Topic:Coagulation
Coagulation in horses refers to the complex process by which blood forms clots, a critical function that prevents excessive bleeding following injury. This process involves a series of enzymatic reactions that lead to the transformation of liquid blood components into a stable clot. Key elements in equine coagulation include platelets, clotting factors, and fibrinogen. Abnormalities in the coagulation process can result in disorders such as excessive bleeding or thrombosis. Research in this area focuses on understanding the mechanisms of coagulation, identifying potential genetic or environmental influences, and developing diagnostic and therapeutic strategies for coagulation-related disorders in horses. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, regulation, and clinical implications of coagulation in equine health.
Clinical, hematologic, hemostatic, and serum biochemical findings related to survival in Arabian horses with colic. The efficacy of clinical examinations, and hematologic, hemostatic, and serum biochemical assessments to determine appropriate early medical or surgical therapy in Arabian horses with colic have not been well-described. Objective: We aimed to evaluate clinical and hematologic findings, coagulation-fibrinolytic parameters, and organ dysfunction markers in association with survival in horses with colic. Methods: Seventeen Arabian horses with colic and ten healthy horses were enrolled. After clinical examinations, including heart rates (HRs), capillary refill times (CRTs), abdominal sounds, recta...
Hydroxyethyl starches in equine medicine. To review and discuss the use of hydroxyethyl starches (HES) in equine veterinary medicine, and to provide recommendations for its use. Methods: Veterinary and human peer-reviewed medical literature including scientific reviews, meta-analyses, and original research articles. Results: Increasing evidences on adverse effects after HES use and decreasing support for beneficial effects with regards to volume expansion and colloid osmotic pressure (COP) support in critically ill subjects have led to a recent guideline to limit the use of HES in critically ill people. Unassigned: The rationale for H...
Assessment of the CoaguChek-XS portable prothrombin time point-of-care analyzer for horses. Coagulopathies in horses are common and potentially life-threatening. In equine field medicine, a portable point-of-care (POC) prothrombin time (PT) testing device could be useful to identify early changes in extrinsic clotting. The CoaguChek-XS (Roche Diagnostics) is a small, portable POC PT analyzer used in human medicine. Our preliminary study assessed the suitability of CoaguChek-XS for testing PT in horses and established the PT reference interval (PT RI) in healthy horses using this instrument. Blood samples collected from 102 healthy and ill horses were analyzed with the CoaguChek-XS an...
Gene set enrichment analysis of the bronchial epithelium implicates contribution of cell cycle and tissue repair processes in equine asthma. Severe equine asthma is a chronic inflammatory condition of the lower airways similar to adult-onset asthma in humans. Exacerbations are characterized by bronchial and bronchiolar neutrophilic inflammation, mucus hypersecretion and airway constriction. In this study we analyzed the gene expression response of the bronchial epithelium within groups of asthmatic and non-asthmatic animals following exposure to a dusty hay challenge. After challenge we identified 2341 and 120 differentially expressed genes in asthmatic and non-asthmatic horses, respectively. Gene set enrichment analysis of changes...
Evaluating continuous blood coagulopathy in assessing the severity of acute colitis in Thoroughbred racehorses. Although severe blood coagulopathy in horses with acute colitis causes multiple organ failure, which may be fatal, few studies have focused on the correlation between the fluctuations of coagulation parameters and severity of colitis. In this study, we evaluated the fluctuations of coagulation parameters in 14 Thoroughbred racehorses with acute colitis for 5 days from the day of hospitalization and compared them between 5 survivors and 9 non-survivors. Noteworthy features in the non-survivors were that antithrombin activity and fibrin degradation products continuously decreased and increased, ...
Coagulation parameters following equine herpesvirus type 1 infection in horses. Equine herpesvirus type 1 (EHV-1) is the cause of respiratory disease, abortion storms, and outbreaks of herpesvirus myeloencephalopathy (EHM). Infection of the spinal cord is characterised by multifocal regions of virally infected vascular endothelium, associated with vasculitis, thrombosis and haemorrhage that result in ischaemia and organ dysfunction. However, the mechanism of thrombosis in affected horses is unknown. Objective: To evaluate tissue factor (TF) procoagulant activity and thrombin-antithrombin complex (TAT) levels in horses following infection with EHV-1. Methods: In vitro and ...
Viscoelasticity and structure of blood clots generated in-vitro by rheometry: A comparison between human, horse, rat, and camel. Although the coagulation system is evolutionary well preserved, profound species differences exist in viscoelastic as well as in common laboratory tests of coagulation. Objective: Evaluating differences in clot formation and material characterisation of clots of four mammalian species on macro-, micro- and nanoscales by the means of rheometry, scanning electron microscopy (SEM) and small angle x-ray scattering (SAXS). Methods: Blood samples were collected from healthy human volunteers, laboratory rats (HL/LE inbred strain), warmblood horses and dromedary camels. Clot formation was observed by ...
Diagnosis and Treatment of Undifferentiated and Infectious Acute Diarrhea in the Adult Horse. Acute, infectious, diarrhea in adult horses is a major cause of morbidity and is associated with numerous complications. Common causes include salmonellosis, clostridiosis, Coronavirus, and infection with Neorickettsia risticii (Potomac horse fever). Treatment is empirical and supportive until results of specific diagnostic tests are available. Supportive care is aimed at restoring hydration, correcting electrolyte imbalances, and limiting the systemic inflammatory response. The mainstays of therapy are intravenous fluid therapy, electrolyte supplementation where necessary, nonsteroidal anti-i...
Normal reference intervals and the effects of sample handling on dynamic viscoelastic coagulometry (Sonoclot) in healthy adult horses. To determine reference intervals and the effect of sample agitation and rest time on Sonoclot analysis in healthy adult horses. Methods: Original prospective study. Methods: University veterinary medical teaching hospital. Methods: Sixty healthy adult horses. Methods: Blood was collected for assessment of complete blood count, serum biochemical analysis, and Sonoclot analysis. Results: Horses were determined to be healthy based upon physical examination, CBC, and serum biochemistry analysis. Blood was analyzed in a glass bead-containing cuvette using the Sienco Sonoclot analyzer following 2 re...
Comparison of two blood sampling techniques for the determination of coagulation parameters in the horse: Jugular venipuncture and indwelling intravenous catheter. Evaluation of coagulation status is an important component of critical care. Ongoing monitoring of coagulation status in hospitalised horses has previously been via serial venipuncture due to concerns that sampling directly from the intravenous catheter (IVC) may alter the accuracy of the results. Adverse effects such as patient anxiety and trauma to the sampled vessel could be avoided by the use of an indwelling IVC for repeat blood sampling. Objective: To compare coagulation parameters from blood obtained by jugular venipuncture with IVC sampling in critically ill horses. Methods: Prospectiv...
Randomized placebo-controlled study of the effects of Yunnan Baiyao on hemostasis in horses. OBJECTIVE To determine effects of oral administration of Yunnan Baiyao on platelet activation, coagulation, and fibrinolysis in healthy horses. ANIMALS 12 healthy adult horses. PROCEDURES In a randomized blinded crossover study that included a 4-week washout period between treatments, horses were orally administered a paste containing Yunnan Baiyao (15 mg/kg) or placebo at 12-hour intervals for 3 days. Blood samples were collected before start of treatment (time 0) and at 24 and 72 hours for a CBC, measurement of fibrinogen concentration, coagulation screening tests, and a panel of assays to a...
Operator-based variability of equine thromboelastography. To determine the extent of intraoperator (between duplicate samples) and interoperator (between different operators) variability in equine thromboelastography (TEG). Methods: Kaolin-activated TEG was performed in duplicate by operator-pair A/B or A/C (2 groups of 10 horses) using discrete setups, within 30-45 minutes of vacuum-assisted blood collection. Recorded TEG variables included clot initiation time (R), clot formation time (K), rate of clot formation (α), clot strength (MA), and viscoelastic/shear strength (G). Operators independently determined the clinical coagulation status for each...
Platelet lysate obtained via plateletpheresis performed in standing and awake equine donors. Platelet preparations containing growth factors, attachment factors, and enzymes are appealing to enhance healing of injured tissues and as an alternative to xenogenic serum in cell culture media. Plateletpheresis is commonly used to collect platelets in human medicine but has not been validated in horses. Plateletpheresis to collect platelet concentrate was performed on six female, mixed breed, chemically restrained horses using commercially available apheresis equipment. Before and immediately after plateletpheresis, we performed physical examinations and collected blood for chemistry and co...
Are pulmonary hemostasis and fibrinolysis out of balance in equine chronic pneumopathies? Clinical examination, bronchoalveolar lavage fluid (BALF) cytology, acute-phase protein, and pulmonary hemostasis and fibrinolysis marker (fibrinogen, serum amyloid A [SAA], and D-dimer) results were compared between control and respiratory disease-affected horses. Using a clinical scoring system, horses (n = 58) were classified as respiratory disease-free (Controls, n = 15) or with recurrent airway obstruction (RAO; n = 18), inflammatory airway disease (n = 14) or chronic interstitial pneumopathy (n = 11). There were no significant differences in fibrinogen concentrations among groups, but th...
Evaluation of an oral direct factor Xa inhibitor anticoagulant in healthy adult horses. To assess whether an oral direct factor Xa inhibitor (DiXaI) anticoagulant drug used at the low end of the recommended dose in people achieves presumed prophylactic plasma concentrations and does not induce bleeding in horses. Methods: Experimental study. Methods: Field study. Methods: Ten healthy adult horses. Methods: A DiXaI was administered at a dose of 0.125 mg/kg every 24 h orally for 4 days. Following a wash-out period of 2 weeks, 8 of 10 horses received daily subcutaneous doses of a low molecular weight heparin (dalteparin) for 4 consecutive days at 50 IU/kg. In both trials, antifactor...
Assessment of method reliability and determination of reference intervals for rotational thromboelastometry in horses. To assess the measurement reliability of rotational thromboelastometry (ROTEM) measurements in horses, establish reference intervals for healthy horses, and evaluate the relationship between ROTEM variables, hematologic variables, and standard coagulation tests. Methods: Prospective observational study. Methods: University teaching hospital. Methods: Fifty healthy and 10 diseased adult horses. Methods: None. Results: Blood was sampled from 10 healthy and 10 diseased horses and samples were repeatedly analyzed to evaluate measurement reliability of various ROTEM variables. Four different ROTEM ...
A comparison of the effects of a 4% modified fluid gelatin and a 6% hydroxyethyl starch on haemodilution, colloid osmotic pressure, haemostasis and renal parameters in healthy ponies. Adverse effects on renal health and haemostasis have been documented in human patients administered hydroxyethyl starches (HESs). Gelatins may represent useful substitutes should similar adverse effects be identified in horses. Objective: To compare the effects of a 4% modified fluid gelatin (MFG) with a 6% (130/0.4) HES on haemodilution, colloid osmotic pressure (COP), haemostasis and renal parameters in healthy ponies. Methods: Randomised crossover experiment. Methods: Three treatments (Treatment A: 10 ml/kg bwt HES; Treatment B: 10 ml/kg bwt MFG; Treatment C: 20 ml/kg bwt MFG) were administ...
Response to Intravenous Allogeneic Equine Cord Blood-Derived Mesenchymal Stromal Cells Administered from Chilled or Frozen State in Serum and Protein-Free Media. Equine mesenchymal stromal cells (MSC) are commonly transported, chilled or frozen, to veterinary clinics. These MSC must remain viable and minimally affected by culture, transport, or injection processes. The safety of two carrier solutions developed for optimal viability and excipient use were evaluated in ponies, with and without allogeneic cord blood-derived (CB) MSC. We hypothesized that neither the carrier solutions nor CB-MSC would elicit measurable changes in clinical, hematological, or biochemical parameters. In nine ponies (study 1), a bolus of HypoThermosol(®) FRS (HTS-FRS), CryoSt...
Abnormal coagulation factor VIII transcript in a Tennessee Walking Horse colt with hemophilia A. Hemophilia A is an X-chromosome-linked disorder caused by a deficiency in factor VIII (FVIII). Although foals have been diagnosed with hemophilia A based on deficiency in FVIII activity, causative gene mutations have not been identified. The genomic DNA and cDNA encoding FVIII of a Tennesee Walking Horse colt affected with hemophilia A and the genomic DNA of his dam and a normal unrelated horse were analyzed with no splice site or coding sequence abnormalities identified in any of the horses. Polymerase chain reactions (PCR) were then performed on hepatic cDNA from the affected colt and an unr...
Evaluation of coagulation and fibrinolysis in horses with atrial fibrillation. To evaluate horses with atrial fibrillation for hypercoagulability; plasma D-dimer concentrations, as a marker of a procoagulant state; and a relationship between coagulation profile results and duration of atrial fibrillation or presence of structural heart disease. Methods: Case-control study. Methods: Plasma samples from 42 horses (25 with atrial fibrillation and 17 without cardiovascular or systemic disease [control group]). Methods: Results of hematologic tests (ie, plasma fibrinogen and D-dimer concentrations, prothrombin and activated partial thromboplastin times, and antithrombin activ...
Evaluation of coagulation via thromboelastography in healthy horses administered dexamethasone. Dexamethasone was administered to healthy horses daily for 7 days. Blood samples were collected at 3 time points from both treatment and non-treatment groups, and analyzed via thromboelastography (TEG). There were no significant differences in TEG parameters between treated and untreated horses, or within treatment groups over time. La dexaméthasone a été administrée à des chevaux en santé pendant 7 jours. Des échantillons de sang ont été prélevés à trois moments auprès des groupes de traitement et des groupes sans traitement et ensuite analysés par thrombo-élastographie (TEG)....
Association Between Necropsy Evidence of Disseminated Intravascular Coagulation and Hemostatic Variables Before Death in Horses With Colic. Disseminated intravascular coagulation (DIC) is frequent in horses with severe gastrointestinal disorders. Postmortem studies have found fibrin microthrombi in tissues of these horses, but studies relating these histopathological findings with antemortem hemostatic data are lacking. Objective: Antemortem classification of coagulopathy is related to the presence and severity of fibrin deposits observed postmortem in horses with severe gastrointestinal disorders. Methods: Antemortem hemostatic profile data and postmortem tissue samples (kidney, lung, liver) from 48 horses with colic. Methods: Ti...
Biological variation of thromboelastrography variables in 10 clinically healthy horses. To assess the utility of population-based reference intervals (PRIs) for interpreting thromboelastography (TEG) variables in horses using biological variation data. Methods: Prospective cohort biologic variation study conducted over a 5-week period. Methods: Veterinary teaching hospital and research facility. Methods: Ten clinically healthy horses randomly selected from a veterinary school research and teaching herd. Methods: Horse health was determined using physical examination, CBC, and biochemical and coagulation profiles prior to the start of the study. Subsequently, once weekly blood sam...
Thromboelastographic Clot Characteristics of Autologous Equine Blood Products After Activation by Autologous Thrombin, Bovine Thrombin, or Calcium Chloride. To compare clotting efficiency of platelet-rich plasma (PRP) and concentrated platelet-poor plasma (cPPP) to citrated whole blood after activation by autologous thrombin, bovine thrombin, or calcium chloride (CaCl2 ). Methods: Experimental study. Methods: Healthy adult horses (n = 6). Methods: PRP and cPPP were prepared by commercial devices. Using thromboelastography, clotting variables were compared after activation of citrated autologous blood, PRP, and cPPP by autologous thrombin, bovine thrombin, or CaCl2 , respectively. Results: PRP had the greatest clot strength and quickest clot rate, ...
Blood hypercoagulability and systemic inflammation in horses with heaves. As inflammation and coagulation are intertwined processes, the efficiency of blood coagulation of heaves-affected horses and controls were compared in an observational case-control study, using thrombelastography. In experiment 1 (Exacerbation, six heaves, five controls), horses were housed indoors and fed hay. Thrombelastography, functional fibrinogen, platelet count, hematology, and antithrombin were measured. In experiment 2 (Remission, eight heaves, 11 controls), horses were housed in a low-dust environment for at least a month when thrombelastography was performed. Heaves-affected horses ...
Evaluation of contact activation of citrated equine whole blood during storage and effects of contact activation on results of recalcification-initiated thromboelastometry. To evaluate the degree of activation of the contact pathway in citrated equine whole blood over holding times ≤ 30 minutes and assess effects of contact activation on recalcification-initiated thromboelastometry. Methods: 11 healthy adult mixed-breed horses. Methods: Blood was collected by atraumatic jugular venipuncture into prewarmed evacuated siliconized glass tubes containing citrate anticoagulant and held at 37°C for ≤ 30 minutes. Thromboelastometry was performed with an in vitro viscoelasticity (thromboelastometry) monitoring system. Factor XII and factor XI procoagulant activities ...
Differences in serum protein 2D gel electrophoresis patterns of Przewalski’s (Mongolian wild horse) and thoroughbred horses. The objective of this study was to assess differences in serum protein expression profiles of Przewalski's (Mongolian wild horse) and thoroughbred horses using proteome analysis. The serum proteins were separated by two-dimensional electrophoresis (2-DE) and five different gene products were identified. Proteins represented by the five spots were identified by matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry (MS)/MS technology. The identities of all proteins were deduced based on their similarity to proteins in the human plasma protein database. Three pr...
The use of nonsteroidal anti-inflammatory drugs in critically ill horses. To review the physiology of the cyclooxygenase (COX) enzymes with reference to the beneficial effects of nonsteroidal anti-inflammatory drugs (NSAIDs) related to their analgesic and antiendotoxic properties as well as the mechanisms responsible for adverse gastrointestinal, renal, and coagulation effects. Methods: Human and veterinary peer reviewed literature Results: NSAIDs are frequently administered to critically ill horses for their analgesic and anti-inflammatory effects. However, NSAIDs have significant side effects principally on the gastrointestinal mucosa and kidneys. These side effec...
Progression of plasma D-dimer concentration and coagulopathies during hospitalization in horses with colic. To assess the progression of plasma D-dimer concentrations and coagulation status in horses with different types of colic. Methods: Prospective clinical observational study performed between March 2004 and September 2008. Methods: Veterinary university teaching hospital. Methods: Horses admitted and treated for colic and hospitalized for >48 hours were considered. Animals were classified by diagnosis into medical obstructive conditions (MO), surgical obstructive conditions (SO), inflammatory conditions, and ischemic lesions (IS). Methods: Three blood samples were obtained from each horse (a...
Coagulopathies in horses. Although primary coagulopathies are rare in horses, changes in coagulation and fibrinolysis are commonly associated with inflammatory diseases. A clear understanding of the pathophysiology of normal and abnormal hemostasis is required to be able to choose and interpret diagnostic tests evaluating coagulation and fibrinolysis. After diagnosis, treatment of the underlying disease must occur regardless of whether clinical manifestations (excessive bleeding or thrombosis) of the coagulopathy are present or not. Specific treatment may be initiated if there are clinical signs of coagulopathy.