North South Wales, Australia
| | - Leonardo Pasalic
- Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, North South Wales, Australia.,Sydney Centres for Thrombosis and Haemostasis, Westmead, North South Wales, Australia.,Westmead Clinical School, University of Sydney, Westmead, North South Wales, Australia
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Biss T, Sibson K, Baker P, Macartney C, Grayson C, Grainger J, Chalmers E, Dixon S. Haematological evaluation of bruising and bleeding in children undergoing child protection investigation for possible physical maltreatment: A British Society for Haematology Good Practice Paper. Br J Haematol 2022; 199:45-53. [PMID: 35881677 DOI: 10.1111/bjh.18361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 07/01/2022] [Accepted: 07/05/2022] [Indexed: 01/12/2023]
Affiliation(s)
- Tina Biss
- The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | | | - Peter Baker
- Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | | | - Caroline Grayson
- The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - John Grainger
- Royal Manchester Children's Hospital, Manchester, UK
| | | | - Sarah Dixon
- Manchester Health and Care Commissioning, Manchester, UK
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Favaloro EJ, Pasalic L, Lippi G. Towards 50 years of platelet function analyser (PFA) testing. Clin Chem Lab Med 2022; 61:851-860. [PMID: 35859143 DOI: 10.1515/cclm-2022-0666] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Accepted: 07/11/2022] [Indexed: 11/15/2022]
Abstract
The platelet function analyser (PFA) is a prevalent platelet function screening instrument, and comes in two models-the original PFA-100 and the contemporary PFA-200. The instruments have 'identical' output, being a 'closure time' (CT). Moreover, normal reference ranges provided by the manufacturer, for the specific test cartridges, are the same for both models. There are three different types of test cartridge: collagen/epinephrine (C/Epi), collagen/adenosine diphosphate (C/ADP), and "Innovance PFA P2Y" (only available in certain geographical locations). The PFA-100 was released in the mid 1990s, and so is approaching 50 years of age. The PFA-200, released in some locations in the mid 2010s, is destined to eventually replace the PFA-100, but is not yet available in the USA. The test system is highly sensitive to von Willebrand disease (VWD; C/Epi and C/ADP) and to aspirin therapy (C/Epi only), but only has moderate sensitivity to defects in platelet function and/or deficiencies in platelet number. Accordingly, recommendations for use for screening platelet function vary according to user experience. Some workers have alternatively used the PFA to assess thrombosis risk or pre-operative bleeding risk. In this review, we provide an overview of the history of PFA, and summarise its current clinical utility.
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Affiliation(s)
- Emmanuel J Favaloro
- Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, NSW, Australia.,Sydney Centres for Thrombosis and Haemostasis, Westmead, NSW, Australia.,Faculty of Science and Health, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Leonardo Pasalic
- Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, NSW, Australia.,Sydney Centres for Thrombosis and Haemostasis, Westmead, NSW, Australia.,Westmead Clinical School, University of Sydney, Westmead, NSW, Australia
| | - Giuseppe Lippi
- Section of Clinical Biochemistry and School of Medicine, University of Verona, Verona, Italy
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Favaloro EJ, Mohammed S, Vong R, Chapman K, Kershaw G, Just S, Connelly L, Ryan M, Zebeljan D, Brighton T, Pasalic L. Harmonizing platelet function analyzer testing and reporting in a large laboratory network. Int J Lab Hematol 2022; 44:934-944. [PMID: 35754202 PMCID: PMC9545980 DOI: 10.1111/ijlh.13907] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 05/30/2022] [Indexed: 11/29/2022]
Abstract
INTRODUCTION The platelet function analyzer (PFA) is a popular platelet function screening instrument, highly sensitive to von Willebrand disease (VWD) and to aspirin therapy, with moderate sensitivity to defects in platelet function and/or deficiencies in platelet number. There are two models, the original PFA-100 and the contemporary PFA-200. Normal reference ranges (NRRs) provided by the manufacturer are the same for both models, instead being based on the type of test cartridge, for which there are two main ones: collagen/epinephrine (C/Epi) and collagen/adenosine diphosphate (C/ADP). METHODS Comparative evaluations of PFA testing and reporting in six different sites of a large pathology network, aiming to harmonize NRRs and test reporting across all network sites. A separate comparative study of testing a range of samples (n > 150) on a PFA-100 versus that on a PFA-200. Review of contemporary literature. RESULTS Each site was identified to have a different reporting NRR, which after consolidating data permitted establishment of an agreed harmonized NRR for use across the network (C/Epi: 90-160; C/ADP: 70-124; based on n > 180). Similarly, each site reported and interpreted results in different ways, and after discussion and consolidation, a harmonized approach to interpretation and reporting was achieved. The separate comparative study of PFA-100 versus PFA-200 testing confirmed instrument equivalence. CONCLUSION We achieved harmonized NRRs and reporting for PFA testing across a large pathology network. Our approach may be useful for other laboratory networks wishing to harmonize PFA testing.
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Affiliation(s)
- Emmanuel J Favaloro
- Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, New South Wales, Australia.,Sydney Centres for Thrombosis and Haemostasis, Westmead, New South Wales, Australia.,Faculty of Science and Health, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - Soma Mohammed
- Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, New South Wales, Australia
| | - Ronny Vong
- Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, New South Wales, Australia
| | - Kent Chapman
- Haematology, NSW Health Pathology, John Hunter Hospital, Newcastle, New South Wales, Australia
| | - Geoffrey Kershaw
- Haematology, NSW Health Pathology, Prince Alfred Hospital, Camperdown, New South Wales, Australia
| | - Sarah Just
- Haematology, NSW Health Pathology, Royal North Shore Hospital, St Leonards, New South Wales, Australia
| | - Lynne Connelly
- Haematology, NSW Health Pathology, Royal North Shore Hospital, St Leonards, New South Wales, Australia
| | - Michael Ryan
- Haematology, NSW Health Pathology, Wollongong Hospital, Wollongong, New South Wales, Australia
| | - Diane Zebeljan
- Haematology, NSW Health Pathology, Liverpool Hospital, Liverpool, New South Wales, Australia
| | - Timothy Brighton
- Haematology, NSW Health Pathology, Prince of Wales Hospital, Randwick, New South Wales, Australia
| | - Leonardo Pasalic
- Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, New South Wales, Australia.,Sydney Centres for Thrombosis and Haemostasis, Westmead, New South Wales, Australia.,Westmead Clinical School, University of Sydney, Westmead, New South Wales, Australia
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10
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Kanji R, Vandenbriele C, Arachchillage DRJ, Price S, Gorog DA. Optimal Tests to Minimise Bleeding and Ischaemic Complications in Patients on Extracorporeal Membrane Oxygenation. Thromb Haemost 2022; 122:480-491. [PMID: 33984868 DOI: 10.1055/a-1508-8230] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Patients supported with extracorporeal membrane oxygenation (ECMO) experience a very high frequency of bleeding and ischaemic complications, including stroke and systemic embolism. These patients require systemic anticoagulation, mainly with unfractionated heparin (UFH) to prevent clotting of the circuit and reduce the risk of arterial or venous thrombosis. Monitoring of UFH can be very challenging. While most centres routinely monitor the activated clotting time and activated partial thromboplastin time (aPTT) to assess UFH, measurement of anti-factor Xa (anti-Xa) level best correlates with heparin dose, and appears to be predictive of circuit thrombosis, although aPTT may be a better predictor of bleeding. Although monitoring of prothrombin time, platelet count and fibrinogen is routinely undertaken to assess haemostasis, there is no clear guidance available regarding the optimal test.Additional tests, including antithrombin level and thromboelastography, can be used for risk stratification of patients to try and predict the risks of thrombosis and bleeding. Each has their specific role, strengths and limitations. Increased thrombin generation may have a role in predicting thrombosis. Acquired von Willebrand syndrome is frequent with ECMO, contributing to bleeding risk and can be detected by assessing the von Willebrand factor activity-to-antigen ratio, while the platelet function analyser can be used in urgent situations to detect this, with a high negative predictive value. Tests of platelet aggregation can aid in the prediction of bleeding.To personalise management, a selection of complementary tests to collectively assess heparin-effect, coagulation, platelet function and platelet aggregation is proposed, to optimise clinical outcomes in these high-risk patients.
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Affiliation(s)
- Rahim Kanji
- Faculty of Medicine, National Heart and Lung Institute, Imperial College, London, United Kingdom
| | - Christophe Vandenbriele
- Department of Cardiovascular Diseases, University Hospitals Leuven, Leuven, Belgium.,Intensive Care Unit, Royal Brompton Hospital, London, United Kingdom
| | - Deepa R J Arachchillage
- Haematology Department, Royal Brompton Hospital, London, United Kingdom.,Centre for Haematology, Imperial College Healthcare NHS Trust & Imperial College, London, United Kingdom
| | - Susanna Price
- Faculty of Medicine, National Heart and Lung Institute, Imperial College, London, United Kingdom.,Intensive Care Unit, Royal Brompton Hospital, London, United Kingdom
| | - Diana Adrienne Gorog
- Faculty of Medicine, National Heart and Lung Institute, Imperial College, London, United Kingdom
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11
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Heubel-Moenen FCJI, Brouns SLN, Herfs L, Boerenkamp LS, Jooss NJ, Wetzels RJH, Verhezen PWM, Machiels P, Megy K, Downes K, Heemskerk JWM, Beckers EAM, Henskens YMC. Multiparameter platelet function analysis of bleeding patients with a prolonged platelet function analyser closure time. Br J Haematol 2022; 196:1388-1400. [PMID: 35001370 PMCID: PMC9303561 DOI: 10.1111/bjh.18003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 12/02/2021] [Indexed: 11/30/2022]
Abstract
Patients referred for evaluation of bleeding symptoms occasionally have a prolonged platelet function analyser (PFA) closure time, without evidence for von Willebrand disease or impaired platelet aggregation. The aim of this study was to establish a shear‐dependent platelet function defect in these patients. Patients were included based on high bleeding score and prior PFA prolongation. Common tests of von Willebrand factor (VWF) and platelet function and exome sequencing were performed. Microfluidic analysis of shear‐dependent collagen‐induced whole‐blood thrombus formation was performed. In 14 PFA‐only patients, compared to healthy volunteers, microfluidic tests showed significantly lower platelet adhesion and thrombus formation parameters. This was accompanied by lower integrin activation, phosphatidylserine exposure and P‐selectin expression. Principal components analysis indicated VWF as primary explaining variable of PFA prolongation, whereas conventional platelet aggregation primarily explained the reduced thrombus parameters under shear. In five patients with severe microfluidic abnormalities, conventional platelet aggregation was in the lowest range of normal. No causal variants in Mendelian genes known to cause bleeding or platelet disorders were identified. Multiparameter assessment of whole‐blood thrombus formation under shear indicates single or combined effects of low–normal VWF and low–normal platelet aggregation in these patients, suggesting a shear‐dependent platelet function defect, not detected by static conventional haemostatic tests.
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Affiliation(s)
- Floor C J I Heubel-Moenen
- Department of Hematology, Internal Medicine, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Sanne L N Brouns
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - Linda Herfs
- Central Diagnostic Laboratory, Unit for Hemostasis and Transfusion, Maastricht University Medical Centre+, Maastricht, The Netherlands.,Flowchamber, Maastricht, The Netherlands
| | - Lara S Boerenkamp
- Department of Hematology, Internal Medicine, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Natalie J Jooss
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands.,Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Rick J H Wetzels
- Central Diagnostic Laboratory, Unit for Hemostasis and Transfusion, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Paul W M Verhezen
- Central Diagnostic Laboratory, Unit for Hemostasis and Transfusion, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | | | - Karyn Megy
- Department of Hematology, University of Cambridge and National Institute for Health Research (NIHR) BioResource, Cambridge University Hospitals, Cambridge, United Kingdom
| | - Kate Downes
- Department of Hematology, University of Cambridge and National Institute for Health Research (NIHR) BioResource, Cambridge University Hospitals, Cambridge, United Kingdom.,East Genomic Laboratory Hub, Cambridge University Hospitals Foundation Trust, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Johan W M Heemskerk
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands.,Flowchamber, Maastricht, The Netherlands
| | - Erik A M Beckers
- Department of Hematology, Internal Medicine, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Yvonne M C Henskens
- Central Diagnostic Laboratory, Unit for Hemostasis and Transfusion, Maastricht University Medical Centre+, Maastricht, The Netherlands
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12
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Geevar T, Dave RG, Mathews NS, Kumar S, Mammen JJ, Vijayan R, Aboobacker FN, Abraham A, Srivastava A, Nair SC. Laboratory characterization of obligate carriers of type 3 von Willebrand disease with a potential role for Platelet Function Analyzer (PFA-200). Int J Lab Hematol 2022; 44:603-609. [PMID: 34986515 DOI: 10.1111/ijlh.13787] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 12/08/2021] [Accepted: 12/10/2021] [Indexed: 01/13/2023]
Abstract
INTRODUCTION Type 3 von Willebrand disease (VWD) is a rare autosomal recessive disorder characterized by undetectable von Willebrand Antigen (VWF:Ag). Carriers of type 3 VWD carry one null allele and have von Willebrand factor (VWF) at about 50% of normal. The aim of this study was to characterize type 3 VWD carriers and to study the role of Platelet Function Analyzer (PFA-200) in this cohort. METHODS This was a cross-sectional study where data were collected from carriers (parents/offspring) of type 3 VWD patients and evaluated with activated partial thromboplastin time, factor VIII, blood group, ristocetin cofactor assay (VWF:RCo), VWF:Ag, and closure time on PFA-200 with collagen/epinephrine (COL/EPI), and collagen/ADP (COL/ADP). RESULTS One hundred carriers were included in the study of which 85 were included for PFA-200 analysis. The mean (SD) of VWF:Ag (IU/ml) and VWF:RCo (IU/ml) was 0.63 (0.24) and 0.61 (0.26), respectively. Among the 100 carriers, based on VWF levels (VWF:Ag and/or VWF:RCo) and bleeding history, there were 7 type 1 VWD, 10 type 2 VWD, 25 borderline VWF (0.30-0.50 IU/ml and no bleeding), and 58 normal VWF (>0.50 IU/ml). PFA-200 was prolonged in 71% of the carriers, all carriers with type 1 and type 2 VWD phenotype, 80% carriers with borderline VWF, and 59% with normal VWF. COL/EPI was more sensitive than COL/ADP and showed better correlation with VWF parameters than COL/ADP. CONCLUSION Carriers of type 3 VWD can have a variable laboratory phenotype. PFA-200 showed good sensitivity among the carriers at VWF levels <0.50 IU/ml.
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Affiliation(s)
- Tulasi Geevar
- Department of Transfusion Medicine and Immunohematology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Rutvi Gautam Dave
- Department of Transfusion Medicine and Immunohematology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Nitty Skariah Mathews
- Department of Transfusion Medicine and Immunohematology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Snehil Kumar
- Department of Transfusion Medicine and Immunohematology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Joy John Mammen
- Department of Transfusion Medicine and Immunohematology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Ramya Vijayan
- Department of Transfusion Medicine and Immunohematology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Fouzia N Aboobacker
- Department of Clinical Hematology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Aby Abraham
- Department of Clinical Hematology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Alok Srivastava
- Department of Clinical Hematology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Sukesh Chandran Nair
- Department of Transfusion Medicine and Immunohematology, Christian Medical College, Vellore, Tamil Nadu, India
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Belkacemi M, Merad Y. Variables that Influence Platelet Function Analyzer-100™ Closure Times in Healthy Algerian Adults. Int J Appl Basic Med Res 2021; 11:154-159. [PMID: 34458117 PMCID: PMC8360221 DOI: 10.4103/ijabmr.ijabmr_532_20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 04/20/2021] [Accepted: 06/02/2021] [Indexed: 11/05/2022] Open
Abstract
Context: The Platelet Function Analyzer (PFA-100™) assesses primary hemostasis in vitro under high shear stress to simulate the conditions to which platelets are exposed at the site of an injured blood vessel wall. Aims: We investigated preanalytical variables in healthy Algerian adults, and we also assess the performance of the test. Subjects and Methods: Closure time (CT) was measured in 302 well-characterized healthy Algerian adults with the collagen/epinephrine (CEPI) and the collagen/adenosine diphosphate (CADP) cartridges. Results: Age and sex did not affect CT values. Blood group O was associated significantly with longer CEPI CT and CADP CT than non-O groups (P ≤ 0.0001 for both). CTs were shorter in samples collected in the morning vs the afternoon (P < 0.0001 for both). We found a strong positive correlation between CT CEPI and CT CADP with r = 0.72 and P < 0.001 and an inverse mean correlation between von Willebrand factor level and CT with r = −0.56, r = −0.45 for CT CEPI and CT CADP, respectively P < 0.001. Duplicate analysis of PFA-100™ CT revealed a mean difference of 3.6% ±19.1% for the CEPI cartridge and 1.5% ±10% for the CADP cartridge. The mean coefficient of variation was 7.4% for the CADP CT and 7.6% for the CEPI CT. No marked difference between test positions. Conclusions: The PFA-100™ showed good reproducibility. The variables influencing the test in healthy Algerian adults are similar to Western and Asian populations. Standardization of preanalytical and analytical conditions is essential for obtaining reliable PFA-100™ results.
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Affiliation(s)
- Malika Belkacemi
- Department of Blood Transfusion, Hassani Abdelkader Hospital, University Center, Sidi-Bel Abbès, Algeria.,Faculty of Medicine, University Djellali Liabes, Sidi-Bel Abbès, Algeria
| | - Yassine Merad
- Faculty of Medicine, University Djellali Liabes, Sidi-Bel Abbès, Algeria.,Department of Parasitology-Mycology, Central Laboratory, Hassani Abdelkader Hospital, University Center, Sidi-Bel Abbès, Algeria
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Favaloro EJ, Mohammed S, Vong R, Oliver S, Brennan Y, Favaloro JW, Curnow J. How we diagnose 2M von Willebrand disease (VWD): Use of a strategic algorithmic approach to distinguish 2M VWD from other VWD types. Haemophilia 2020; 27:137-148. [PMID: 33215808 DOI: 10.1111/hae.14204] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 10/09/2020] [Accepted: 11/02/2020] [Indexed: 12/23/2022]
Abstract
INTRODUCTION von Willebrand disease (VWD) is the most common inherited bleeding disorder and caused by an absence, deficiency or defect in von Willebrand factor (VWF). VWD is currently classified into six different types: 1, 2A, 2B, 2N, 2M, 3. Notably, 2M VWD is more often misdiagnosed as 2A or type 1 VWD than properly identified as 2M VWD. AIM To describe an algorithmic approach to better ensure appropriate identification of 2M VWD, and reduce its misdiagnosis, as supported by sequential laboratory testing. METHODS Comparative assessment of types 1, 2A, 2B and 2M VWD using various laboratory tests, including VWF antigen and several VWF activity assays, plus DDAVP challenge data, ristocetin-induced platelet agglutination (RIPA) data, multimer analysis and genetic testing. RESULTS Types 1, 2A, 2B and 2M VWD give characteristic test patterns that can provisionally classify patients into particular VWD types. Notably, type 1 VWD shows low levels of VWF, but VWF functional concordance (VWF activity/Ag ratios >0.6), with both baseline assessment and post-DDAVP. Types 2A, 2B and 2M VWD show VWF functional discordance (low VWF activity/Ag ratio(s)) dependent on the defect, but type 2M separates from 2A/2B VWD based on specific test patterns, especially with collagen binding vs glycoprotein Ib binding assays. RIPA identifies 2B VWD. Multimers separate 2M from 2A/2B. CONCLUSION We provide strategies to improve correct diagnosis of VWD, especially focussed on 2M VWD, and which can be used by most diagnostic haemostasis laboratories, reserving genetic analysis (if required) for confirmation.
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Affiliation(s)
- Emmanuel J Favaloro
- Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, NSW, Australia.,Sydney Centres for Thrombosis and Haemostasis, Westmead Hospital, Westmead, NSW, Australia.,School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Soma Mohammed
- Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, NSW, Australia
| | - Ronny Vong
- Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, NSW, Australia
| | - Susan Oliver
- Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, NSW, Australia
| | - Yvonne Brennan
- Department of Haematology, Royal Adelaide Hospital, Adelaide, SA, Australia
| | - James W Favaloro
- Institute of Haematology, NSW Health Pathology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia
| | - Jennifer Curnow
- Sydney Centres for Thrombosis and Haemostasis, Westmead Hospital, Westmead, NSW, Australia.,Department of Haematology, Westmead Hospital, Sydney, NSW, Australia.,Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
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15
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Mondal S, Hollander KN, Ibekwe SO, Williams B, Tanaka K. Heyde Syndrome-Pathophysiology and Perioperative Implications. J Cardiothorac Vasc Anesth 2020; 35:3331-3339. [PMID: 33132021 DOI: 10.1053/j.jvca.2020.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 10/02/2020] [Accepted: 10/04/2020] [Indexed: 11/11/2022]
Abstract
Gastrointestinal (GI) bleeding in patients with calcific aortic valve stenosis (AVS), termed Heyde syndrome, was first described by Edward C. Heyde. The strong association between valvular replacement and the eradication of clinically significant GI bleeding confirmed an underlying pathophysiologic relationship. The rheologic stress created by AVS increases proteolysis of von Willebrand factor (VWF), resulting in loss of predominantly high-molecular-weight VWF (Hmw VWF). Angiodysplastic vessels present in patients with AVS, coupled with the lack of functioning Hmw VWF, increase the risk for GI bleeds. Aortic valve replacement, both surgical and transcatheter-based, is often a definitive treatment for GI bleeding, leading to recovery of Hmw VWF multimers. Perioperative management of patients involves monitoring their coagulation profiles with relevant laboratory tests and instituting appropriate management. Management can be directed in the following two ways: by improving internal release of VWF or by administration of external therapeutics containing VWF. It is important for perioperative physicians to obtain an understanding of the pathophysiology of this disease process and closely monitor the bleeding pattern so that targeted therapies can be initiated.
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Affiliation(s)
- Samhati Mondal
- Department of Anesthesiology, Cardiac Anesthesia Division, University of Maryland School of Medicine, Baltimore, MD.
| | - Kimberly N Hollander
- Department of Anesthesiology, Cardiac Anesthesia Division, University of Maryland School of Medicine, Baltimore, MD
| | - Stephanie O Ibekwe
- Department of Anesthesiology, Cardiovascular Division, BTGH, Baylor College of Medicine, Houston, TX
| | - Brittney Williams
- Department of Anesthesiology, Cardiac Anesthesia Division, University of Maryland School of Medicine, Baltimore, MD
| | - Kenichi Tanaka
- Department of Anesthesiology, Cardiac Anesthesia Division, University of Maryland School of Medicine, Baltimore, MD
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Ibrahim-Kosta M, Alessi MC, Hezard N. Laboratory Techniques Used to Diagnose Constitutional Platelet Dysfunction. Hamostaseologie 2020; 40:444-459. [PMID: 32932546 DOI: 10.1055/a-1223-3306] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Platelets play a major role in primary hemostasis, where activated platelets form plugs to stop hemorrhaging in response to vessel injuries. Defects in any step of the platelet activation process can cause a variety of platelet dysfunction conditions associated with bleeding. To make an accurate diagnosis, constitutional platelet dysfunction (CPDF) should be considered once von Willebrand disease and drug intake are ruled out. CPDF may be associated with thrombocytopenia or a genetic syndrome. CPDF diagnosis is complex, as no single test enables the analysis of all aspects of platelet function. Furthermore, the available tests lack standardization, and repeat tests must be performed in specialized laboratories especially for mild and moderate forms of the disease. In this review, we provide an overview of the laboratory tests used to diagnose CPDF, with a focus on light transmission platelet aggregation (LTA), flow cytometry (FC), and granules assessment. Global tests, mainly represented by LTA, are often initially performed to investigate the consequences of platelet activation on platelet aggregation in a single step. Global test results should be confirmed by additional analytical tests. FC represents an accurate, simple, and reliable test to analyze abnormalities in platelet receptors, and granule content and release. This technique may also be used to investigate platelet function by comparing resting- and activated-state platelet populations. Assessment of granule content and release also requires additional specialized analytical tests. High-throughput sequencing has become increasingly useful to diagnose CPDF. Advanced tests or external research laboratory techniques may also be beneficial in some cases.
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Affiliation(s)
- Manal Ibrahim-Kosta
- Aix Marseille University, INSERM, INRAE, Marseille Cedex 05, France.,Laboratory of Hematology, CHU Timone, Marseille Cedex 05, France
| | - Marie-Christine Alessi
- Aix Marseille University, INSERM, INRAE, Marseille Cedex 05, France.,Laboratory of Hematology, CHU Timone, Marseille Cedex 05, France
| | - Nathalie Hezard
- Laboratory of Hematology, CHU Timone, Marseille Cedex 05, France
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Charpy J, Chaghouri PE, Benattar N, Castet SM, Huguenin Y, James C, Fiore M. Evaluation of the potential utility of the total thrombus-formation analysis system in comparison to the platelet function analyser in subjects with primary haemostatic defects. Br J Haematol 2020; 191:e7-e10. [PMID: 32609384 DOI: 10.1111/bjh.16925] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | | | - Sabine-Marie Castet
- Centre de Ressources et de Compétence des Maladies Hémorragiques Constitutionnelles, CHU de Bordeaux, Bordeaux, France
| | - Yoann Huguenin
- Centre de Ressources et de Compétence des Maladies Hémorragiques Constitutionnelles, CHU de Bordeaux, Bordeaux, France
| | - Chloé James
- Laboratoire d'hématologie, CHU de Bordeaux, Pessac, France.,Inserm U1034, Biology of Cardiovascular Disease, Pessac, France
| | - Mathieu Fiore
- Laboratoire d'hématologie, CHU de Bordeaux, Pessac, France.,Centre de Référence des Pathologies Plaquettaires Constitutionnelles, CHU de Bordeaux, Pessac, France
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18
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Zhu S, Gilbert JC, Liang Z, Kang D, Li M, Tarantino PM, Jilma B. Potent and rapid reversal of the von Willebrand factor inhibitor aptamer BT200. J Thromb Haemost 2020; 18:1695-1704. [PMID: 32275107 PMCID: PMC7384040 DOI: 10.1111/jth.14822] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/26/2020] [Accepted: 03/31/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND BT200, a pegylated form of the aptamer BT100, inhibits binding of von Willebrand factor (VWF) to platelet glycoprotein GPIb, preventing arterial thrombosis in cynomolgus monkeys. It is being developed for secondary prevention of arterial thrombosis such as stroke or myocardial infarction. Inhibition of thrombogenesis by BT200 is expected to provide a therapeutic benefit. However, there may be unexpected bleeding (eg, incidental trauma) in which a reversal agent is required. To address this need, BT101, a complementary aptamer, has been developed to specifically inhibit BT100 and BT200 function. OBJECTIVES To characterize the effects of BT101 both in vitro and in vivo. METHODS The direct interaction between BT101 and the core aptamer BT100 was evaluated using polyacrylamide gel electrophoresis. The binding of BT200 to purified human VWF and inhibition of VWF activity was further characterized using enzyme-linked immunosorbent assay. VWF-dependent platelet function was measured by the platelet function analyzer and aggregometry in whole blood. In addition, both the in vivo pharmacokinetic profile of BT101 as well as its ability to reverse BT200 activity, were evaluated in cynomolgus monkeys. RESULTS BT101 bound to the core aptamer BT100 at a 1:1 ratio, inhibited BT200 binding to purified human VWF, and reversed BT200-induced inhibition of both VWF activity and VWF-dependent platelet function in vitro. After intravenous injection to monkeys, BT101 reversed BT200-induced effects on VWF activity and platelet function within minutes, without causing any adverse effects. CONCLUSIONS The results of this study demonstrate that BT101 is an effective reversal agent for BT200.
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Affiliation(s)
| | | | - Zicai Liang
- Suzhou Ribo Life Science Co., LtdKunshan CityChina
| | - Daiwu Kang
- Suzhou Ribo Life Science Co., LtdKunshan CityChina
| | - Ming Li
- Shanghai Institute of Materia MedicaChinese Academy of SciencesShanghaiChina
| | | | - Bernd Jilma
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria
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Favaloro EJ, Oliver S, Mohammed S, Vong R. Comparative assessment of von Willebrand factor multimers vs activity for von Willebrand disease using modern contemporary methodologies. Haemophilia 2020; 26:503-512. [PMID: 32159272 DOI: 10.1111/hae.13957] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 02/02/2020] [Accepted: 02/24/2020] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Diagnosis of von Willebrand disease (VWD) is challenging due to heterogeneity of VWD and test limitations. Many von Willebrand factor (VWF) assays are utilized, including antigen (Ag), activity and multimer analysis. Activity assays include ristocetin cofactor using platelets (VWF:RCo) or other particles incorporating recombinant glycoprotein I ('VWF:GPIbR'), or other GPI binding assays using gain-of-function mutations ('VWF:GPIbM'), or collagen binding (VWF:CB). AIM To comparatively evaluate modern contemporary VWF activity assays vs VWF multimer analysis using modern contemporary methods. MATERIALS AND METHODS Several VWF activity assays (VWF:RCo, VWF:GPIbR, VWF:GPIbM, VWF:CB) assessed (typically as a ratio against VWF:Ag) against a new semi-automated procedure for different types of VWD (1, 3, 2A, 2B, 2M), plus control material (n = 580). The evaluation also focussed on relative loss of high and very high molecular weight multimers (HMWM and VHMWM) by densitometric scanning. RESULTS All evaluated VWF activity/Ag ratios showed high correlation to the presence/absence of HMWM and VHMWM, although VWF:CB/Ag and VWF:GPIbR/Ag ratios using an automated chemiluminescence method yielded highest correlation coefficients (r = .909 and .874, respectively, for HMWM). Use of the investigative procedure (VHMWM) identified fewer false positives for 'loss' in type 1 VWD. CONCLUSIONS This comparative investigation identified that new automated chemiluminescence VWF activity assays best identified relative loss or presence of HMWM and VHMWM according to activity to Ag ratios and an alternative investigative method for identifying VHMWM in multimer testing for a new commercial multimer method may lead to fewer false identifications of HMW loss in type 1 VWD.
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Affiliation(s)
- Emmanuel J Favaloro
- Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, NSW, Australia.,Sydney Centres for Thrombosis and Haemostasis, Westmead Hospital, Westmead, NSW, Australia
| | - Susan Oliver
- Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, NSW, Australia
| | - Soma Mohammed
- Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, NSW, Australia
| | - Ronny Vong
- Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, NSW, Australia
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