Association of Admission Plasma D-Dimer Concentration with Diagnosis and Outcome in Horses with Colic

Association of the severity of colic in horses with oxidative stress biomarkers, acute-phase proteins, and certain trace elements

Sixty-one horses were enrolled in this study and divided into 3 different groups according to their severity of colic (heart rate, oral mucous membrane color, and abdominal distention): a strangulating colic (SC) group (n=21), non-strangulating colic (NC) group (n=20), and control group (n=20) consisting of randomly selected normal horses without signs of colic. The serum concentrations of haptoglobin, tumor necrosis factor-α (TNFα), nitric oxide (NO), malondialdehyde (MDA), zinc, iron, and copper were evaluated in all horses. The average concentration of TNFα in the SC group was higher than that in the control group (P<0.001). The TNFα concentration was higher in the NC group compared with the control group (P<0.001). Furthermore, the average concentration of TNFα tended to be higher in the SC group compared with the NC group (P=0.052). The average concentration of haptoglobin in the SC group was higher than that in the control group (P<0.001). The average concentration of NO was higher in the SC group compared with the NC group. (P=0.016) The average concentration of MDA was higher in the SC group compared with the control group (P=0.042). Furthermore, the concentration of MDA was higher in the SC group compared with the NC group (P=0.048). TNFα in horses with signs of colic may be a reliable indicator of prognosis and the severity of clinical signs. The haptoglobin concentration may be a useful marker in cases where animals are referred to clinicians a few days after the onset of colic. The concentrations of MDA and NO should be interpreted with caution.

Preliminary evaluation of reference intervals for a point-of-care viscoelastic coagulation monitor (VCM Vet) in healthy adult horses

OBJECTIVE

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.

DESIGN

Prospective observational study.

SETTING

Two university teaching hospitals.

ANIMALS

Healthy adult horses (n = 68).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN 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, amplitude at 10 and 20 minutes, maximum clot firmness, and lysis index at 30 and 45 minutes. CVs for each parameter were within clinical tolerance. There was a significant difference in CT between institutions (P < 0.001). Differences in CV were found between institutions for CT (P = 0.003) and CFT (P = 0.01). Healthy horse RIs were calculated for the overall data set and each individual institution. Calculated RIs were as follows: CT, 255.6-1233.9 seconds; CFT, 89.4-581 seconds; alpha angle, 11.4-53.6°; maximum clot firmness, 18-37.7; lysis index at 30 minutes, 97.3%-102.1%; lysis index at 45 minutes, 80.8%-103.3%; amplitude at 10 minutes, 8.7-28.3; and amplitude at 20 minutes, 17.4-35.7.

CONCLUSIONS

VCM Vet is a repeatable and practical option for rapid point-of-care assessment of hemostasis in horses but has a wide RI and is susceptible to variability. Establishment of institution-specific RIs is recommended.

Spontaneous Sepsis in Adult Horses: From Veterinary to Human Medicine Perspectives

Sepsis is a life-threatening disease defined as an organ dysfunction caused by a dysregulated host response to an infection. Early diagnosis and prognosis of sepsis are necessary for specific and timely treatment. However, no predictive biomarkers or therapeutic targets are available yet, mainly due to the lack of a pertinent model. A better understanding of the pathophysiological mechanisms associated with sepsis will allow for earlier and more appropriate management. For this purpose, experimental models of sepsis have been set up to decipher the progression and pathophysiology of human sepsis but also to identify new biomarkers or therapeutic targets. These experimental models, although imperfect, have mostly been performed on a murine model. However, due to the different pathophysiology of the species, the results obtained in these studies are difficult to transpose to humans. This underlines the importance of identifying pertinent situations to improve patient care. As humans, horses have the predisposition to develop sepsis spontaneously and may be a promising model for spontaneous sepsis. This review proposes to give first an overview of the different animal species used to model human sepsis, and, secondly, to focus on adult equine sepsis as a spontaneous model of sepsis and its potential implications for human and veterinary medicine.

Investigation of two different human d-dimer assays in the horse

Background

D-dimer has value as a marker of thrombosis in critically ill horses and can provide additional information about prognosis. However, there are currently no equine species-specific d-dimer assays available, nor has there been any formal investigation of the applicability of human d-dimer assays in horses, so it is unknown, which assay performs best in this species. The aim of this study was therefore to evaluate and compare two human d-dimer assays for their applicability in horses.

The study included four groups of horses: clinically healthy horses, horses with gastrointestinal (GI) disease and mild systemic inflammation based on low serum amyloid A (SAA) (low SAA group), horses with GI disease and strong systemic inflammation based on high SAA (high SAA group) and, horses with thrombotic GI disease caused by Strongylus vulgaris (also called non-strangulating intestinal infarction (NSII)) (NSII group). The assays evaluated were the STAGO STA-Liatest D-di + (Stago) and NycoCard™ D-dimer (NycoCard). Intra- and inter-coefficients of variation (CV) were assessed on two d-dimer concentrations, and linearity under dilution was evaluated. A group comparison was performed for both assays across the four groups of horses. A Spaghetti plot, Spearman Correlation, Passing Bablok regression and Bland–Altman plot were used to compare methods in terms of agreement.

Results

Ten horses were included in the clinically healthy group, eight in the low SAA group, eight in the high SAA group, and seven in the NSII group. For the Stago assay, intra- and inter-CVs were below the accepted level except for one inter-CV. The NycoCard assay did not meet the accepted level for any of the CVs. The linearity under dilution was acceptable for both the Stago and NycoCard. In the group comparison, both methods detected a significantly higher d-dimer concentration in the high SAA and NSII groups compared to the clinically healthy group. Method agreement showed slightly higher d-dimer concentrations with NycoCard compared to Stago. The overall agreement was stronger for the lower d-dimer concentrations.

Conclusion

Both the Stago and the NycoCard were found to be applicable for use in horses but were not directly comparable.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03313-5.

A pilot study evaluating the Calibrated Automated Thrombogram assay and application of plasma-thromboelastography for detection of hemostatic aberrations in horses with gastrointestinal disease

Background

Critically ill horses, such as horses with gastrointestinal (GI) disease, often suffer from hemostatic aberrations. Global hemostatic tests examining the initiation of coagulation, clot strength and fibrinolysis, such as the Calibrated Automated Thrombogram (CAT) and plasma-thromboelastography (TEG) have not been evaluated in horses. This study aimed to evaluate CAT and apply plasma-TEG in horses.

Test performance of CAT was evaluated on equine platelet poor plasma with intra- and inter-assay variability (CV) and a heparin dilution curve. To examine clinical performance of both tests, group comparisons were assessed comparing healthy horses, horses with mild and severe GI disease with both CAT and plasma-TEG.

Results

For CAT, intra- and inter-assay CVs were established for lag-time (1.7, 4.7%), endogenous thrombin potential (1.6, 4.6%), peak (2.6, 3.9%) and time to peak (ttPeak) (1.9, 3.4%). Increasing heparin concentrations led to the expected decrease in thrombin generation. In the group comparison analysis, CAT showed significant higher peak (p = 0.04) and ttPeak (p = 0.008) in the severe GI disease group compared to horses with mild GI disease and healthy horses, respectively. Plasma-TEG showed an increased angle (p = 0.032), maximum amplitude (p = 0.017) and shear elastic force (G) (p = 0.017) in the severe GI disease group compared to healthy horses.

Conclusions

CAT performed well in horses. Both CAT and plasma-TEG identified hemostatic aberrations in horses with severe GI disease compared to healthy horses. Further studies including more horses, are needed to fully appreciate the use of CAT and plasma-TEG in this species.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-03058-7.

Prognostic value of measuring heart rate variability at the time of hospital admission in horses with colic

OBJECTIVE

To evaluate the prognostic value of measuring heart rate variability (HRV) in horses with colic at the time of admission to a referral hospital.

ANIMALS

51 horses > 1 year of age with colic (41 that survived [survivors] and 10 that died or were euthanized [nonsurvivors]).

PROCEDURES

HRV was recorded within 1 hour after admission by use of heart rate sensors with horses restrained in stocks. A 5-minute recording period was analyzed to obtain HRV measurements (eg, SD of R-R intervals [SDRR], root mean square of successive differences between R-R intervals [RMSSD], and geometric SDs determined from Poincaré plots [SD1 and SD2]). Variables associated with outcome (survival vs nonsurvival) were identified. Measurements were compared among diagnostic categories for colic (obstructive, inflammatory, or ischemic).

RESULTS

SDRR and RMSSD were significantly higher in survivors (median [25th to 75th percentile], 91.0 milliseconds [78.9 to 114.6 milliseconds] and 64.8 milliseconds [40.9 to 78.4 milliseconds], respectively) than in nonsurvivors (50.7 milliseconds [29.1 to 69.2 milliseconds] and 33.4 milliseconds [12.6 to 47.9 milliseconds], respectively). Similarly, SD1 and SD2 were significantly higher in survivors (48.3 milliseconds [28.9 to 60.9 milliseconds] and 111.3 milliseconds [93.0 to 146.6 milliseconds], respectively) than in nonsurvivors (23.7 milliseconds [8.9 to 33.9 milliseconds] and 65.1 milliseconds [33.7 to 91.9 milliseconds], respectively). The SDRR and SD2 were significantly higher for horses with obstructive colic than for horses with ischemic colic.

CONCLUSIONS AND CLINICAL RELEVANCE

Analysis of HRV in horses with colic may provide information on the underlying cause and be helpful in identifying horses less likely to survive.

Proteinase Activated Receptor 4 in the Jejunum of Healthy Horses and of Horses With Epiploic Hernia

Proteinase activated receptor 4 (PAR₄) in the gastrointestinal tract is involved in the regulation of inflammation and pain pathways. The aim of the present study was to evaluate the distribution and expression of PAR₄ in the jejunum of healthy horses and in the pathologic tracts from horses undergoing surgery for herniation of the small intestine through the epiploic foramen. Eight healthy horses (Group H) and eight horses with epiploic hernia (Group EH) were included; the jejunum samples were collected at the slaughter or intraoperatively after enterectomy, respectively. To evaluate PAR₄ expression in sections of the jejunum, immunofluorescence, western blot and quantitative polymerase chain reaction (qRT-PCR) were performed. Immunohistochemistry of PAR₄ in the jejunum of the healthy horses showed that receptors are predominantly expressed in the immune cell population scattered throughout the lamina propria of the mucosa and in the submucosa. Quantitative PCR data demonstrated that PAR₄ mRNA was detectable in all of the samples analyzed without any difference between the H and the EH groups, however the PAR₄ protein level was significantly lower in the jejunums of the EH horses. In the Group EH horses, PAR₄ immunoreactivity was mainly expressed in the mast cells and was extensively distributed in the sierosa. In the lamina propria of mucosa of Group EH, leukocytes were less abundant than in Group H. In this study, the distribution and expression of PAR₄ in the jejunums of the healthy horses and in those with spontaneous occurring epiploic hernia was demonstrated.

Usefulness of a Point-of-Care Analyzer to Measure Cardiac Troponin I and D-Dimer Concentrations in Critically Ill Horses With Gastrointestinal Diseases

Point-of-care (POC) systems for the joint measurement of Troponin and D-dimers have not been studied in horses. The aim of this study was to perform the validation of a POC system (AQT90 FLEX) for the measurement of cardiac troponin I (cTnI) and D-dimers in the serum of horses with gastrointestinal diseases. The main objective was to evaluate whether or not this system can distinguish healthy animals from diseased animals. A sample of 33 horses was included in the study: control group (n = 10) and horses with gastrointestinal disorders (n = 21), which were classified according to their outcome in survivors (subgroup A = 9) and nonsurvivors (subgroup B = 12). Considering the diagnosis of the process, ill horses were classified into three groups: inflammatory (I = 7), obstructive (O = 9), and strangulating diseases (S = 5). The clinical usefulness of AQT90 FLEX was validated by the study of linearity, coefficient of variation, and detection limits. Later, concentrations of D-dimers and cTnI were measured. A significant increase in both parameters was detected in ill animals (cTnI: control: 0.014 ± 0.01 μg/mL, survivors: 0.27 ± 0.37 μg/mL, nonsurvivors: 0.60 ± 1.21 μg/mL; D-dimers: control: 104.90 ± 30.82 ng/mL, survivors: 1,217.22 ± 1,213.28 ng/mL, nonsurvivors: 1,613.67 ± 1,426.75 ng/mL), although there were no statistically significant differences in concentrations according to diagnosis and outcome. In conclusion, AQT90 FLEX POC analyzer can be used in horses with gastrointestinal diseases to measure cTnI and D-dimer concentrations. It is a quick, practical, and minimally invasive tool that helps in determining the severity of illness.

Coagulation Assessment in the Equine Patient

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.

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 there was a trend toward a lower value in controls (median 0.0024 g/L) than in horses with chronic pneumopathies (median 0.0052 g/L), in particular, those with RAO (median 0.0062 g/L). Fibrinogen concentration was positively correlated with percentage of neutrophils in BALF (r_s = 0.377, p = 0.004). SAA concentrations were low; 65.5% of samples were below the detection limit. D-dimer concentrations were also low and quantifiable concentrations were only obtained after ultrafiltration and only in RAO (median 0.1 mg/L). In conclusion, there was limited evidence of increased coagulatory activity in chronic pneumopathies, apart from RAO. It is uncertain whether fibrinogen and D-dimer concentrations increased due to their role as acute-phase proteins or as a misbalance of coagulation and fibrinolysis.

Synovial fluid D-dimer concentration in horses with osteochondritis dissecans and osteoarthritis

Objective: 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-dimer concentrations of horses with OCD and OA were both higher when compared with controls, but were only significantly different in horses with OCD (p = 0.005). However, no statistical differences were observed when comparing synovial D-dimer concentrations from the OCD horses with the OA-affected horses (p = 0.444).

Clinical significance: Activation of coagulation and fibrinolysis play a role in the pathophysiology of equine OCD and OA.

Comparison of two blood sampling techniques for the determination of coagulation parameters in the horse: Jugular venipuncture and indwelling intravenous catheter

BACKGROUND

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.

OBJECTIVES

To compare coagulation parameters from blood obtained by jugular venipuncture with IVC sampling in critically ill horses.

STUDY DESIGN

Prospective observational study.

METHODS

A single set of paired blood samples were obtained from horses (n = 55) admitted to an intensive care unit by direct jugular venipuncture and, following removal of a presample, via an indwelling IVC. The following coagulation parameters were measured on venipuncture and IVC samples: whole blood prothrombin time (PT), fresh plasma PT and activated partial thromboplastin time (aPTT) and stored plasma antithrombin activity (AT) and fibrinogen concentration. D-dimer concentration was also measured in some horses (n = 22). Comparison of venipuncture and IVC results was performed using Lin's concordance correlation coefficient. Agreement between paired results was assessed using Bland Altman analysis.

RESULTS

Correlation was substantial and agreement was good between sample methods for all parameters except AT and D-dimers.

MAIN LIMITATIONS

Each coagulation parameter was tested using only one assay. Sampling was limited to a convenience sample and timing of sample collection was not standardised in relation to when the catheter was flushed with heparinised saline.

CONCLUSIONS

With the exception of AT and D-dimers, coagulation parameters measured on blood samples obtained via an IVC have clinically equivalent values to those obtained by jugular venipuncture.

Proteinase-activated receptor 2 distribution and expression in equine small intestine tracts following herniation through the epiploic foramen

Proteinase-activated receptor 2 (PAR₂) is a G-protein-coupled receptor for trypsin and mast cell tryptase; it is highly expressed at the intestinal level with multiple functions, such as epithelial permeability and intestinal motility. The aim of the study was to evaluate the distribution and expression of proteinase-activated receptor 2 in the small intestine during herniation through epiploic foramen. In this prospective clinical study, eight horses admitted for colic and which underwent exploratory laparotomy were considered. During surgery, the jejunum or the ileum was sampled by enterectomy. Morphological examination (histology, PAR₂ immunohistochemistry) and molecular biology analysis (western blot and quantitative polymerase chain reaction) were carried out on the resected intestinal samples. The Marginal Injured Tracts (MITs) and Central Injury Tracts (CITs) were defined as the oral and caudal marginal segments of the resected bowel tract and as the geometric centre of the intestinal ischaemic lesion length, respectively. The PAR₂ immunoreactivity was particularly evident in the epithelial cells, with higher immunoreactivity in the MIT rather than in the CIT. Moreover, a different immune localisation was observed in the MITs at the cell membrane level and in the CITs in the cytoplasm. No statistical difference was observed in PAR₂ mRNA and protein (44kDa) expression between the MIT and the CIT. The PAR₂ protein content in the intestinal tracts which were removed from horses with herniation was lower when compared with the control animals. This study provided data concerning the PAR₂ presence and distribution in horses with intestinal herniation through the epiploic foramen.

Evaluation of an oral direct factor Xa inhibitor anticoagulant in healthy adult horses

OBJECTIVE

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.

DESIGN

Experimental study.

SETTING

Field study.

ANIMALS

Ten healthy adult horses.

INTERVENTIONS

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 Xa activity was measured at baseline time and 3 hours after each dose administration. Activated partial thromboplastin time, prothrombin time, hematocrit, erythrocyte agglutination, and platelet aggregation were monitored throughout the study. In addition, an in vitro spiking experiment was performed to demonstrate anticoagulant activity of this DiXaI in horse plasma.

MAIN RESULTS

When treated with the DiXaI, this group of horses did not achieve the suggested thromboprophylactic plasma range of antifactor Xa activity (0.1-0.2 IU/mL), except for 1 horse after the first administration of the drug. In contrast, median values of plasma antifactor Xa activity 3 hours after receiving dalteparin were within the prophylactic range (0.16 IU/mL). No hemorrhagic events or erythrocyte agglutination were observed. In vitro addition of this DiXaI caused a concentration-dependent effect in antifactor Xa activity.

CONCLUSIONS

At the low end of the recommended dose in people this oral formulation of DiXaI did not reach prophylactic plasma antifactor Xa activity in this group of healthy adult horses. Further studies are warranted in order to establish the prophylactic dose for horses.

Association Between Necropsy Evidence of Disseminated Intravascular Coagulation and Hemostatic Variables Before Death in Horses With Colic

Background

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.

Hypothesis

Antemortem classification of coagulopathy is related to the presence and severity of fibrin deposits observed postmortem in horses with severe gastrointestinal disorders.

Animals

Antemortem hemostatic profile data and postmortem tissue samples (kidney, lung, liver) from 48 horses with colic.

Methods

Tissue samples were stained with phosphotungstic acid hematoxylin and immunohistochemical methods for histological examination. A fibrin score (grades 0–4) was assigned for each technique, tissue and horse, as well as the presence or absence of DIC at postmortem examination. D‐dimer concentration, prothrombin time (PT), activated partial thromboplastin time (aPTT), and antithrombin (AT) activity, as well as the clinicopathological evidence of coagulopathy, were determined from plasma samples collected 0–24 hours before death or euthanasia. Histologic and clinicopathologic data from the same horses were compared retrospectively.

Results

No association was found between antemortem classification of coagulopathy and postmortem diagnosis of DIC based on tissue fibrin deposition. None of the hemostatic parameters was significantly different between horses with or without postmortem diagnosis of DIC. There was no association between horses with fibrin in tissues or different cut‐offs for D‐dimer concentration and postmortem evidence of DIC.

Conclusions and Clinical Importance

Abnormalities of the routine clotting profile, including D‐dimer concentration, were not useful in predicting histologic evidence of DIC at necropsy in horses with severe gastrointestinal disorders.

The Combination of D-Dimer and Peritoneal Irritation Signs as a Potential Indicator to Exclude the Diagnosis of Intestinal Necrosis

Intestinal necrosis is a life-threatening disease, and its prompt and accurate diagnosis is very important. This study aimed to evaluate the value of D-dimer as a marker for early diagnosis of bowel necrosis. From 2009 to 2013, patients undergoing operation due to acute intestinal obstruction were retrospectively analyzed. Clinicopathologic characteristics were compared among no ischemia group, reversible ischemia group, and bowel necrosis group. There were totally 274 patients being included for analyses. Patients with bowel necrosis had a significant highest level of D-dimer compared with other 2 groups (P =  .007) when FEU unit was applied. The optimal cutoff value of D-dimer levels as an indicator in diagnosing bowel necrosis was projected to be 1.965 mg/L, which yielded a sensitivity of 84.0%, a specificity of 45.6%, a positive predictive value of 60.7%, and a negative predictive value of 74.0%. And the sensitivity of 84.0% and specificity of 70.0% were detected, when 1.65 mg/L of D-dimer was set as the cutoff value to distinguish the reversible ischemia and bowel necrosis. The corresponding results in patients with no or slight peritoneal irritation signs were 85.2%, 44.7%, 35.4% and 89.5% respectively. The sensitivity and negative predictive value were 96.0% and 91.7%, respectively, when D-dimer and peritoneal irritation signs were combined to perform the parallel analysis. The combination of D-dimer and peritoneal irritation signs could generate a reliable negative predictive value, which is helpful to exclude the diagnosis of intestinal necrosis. However, it should also be proved in well-designed large-scale prospective study.

Serum amyloid A, haptoglobin, and ferritin in horses with colic: Association with common clinicopathological variables and short-term outcome

Equine colic may be associated with an acute phase response (APR). Measurement of acute phase proteins (APPs) allows the detection of an APR and may help clinicians in monitoring the disease; however, the role of APPs in colic is unclear. This study aimed to evaluate the clinical usefulness of serum amyloid A (SAA), haptoglobin and ferritin in combination with an extended clinicopathological profile in equine colic. The medical records of 54 horses were retrospectively selected. Horses were grouped based on outcome (survivors vs. non-survivors), diagnosis (ischaemic/strangulating vs. non-ischaemic/non-strangulating), and treatment (medical treatment vs. surgery). Laboratory data were compared, and a logistic regression analysis was performed for outcome prediction upon admission. A high percentage of horses had abnormal SAA (29/54), haptoglobin (20/54), and ferritin (31/54) concentrations. In particular, haptoglobin was below the reference interval in 13/54 horses. Non-survivors had significantly decreased haptoglobin and increased ferritin concentrations compared with survivors. The ischaemic/strangulating group had significantly increased creatinine and ferritin and decreased haptoglobin concentrations compared with the non-ischaemic/non-strangulating group. Creatinine was the only significant predictor of mortality in the regression analysis. In conclusion, APPs including SAA, haptoglobin, and ferritin combined with clinicopathological variables may help clinicians to understand the pathogenesis of APR and underline potential complications of equine colic. The reduction in haptoglobin concentration may suggest haemolysis or muscle fibre damage; ferritin may indicate alteration in iron metabolism and tissue damage. Further prospective studies are needed to assess diagnostic and prognostic values of APPs in colic horses.

Peritoneal reactivity evaluation in horses subjected to experimental small colon enterotomy and treated with subcutaneous heparin

Heparin is routinely administered in postoperative abdominal surgery aiming to prevent adhesions formation; however, there is no consensus indicating its effectiveness. This study evaluated the effect of heparin on peritoneal reactivity after abdominal surgery, through the association between peritoneal fluid features and ultrasonographic and laparoscopic examination. Ten adult horses were used: control group (CG) and treated group (TG). Both groups underwent laparotomy and small colon enterotomy. TG received subcutaneous heparin at 150 IU/kg every 12 hours for 5 days. The animals underwent ultrasonography and peritoneal fluid examination prior to enterotomy (M0) 12 hours (M1), 1 day (M2), 2 days (M3), 4 days (M4), 6 days (M5), 10 days (M6), and 14 days after enterotomy (M7) with laparoscopic examination being performed on the fifth postoperative day. Peritoneal inflammatory response was observed in both groups. The peritoneal fluid of TG animals showed higher echogenicity during heparin therapy. No inflammatory difference was observed between groups through peritoneal fluid features, except for the higher D-dimer concentration in CG. On laparoscopy, slightly diffuse peritoneal reactivity for both groups was observed, being higher for TG. Laparoscopy and ultrasonography association allowed detailed access to the abdominal cavity. Ultrasonography assessed the diffuse peritoneal inflammation, and laparoscopy allowed the detailed analysis of the segments. No gross beneficial reactions resulting from the use of heparin on peritoneal reactivity were observed; however, it was observed by D-dimer evaluation that the TG had less fibrin deposition, which is directly related to a lower rate of abdominal adhesions formation.

Progression of plasma D-dimer concentration and coagulopathies during hospitalization in horses with colic

OBJECTIVE

To assess the progression of plasma D-dimer concentrations and coagulation status in horses with different types of colic.

DESIGN

Prospective clinical observational study performed between March 2004 and September 2008.

SETTING

Veterinary university teaching hospital.

ANIMALS

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).

INTERVENTIONS

Three blood samples were obtained from each horse (admission, at 24-48 h [or after surgery] and upon discharge). For each sample, plasma D-dimer concentration, prothrombin time, activated partial thromboplastin time, antithrombin activity, and the presence of subclinical disseminated intravascular coagulation were determined.

MEASUREMENTS AND MAIN RESULTS

When median plasma D-dimer concentration values at admission and after 24-48 hours were compared, they were different but stable in horses with MO (1.29-1.95 nmol/L) and inflammatory conditions (5.70-6.69 nmol/L). However, 10-fold and 5-fold increases were observed, respectively, in SO (2.08 to 16.38 nmol/L) and IS (3.08 to 15.91 nmol/L) in the postoperative period. By 24-48 hours, the percentage of horses with coagulopathy increased in most groups (MO, 43 to 58%; SO, 50 to 96%, IS, 53 to 90%). By the time of discharge, 87% of horses with SO problems and 89% of horses with IS still had some form of coagulopathy documented.

CONCLUSIONS

Throughout hospitalization, horses with MO problems had less severe coagulopathy and lower plasmatic D-dimer concentrations compared to other groups of horses. On admission, most horses with inflammatory conditions presented with coagulopathy. At 24-48 hours of hospitalization and following surgery, the hemostatic profile can differ markedly when compared to admission values.

Proteinase-activated receptor 2 expression in the intestinal tract of the horse

Proteinase-activated receptor 2 (PAR2) is a G-protein-coupled receptor for trypsin and mast cell tryptase; it is highly expressed at the intestinal level with multiple functions, such as epithelial permeability and intestinal motility. Many proteases activate PAR2 during tissue damage, suggesting a role of the inflammatory response receptors. The aim of the study was to evaluate the distribution and expression of PAR2 in the jejunum, the ileum and the pelvic flexure, using samples collected from healthy adult horses after slaughter. Proteinase-activated receptor 2 immunoreactivity (PAR2-IR) was observed in the enterocytes, intestinal glands, the smooth muscle of the muscularis mucosae, and the longitudinal and circular muscle layers; there were no differences in the distribution of PAR2-IR in the different sections of the intestinal tract. The protein expression level showed that the relative amount of the PAR2 content in the mucosa of the intestinal tract decreased from the small to the large intestine while the PAR2 mRNA analysed showed similar values. This study provides relevant findings concerning the distribution of the PAR2 in the intestines of healthy horses and represents the starting point for evaluating the role of the PAR2 during strangulative intestinal disease and consequent systemic intestinal reperfusion/injury complications in horses in order to identify and employ antagonist PAR2 molecules.

Synovial fluid D-dimer concentration in foals with septic joint disease

BACKGROUND

Increased synovial fibrinolytic activity (detected by increases in synovial D-Dimer concentrations) has been observed in different joint diseases in humans and adult horses, presumably in order to minimize fibrin deposition within the joint and thus avoid its detrimental effects.

OBJECTIVE

To investigate fibrinolytic pathway activation in joint sepsis in foals by measuring synovial D-Dimer concentrations.

ANIMALS

Eighteen septic foals with septic joints, 9 septic foals without septic joints, 9 systemically healthy foals with septic joint, and 3 controls are included.

METHODS

Prospective observational clinical study of foals admitted for septic arthritis. Synovial D-Dimer concentration and routine synovial fluid analysis were performed. Diagnosis of joint sepsis was made whenever synovial total nucleated cell count was >30,000 cells/μL, synovial total protein >4 g/dL, and neutrophil percentage of >80%, or synovial fluid culture resulted positive. Results were compared among groups by general lineal models.

RESULTS

Synovial D-Dimer concentration was significantly (P < .001) higher in the foals with septic joints compared with foals without joint disease (P < .001).

CONCLUSIONS AND CLINICAL IMPORTANCE

Septic joint disease is associated with a marked increase of synovial D-Dimer concentration (marked activation of the fibrinolytic activity) within the affected joint. Although further studies are needed, the measurement of synovial D-Dimer concentration may be considered a complementary diagnostic marker of septic joint disease.

Coagulation profiles of healthy Andalusian donkeys are different than those of healthy horses

BACKGROUND

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.

OBJECTIVES

To determine whether the most common coagulation parameters used in equine practice are different between healthy donkeys and horses.

ANIMALS

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 (prothrombin time [PT] and activated partial thromboplastin time [aPTT]), fibrin degradation products (FDP) and D-Dimer concentrations.

RESULTS

PT and aPTT in donkeys were significantly (P < .05) shorter than those of horses. In contrast, FDP and D-Dimer concentrations were significantly (P < .05) higher in donkeys than in horses.

CONCLUSIONS AND CLINICAL IMPORTANCE

The coagulation parameters most commonly determined in equine practice are different in donkeys compared with horses. Thus, the use of normal reference ranges reported previously for healthy horses in donkeys might lead to a misdiagnosis of coagulopathy in healthy donkeys, and unnecessary treatments in sick donkeys. This is the first report of normal coagulation profile results in donkeys, and further studies are warranted to elucidate the physiological mechanisms of the differences observed between donkeys and horses.

Thrombelastography in horses with acute gastrointestinal disease

BACKGROUND

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.

ANIMALS

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 compared for lesion type, presence of SIRS, complications, and survival.

RESULTS

Changes in individual parameters and increased incidence of coagulopathies were associated with fatality (R, P= .007; k-value [K], P= .004; clot lysis [CL]30, P= .037; CL60, P= .050; angle [Ang], P= .0003; maximum amplitude [MA], P= .006; lysis [Ly]30, P= .042; Ly60, P= .027; CI, P= .0004; ≥ 2 TEG coagulopathies, P= .013; ≥ 3 TEG coagulopathies, P= .038; TF-R, P= .037; TF-K, P= .004; TF-CL30, P < .0001; TF-CL60, P < .0001; TF-Ang, P= .005; TF-Ly30, P= .0002; TF-Ly60, P < .0001; TF-CI, P= .043; ≥ 1 TF-TEG coagulopathies, P= .003; ≥ 2 TF-TEG coagulopathies, P= .0004; prothrombin tme [PT], P < .0001; activated partial throboplastin time [aPTT], P= .021), inflammatory lesions (MA, P= .013; TF-CL30, P= .033; TF-CL60, P= .010; TF-Ly60, P= .011; ≥ 1 TF-TEG coagulopathy, P= .036; ≥ 2 TF-TEG coagulopathy, P= .0007; PT, P= .0005; fibrinogen, P= .019), SIRS (MA, P= .004; TF-CL30, P= .019; TF-CL60, P= .013; TF-Ly30, P= .020; TF-Ly60, P= .010; PT, P < .0001; aPTT, P= .032; disseminated intravascular coagulation, P= .005), and complications (ileus: aPTT, P= .020; diarrhea: TF-CL30, P= .040; TF-Ly30, P= .041; thrombophlebitis: ≥ 1 TF-TEG coagulopathy, P= .018; laminitis: MA, P= .004; CL60, P= .045; CI, P= .036; TF-MA, P= .019; TF-TEG CI, P= .019). Abnormalities in TEG and TF-TEG parameters were indicative of hypocoagulation and hypofibrinolysis.

CONCLUSIONS AND CLINICAL IMPORTANCE

TEG identifies changes in coagulation and fibrinolysis associated with lesion type, SIRS, morbidity, and fatality in horses with gastrointestinal disease.