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Dickinson M, Abrams-Ogg A, Blois SL, Wood RD, Monteith G. Extended sample storage for platelet function testing in healthy dogs. Vet Clin Pathol 2023; 52:402-411. [PMID: 37385948 DOI: 10.1111/vcp.13226] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 09/13/2022] [Accepted: 11/27/2022] [Indexed: 07/01/2023]
Abstract
BACKGROUND Platelet function testing is important for monitoring the effects of antiplatelet therapy but is not readily used due to time constraints for testing and the need for specialized equipment. OBJECTIVES This study evaluated the effects of various storage methods on selected platelet function tests to determine if delayed platelet function testing is feasible in canine blood samples. Our hypotheses were that platelet function would not decline during storage and, thus, no differences in test results would be found over time. METHODS Thirteen healthy dogs were studied. Citrated blood samples were tested with a Platelet Function Analyzer-200 (PFA), which mimics high-shear conditions, using P2Y and CADP cartridges, after being held at room temperature for 2 h and refrigerated for 24 and 48 h. Plateletworks (PW), which measures aggregation based on platelet counting, was performed on an optical hematology analyzer using 10-min-old native samples, citrated samples held at room temperature for 3-4 h and refrigerated for 24 and 48 h, and samples stored in the preservative solution, AGGFix, up to 7 days. RESULTS PFA closure times increased with storage, especially with the P2Y cartridge. Median aggregation with fresh PW was 94%, and this was maintained at all time points (range of median values 88%-94%). Most samples showed decreased, yet still robust (>70%), aggregation with longer storage. Spontaneous aggregation in citrate was noted in most dogs. AGGFix stabilized platelet aggregates to allow for delayed testing. CONCLUSIONS Delayed platelet function testing is feasible, but ranges of expected values may differ from tests using fresh samples.
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Affiliation(s)
- Melanie Dickinson
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | - Anthony Abrams-Ogg
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | - Shauna L Blois
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | - R Darren Wood
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | - Gabrielle Monteith
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
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2
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Pfaff A, de Laforcade AM, Rozanski EA. The Use of Antithrombotics in Critical Illness. Vet Clin North Am Small Anim Pract 2020; 50:1351-1370. [PMID: 32893002 DOI: 10.1016/j.cvsm.2020.07.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Hypercoagulable tendencies may develop in critically ill dogs and to a less known extent, cats. Although the use of antithrombotics is well-established in critically ill people, the indications and approach are far less well-known in dogs and cats. The goal of this article was to review the relevant CURATIVE guidelines, as well as other sources, and to provide recommendations for critically ill patients with directions for future investigation.
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Affiliation(s)
- Alexandra Pfaff
- Tufts University, Cummings School of Veterinary Medicine, 200 Westboro Road, North Grafton, MA 01536, USA
| | - Armelle M de Laforcade
- Tufts University, Cummings School of Veterinary Medicine, 200 Westboro Road, North Grafton, MA 01536, USA
| | - Elizabeth A Rozanski
- Tufts University, Cummings School of Veterinary Medicine, 200 Westboro Road, North Grafton, MA 01536, USA.
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3
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Goggs R. Therapeutic Strategies for Treatment of Immune-Mediated Hemolytic Anemia. Vet Clin North Am Small Anim Pract 2020; 50:1327-1349. [PMID: 32814628 DOI: 10.1016/j.cvsm.2020.07.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Immune-mediated hemolytic anemia is a common hematologic disorder in dogs. Disease management involves immunosuppression using glucocorticoids, potentially in combination with other medications such as azathioprine, cyclosporine, or mycophenolate mofetil. Therapeutic drug monitoring may enhance the utility and maximize the safety of cyclosporine and mycophenolate mofetil. The disease is proinflammatory and prothrombotic. Antithrombotic drug administration is therefore essential, and anticoagulant therapy should be initiated at the time of diagnosis. Additional therapies include red blood cell transfusion to support blood oxygen content. Future therapies may include therapeutic plasma exchange, anti-CD20 monoclonal antibodies, and complement inhibitors.
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Affiliation(s)
- Robert Goggs
- Emergency and Critical Care, Department of Clinical Sciences, Cornell University College of Veterinary Medicine, 930 Campus Road, Ithaca, NY 14853, USA.
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van Rooyen LJ, Hooijberg EH, Schoeman JP, Goddard A. Thromboelastographic platelet mapping in dogs with complicated Babesia rossi infection. Vet Clin Pathol 2019; 48:11-18. [PMID: 30924545 DOI: 10.1111/vcp.12689] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 05/22/2018] [Accepted: 06/25/2018] [Indexed: 11/27/2022]
Abstract
BACKGROUND Dogs with Babesia rossi infection display a normocoagulable thromboelastogram, despite being markedly thrombocytopenic, which is purportedly due to large-scale platelet activation. Thromboelastographic platelet mapping (TEG-PM) evaluates individual contributions of thrombin, fibrinogen, and platelets to clot formation, and may elucidate some of the pathomechanisms of thrombocytopenia-associated hemostatic alterations. OBJECTIVE This study investigated potential differences in TEG-PM variables in dogs with complicated B rossi infection compared with healthy controls, and whether these variables correlated with platelet activation indices. METHODS The maximum amplitude (MA) following thrombin generation (MAThrombin ) was determined using kaolin-activated TEG. The TEG-PM variables included MA following the addition of platelet agonists arachidonic acid (MAAA ) and adenosine diphosphate (MAADP ), and MA due to fibrin alone (MAFibrin ). In addition, platelet indices and fibrinogen concentrations were determined. RESULTS Thirteen dogs with complicated B rossi infection and five healthy controls were included. The median MAFibrin and fibrinogen concentrations were significantly higher (P < 0.01 for both) and median platelet count was significantly lower (P < 0.01) in the babesiosis group vs the control group. No significant differences were found for MAThrombin and MAAA/ADP . maximum amplitude due to fibrin alone was positively correlated with fibrinogen concentration (r = 0.735), mean platelet volume (r = 0.517), and mean platelet mass (r = 0.498), and negatively correlated with hematocrit (r = -0.685), platelet count (r = -0.476), and plateletcrit (r = -0.479) (P < 0.05 for all). CONCLUSIONS This study suggests that the presence of hyperfibrinogenemia offsets the severe thrombocytopenia associated with B rossi to result in normal thromboelastograms and lack of overt clinical bleeding.
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Affiliation(s)
- Liesl J van Rooyen
- Department of Companion Animal Clinical Studies, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.,IDEXX Laboratories (Pty) Ltd., Johannesburg, South Africa
| | - Emma H Hooijberg
- Department of Companion Animal Clinical Studies, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Johan P Schoeman
- Department of Companion Animal Clinical Studies, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Amelia Goddard
- Department of Companion Animal Clinical Studies, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
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Dunning M, May J, Adamany J, Heptinstall S, Fox S. A Remote Assay for Measuring Canine Platelet Activation and the Inhibitory Effects of Antiplatelet Agents. J Vet Intern Med 2017; 32:119-127. [PMID: 29197128 PMCID: PMC5787215 DOI: 10.1111/jvim.14845] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 06/16/2017] [Accepted: 08/28/2017] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Antiplatelet medications are increasingly used in dogs. Remote analysis of platelet activity is challenging, limiting assessment of antiplatelet drug efficacy. HYPOTHESIS/OBJECTIVES To evaluate a method used in humans for stimulation and remote analysis of canine platelet activity. ANIMALS Forty-five dogs of various ages without a coagulopathy or thrombocytopenia. Six were receiving antiplatelet medication. METHODS Prospective observational study. Platelets were stimulated with combinations of arachidonic acid (AA) and epinephrine (Epi) or adenosine diphosphate (ADP) and the thromboxane A2 -mimetic U46619 (U4). PAMFix was added to the blood samples to facilitate delayed analysis of platelet activity. Activity was assessed by flow cytometric measurement of surface P-selectin (CD62P) expression. RESULTS Canine platelets could be stimulated with both AA/Epi and ADP/U4. The levels of P-selectin were significantly greater than paired, unstimulated samples (P < 0.001). Inhibition of P-selectin expression occurred after this stimulation by adding antiplatelet drugs in vitro. The efficacy of antiplatelet drugs in samples from treated dogs was also measurable ex vivo using this method. Delayed analysis of platelet activity at time points up to 22 days demonstrated excellent correlation between respective mf values at each time point (r2 = 0.92, P < 0.0001). CONCLUSIONS AND CLINICAL IMPORTANCE This study evaluated a new method to remotely assess canine platelet activity. It shows that PAMFix can be used for this purpose. This provides opportunities to interrogate the inhibitory action of antiplatelet drugs in clinical settings.
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Affiliation(s)
- M Dunning
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, UK
| | - J May
- Clinical Neuroscience, Queen's Medical Centre, Nottingham, UK
| | - J Adamany
- Pride Veterinary Centre, Derbyshire, UK
| | - S Heptinstall
- Clinical Neuroscience, Queen's Medical Centre, Nottingham, UK
| | - S Fox
- Clinical Neuroscience, Queen's Medical Centre, Nottingham, UK
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Nash KJ, Bacek LM, Christopherson PW, Spangler EA. In vitro effect of blood cell counts on multiple-electrode impedance aggregometry in dogs. Am J Vet Res 2017; 78:1380-1386. [PMID: 29182390 DOI: 10.2460/ajvr.78.12.1380] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To assess the effect of decreased platelet and WBC counts on platelet aggregation as measured by a multiple-electrode impedance aggregometer in dogs. ANIMALS 24 healthy dogs. PROCEDURES From each dog, 9 mL of blood was collected into a 10-mL syringe that contained 1 mL of 4% sodium citrate solution to yield a 10-mL sample with a 1:9 citrate-to-blood ratio. Each sample was then divided into unmanipulated and manipulated aliquots with progressively depleted buffy-coat fractions such that 2 to 3 blood samples were evaluated per dog. The Hct for manipulated aliquots was adjusted with autologous plasma so that it was within 2% of the Hct for the unmanipulated aliquot for each dog. All samples were analyzed in duplicate with a multiple-electrode impedance aggregometer following the addition of ADP as a platelet agonist. The respective effects of platelet count, plateletcrit, Hct, and WBC count on platelet aggregation area under the curve (AUC), aggregation, and velocity were analyzed with linear mixed models. RESULTS WBC count was positively associated with platelet AUC, aggregation, and velocity; blood samples with leukopenia had a lower AUC, aggregation, and velocity than samples with WBC counts within the reference range. Platelet count, plateletcrit, and Hct did not have an independent effect on AUC, aggregation, or velocity. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that WBC count was positively associated with platelet aggregation when ADP was used to activate canine blood samples for impedance aggregometry. That finding may be clinically relevant and needs to be confirmed by in vivo studies.
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Takashima Y, Onoda I, Chiou SP, Kitoh K. In vitro canine platelet aggregation caused by Dirofilaria immitis extract. J Vet Med Sci 2016; 79:387-392. [PMID: 28049921 PMCID: PMC5326946 DOI: 10.1292/jvms.16-0461] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Platelet function hyper-activity has been reported in Dirofilaria
immitis (heartworm, HW)-infected dogs. Although the mechanism of increased
platelet hyper-activity has not yet been elucidated, it is suggested to be mediated by
unknown factors, which may be related to adult HW components. This study aims to determine
whether adult male HW whole body extract induces canine platelet aggregation in
vitro. The results indicate that HW extract caused an aggregation of canine
platelets in a concentration-dependent manner. This aggregation ability of the HW extract
was not mediated by the adenosine diphosphate receptor. In addition, the mechanisms of
aggregation did not require cyclooxygenase-dependent pathways, and the aggregating
activity of substances contained in the HW extract was heat stable; therefore, the active
substances may be different from collagen. Furthermore, the platelet aggregating activity
remained within the molecular weight (MW)≥100,000 fraction obtained by ultrafiltrating the
HW extract. In contrast, the MW <100,000 fraction also had a platelet aggregation
ability, but the aggregation pattern was reversible and the maximum extent decreased,
compared with the MW≥100,000 fraction response. Our experiments have been conducted using
a whole body extract from adult HWs to determine with certainty the aggregating activity
of HW elements on canine platelets. More studies are necessary to evaluate the effects of
the metabolic products released from live adult worms in pulmonary arteries and the
symbiont bacterium Wolbachia-derived antigens on canine platelet
aggregation.
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Affiliation(s)
- Yasuhiro Takashima
- Laboratory of Veterinary Parasitology, Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
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Blois SL, Lang ST, Wood RD, Monteith G. Biologic variability and correlation of platelet function testing in healthy dogs. Vet Clin Pathol 2015; 44:503-10. [DOI: 10.1111/vcp.12290] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Shauna L. Blois
- Department of Clinical Studies; Ontario Veterinary College; University of Guelph; Guelph ON Canada
| | - Sean T. Lang
- Department of Clinical Studies; Ontario Veterinary College; University of Guelph; Guelph ON Canada
| | - R. Darren Wood
- Department of Pathobiology; Ontario Veterinary College; University of Guelph; Guelph ON Canada
| | - Gabrielle Monteith
- Department of Clinical Studies; Ontario Veterinary College; University of Guelph; Guelph ON Canada
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Majoy SB, de Laforcade AM, Barnard MR, Shaw SP. Platelet activation in a population of critically ill dogs as measured with whole blood flow cytometry and thromboelastography. Am J Vet Res 2015; 76:328-37. [PMID: 25815574 DOI: 10.2460/ajvr.76.4.328] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine whether critically ill dogs had increased platelet activation and whether the proportion of activated platelets correlated with severity of illness. ANIMALS 82 dogs in the intensive care unit of a veterinary teaching hospital and 24 healthy control dogs. PROCEDURES Flow cytometry with monoclonal mouse anti-human CD61 and CD62 antibodies in resting and ADP-treated samples and kaolin-activated thromboelastography were used to compare platelet activation in blood samples of critically ill and control dogs. Serum antithrombin, von Willebrand factor, fibrinogen, and activated protein C concentrations; prothrombin time (PT); and activated partial thromboplastin time (aPTT) were measured. Revised survival prediction index, acute patient physiology and laboratory evaluation, systemic inflammatory response syndrome, and multiple organ dysfunction syndrome scores were used to estimate severity of illness. Severity of illness scores and platelet activation measurements were compared with survival time and duration and cost of hospitalization. RESULTS Critically ill and control dogs had no differences in platelet activation for non-ADP-treated samples measured. Critically ill dogs had significantly increased platelet activation in response to 2, 6, and 10 μM ADP. Critically ill dogs had significantly increased maximum amplitude, α angle, and global clot strength and significantly decreased clot formation time. Critically ill dogs had significantly increased fibrinogen concentration, PT, and aPTT and significantly decreased antithrombin concentration. Survivors and nonsurvivors had similar flow cytometry and thromboelastography values. Three dogs developed macrothrombosis. CONCLUSIONS AND CLINICAL RELEVANCE In this study, critically ill dogs had hyperreactive platelets, which may have contributed to a high incidence of hypercoagulability in this patient population.
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Affiliation(s)
- Sean B Majoy
- Department of Clinical Sciences, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA 01536
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Platelet parameters from an automated hematology analyzer in dogs with inflammatory clinical diseases. Vet J 2014; 201:406-11. [DOI: 10.1016/j.tvjl.2014.07.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 07/09/2014] [Accepted: 07/12/2014] [Indexed: 02/02/2023]
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