1
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Pierre C, Alcorn KW, Chen D, Fesler J, Landis D, Litvack ZN, Konkle BA, Hegerova L. Neurosurgical bleeding in platelet storage pool disorder: a case report. Platelets 2024; 35:2380374. [PMID: 39041657 DOI: 10.1080/09537104.2024.2380374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Accepted: 07/11/2024] [Indexed: 07/24/2024]
Abstract
Dense-granule deficiency (DGD) is an inherited platelet disorder due to the absence of dense granules essential for activation of platelets in the event of vascular injury. Decreased platelet dense granules can be detected by electron microscopy, while other tests of hemostasis, including platelet function analyzer (PFA®) closure times, may be normal. The present case report describes a patient with a lifelong history of mucocutaneous bleeding and excessive hemorrhage with resection of vestibular Schwannoma. After hemostasis was obtained the case was aborted and the neurosurgeon noted bleeding resembled as if patient was on an antiplatelet drug. Subsequent hematologic workup revealed a severe platelet function disorder. There is a paucity of literature on management of intracranial neurosurgery in patients with inherited platelet disorders. Patients undergoing major surgical procedures often receive tranexamic acid (TXA), desmopressin, and/or human-leukocyte antigen (HLA)-matched platelet transfusions. We review the clinical management of intracranial tumor surgery, as well as Cyberknife radiosurgery, in our patient with DGD. After diagnosis was known, thoughtful hemostatic planning with empiric platelet transfusions and TXA prevented recurrent bleeding.
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Affiliation(s)
- Clifford Pierre
- Neurosurgery, Swedish Neuroscience Institute, Seattle, WA, USA
| | | | - Dong Chen
- Division of Hematopathology, Mayo Clinic, Rochester, MN, USA
| | - Joanna Fesler
- Hematology, Swedish Center for Blood Disorders and Stem Cell Transplantation, Seattle, WA, USA
| | - Daniel Landis
- Radiology, Swedish Radiosurgery Center, Seattle, WA, USA
| | | | - Barbara A Konkle
- Division of Hematology, and Washington Center for Bleeding Disorders, University of Washington, Seattle, WA, USA
| | - Livia Hegerova
- Division of Hematology, and Washington Center for Bleeding Disorders, University of Washington, Seattle, WA, USA
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2
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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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3
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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: 6] [Impact Index Per Article: 3.0] [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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4
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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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5
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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: 5] [Impact Index Per Article: 1.3] [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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6
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Dupuis A, Bordet JC, Eckly A, Gachet C. Platelet δ-Storage Pool Disease: An Update. J Clin Med 2020; 9:jcm9082508. [PMID: 32759727 PMCID: PMC7466064 DOI: 10.3390/jcm9082508] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/21/2020] [Accepted: 07/28/2020] [Indexed: 12/15/2022] Open
Abstract
Platelet dense-granules are small organelles specific to the platelet lineage that contain small molecules (calcium, adenyl nucleotides, serotonin) and are essential for the activation of blood platelets prior to their aggregation in the event of a vascular injury. Delta-storage pool diseases (δ-SPDs) are platelet pathologies leading to hemorrhagic syndromes of variable severity and related to a qualitative (content) or quantitative (numerical) deficiency in dense-granules. These pathologies appear in a syndromic or non-syndromic form. The syndromic forms (Chediak–Higashi disease, Hermansky–Pudlak syndromes), whose causative genes are known, associate immune deficiencies and/or oculocutaneous albinism with a platelet function disorder (PFD). The non-syndromic forms correspond to an isolated PFD, but the genes responsible for the pathology are not yet known. The diagnosis of these pathologies is complex and poorly standardized. It is based on orientation tests performed by light transmission aggregometry or flow cytometry, which are supplemented by complementary tests based on the quantification of platelet dense-granules by electron microscopy using the whole platelet mount technique and the direct determination of granule contents (ADP/ATP and serotonin). The objective of this review is to present the state of our knowledge concerning platelet dense-granules and the tools available for the diagnosis of different forms of δ-SPD.
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Affiliation(s)
- Arnaud Dupuis
- INSERM, EFS Grand Est, BPPS UMR-S 1255, FMTS, Université de Strasbourg, F-67000 Strasbourg, France; (A.E.); (C.G.)
- Correspondence: ; Tel.: +33-38-821-2506
| | - Jean-Claude Bordet
- Laboratoire D’hématologie, Hospices Civils de Lyon, 59 Bd Pinel, CEDEX, 69677 Bron, France;
| | - Anita Eckly
- INSERM, EFS Grand Est, BPPS UMR-S 1255, FMTS, Université de Strasbourg, F-67000 Strasbourg, France; (A.E.); (C.G.)
| | - Christian Gachet
- INSERM, EFS Grand Est, BPPS UMR-S 1255, FMTS, Université de Strasbourg, F-67000 Strasbourg, France; (A.E.); (C.G.)
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7
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Abstract
Platelet function testing has evolved from crude tests, such as the bleeding time, to tests that permit a relatively sophisticated evaluation of platelet activity. Nonetheless, these tests are hampered by lack of specificity and sensitivity, and poor standardization of methods and techniques. The bleeding time, which has long been a staple of hemostasis testing, has been dropped from the test menu at many laboratories. In its place, tests such as the Platelet Function Analyzer-100 are increasingly used to screen patients with possible bleeding disorders. Older tests, such as platelet aggregometry and lumiaggregometry, are still used frequently because they provide insight into receptor, signaling pathway and granule release mechanisms. Flow cytometry is available in some specialized laboratories and allows for quantitative and qualitative assessment of some platelet functions, although the expense of testing is often prohibitive. Finally, the wider availability of platelet function testing has stimulated interest and demand for monitoring the effect of platelet inhibitory drugs, such as aspirin and clopidogrel. As platelet function pathways become better understood, the demand for these type of monitoring tests is likely to increase.
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Affiliation(s)
- Amer M Zeidan
- Division of Hospital Medicine, Department of Medicine, Rochester General Hospital, Rochester, NY 14621, USA.
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8
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Abstract
The platelet-function analyzer, PFA-100, is a relatively novel method for rapid in vitro global evaluation of primary hemostasis. The aim of this review is to summarize the published studies reporting on the utility of the PFA-100 device as a screening tool for primary hemostasis. Data were identified by searches of the published literature, including PubMed, references from reviews and abstracts from the most important meetings on this topic. The literature data support the use of the PFA-100 as a useful screening tool for the investigation of von Willebrand's disease and other acquired and congenital intrinsic platelet function disorders. Moreover, it is useful for evaluating primary hemostasis before surgical procedures and for monitoring desmopressin therapy in both von Willebrand's disease and platelet function disorders. Given its high sensitivity, speed and simplicity of use, we conclude that the PFA-100 could replace the in vivo bleeding time as a screening test for primary hemostasis in routine clinical practice.
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Affiliation(s)
- Massimo Franchini
- Servizio di Immunoematologia e Trasfusione, Centro Emofilia, Azienda Ospedaliera di Verona, Verona, Italy.
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9
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Harrison P, Mackie I, Mumford A, Briggs C, Liesner R, Winter M, Machin S. Guidelines for the laboratory investigation of heritable disorders of platelet function. Br J Haematol 2011; 155:30-44. [DOI: 10.1111/j.1365-2141.2011.08793.x] [Citation(s) in RCA: 254] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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10
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Akin M, Karapinar DY, Balkan C, Ay Y, Kavakli K. An Evaluation of the DDAVP Infusion Test With PFA-100 and vWF Activity Assays to Distinguish vWD Types in Children. Clin Appl Thromb Hemost 2010; 17:441-8. [DOI: 10.1177/1076029610366440] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
von Willebrand disease (vWD) is classified into partial (type 1), qualitative (type 2), and total deficiency (type 3).The aims of the study were to evaluate prospectively the potency of the DDAVP infusion test together with von Willebrand factor (vWF) ristocetin cofactor (vWF:RCo), vWF antigen (vWF:Ag), factor VIII coagulant activity (FVIII:C), and platelet function analyzer (PFA)-100 to distinguish vWD types. Genetic analysis and multimeric analysis of vWF was not applied. We classified the 112 patients and 47 healthy children phenotypically according to the laboratory test results and bleeding severity score. PFA-100 closure times (CT), FVIII:C, vWF:RCo, vWF:Ag, ristocetin-induced platelet aggregation (RIPA), and the response of FVIII:C and vWF parameters to desmopressin (DDAVP) were used to define types 1, 2, and 3 vWD. Type 1 vWD is mild in 34 cases (vWF:RCo % 40-55), moderate in 29 (vWF:RCo %27-40), severe type 1 vWD or nonclassical type 2 vWD in 12 cases (vWF:RCo % 4-16), and type 2 vWD in 23 cases (vWF:RCo %4-38).The response to DDAVP of vWF parameters is normal in all patients with mild/moderate type 1 vWD, 6 patients with severe type 1 vWD or nonclassical type 2 vWD and 11 patients with type 2 vWD. In conclusion, this study showed that measurement of vWF:RCo, vWF:Ag, FVIII:C, and PFA-100 parameters can differentiate vWD types but not severe type 1 vWD or nonclassical type 2 vWD. In the differentiation of severe type 1 vWD and nonclassical type 2 vWD, DDAVP response may be used.
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Affiliation(s)
- Mehmet Akin
- Department of Pediatric Hematology, Ege University Faculty of Medicine, Izmir, Turkey
| | | | - Can Balkan
- Department of Pediatric Hematology, Ege University Faculty of Medicine, Izmir, Turkey
| | - Yilmaz Ay
- Department of Pediatric Hematology, Ege University Faculty of Medicine, Izmir, Turkey
| | - Kaan Kavakli
- Department of Pediatric Hematology, Ege University Faculty of Medicine, Izmir, Turkey
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11
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Abstract
Children with symptoms of bleeding and bruising are commonly seen in clinical practice. Primary care providers should be able to decide when and whether evaluation for bleeding disorder is warranted. This decision depends on one's index of suspicion for bleeding disorder based on history, physical examination, and screening laboratory investigations. Knowledge of the hemostatic physiology is essential to be able to order appropriate laboratory investigations and their accurate interpretation. Prothrombin time (PT), activated partial thromboplastin time (aPTT), and blood platelet concentration constitute the initial diagnostic work up of any bleeding disorder. Abnormality in any of these parameters in a child with excessive bleeding should lead to presumptive diagnosis of bleeding disorder and trigger referral to a hematologist for confirmation and definitive treatment. Awareness of basic treatment principles for management of bleeding/clotting disorders may prepare the provider to develop appropriate management plans, especially in a life threatening situation.
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Affiliation(s)
- Amit Sarnaik
- Children's Hospital of Michigan, Detroit, MI 48201, USA.
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12
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Koscielny J. Präoperative Hämostasediagnostik. Hamostaseologie 2010. [DOI: 10.1007/978-3-642-01544-1_39] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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13
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Toth J, Kappelmayer J, Udvardy ML, Szanto T, Szarvas M, Rejto L, Soltesz P, Udvardy M, Harsfalvi J. Increased platelet glycoprotein Ib receptor number, enhanced platelet adhesion and severe cerebral ischaemia in a patient with polycythaemia vera. Platelets 2009; 20:282-7. [PMID: 19459135 DOI: 10.1080/09537100902878421] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The present study describes severe multiplex cerebral ischaemic laesions in a male patient being diagnosed with polycythaemia vera (PV). In contrast to previous publications, unique platelet receptor pattern with normal platelet count was identified. Glycoprotein Ib receptor number on the surface of resting platelets was increased two-fold and almost three-fold in case of activated platelets compared to the controls. More over, in an in vitro study when whole blood was circulated both at venous and arterial shear conditions and shear rate was adjusted according to the blood viscosity, platelet aggregate/thrombus formation was characteristic on surfaces covered with purified von Willebrand factor while in case of controls the surface was covered with single platelets or platelet monolayer. Similar results with pathological findings have not been published in PV until now. Our result undersigns the necessity of antiplatelet therapy of PV patients, even at normal platelet count.
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Affiliation(s)
- Judit Toth
- Clinical Research Center, University of Debrecen, Debrecen, Hungary
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14
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Karger R, Donner-Banzhoff N, Müller HH, Kretschmer V, Hunink M. Diagnostic performance of the platelet function analyzer (PFA-100®) for the detection of disorders of primary haemostasis in patients with a bleeding history–a systematic review and meta-analysis. Platelets 2009; 18:249-60. [PMID: 17538845 DOI: 10.1080/09537100601100366] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The Platelet Function Analyzer (PFA-100) is increasingly being used in the workup of patients with a bleeding diathesis. A profound knowledge of the possible diagnostic performance of this test is essential in order to make sound clinical decisions based on its results. It was the aim of this study to systematically review the published literature and provide valid estimates of the diagnostic performance of the PFA-100 for detecting disorders of primary haemostasis in newly presenting patients with a bleeding diathesis. A comprehensive literature search was performed for studies published between January 1994 and February 2006. Studies were eligible for the systematic review if they provided data supposed to be applicable to the determination of the diagnostic performance of the PFA-100. Furthermore, they were included in a meta-analysis if study reporting allowed calculation of sensitivity and specificity and if study quality ensured minimized biases of these estimates for the described clinical setting. Pooled weighted sensitivity, specificity and diagnostic odds ratio were calculated applying random effects modelling and constructing summary operator characteristic curves. This was done separately for the available test modifications using either collagen/epinephrine (PFA-EPI) or collagen/adenosine-diphosphate (PFA-ADP) for platelet activation. Thirty-six articles were included in the systematic review. Six studies met our eligibility criteria for a meta-analysis. The major reason for exclusion from the meta-analysis was a case-control design. A total of 1486 and 1259 patients were included in the meta-analysis of the diagnostic performance of the PFA-EPI and PFA-ADP, respectively. Pooled weighted sensitivity and specificity of the PFA-EPI/PFA-ADP in detecting a disorder of primary haemostasis were: 82.5/66.9% (95%-confidence interval (95%-CI): 76.0-88.9%/57.9-75.9%), and 88.7/85.5% (95%-CI: 84.3-93.1%/82.0-89.1%). 83/75% of patients with a positive PFA-EPI/PFA-ADP result do have a disorder of primary haemostasis whereas 88/79% with a negative PFA-EPI/PFA-ADP result do not. The PFA-EPI appeared to have a higher sensitivity and better predictive values than the PFA-ADP in detecting disorders of primary haemostasis, although a rigorous gold standard definition for a disorder of primary haemostasis, particularly for platelet disorders, was not applied in most studies. The majority of the studies lacked important requirements for quality and reporting, precluding a more precise and definitive characterization of the clinical utility of the PFA-100. This emphasizes the need for an evidence-based critical appraisal of diagnostic studies in haemostasis research in order to promote the conducting of studies that produce clinically relevant results.
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Affiliation(s)
- Ralf Karger
- Institute for Transfusion Medicine and Haemostaseology, Philipps University, Marburg, Germany.
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15
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Podda GM, Bucciarelli P, Lussana F, Lecchi A, Cattaneo M. Usefulness of PFA-100 testing in the diagnostic screening of patients with suspected abnormalities of hemostasis: comparison with the bleeding time. J Thromb Haemost 2007; 5:2393-8. [PMID: 18034764 DOI: 10.1111/j.1538-7836.2007.02752.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Global tests of hemostasis that are used to screen patients with clinical suspicion of bleeding disorders should help the physician to identify the phase of the hemostatic system that is abnormal and guide further diagnostic workup. PATIENTS AND METHODS We compared the performance of Platelet Function Analyzer-100 (PFA-100) closure time (CT) with bleeding time (BT), both of which are screening tests for primary hemostasis, in the diagnostic workup of 128 consecutive patients who were screened for bleeding disorders. The sensitivities of BT and PFA-100 CT for known defects of hemostasis were evaluated; in addition, we calculated their correlation with the levels of severity of the bleeding symptoms, which were recorded using a standardized questionnaire. RESULTS The sensitivity of PFA-100 testing was 71% for von Willebrand disease (VWD) [with both collagen-adenosine diphosphate (C-ADP) and collagen-epinephrine (C-EPI) cartridges]; 58% (C-EPI) and 8% (C-ADP) for platelet function disorders (PFDs); and the sensitivity of BT was 29% (VWD) and 33% (PFD). C-EPI CT was also prolonged in about 20% of patients with abnormalities of coagulation or fibrinolysis. Only the C-EPI CT was significantly associated with the levels of severity of the patients' bleeding scores. CONCLUSIONS BT and C-EPI are insufficiently sensitive to be recommended as hemostasis screening tests. The C-ADP cartridge, which is sensitive to VWD only, might prove useful in further diagnostic workup of defects of primary hemostasis. The association of C-EPI CT with the severity of bleeding symptoms as a useful predictor of risk of bleeding in clinical practise should be tested in properly designed studies.
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Affiliation(s)
- G M Podda
- Dipartimento di Medicina e Specialità Mediche, IRCCS Fondazione Ospedale Maggiore, Mangiagalli e Regina Elena, Italy
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The Platelet Function Analyzer (PFA)-100. Platelets 2007. [DOI: 10.1016/b978-012369367-9/50790-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Abstract
The present understanding of the coagulation process emphasizes the final common pathway and the proteolytic systems that result in the degradation of formed clots and the prevention of unwanted clot formations, as well as a variety of defense systems that include tissue repair, autoimmune processes, arteriosclerosis, tumor growth, the spread of metastases, and defense systems against micro-organisms. This article discusses diagnosis and management of some of the most common bleeding disorders. The goals are to provide a simple guide on how best to manage patients afflicted with congenital or acquired clotting abnormalities during the perioperative period, present a brief overview of the methods of testing and monitoring the coagulation defects, and discuss the appropriate pharmacologic or blood component therapies for each disease.
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Affiliation(s)
- Doreen E Soliman
- Division of Pediatric Anesthesiology, University of Pittsburgh Medical Center and Children's Hospital of Pittsburgh, 3705 Fifth Avenue, Pittsburgh, PA 15213, USA.
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Webb JA, Allen DG, Abrams-Ogg ACG, Gentry PA. Effects of doxycycline, amoxicillin, cephalexin, and enrofloxacin on hemostasis in healthy dogs. Am J Vet Res 2006; 67:569-76. [PMID: 16579747 DOI: 10.2460/ajvr.67.4.569] [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] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine the effects of enteral administration of doxycycline, amoxicillin, cephalexin, and enrofloxacin at therapeutic dosages for a typical duration on hemostatic variables in healthy dogs. ANIMALS 14 Beagles. PROCEDURE Doxycycline (10 mg/kg, PO, q 12 h), amoxicillin (30 mg/kg, PO, q 12 h), cephalexin (30 mg/kg, PO, q 12 h), and enrofloxacin (20 mg/kg, PO, q 24 h) were administered in random order to 10 healthy dogs at standard therapeutic dosages for 7 days, with a 7-day washout period between subsequent antimicrobials. In addition, 4 Beagles served as control dogs. Variables were evaluated before and after antimicrobial administration; they included platelet count, Hct, 1-stage prothrombin time (PT), activated partial thromboplastin time (PTT), fibrinogen concentration, and platelet function. Platelet function was assessed via buccal mucosal bleeding time, aggregation, and a platelet-function analyzer. RESULTS Administration of all antimicrobials caused a slight prolongation of 1-stage PT and activated PTT and slight decrease in fibrinogen concentration. Cephalexin caused a significant increase in 1-stage PT and activated PTT, amoxicillin caused a significant increase in activated PTT, and enrofloxacin caused a significant decrease in fibrinogen concentration. Platelet count or function did not differ significantly after administration of any antimicrobial. CONCLUSIONS AND CLINICAL RELEVANCE Oral administration of commonly used antimicrobials in healthy dogs resulted in minor secondary hemostatic abnormalities, with no change in platelet count or function. Although these changes were clinically irrelevant in healthy dogs, additional studies of the effects of antimicrobial administration on hemostasis in animals with underlying disease processes are warranted.
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Affiliation(s)
- Jinelle A Webb
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada
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20
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Hayward CPM, Harrison P, Cattaneo M, Ortel TL, Rao AK. Platelet function analyzer (PFA)-100 closure time in the evaluation of platelet disorders and platelet function. J Thromb Haemost 2006; 4:312-9. [PMID: 16420557 DOI: 10.1111/j.1538-7836.2006.01771.x] [Citation(s) in RCA: 249] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Closure time (CT), measured by platelet function analyzer (PFA-100) device, is now available to the clinical laboratory as a possible alternative or supplement to the bleeding time test. AIM On behalf of the Platelet Physiology Subcommittee of the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis (ISTH-SSC), a working Group was formed to review and make recommendations on the use of the PFA-100 CT in the evaluation of platelet function within the clinical laboratory. METHODS The Medline database was searched to review the published information on the PFA-100 CT in the evaluation of platelet disorders and platelet function. This information, and expert opinion, was used to prepare a report and generate consensus recommendations. RESULTS Although the PFA-100 CT is abnormal in some forms of platelet disorders, the test does not have sufficient sensitivity or specificity to be used as a screening tool for platelet disorders. A role of the PFA-100 CT in therapeutic monitoring of platelet function remains to be established. CONCLUSIONS The PFA-100 closure time should be considered optional in the evaluation of platelet disorders and function, and its use in therapeutic monitoring of platelet function is currently best restricted to research studies and prospective clinical trials.
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Affiliation(s)
- C P M Hayward
- McMaster University and the Hamilton Regional Laboratory Medicine Program, Hamilton, ON, Canada.
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Harrison P, Mackie I, Mathur A, Robinson MSC, Hong Y, Erusalimsky JD, Machin SJ, Martin JF. Platelet hyper-function in acute coronary syndromes. Blood Coagul Fibrinolysis 2005; 16:557-62. [PMID: 16269928 DOI: 10.1097/01.mbc.0000187252.09759.ba] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Previous studies have demonstrated shortened bleeding times in patients with acute coronary syndromes, especially in myocardial infarction (MI). In this study we have investigated platelet hyper-function using the PFA-100 with collagen/adenosine diphosphate and collagen/epinephrine cartridges in 78 patients presenting with acute chest pain. Patients were classified into MI, unstable angina (UA) and non-specific chest pain. All patients received 300 mg aspirin (ASA) more than 2 h before blood samples were collected. Twenty healthy normal subjects were also tested before and 2 h after 300 mg ASA (n = 10). The collagen/adenosine diphosphate closure time was significantly shorter in MI patients (median, 71 s; P = 0.0237) but not in UA patients (median, 81 s; P > 0.05) compared with normal subjects (median, 92.5 s). The collagen/epinephrine closure times were significantly longer in UA patients (median, 233 s) than in untreated controls (median, 125 s; P < 0.0001), as expected, but there was no difference in MI patients (median, 149.24 s; P > 0.05), suggesting that the MI patients were not all responding to ASA. Analysis of a subset of the apparent ASA non-responders (n = 5) by platelet aggregation demonstrated that this was not related to failure of ASA to block cyclo-oxygenase activity. Von Willebrand factor levels were significantly elevated in both UA and MI patients compared with normal subjects (mean, 175.5 and 248.9 versus 89.1 s; P < 0.0001 and P < 0.0001, respectively) and were also significantly higher in the MI group compared with the UA group (P < 0.05). There is evidence for platelet hyper-function and elevated von Willebrand factor levels in the MI group that could explain their decreased responsiveness to ASA on the collagen/epinephrine cartridge.
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Affiliation(s)
- Paul Harrison
- Haemostasis Research Unit, Department of Haematology, University College London, UK.
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22
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Segura D, Monreal L, Espada Y, Pastor J, Mayós I, Homedes J. Assessment of a platelet function analyser in horses: reference range and influence of a platelet aggregation inhibitor. Vet J 2005; 170:108-12. [PMID: 15993794 DOI: 10.1016/j.tvjl.2004.05.013] [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] [Accepted: 05/21/2004] [Indexed: 10/26/2022]
Abstract
The objective of this study was to assess whether a new human platelet function analyser (the PFA-100) could be used to evaluate platelet function in horses and detect acetylsalicylic acid (ASA)-induced platelet dysfunctions. Citrated blood samples from 40 healthy horses were processed to obtain reference values for closure time (CT) using cartridges with collagen-ADP (CT-ADP) and collagen-epinephrine (CT-EPI) as platelet agonists. In addition, CT-ADP and CT-EPI were also measured before and 24 h after oral ASA administration in another 12 healthy horses. The sensitivity and specificity of the test were also determined. In normal horses, means+/-SD value for CT-ADP was 85.1+/-13.1 s (median, 82 s), and CT-EPI ranged from 158 to >300 s (median 291 s). Calculated reference ranges were 60.5-115.9 s and 158.5->300 s for CT-ADP and CT-EPI, respectively. Administration of ASA significantly (P<0.001) prolonged CT-ADP values from 91.0+/-13 to 113.5+/-14.4 s, and CT-EPI values were also significantly (P<0.008) prolonged after ASA administration. Sensitivity and specificity results for ADP cartridges showed that a prolonged CT value would be highly suggestive of a platelet aggregation inhibition. In conclusion, ADP cartridges can be used in horses to assess primary haemostasis and may be a valuable test for the detection of platelet aggregation inhibition.
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Affiliation(s)
- D Segura
- Departament de Medicina i Cirurgia Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona.
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23
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Munsterhjelm E, Niemi TT, Ylikorkala O, Silvanto M, Rosenberg PH. Characterization of inhibition of platelet function by paracetamol and its interaction with diclofenac in vitro. Acta Anaesthesiol Scand 2005; 49:840-6. [PMID: 15954969 DOI: 10.1111/j.1399-6576.2005.00707.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Paracetamol (acetaminophen) is an effective analgesic and a weak inhibitor of cyclo-oxygenase (COX). Clinically paracetamol is often used together with traditional NSAIDs, which are strong inhibitors of COX. We studied binding of paracetamol to COX and its action on platelet function together with diclofenac. METHODS Blood was collected from healthy donors and platelet function was assessed by photometric aggregometry, a platelet function analyser (PFA-100, Dade Behring, Deerfield, IL) and by measuring the release of thromboxane B(2) (TxB(2)), the stable metabolite of thromboxane A(2), after addition of paracetamol (10-80 microg ml(-1)). A concentration-inhibition relationship was established and the inhibition coefficient (K(i)) demonstrating 50% binding to COX was determined using a Schild-plot. Interaction of paracetamol (5-20 microg ml(-1)) and diclofenac (0.1-0.8 microg ml(-1)) was determined and an isobolographic analysis was performed. RESULTS Paracetamol added to platelet-rich plasma (PRP) caused a concentration-dependent inhibition of platelet function. Photometric aggregometry and TxB(2) release was significantly inhibited by paracetamol from 10 microg ml(-1) onwards. The PFA-100 closure time was significantly prolonged by paracetamol at a high concentration only. K(i) was 15.2 microg ml(-1) with a 95% confidence interval of 11.8-18.6 microg ml(-1). Inhibition of aggregation by diclofenac was augmented by paracetamol. Isobolographic analysis showed synergism. CONCLUSIONS The 95% confidence interval of K(i) equals the antipyretic plasma concentration of paracetamol, i.e. 10-20 microg ml(-1). High doses of paracetamol and a combination of diclofenac and paracetamol cause platelet inhibition and thus may increase risk of surgical bleeding.
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Affiliation(s)
- E Munsterhjelm
- Department of Anaesthesiology and Intensive Care Medicine, Helsinki University Hospital, Helsinki, Finland.
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Harrison P. The role of PFA-100R testing in the investigation and management of haemostatic defects in children and adults. Br J Haematol 2005; 130:3-10. [PMID: 15982339 DOI: 10.1111/j.1365-2141.2005.05511.x] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The PFA-100 provides a simple global measure of high shear-dependent platelet function, and as such is not diagnostic or specific to any disorder. Prolonged closure times must be interpreted in conjunction with a full blood count, von Willebrand factor (VWF) screen and other platelet tests. The PFA-100 may also give false negative results with relatively common platelet defects. If clinical suspicion is high, further detailed platelet function testing and VWF screening are required to exclude abnormal platelet function, even if the PFA-100 is normal. In more recent studies the PFA-100 has been used for preoperative identification and management of surgical patients with haemostatic defects and for assessing the clinical effectiveness of platelet transfusion therapy. This review highlights the up to date, evidence-based, advantages and disadvantages of the PFA-100 test in the investigation and management of haemostatic disorders in both children and adults.
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Affiliation(s)
- Paul Harrison
- Oxford Haemophilia Centre and Thrombosis Unit, Churchill Hospital, Headington, Oxford, UK.
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Kerényi A, Soltész P, Veres K, Szegedi G, Muszbek L. Monitoring platelet function by PFA-100 closure time measurements during thrombolytic therapy of patients with myocardial infarction. Thromb Res 2005; 116:139-44. [PMID: 15907529 DOI: 10.1016/j.thromres.2004.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2004] [Revised: 08/22/2004] [Accepted: 10/03/2004] [Indexed: 11/27/2022]
Affiliation(s)
- Adrienne Kerényi
- Department of Clinical Biochemistry and Molecular Pathology, University of Debrecen, Medical and Health Science Center, Debrecen, Hungary
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Koscielny J, von Tempelhoff GF, Ziemer S, Radtke H, Schmutzler M, Sinha P, Salama A, Kiesewetter H, Latza R. A practical concept for preoperative management of patients with impaired primary hemostasis. Clin Appl Thromb Hemost 2004; 10:155-66. [PMID: 15094936 DOI: 10.1177/107602960401000206] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
In a prospective study, 254 of 5649 unselected patients scheduled for surgery at our hospital were identified preoperatively as having either acquired (n=182) or inherited (n=72) impaired primary hemostasis (platelet dysfunction including von Willebrand disease). All patients were initially pretreated with desmopressin (DDAVP). Response to DDAVP or subsequent treatment(s) was defined as correction of any one of the abnormal PFA-100 platelet function tests. The non-responders were additionally treated with tranexamic acid or aprotinin; those with von Willebrand disease (vWD) received factor VIII concentrates with von Willebrand factor (vWF). Those still unresponsive to therapy received conjugated estrogens and, as a last attempt, a platelet transfusion. The administration of DDAVP led to a correction of platelet dysfunction in 229 of the 254 patients treated (90.2%). Tranexamic acid was effective in 12 of 16, aprotinin in 3 of 5, and factor VIII concentrates with vWF in all 4 patients with unresponsive to DDAVP. The remaining 6 patients were pretreated with conjugated estrogens, and 2 of these patients were additionally treated with platelet transfusion. The frequency of blood transfusion was lower, but not statistically significant (9.4% vs. 12.2%: p = 0.202) in preoperatively treated patients with impaired hemostasis than in patients without impaired hemostasis. In a retrospective group, the frequency of blood transfusion was statistically significant higher (89.3% vs. 11.3%: p < 0.001) in patients without preoperative correction of impaired hemostasis than in patients without impaired hemostasis. Preoperative correction of impaired primary hemostasis is possible in nearly all patients affected, and results in a reduction of homologous blood transfusions.
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Affiliation(s)
- Juergen Koscielny
- Institute for Transfusion Medicine, Charité Humboldt-University, Schumannstr. 20/21, 10117 Berlin, Germany.
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27
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Quiroga T, Goycoolea M, Muñoz B, Morales M, Aranda E, Panes O, Pereira J, Mezzano D. Template bleeding time and PFA-100 have low sensitivity to screen patients with hereditary mucocutaneous hemorrhages: comparative study in 148 patients. J Thromb Haemost 2004; 2:892-8. [PMID: 15140124 DOI: 10.1111/j.1538-7836.2004.00693.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVES AND PATIENTS We compared the template bleeding time (BT) and closure time (CT) in the PFA-100 as screening tests in 148 consecutive patients with unequivocal mucocutaneous bleeding and positive family history. EXCLUSION CRITERIA drug intake, concomitant diseases including minor infections, low platelet count, diseases of secondary hemostasis. RESULTS Type 1 von Willebrand disease (VWD-1) was diagnosed in 26 patients, primary platelet secretion defect (PSD) in 33, VWD-1 + PSD in nine, whereas 80 patients did not comply with the criteria for known hemostatic disorders (UD, unknown diagnosis). BT and CT were prolonged in 35.8% and 29.7% of all the patients, respectively (P = 0.23). Sensitivity increased to 48% if an abnormality of BT and/or CT was considered. Same comparisons for BT and CT in each diagnostic category were, respectively: 42 vs. 61.5% in VWD-1 (P = 0.18), 42 vs. 24% in platelet secretion defects (P = 0.11), 67 vs. 89% in VWD-1 + PSD (P = 0.50), and 27.5 vs. 15% in UD (P = 0.06). CONCLUSION Both tests were relatively insensitive and not significantly different in detecting incoming patients with mucocutaneous hemorrhages. In patients with VWD-1, the PFA-100 performed slightly better, whereas the opposite occurred in those patients with platelet secretion defects. In the UD group, both tests lost sensitivity, but the BT detected 1.8 times more patients than the PFA-100. Given the large proportion of undiagnosed bleeders and the overall low sensitivity of these tests, clinical decisions still rely on the medical history and etiological diagnosis of the bleeding disorder.
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Affiliation(s)
- T Quiroga
- Clinical Laboratory and Department of Hematology-Oncology, School of Medicine, P.Catholic University of Chile, Santiago, Chile
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28
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Fricke W, Kouides P, Kessler C, Schmaier AH, Krijanovski Y, Jagadeesan K, Joist J. A multicenter clinical evaluation of the Clot Signature Analyzer. J Thromb Haemost 2004; 2:763-8. [PMID: 15099283 DOI: 10.1111/j.1538-7836.2004.00695.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND The Clot Signature Analyzer (CSA) was designed to assess global hemostasis as a screening assay using non-anticoagulated whole blood. Three different measurements are produced by the instrument: platelet hemostasis time (PHT), clot time (CT), and collagen-induced thrombus formation (CITF). OBJECTIVES The purpose of the present study was to determine normal ranges for these measurements and assess the performance of the CSA in patients with well-characterized hemostatic disorders and in normal subjects. PATIENTS AND METHODS Four institutions participated in the study. Each established their own normal reference ranges. Patients with well-characterized hemostatic disorders and concurrent normal controls were subsequently examined. RESULTS Normal ranges between institutions were similar although statistically different. One hundred and eight patients were examined: 46 individuals with von Willebrand disease (VWD) (type 1, 26; type 2A, 11; type 2B, six; type 3, three); 38 patients with a coagulation factor deficiency; 13 individuals with platelet function defects; 10 patients taking warfarin; and one individual on low-molecular-weight heparin. Of these patients, 89% had at least one abnormality by CSA: 42/46 VWD patients, 35/38 coagulation protein defect patients, 9/13 patients with platelet function defects, 9/10 patients on warfarin and 1/1 patient on low-molecular-weight heparin. Of 116 normal subjects, 103 (89%) fell within the centers' normal range. These data suggest that the CSA has a good sensitivity for bleeding disorders.
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Affiliation(s)
- W Fricke
- Department of Internal Medicine, Georgetown University, Washington, DC, USA.
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Munsterhjelm E, Niemi TT, Syrjälä MT, Ylikorkala O, Rosenberg PH. Propacetamol augments inhibition of platelet function by diclofenac in volunteers. Br J Anaesth 2003; 91:357-62. [PMID: 12925474 DOI: 10.1093/bja/aeg195] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Acetaminophen (paracetamol) enhances the analgesic effect of non-steroidal anti-inflammatory drugs (NSAIDs). Acetaminophen is a weak inhibitor of cyclooxygenase (COX), and its combination with an NSAID may augment COX inhibition-related side effects. METHODS Ten healthy male volunteers (21-30 yr) were given diclofenac 1.1 mg kg(-1) alone, a combination of propacetamol 30 mg kg(-1) (which is hydrolysed to 50% acetaminophen) and diclofenac 1.1 mg kg(-1) or placebo intravenously in a double blind, crossover study. Platelet function was assessed at 5 min, 90 min and 22-24 h by photometric aggregometry, platelet function analyser (PFA-100(TM)) and by measuring the release of thromboxane B(2) (TxB(2)). Analgesia was assessed with the cold pressor test. RESULTS Platelet aggregation induced with arachidonic acid was fully inhibited by both diclofenac alone and the combination at the end of the 30-min drug infusion. Propacetamol augmented the inhibition by diclofenac at 90 min (P=0.014). At 22-24 h, platelet function had fully recovered. TxB(2) release was inhibited by the combination of propacetamol and diclofenac at 90 min in comparison with diclofenac alone (P=0.027). PFA-100(TM) detected no difference in platelet function between these two groups. No analgesic effect was detected with the cold pressor test. CONCLUSIONS The combination of propacetamol and diclofenac inhibits platelet function more than diclofenac alone. This should be considered when assessing the risk of surgical bleeding.
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Affiliation(s)
- E Munsterhjelm
- Department of Anaesthesiology and Intensive Care Medicine, Helsinki University Hospital, PO Box 340 (P-floor), FIN-00029 HUS, Helsinki, Finland.
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Tarnow I, Kristensen AT, Texel H, Olsen LH, Pedersen HD. Decreased Platelet Function in Cavalier King Charles Spaniels with Mitral Valve Regurgitation. J Vet Intern Med 2003; 17:680-6. [PMID: 14529135 DOI: 10.1111/j.1939-1676.2003.tb02500.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
With aggregometry, increased platelet activity has been reported in Cavalier King Charles Spaniels (CKCS) without mitral regurgitation (MR). In contrast, dogs with MR have been found to have decreased platelet activity. The purpose of this study was to test an easy bedside test of platelet function (the Platelet Function Analyzer [PFA-100]) to see if it could detect an increase in platelet activity in CKCS without MR and a decrease in platelet activity in CKCS with MR. This study included 101 clinically healthy dogs > 1 year of age: 15 control dogs of different breeds and 86 CKCS. None of the dogs received medication or had a history of bleeding. The PFA-100 evaluates platelet function in anticoagulated whole blood under high shear stress. Results are given as closure times (CT): the time it takes before a platelet plug occludes a hole in a membrane coated by agonists. The CT with collagen and adenosine-diphosphate as agonists was similar in control dogs (median 62 seconds; interquartile interval 55-66 seconds) and CKCS with no or minimal MR (55; 52-64 seconds). The CT was higher in CKCS with mild MR (regurgitant jet occupying 15-50% of the left atrial area) (75; 60-84 seconds; P = .0007) and in CKCS with moderate to severe MR (jet > 50%) (87: 66-102 seconds; P < .0001). CKCS with mild, moderate, and severe, clinically inapparent MR have decreased platelet function. The previous finding of increased platelet reactivity in nonthrombocytopenic CKCS without MR could not be reproduced with the PFA-100 device.
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Affiliation(s)
- Inge Tarnow
- Department of Anatomy and Physiology, The Royal Veterinary and Agricultural University, Frederiksberg, Denmark.
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31
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Cariappa R, Wilhite TR, Parvin CA, Luchtman-Jones L. Comparison of PFA-100 and bleeding time testing in pediatric patients with suspected hemorrhagic problems. J Pediatr Hematol Oncol 2003; 25:474-9. [PMID: 12794526 DOI: 10.1097/00043426-200306000-00009] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND The bleeding time test is difficult to perform, standardize, and interpret in children. In this study the authors evaluated the sensitivity, specificity, and efficiency of the bleeding time test and the PFA-100 in a series of children referred for possible bleeding problems. PATIENTS AND METHODS Between February 2000 and August 2001 patients aged more than 6 months and less than 18 years of age who were referred to the authors' institution for a hemostatic evaluation were included in the study if residual blood was available for testing on the PFA-100 instrument. Fifty-two children had platelet count, prothrombin time, partial thromboplastin time, bleeding time, and PFA-100 testing performed as well as an evaluation by a hematologist. For PFA-100 testing, 52 patients had Col/Epi measurements; adequate sample remained for Col/ADP testing on 32. Additional testing for diagnostic purposes was at the discretion of the treating physician. RESULTS Use of the Col/Epi cartridge in the PFA-100 instrument offered 100% sensitivity and 97% specificity for detection of qualitative platelet abnormalities, compared with 37% and 88%, respectively, for bleeding time testing. For pediatric patients with von Willebrand disease, the sensitivity was 100% using the Col/Epi cartridge, compared with 17% for the bleeding time test. The sensitivities for combined qualitative platelet defects and von Willebrand disease using the Col/Epi or Col/ADP cartridges were 100% and 87%, respectively, compared with 37% for the bleeding time test. CONCLUSIONS The PFA-100 is a more efficient test; it can replace the bleeding time test as a component of the laboratory evaluation of children with a potential bleeding problem.
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Affiliation(s)
- Rohit Cariappa
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Callan MB, Giger U. Effect of desmopressin acetate administration on primary hemostasis in Doberman Pinschers with type-1 von Willebrand disease as assessed by a point-of-care instrument. Am J Vet Res 2002; 63:1700-6. [PMID: 12492285 DOI: 10.2460/ajvr.2002.63.1700] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate primary hemostasis following administration of desmopressin acetate (DDAVP) to Doberman Pinschers with type-1 von Willebrand disease (vWD). ANIMALS 16 nonanemic Doberman Pinschers with type-1 vWD. PROCEDURE Closure time (CT), defined as time required for occlusion of an aperture by a platelet plug assessed within the point-of-care instrument, plasma von Willebrand factor (vWF) concentration, and buccal mucosal bleeding time (BMBT) were determined before and 1 hour after administration of DDAVP (1 microg/kg, SC). RESULTS Baseline closure times measured with adenosine diphosphate ([ADP-CT], 108 to > 300 seconds; reference range, 52 to 86 seconds) and epinephrine ([EPI-CT], 285 to > 300 seconds; 97 to 225 seconds) as platelet agonists were prolonged in all dogs. Following DDAVP administration, ADP-CT (59 to 186 seconds) was significantly shortened from baseline, but there was no decrease in EPI-CT. Although mean plasma vWF concentration increased significantly after DDAVP administration, only 1 dog had an increase of > 35 U/dL. There was no correlation between increase in plasma vWF concentration and shortening of the ADP-CT. Baseline BMBT was prolonged in 12 of 14 dogs, with significant shortening of BMBT after DDAVP administration in 6 of 7 dogs. In vitro replacement of vWF-deficient plasma with plasma from an unaffected dog shortened the ADP-CT whereas in vitro addition of DDAVP had no effect. CONCLUSIONS AND CLINICAL RELEVANCE Administration of DDAVP to Doberman Pinschers with type-1 vWD resulted in improved hemostatic function, as assessed by the point-of-care instrument and shortening of BMBT, despite minimal increase in plasma vWF concentration.
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Affiliation(s)
- Mary Beth Callan
- Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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Abstract
Because bruising and bleeding are normal events of childhood, the pediatrician must be able to determine whether a child's symptoms are normal or perhaps indicative of a defective hemostasis. A thorough medical history and physical examination should enable the clinician to choose those patients warranting further evaluation. Rather than referral to a hematologist at that point in time, pediatricians should be quite capable of performing the initial laboratory evaluation and making the correct diagnosis in a majority of cases.
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Affiliation(s)
- Geoffrey A Allen
- Division of Hematology/Oncology, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
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Abstract
The PFA-100 (platelet function analyzer) is a relatively new tool for the investigation of primary hemostasis. Recent studies have shown its utility as a screening tool for investigating possible von Willebrand disorder (VWD) and various platelet disorders. More recently, the PFA-100 has been shown to be valuable in monitoring desmopressin acetate (DDAVP) therapy in both VWD and platelet disorders. The PFA-100 has also been evaluated in many other studies for its utility in assessing drug effects, for potential monitoring of antiplatelet medication (including aspirin), or for evaluation of overall primary hemostasis in various clinical disorders or during surgical procedures. This article reviews current findings and highlights the benefits and limitations of the clinical utility of the PFA-100. Ultimately, the greatest strengths of the PFA-100 are its simplicity of use and excellent sensitivity to particular hemostatic disturbances such as VWD, platelet disorders, and platelet-affecting medication. However, because it is thus a global test system, this also creates a significant limitation because the PFA-100 is not specific for, nor predictive of, any particular disorder. However, used appropriately, the PFA-100 can be considered a worthwhile addition to any hemostasis laboratory involved in the diagnosis or therapeutic monitoring of bleeding disorders and potentially of antiplatelet medication. This review should be valuable to both hemostasis scientists and clinical specialists.
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Affiliation(s)
- Emmanuel J Favaloro
- Diagnostic Haemostasis Laboratory, Department of Hematology, Institute of Clinical Pathology and Medical Research, Westmead Hospital, Western Sydney Area Health Service, Westmead, NSW, 2145, Australia.
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Pieniaszek HJ, Sy SKB, Ebling W, Fossler MJ, Cain VA, Mondick JT, Ma S, Kornhauser DM. Safety, tolerability, pharmacokinetics, and time course of pharmacologic response of the active metabolite of roxifiban, XV459, a glycoprotein IIb/IIIa antagonist, following oral administration in healthy volunteers. J Clin Pharmacol 2002; 42:738-53. [PMID: 12092741 DOI: 10.1177/009127002401102687] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Roxifiban is an esterprodrug that is hydrolyzed, after oral administration, to the active glycoprotein (GP) IIb/IIIa antagonist, XV459. The objectives of the study were to investigate the safety, tolerability, pharmacokinetics, and the time course of the pharmacologic response of XV459 in escalating doses of roxifiban and to assess the effect of age, loading dose of roxifiban, and aspirin pretreatment on XV459 pharmacokinetics, pharmacologic response, and safety profile in a five-part double-blind, placebo-controlled study. Healthy male volunteers (ages 18-46 years) received 7 (0.75-1.5 mg; n = 20) and 10 (0.75-1.0 mg; n = 8) multiple, oral, qd doses of roxifiban or placebo (n = 5). Healthy older male and female volunteers (ages 47-75 years) received roxifiban qd doses (0.5-0.75 mg; n = 8) or placebo (n = 3) for 7 days. Healthy male subjects (ages 18-46 years; n = 16) received a 1.5 or 1.0 mg loading dose either with or without pretreatment of 325 mg aspirin once daily for 3 days followed by single daily doses of 1.0 mg roxifiban for 6 days. Measurable plasma concentrations of XV459 appeared rapidly and were sustained throughout the dosing interval of 24 hours. The pharmacokinetics of XV459 were nonlinear. Systemic exposure of XV459 plateaued at the 1-mg dose level; plasma concentrations approached steady state in 4 to 6 days for doses greater than 1.0 mg. The time course of pharmacologic response as measured by the inhibition of platelet aggregation in response to an ex vivo 10 microM adenosine 5'-diphosphate (ADP) agonist correlated closely to the plasma concentration of XV459. Potent inhibition of ADP-induced platelet aggregation (IPA) persisted over the entire dosing interval. A clear dose response was achieved with roxifiban doses of 0.5 and 1.0 mg. For doses greater than 1.0 mg, a dose-proportional increase in IPA was not observed. Both the pharmacokinetics and pharmacologic response of XV459 exhibited low intraindividual variability (coefficient of variation [CV] < 15%) and higher interindividual variability (CV < 30%). Pretreatment with aspirin and/or a loading dose of 1.5 mg roxifiban had no significant effect on the pharmacokinetics and pharmacologic response of XV459. A dose-related increase in template bleeding time was observed at 1.25- and 1.5-mg doses of roxifiban, as compared to placebo. However, these bleeding time increases in the 1.25- and 1.5-mg dose groups were not significantly different from those at the lower dose groups. Overall, once-daily oral administration of roxifiban was fairly well tolerated and provided sustained systemic drug exposure and pharmacologic response over the entire administration interval.
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Affiliation(s)
- Henry J Pieniaszek
- Drug Metabolism and Pharmacokinetics, Bristol-Myers Squibb Pharma Company, Newark, Delaware, USA
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Buyukasik Y, Karakus S, Goker H, Haznedaroglu IC, Ozatli D, Sayinalp N, Ozcebe OI, Dundar SV, Kirazli S. Rational use of the PFA-100 device for screening of platelet function disorders and von Willebrand disease. Blood Coagul Fibrinolysis 2002; 13:349-53. [PMID: 12032401 DOI: 10.1097/00001721-200206000-00011] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Two hundred and five patients referred for evaluation of platelet functions and 126 healthy controls were tested with the PFA-100 instrument. A cut-off value of 150 s for collagen/epinephrine (CEPI) closure time (CT) produced most acceptable sensitivity (90%), specificity (85.2%), and positive (82.6%) and negative (91.6%) predictivity values for screening of platelet function disorders and von Willebrand disease (vWD). All patients with vWD and Glanzmann thrombasthenia could be detected by PFA-100. Both CEPI and collagen/adenosine diphosphate (CADP) CTs were elevated in all of these cases. Sensitivity of the device was 81.6% for patients with platelet secretion defects. CADP CT was normal in 63.9% of the patients in this subgroup. Specificity (47%) and positive predictivity (57%) of the instrument were diminished in patients with low hemoglobin concentrations. Depending on the results, an algorithm was developed for screening of platelet function disorders and vWD with PFA-100.
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Affiliation(s)
- Y Buyukasik
- Department of Hematology, Hacettepe University Medical School, Ankara, Turkey.
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Abstract
The evaluation of menorrhagia should no longer be solely the task of the gynaecologist. In women with ovulatory bleeding (regular cycles), the prevalence of von Willebrand disease (vWD) in about 15% of these, as well as disorders of platelet function and fibrinolysis causing menorrhagia, warrants an active role by the haematologist. Initial intake should include documentation of menorrhagia by the pictorial chart assessment of menstrual flow. Baseline characteristics of menstrual flow should also be documented, including the frequency of changing the sanitary pad on the heaviest day, use of more than one sanitary pad at a time, number of days lost from school/work and the impact of menses on various quality-of-life parameters. Menorrhagia since menarche, a past history of surgical- and/or dental-related bleeding and a past history of postpartum haemorrhage are items of the bleeding symptom audit that appear in part to predict vWD in women with menorrhagia. Epistaxis and easy bruising do not appear to be clearly discriminatory symptoms. Initial testing should include the complete blood cell count, prothrombin time, activated partial thromboplastin time, iron profile, serum creatinine, thyroid stimulating hormone level, factor VIII level, vWF antigen, ristocetin cofactor and platelet aggregation studies. Additional haemostatic studies may also include a factor XI level and euglobulin clot lysis time. This extensive medical evaluation should assure both the patient and the gynaecologist that the possibility of an underlying haemostatic disorder has been thoroughly investigated, to avoid the patient undergoing further costly procedures and surgical interventions if an underlying haemostatic disorder remains unrecognized.
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Affiliation(s)
- P A Kouides
- Mary Gooley Hemophilia Center, and the University of Rochester School of Medicine, Rochester, NY 14621, USA.
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Jilma B. Platelet function analyzer (PFA-100): a tool to quantify congenital or acquired platelet dysfunction. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 2001; 138:152-63. [PMID: 11528368 DOI: 10.1067/mlc.2001.117406] [Citation(s) in RCA: 222] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- B Jilma
- Department of Clinical Pharmacology-TARGET, University of Vienna, Austria
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39
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Favaloro EJ. Appropriate laboratory assessment as a critical facet in the proper diagnosis and classification of von Willebrand disorder. Best Pract Res Clin Haematol 2001; 14:299-319. [PMID: 11686101 DOI: 10.1053/beha.2001.0135] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The correct diagnosis and classification of von Willebrand disease or disorder (VWD) is crucial because the presenting biological activity of von Willebrand factor (VWF) determines both the haemorrhagic risk and the subsequent clinical management. A variety of laboratory assays may be employed, not necessarily restricted to assessments of VWF. Because of assay limitations and von Willebrand disease heterogeneity, no single test procedure is sufficiently 'robust' to permit the detection of all VWD variants. Classically, the test panel might include any combination of: (a) skin bleeding time, (b) von Willebrand factor antigen assay, (c) factor VIII C level, (d) assessment of 'functional' von Willebrand factor (collagen-binding activity or ristocetin co-factor assay), (e) ristocetin-induced platelet aggregation, and (f) multimer analysis. There have also been many new diagnostic developments that have begun to influence the diagnostic process. These include the automation of existing assay procedures, new automated platelet function analyzers such as the PFA-100, and specific von Willebrand factor-factor VIII-binding assays. This chapter focuses on the recommended laboratory process for the investigation of VWD. The selection of an appropriate combination test panel and testing sequence is crucial for the proper diagnosis and classification of congenital von Willebrand disease.
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Affiliation(s)
- E J Favaloro
- Diagnostic Haemostasis Laboratory, Department of Haematology, Institute of Clinical Pathology and Medical Research, Westmead Hospital, Western Sydney Area Health Service, Westmead, NSW, Australia
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40
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Callan MB, Giger U. Assessment of a point-of-care instrument for identification of primary hemostatic disorders in dogs. Am J Vet Res 2001; 62:652-8. [PMID: 11341380 DOI: 10.2460/ajvr.2001.62.652] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To assess a point-of-care instrument for identification of primary hemostatic disorders in dogs. ANIMALS 29 healthy dogs and 23 nonanemic dogs with primary hemostatic disorders (thrombocytopenia, n = 6; thrombopathia, 6; von Willebrand disease [vWD], 11). PROCEDURE Citrated blood was obtained and closure times (CT) were determined by measuring the time required for occlusion of an aperture by a platelet plug within the point-of-care instrument. Reference ranges for CT were established, and CT were determined for dogs with primary hemostatic disorders. RESULTS CT measured with adenosine diphosphate as the platelet agonist (ADP-CT) ranged from 52 to 86 seconds for healthy dogs (mean +/- 2 SD, 67 +/- 7.8 seconds; median, 65 seconds), and CT measured with epinephrine as the agonist (EPI-CT), from 97 to 225 seconds (151 +/- 38 seconds; 148 seconds). In thrombocytopenic dogs, ADP- and EPI-CT were prolonged (> 165 and > 264 seconds, respectively). Five of 6 dogs with thrombopathia had prolonged ADP-CT, whereas EPI-CT was prolonged in all 6 dogs. In all dogs with vWD, ADP-CT was prolonged; EPI-CT was prolonged in 10 of these dogs. Sensitivity and specificity for ADP-CT were 95.7 and 100%, respectively, and positive and negative predictive values, 100 and 96.7%, respectively, whereas for EPI-CT, these values were 95.7 and 82.8%, respectively, and 81.5 and 96%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE The point-of-care instrument allowed quick assessment of primary hemostasis in nonanemic dogs. Use of this instrument may be helpful for making decisions regarding management of dogs with primary hemostatic disorders.
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Affiliation(s)
- M B Callan
- Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia 19104-6010, USA
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41
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Favaloro EJ, Kershaw G, Bukuya M, Hertzberg M, Koutts J. Laboratory diagnosis of von Willebrand disorder (vWD) and monitoring of DDAVP therapy: efficacy of the PFA-100 and vWF:CBA as combined diagnostic strategies. Haemophilia 2001; 7:180-9. [PMID: 11260278 DOI: 10.1046/j.1365-2516.2001.00487.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have coevaluated a combination of test processes for diagnosing von Willebrand disease (vWD) and monitoring deamino-delta-D-arginine vasopressin (DDAVP) therapy. Using normal controls (n = 23), closure time (CT) ranges measured by PFA-100(R) were (mean +/- 2SD): (i) collagen/ADP cartridge (C/ADP): 67-127 s (ii) collagen/epinephrine (C/Epi): 94-162 s. From a panel of 125 patients undergoing evaluation for clinical haemostatic defects, 29/30 samples from patients with vWD [17/18 type 1, 1/1 type 3, 3/3 type 2A, 7/7 type 2B and 1/1 pseudo-vWD] gave prolonged CTs using C/Epi. The C/ADP was less sensitive, being normal in 7/18 of the type 1 vWD individuals, with higher sensitivity to more severe vWD. Individuals with haemophilia (six factor VIII-deficient, one factor XI-deficient) gave normal CTs, while those with clinical thrombocytopenia (n=13) gave normal or prolonged CTs, somewhat dependent on platelet count. The PFA-100 was also evaluated as a part of the laboratory monitoring procedure in patients with either vWD or haemophilia undergoing a DDAVP trial as a therapeutic management process. For vWD, correction of an initially prolonged CT by DDAVP, accompanied by normalization of von Willebrand factor (vWF) measurable by von Willebrand factor antigen, vWF collagen binding activity and vWF ristocetin cofactor assays (vWF:Ag, vWF:CBA and vWF:RCof), was achieved in type 1 vWD (n=5). In an individual with type 2A vWD, DDAVP normalized vWF:Ag and vWF:RCof, but had no apparent effect on the baseline maximally prolonged CT. In an individual with type 2B vWD, factor VIII/vWF concentrate also normalized vWF:Ag and vWF:RCof, but similarly had no apparent effect on the baseline maximally prolonged CT. vWF:CBA did not normalize for either of these individuals, potentially suggesting that normalization of vWF:CBA might be required for normalization of CT. This concept is supported by correlation analysis undertaken between CT and various vWF parameters. Among these, vWF:CBA held the strongest relationship in our data set, which showed an inverse progressive rise in CT for falling vWF:CBA. Based on these results, we would conclude that the PFA-100 is highly sensitive to the presence of vWD, and may thus provide a valuable screening test for vWD. Furthermore, the combined utility of the PFA-100 and vWF:CBA as markers of DDAVP responsiveness may prove to be simple, quick but powerful, predictors for its clinical efficacy.
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Affiliation(s)
- E J Favaloro
- Diagnostic Haemostasis Laboratory, Department of Haematology, ICPMR, Westmead Hospital, Australia.
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42
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Favaloro EJ. Utility of the PFA-100 for assessing bleeding disorders and monitoring therapy: a review of analytical variables, benefits and limitations. Haemophilia 2001; 7:170-9. [PMID: 11260277 DOI: 10.1046/j.1365-2516.2001.00486.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The PFA-100 (platelet function analyser) is a relatively new tool for the investigation of primary haemostasis. Recent studies have shown its utility in monitoring antiplatelet therapy (including aspirin) and as a screening tool for investigating possible von Willebrand disease (vWD) and various platelet disorders. More recently, the PFA-100 has been shown to be of value in monitoring DDAVP therapy in both vWD and platelet disorders. This paper reviews current findings, details the utility of the PFA-100 for some of these purposes, as well as reviewing analytical variables that may complicate the interpretation of results. The author highlights the benefits, as well as noting the limitations, of its use. Ultimately, the greatest strengths of the PFA-100 are its simplicity in use and excellent sensitivity to particular haemostatic disturbances such as vWD, platelet disorders and platelet-affecting medication. However, because it is thus a 'global' test system, this also creates a significant limitation, as the PFA-100 is not specific for, nor predictive of, any particular disorder. However, utilized appropriately, the PFA-100 can be considered a worthwhile addition to any haemostasis laboratory involved in the diagnosis or therapeutic-monitoring of bleeding disorders including vWD and platelet-dysfunctions. This review should be of value to both haemostasis scientists and clinical specialists.
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Affiliation(s)
- E J Favaloro
- Diagnostic Haemostasis Laboratory, Department of Haematology, ICPMR, Westmead Hospital, NSW, Australia.
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