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.
Yeo WM, Osterrieder N, Stokol T.The alphaherpesvirus, equine herpesvirus type 1 (EHV-1), is a highly prevalent cause of equine infectious abortion and encephalomyelopathy. These syndromes have been attributed to ischemic necrosis from thrombosis in placental and neural vessels, although the mechanisms underlying thrombosis are unknown. After inhalation, EHV-1 establishes a peripheral blood mononuclear cell-associated viremia, with monocytes being a target of infection. Monocytes are also the main source of tissue factor (TF) in diseased states. Since TF is the primary activator of coagulation, increased monocyte TF expressio...
McGovern KF, Lascola KM, Smith SA, Clark-Price SC, Wilkins PA, Schaeffer DJ, Foreman JH.Hyperglycemia and endotoxemia have been associated with coagulation abnormalities in horses. Studies in humans suggest greater disturbances in coagulation with hyperglycemia and concurrent endotoxemia. Objective: To compare coagulation parameters in horses administered with lipopolysaccharide (LPS) with and without concurrent hyperglycemia. Methods: Twelve healthy adult horses. Methods: Hyperglycemia (180-240 mg/dL) was maintained for 6 hours in 6 horses (GLU-LPS) using 140 mg/kg IV bolus of dextrose followed by a 20% dextrose constant rate infusion. A similar volume of saline was administe...
Uniacke-Lowe T, Chevalier F, Hem S, Fox PF, Mulvihill DM.Rennet-induced coagulation of bovine milk is a complex mechanism in which chymosin specifically hydrolyzes κ-casein, the protein responsible for the stability of the casein micelle. In equine milk, this mechanism is still unclear, and the protein targets of chymosin are unknown. To reveal the proteins involved, the rennetability of equine milk by calf chymosin was examined using gel-free and gel-based proteomic analysis and compared to bovine milk. RP-HPLC analysis of bovine and equine milks showed the release of several peptides following chymosin incubation. The hydrolyses of equine and bov...
Olver CS, Nielsen VG.Carboxyheme and metheme states modulate hemostasis in humans and other species. Further, carbon monoxide and/or nitric oxide production increase in inflammatory disorders involving the gastrointestinal tract, with associated hypercoagulability or hypocoagulability. In particular, the horse suffers both thrombotic or coagulopathic complications during acute gastrointestinal disease. This investigation characterized the thrombelastographic response to carboxyheme (via CORM-2) or metheme (via phenylhydroxylamine, PHA) states without/with addition of tissue type plasminogen activator. Citrated pla...
Ribera T, Monreal L, Delgado MA, Ríos J, Prades M.To assess the synovial fibrinolytic pathway activation in adult horses with developmental and degenerative arthropathies such as osteochondritis dissecans (OCD) and osteoarthritis (OA) by measuring synovial D-dimer concentrations. Methods: Prospective observational clinical study of horses admitted for OCD or OA. Synovial fluid was collected during lameness examination or prior to the surgical procedure, and D-dimer concentration and routine synovial fluid analysis were performed. Results: Fifty-eight horses (14 with OCD, 10 with OA and 34 controls) were included in this study. Synovial D-dime...
Steelman SM, Chowdhary BP.Equine laminitis is a devastating disease that causes severe pain in afflicted horses and places a major economic burden on the horse industry. In acute laminitis, the disintegration of the dermal-epidermal junction can cause the third phalanx to detach from the hoof wall, leaving the horse unable to bear weight on the affected limbs. Horses that survive the acute phase transition into a chronic form of laminitis, which is often termed "founder". Some evidence suggests that chronic laminar inflammation might be associated with alterations in the endocrine and immune systems. We investigated th...
McGovern KF, Lascola KM, Smith SA, Clark-Price SC, McMichael M, Wilkins PA.To determine whether experimentally induced acute moderate hyperglycemia is associated with coagulation activation in healthy adult horses. Methods: Prospective experimental study. Methods: University veterinary teaching hospital. Methods: Six healthy adult horses. Methods: Hyperglycemia (10.0-13.3 mmol/L [180-240 mg/dL]) was induced and maintained for 6 hours using a hyperglycemic clamp technique. Blood glucose concentrations were assessed using a point of care (POC) glucometer at 10- and 20-minute intervals throughout the hyperglycemic clamp procedure. Platelet count, fibrinogen concentratio...
Morello S, Southwood LL, Engiles J, Slack J, Crack A, Springate CM.To evaluate the effect of PERIDAN™ Concentrate on clinical findings, infection, and tissue healing in adult horses undergoing celiotomy and jejunojejunostomy. Methods: Block randomized blinded experimental in vivo study. Methods: Adult horses (n = 12). Methods: Horses had jejunojejunostomy at 2 sites and were administered 5 L of diluted PERIDAN™ Concentrate (6 horses) or Lactated Ringer's Injection (LRS) control intraperitoneally (6 horses) before body wall closure. Postoperative monitoring comprised physical examinations, serial hematology, coagulation and chemistry panels, and ultrasonog...
Scoppetta F, Tartaglia M, Renzone G, Avellini L, Gaiti A, Scaloni A, Chiaradia E.Physical exercise induces various stress responses and metabolic adaptations that have not yet been completely elucidated. Novel biomarkers are needed in sport veterinary medicine to monitor training levels and to detect subclinical conditions that can develop into exercise-related diseases. In this study, protein modifications in horse plasma induced by prolonged, aerobic physical exercise were investigated by using a proteomic approach based on 2-DE and combined mass spectrometry procedures. Thirty-eight protein spots, associated with expression products of 13 genes, showed significant quant...
Chiaradia E, Pepe M, Tartaglia M, Scoppetta F, D'Ambrosio C, Renzone G, Avellini L, Moriconi F, Gaiti A, Bertuglia A, Beccati F, Scaloni A.Osteoarthritis (OA) and osteochondrosis (OC) are two of the main challenges in orthopedics, whose definitive diagnosis is usually based on radiographic/arthroscopic evidences. Their early diagnosis should allow preventive or timely therapeutic actions, which are generally precluded from the poor relationships occurring between symptomatologic and radiographic evidences. These limitations should be overcome by improving the knowledge on articular tissue metabolism and on molecular factors regulating its normal homeostasis, also identifying novel OA and OC biomarkers suitable for their earlier d...
Mendez-Angulo JL, Mudge M, Zaldivar-Lopez S, Vilar-Saavedra P, Couto G.To evaluate citrated recalcified thromboelastography (TEG) in healthy newborn foals, and to determine intra-assay, inter-individual and intra-individual (at 12 h, 24 h and 7 days after birth) variations. Additionally, to compare TEG variables, haematological values and conventional coagulation profiles from healthy, sick non-septic, and septic foals. Methods: Prospective study. Methods: The study group comprised 18 healthy, 15 sick non-septic and 17 septic foals. Two citrated (3.2%; 1 : 9 anticoagulant : blood ratio) blood samples were submitted for haemostatic evaluation using a TEG analyser ...
Tennent-Brown B.Although a range of plasma-based products (e.g., cryoprecipitate, albumin, platelet-rich plasma, individual coagulation factors) are available to human physicians, equine veterinarians are largely restricted to using whole blood, frozen plasma, and fresh frozen plasma for transfusions. The indications for frozen or fresh frozen plasma in human medicine are relatively limited, and there is little evidence supporting the efficacy of these products in many cases. Furthermore, many human physicians have concerns regarding disease transmission and anaphylactic reactions after administration of any ...
Dunkel B, Bolt DM, Smith RK, Cunningham FM.Platelet-rich plasma (PRP) is increasingly used for treatment of orthopaedic injuries. However, the effects of different stimuli on the release pattern of regenerative and proinflammatory factors from equine platelets are largely unknown and an optimal treatment protocol remains to be established. Objective: The aim of this study was to identify a stimulus that enhanced release of histopromotive factors (platelet-derived growth factor BB [PDGF] and transforming growth factor 1β[TGF]) without causing concurrent release of a proinflammatory mediator (CCL5). Methods: Washed platelets were prepar...
Mendoza FJ, Perez-Ecija RA, Monreal L, Estepa JC.Coagulation disorders are frequently diagnosed, especially in hospitalized equidae, and result in increased morbidity and mortality. However, hemostatic reference intervals have not been established for donkeys yet. Objective: To determine whether the most common coagulation parameters used in equine practice are different between healthy donkeys and horses. Methods: Thirty-eight healthy donkeys and 29 healthy horses. Methods: Blood samples were collected to assess both coagulation and fibrinolytic systems by determination of platelet count, fibrinogen concentration, clotting times (prothrombi...
McMichael M, Smith SA, McConachie EL, Lascola K, Wilkins PA.In several species, there is a strong correlation between indicators of red cell mass (RCM) and thromboelastometry results. The horse has a reliable, temporary, polycythemia in response to phenylephrine infusion. Our objective was to evaluate the effects of an in-vivo increase in circulating RCM on thromboelastometry results in an equine model of transient polycythemia. Six healthy research horses had whole blood thromboelastometry with contact activator and tissue factor initiation after recalcification of citrated samples. Additional samples were frozen for thrombin-antithrombin (TAT). Compl...
Epstein KL, Brainard BM, Gomez-Ibanez SE, Lopes MA, Barton MH, Moore JN.Coagulopathies in horses with gastrointestinal disease are frequently identified and associated with morbidity and fatality. Objective: Determine if thrombelastography (TEG) identifies abnormalities associated with lesion type, presence of systemic inflammatory response syndrome (SIRS), morbidity, and fatality more consistently than traditional coagulation testing. Methods: One-hundred and one horses examined for gastrointestinal disease and 20 healthy horses. Methods: TEG, tissue factor (TF)-TEG, and traditional coagulation panels parameters and percentages of horses with coagulopathies were ...
Sanz MG, Wills TB, Christopherson P, Hines MT.A 17-year-old Peruvian Paso mare was evaluated for bilateral epistaxis that had been present for at least 3 years. The mare had mild anemia, platelet count within the reference interval, unremarkable coagulation times, and a negative Coggins test. On endoscopic examination, structural abnormalities were not observed in the nasal cavities, pharynx, larynx, trachea, or either guttural pouch, but petechiation was noted in the nasal mucosa. Additional tests revealed prolonged cutaneous bleeding time, normal concentration of von Willebrand factor antigen, an abnormal clot retraction test, and failu...
Dos-Santos MC, Arroyo C, Solano S, Herrera M, Villalta M, Segura A, Estrada R, Gutiérrez JM, León G.Antivenoms are preparations of immunoglobulins purified from the plasma of animals immunized with snake venoms. Depending on the number of venoms used during the immunization, antivenoms can be monospecific (if venom from a single species is used) or polyspecific (if venoms from several species are used). In turn, polyspecific antivenoms can be prepared by purifying antibodies from the plasma of animals immunized with a mixture of venoms, or by mixing antibodies purified from the plasma of animals immunized separately with single venom. The suitability of these strategies to produce polyspecif...
Dunkel B, Chan DL, Boston R, Monreal L.Coagulopathies are common in horses with ischemic or inflammatory gastrointestinal (GI) disturbances. There is indirect evidence suggesting that early stages of these diseases are characterized by hypercoagulability (HC). Objective: HC, assessed via thromboelastography (TEG), is common in horses with ischemic or inflammatory GI diseases. The degree of HC is correlated with nonsurvival and thrombotic complications. Methods: Thirty client-owned horses with ischemic or inflammatory GI disease, 30 client-owned horses with nonischemic or inflammatory GI disease, and 30 healthy horses (control group...
Cesarini C, Monreal L, Armengou L, Delgado MÁ, Ríos J, Jose-Cunilleras E.Coagulopathies detected in horses with gastrointestinal problems seem to be associated with poor outcome. Plasma D-Dimer concentration is a sensitive test for assessing coagulopathies. Objective: Plasma D-Dimer concentration tested on admission is related to diagnosis and outcome in horses with colic. Methods: Four hundred and ninety three horses referred for evaluation of abdominal pain. Methods: Prospective observational clinical study. Horses were grouped according to diagnosis (medical and surgical intestinal obstructions, ischemic disorders with and without intestinal resection, enteritis...
Giordano A, Meazza C, Salvadori M, Paltrinieri S.Exercise-induced pulmonary hemorrhage (EIPH) commonly occurs in race horses. Thromboelastometry (TEM) investigates the whole hemostatic process by evaluating the viscoelastic properties of the blood clot from its formation to fibrinolysis. The aim of this study was to assess whether horses with EIPH have abnormal thromboelastometric profiles. Intrinsic and extrinsic pathways, fibrinogen activity and fibrinolysis were investigated by TEM before and after the race in negative controls and in horses on which EIPH was confirmed by bronchoscopy. Compared with controls, horses with EIPH had an incre...
Mendez-Angulo JL, Mudge MC, Vilar-Saavedra P, Stingle N, Couto CG.To evaluate the use of citrated recalcified (nonactivated) thromboelastography (TEG) in healthy horses and horses with colitis and suspected coagulopathies. Methods: Prospective, observational study conducted between October 2007 and June 2009. Methods: Veterinary Teaching Hospital. Methods: Forty-five healthy adult horses and 12 sick adult horses with colitis and prolonged prothrombin time (PT) or activated partial thromboplastin time (aPTT). Methods: None. Results: Whole blood was collected on admission. Coagulation profile (PT, aPTT, platelet count, and fibrinogen concentration) and citrate...
Armengou L, Monreal L, Delgado MÁ, Ríos J, Cesarini C, Jose-Cunilleras E.Heparin is used in humans as prophylaxis of hypercoagulable states and disseminated intravascular coagulation (DIC). However, babies need a higher heparin dose than do adults. Septic neonate foals are at high risk of hypercoagulable state and DIC, and there is limited objective information about heparin dose for equine neonates. Objective: To assess whether neonate foals require higher dosages of low-molecular-weight heparin (LMWH) than adults. Methods: Eighteen healthy and 11 septic neonate foals. Methods: Experimental and clinical studies. Firstly, healthy foals were randomly distributed in ...
Garvican ER, Vaughan-Thomas A, Redmond C, Gabriel N, Clegg PD.The plasma serine protease activated protein C (APC) is synthesized by human chondrocytes at sites of pathological cartilage fibrillation. APC levels are increased in osteoarthritis (OA) synovial fluid, and in vitro APC has been shown to synergize with interleukin-1beta (IL-1) to promote degradation from ovine cartilage. A model of equine cartilage degradation was established and used to explore corticosteroid activities. Intraarticular corticosteroids are a commonly prescribed treatment for joint disease, however their role in disease modification remains unclear. APC synergized with IL-1 or ...
Casella S, Giannetto C, Fazio F, Giudice E, Piccione G.The aim of the present study was to assess the effect of different storage conditions on prothrombin time (PT), activated partial thromboplastin time (aPTT), and fibrinogen concentration in clinical samples from healthy horses. A total of 100 healthy horses of varying breeds and gender, ranging in age from 4 to 18 years, with a mean body weight of 480 +/- 70 kg, were used. Blood was collected by jugular venipuncture, and a hemochrome-cytometric examination was conducted on all samples. All blood samples were centrifuged and divided into 4 different aliquots to assess clotting parameters by mea...
Dallap Schaer BL, Bentz AI, Boston RC, Palmer JE, Wilkins PA.To determine if changes in viscoelastic variables are associated with abnormalities observed in the standard coagulation profile and patient outcome in foals with suspected septicemia. Methods: Prospective clinical trial during 2003 and 2004 foal season. Methods: Neonatal intensive care unit at a veterinary teaching hospital. Methods: Thirty critically ill foals <72-hour-old admitted sequentially meeting criteria for systemic inflammatory response associated with infection. Methods: Hemostatic evaluation, using standard coagulation testing and viscoelastic analysis, was performed at admissi...
Dallap Schaer BL, Epstein K.To review the hemostasis literature relevant to development of coagulopathy in the critically ill equine patient. Methods: Original scientific and review articles. Results: Inflammation plays a critical role in the activation and amplification of clot formation, as well as the impairment of physiologic anticoagulant mechanisms, and fibrinolysis. Earlier identification of coagulopathy in patients at risk and restoration of physiologic hemostasis may result in better outcome. Development of scoring systems based on information other than coagulation markers alone may better identify patients wit...
Epstein KL, Brainard BM, Lopes MA, Barton MH, Moore JN.To develop a standardized technique for thrombelastography (TEG) analysis in healthy adult horses, with and without the ex vivo addition of tissue factor (TF) as an activator. To determine reference intervals for TEG parameters in the horse, and to determine if traditional coagulation tests correlate with TEG. Methods: Prospective, observational. Methods: Veterinary teaching hospital. Methods: Twenty-six healthy adult horses. Methods: None. Results: Thrombelastography with (TF-TEG) and without (TEG) the addition of TF performed by 4 operators. Coagulation profiles (prothrombin time, activated ...
Monreal L, Cesarini C.The most common coagulopathy in horses with colic is a hypercoagulable state associated with disseminated intravascular coagulation. The intensity of this coagulopathy depends on the severity and duration of the gastrointestinal lesion, with the ischemic and inflammatory problems and peritonitis being the most frequently affected by coagulopathies. Early initiation of prophylactic therapy significantly reduces the severe hypercoagulable state in horses with intestinal conditions which are recognized to be at high risk for disseminated intravascular coagulation. In addition to the systemic coag...
Delgado MA, Monreal L, Armengou L, Ríos J, Segura D.Plasma D-dimer concentration is a useful marker to assess systemic coagulation and fibrinolytic activities in humans, dogs, and horses. Peritoneal fibrinolytic activity increases in horses with colic, especially in horses with endotoxin in the peritoneal fluid. Objective: Peritoneal D-dimer concentration can be used to assess peritoneal fibrinolytic activity in horses with severe gastrointestinal (GI) disorders and altered peritoneal fluid. Methods: Two hundred and twenty-one colic horses and 15 control horses. Methods: Prospective observational clinical study. Blood and peritoneal fluid were ...
Henninger RW.Severe hemorrhagic diathesis caused by hemophilia A (factor VIII:C deficiency) was diagnosed in 2 related Quarter Horse colts. Clinical signs consisted of dyspnea and dysphagia attributable to cranial cervical hematoma in one colt and to intra-abdominal hemorrhage resulting in death of the second colt. Factor VIII:C deficiency, a defect of the intrinsic coagulation pathway, is suggested by results of coagulation studies--prolonged activated partial thromboplastin time, normal prothrombin time, and normal primary bleeding time. The diagnosis was confirmed by results of factor VIII:C assays. Hem...
Mendoza FJ, Perez-Ecija RA, Monreal L, Estepa JC.Coagulation disorders are frequently diagnosed, especially in hospitalized equidae, and result in increased morbidity and mortality. However, hemostatic reference intervals have not been established for donkeys yet. Objective: To determine whether the most common coagulation parameters used in equine practice are different between healthy donkeys and horses. Methods: Thirty-eight healthy donkeys and 29 healthy horses. Methods: Blood samples were collected to assess both coagulation and fibrinolytic systems by determination of platelet count, fibrinogen concentration, clotting times (prothrombi...
DeNotta SL, Brooks MB.Horses with clinical signs of unprovoked or excessive hemorrhage should be evaluated for underlying platelet defects or coagulopathies. This article provides an overview of preliminary screening and definitive tests to assess coagulation and identify hemostatic defects in horses, as well as a review of the hemostatic disorders most frequently encountered in clinical practice.
Dunkel B, Bolt DM, Smith RK, Cunningham FM.Platelet-rich plasma (PRP) is increasingly used for treatment of orthopaedic injuries. However, the effects of different stimuli on the release pattern of regenerative and proinflammatory factors from equine platelets are largely unknown and an optimal treatment protocol remains to be established. Objective: The aim of this study was to identify a stimulus that enhanced release of histopromotive factors (platelet-derived growth factor BB [PDGF] and transforming growth factor 1β[TGF]) without causing concurrent release of a proinflammatory mediator (CCL5). Methods: Washed platelets were prepar...
Gibson RB, Banzhaf EJ.Gravimetric determinations were recorded for the total and several individual proteins (in the sodium oxalate plasma) fractioned with ammonium sulphate and sodium chloride. At precipitation, the plasma salt mixture had been diluted to a final volume of ten times the amount of plasma employed. Coagulations were on aliquot portions of filtrates, and the individual protein constituents (except serumalbumin) were calculated by difference. The eleven horses had been subjected to simultaneous immunization against diphtheria and tetanus toxins, each horse being subsequently continued on the toxin to ...
Feige K, Ehrat FB, Kästner SB, Wampfler B.The goal of this study was to determine the effects of plasmapheresis on the behaviour, general condition, haematological, biochemical and coagulation variables of donor horses for 32 days following the procedure. Twenty millilitres of plasma/kg body weight were collected via plasmapheresis in six clinically healthy horses. The general behaviour and condition of the horses was not affected by the procedure. During plasmapheresis, there was a mild increase in the haematocrit, haemoglobin concentration and total erythrocyte and leucocyte counts (P < 0.01). The mean concentrations of total pro...
Cotovio M, Monreal L, Navarro M, Segura D, Prada J, Alves A.In humans and experimental animals, disseminated intravascular coagulation (DIC) causes fibrin deposition in several organs, which eventually leads to ischemia and multiorgan failure. Objective: Horses who died or were euthanized for severe gastrointestinal disorders could have fibrin deposits in different tissues. Methods: Tissue-organ samples collected during postmortem examinations on 66 colic horses with poor prognoses (eg, severe intestinal ischemia, enteritis, peritonitis), from 11 colic horses with good prognoses (eg, large-colon obstruction or displacement), and from 16 slaughter horse...
Geor RJ, Jackson ML, Lewis KD, Fretz PB.A 7-year-old Belgian stallion hemorrhaged excessively after castration; the hemostatic mechanism was investigated. The horse had normal one-stage prothrombin time and markedly prolonged activated partial thromboplastin time (APTT). Results of intrinsic coagulation factor assays were all normal with the exception of prekallikrein activity, which was markedly reduced (less than 1% activity; value for control population, 63 to 150%). Two of this horse's full siblings, a brother and sister, had markedly prolonged APTT and low prekallikrein values (2.5% and less than 1%, respectively). The addition...
Duncan SG, Meyers KM, Reed SM.This study was designed to test the efficacy of heparin anticoagulant therapy in the horse and its effect on the formed elements of blood. Nine clinically normal, nontraumatized adult horses were subjected to 4 different heparin maintenance regimens (dosages of 320, 240, 160, and 40 U/kg of body weight). Porcine intestinal mucosa heparin (20,000 U/ml) was injected subcutaneously every 12 hours for 96 hours (total 9 times). A loading dose of one-third the maintenance dose was given IV just before the first heparin injection. Three control horses were given an equivalent volume of 0.9% saline so...
A deep knowledge on metabolic response of athlete horse to exercise is of paramount importance for the development of optimal training programs to attain equilibrium between good performance and animal welfare. This study investigated the dynamic change of metabolic, clotting times and peripheral indices of central fatigue in horses competing in an official 44 km endurance race. From 6 horses blood samples were collected at rest (T), within 5 minutes from the end of race (T), after 30, 60 minutes after the end of race (T and T) to investigate the values of blood lactate, glucose, platelet...
Gerhards H.Low dose calcium heparin was administered subcutaneously at 12 hourly intervals to six healthy horses at an initial dose of 150 iu of heparin/kg bodyweight (bwt) and at a maintenance dose of 120 iu/kg bwt. All injections were given at 0900 and 2100 h. Blood samples for monitoring plasma heparin concentrations were obtained prior to, at 2 hourly intervals for 84 h (treatment period), and at Hours 24, 32, 48 and 96 of the control period. Blood samples for monitoring red blood cell (RBC) mass, plasma antithrombin III activity (AT III), activated partial thromboplastin time (APTT), and thrombin ti...
Uniacke-Lowe T, Chevalier F, Hem S, Fox PF, Mulvihill DM.Rennet-induced coagulation of bovine milk is a complex mechanism in which chymosin specifically hydrolyzes κ-casein, the protein responsible for the stability of the casein micelle. In equine milk, this mechanism is still unclear, and the protein targets of chymosin are unknown. To reveal the proteins involved, the rennetability of equine milk by calf chymosin was examined using gel-free and gel-based proteomic analysis and compared to bovine milk. RP-HPLC analysis of bovine and equine milks showed the release of several peptides following chymosin incubation. The hydrolyses of equine and bov...
Bishop RC, Kemper AM, Burges JW, Jandrey KE, Wilkins PA.To evaluate a point-of-care viscoelastic coagulation monitor (VCM Vet) for use in horses by assessing variability between devices and establish reference intervals (RIs) for healthy adult horses. Methods: Prospective observational study. Methods: Two university teaching hospitals. Methods: Healthy adult horses (n = 68). Methods: None. Results: Blood collected by direct jugular venipuncture was applied directly from the syringe into 2 VCM Vet cassettes to establish coefficients of variation (CVs) and RIs for reported parameters of clotting time (CT), clot formation time (CFT), alpha angle, am...
Greene CE, Tsang VC, Prestwood AK, Meriwether EA.Optimal reaction conditions for the activated partial thromboplastin time (APTT), 1-stage prothrombin time (PT), and Russell's viper venom time were studied for pooled plasmas of horses, cattle, sheep, goats, swine, dogs, cats, and persons. Changes in CaCl2 and NaCl concentrations had significant effects on the APTT and PT reactions. The APTT was more sensitive than the PT to changes in CaCl2 concentration. The CaCl2 concentration recommended by the manufacturer for the APTT was suboptimal for some of plasmas of domesticated animals in ths study. Infusorial earth (Celite, activator) concentrat...
Dos-Santos MC, Arroyo C, Solano S, Herrera M, Villalta M, Segura A, Estrada R, Gutiérrez JM, León G.Antivenoms are preparations of immunoglobulins purified from the plasma of animals immunized with snake venoms. Depending on the number of venoms used during the immunization, antivenoms can be monospecific (if venom from a single species is used) or polyspecific (if venoms from several species are used). In turn, polyspecific antivenoms can be prepared by purifying antibodies from the plasma of animals immunized with a mixture of venoms, or by mixing antibodies purified from the plasma of animals immunized separately with single venom. The suitability of these strategies to produce polyspecif...
Boermans HJ, Johnstone I, Black WD, Murphy M.Six horses gavaged with a commercial brodifacoum (BDF)-containing bait (Talone) at a dosage of 0.125 mg of BDF/kg of body weight showed weight loss, severe hypocoagulability and hemogram alterations. Four of the horses became depressed and anorectic; one required vitamin K1 therapy. Increases in clotting times were observed at 24 h in the partial thromboplastin time (PTT) followed by the thrombotest (TBT) and one-stage prothrombin time (PT) at 48 h. Elevated mean PTT, PT and TBT were observed from days 4 to 8 (p less than 0.05) with levels returning to pretreatment levels by day 12. Maximum pr...
Wilson EM, Holcombe SJ, Lamar A, Hauptman JG, Brooks MB.The extent of preservation of clotting factors and incidence of transfusion reactions to noncommercial equine plasma is not documented. Objective: Equine frozen plasma would retain its coagulation factor activity within the reference range and the incidence of transfusion reactions would be low. Methods: Ten plasma donor horses. Fifty clinically ill hospitalized horses receiving plasma were reviewed to determine the incidence of reactions. Methods: In vitro study and retrospective case review. Plasma was prepared by gravity sedimentation from whole blood refrigerated for 48 hours. The activiti...
Cesarini C, Cotovio M, Ríos J, Armengou L, Jose-Cunilleras E.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...
Lovett AL, Gilliam LL, Sykes BW, McFarlane D.Both obesity and metabolic syndrome are associated with hypercoagulability in people, increasing the risk of cardiovascular disease and thromboembolic events. Whether hypercoagulability exists in obese, insulin-dysregulated horses is unknown. Objective: To determine if coagulation profiles differ between healthy horses and those with obesity and insulin dysregulation. Methods: Fifteen healthy horses (CON) and 15 obese, insulin-dysregulated horses (OBID). Individuals were university or client owned. Methods: Case-control study. Obesity was defined as a body condition score (BCS) ≥7.5/9 (modif...
Dibiasi C, Plewka J, Ploszczanski L, Glanz V, Lichtenegger H, Windberger U.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 ...
Giordano A, Meazza C, Salvadori M, Paltrinieri S.Exercise-induced pulmonary hemorrhage (EIPH) commonly occurs in race horses. Thromboelastometry (TEM) investigates the whole hemostatic process by evaluating the viscoelastic properties of the blood clot from its formation to fibrinolysis. The aim of this study was to assess whether horses with EIPH have abnormal thromboelastometric profiles. Intrinsic and extrinsic pathways, fibrinogen activity and fibrinolysis were investigated by TEM before and after the race in negative controls and in horses on which EIPH was confirmed by bronchoscopy. Compared with controls, horses with EIPH had an incre...
Henry MM, Moore JN.Endotoxin-activated monocytes express a thromboplastin-like procoagulant activity on the cell surface that may serve as a focal point for formation of microvascular thrombi. Because coagulopathy is a common sequela to endotoxemia in the equine species, we investigated the ability of monocytes, isolated from horses with colic, to express procoagulant activity. On the day of admission, and on the third and fifth day of hospitalization, monocytes were isolated from 30 adult horses with colic. A coagulation profile, including prothrombin time, activated partial thromboplastin time, thrombin time, ...
Rawlings CA, Byars TD, Van Noy MK, Bisgard GE.Activated coagulation test (ACT) was performed in 37 adult ponies and 31 adult horses. The mean ACT time of all ponies and horses was 2 minutes 38 seconds, with a standard deviation (SD) of 29 seconds. The ACT was compared with the Lee-White clotting test in heparinized ponies. The correlation of ACT with the Lee-White test was 0.95. Anticoagulation heparinized ponies during prolonged cardiopulmonary bypass was successfully monitored with the ACT. The ACT is simple and reproducible, has a definite end point, and would seem to be an ideal screening test for hemorrhagic diathesis in equine anima...
Weiss DJ, Geor RJ, Johnston G, Trent AM.The hypothesis that equine laminitis is caused by thrombosis of vessels in the laminar corium (dermis) was investigated. Hemostatic alterations were evaluated by determining platelet count, platelet survival, platelet adhesiveness to vascular subendothelium, activated clotting time, and whole blood recalcification time. Thrombosis of vessels in the hoof wall was evaluated by scintigraphic studies of the hoof wall after administration of indium-111 (111In)-labeled platelets, contrast arteriography, and histologic examination. Platelet count remained constant before and at the onset of lameness;...
Dallap BL.Disseminated intravascular coagulation (DIC) is a clinicopathologic syndrome resulting from a multitude of underlying causes that manifests itself clinically as hemostatic/fibrinolytic failure. There is much debate on the definition, diagnosis, and treatment of DIC, a situation that is most likely the result of the multifaceted clinical presentation of the syndrome and the fact that patient outcome is often influenced by the underlying disease process. The fact that DIC increases morbidity and mortality in critical care patients is well established, but the exact mechanism of what specifically...
Monreal L, Villatoro AJ, Monreal M, Espada Y, Anglés AM, Ruiz-Gopegui R.Thirty healthy male horses were allotted to 3 groups and treated blindly during 4 days. Group-1 horses received unfractioned calcium heparin (100 IU/kg of body weight, SC, q 12 h). Group-2 horses received a single dose of a low-molecular-weight heparin (50 anti-Xa IU/kg, SC) every morning, and a similar volume of saline solution every evening. Group-3 horses received the vehicle (saline solution), SC, every 12 hours. Citrated and EDTA-anticoagulated blood samples were collected before starting the medication (T-0) and once daily 3 hours after each morning injection (T-3, T-27, T-51, and T-75)....
Okano S, Hurley DJ, Vandenplas ML, Moore JN.To determine the effect of fetal bovine serum (FBS) and heat-inactivated FBS (HI-FBS) on lipopolysaccharide (LPS)- and zymosan-induced procoagulant activity of equine and canine mononuclear cells. Methods: Mononuclear cells from 18 horses and 3 dogs. Methods: Cells were incubated with various concentrations of FBS, HI-FBS, LPS, zymosan, polymyxin B, and anti-LPS-binding protein monoclonal antibody or combinations of these constituents. A 1 stage recalcification assay was used to determine procoagulant activity. Results: Addition of FBS to media significantly increased procoagulant activity; eq...
Scruggs JL, Flatland B, McCormick KA, Reed A.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...