ACVIM consensus statement on the diagnosis of immune thrombocytopenia in dogs and cats.

Immune thrombocytopenia (ITP) is the most common acquired primary hemostatic disorder in dogs. Immune thrombocytopenia less commonly affects cats but is an important cause of mortality and treatment-associated morbidity in both species. Immune thrombocytopenia remains a diagnosis of exclusion for which diagnostic guidelines are lacking. Primary, or non-associative, ITP refers to autoimmune platelet destruction. Secondary, or associative, ITP arises in response to an underlying disease trigger. However, evidence for which comorbidities serve as ITP triggers has not been systematically evaluated. To identify key diagnostic steps for ITP and important comorbidities associated with secondary ITP, we developed 12 Population Evaluation/Exposure Comparison Outcome (PECO) format questions. These questions were addressed by evidence evaluators utilizing a literature pool of 287 articles identified by the panelists using a structured search strategy. Evidence evaluators, using panel-designed templates and data extraction tools, summarized evidence and created guideline recommendations that then were integrated by diagnosis and comorbidity domain chairs. The revised PECO responses underwent a Delphi survey process to reach consensus on final guidelines. A combination of panel expertise and PECO responses were employed to develop algorithms for diagnosis of ITP in dogs and cats, which also underwent 4 iterations of Delphi review. Comorbidity evidence evaluators employed an integrated measure of evidence (IME) tool to determine evidence quality for each comorbidity; IME values combined with evidence summaries for each comorbidity were integrated to develop ITP screening recommendations, which also were subjected to Delphi review. Commentary was solicited from multiple relevant professional organizations before finalizing the consensus. The final consensus statement provides clinical guidelines for the diagnosis of, and underlying disease screening for, ITP in dogs and cats. The systematic consensus process identified numerous knowledge gaps that should guide future studies. This statement is a companion manuscript to the ACVIM Consensus Statement on the Treatment of Immune Thrombocytopenia.

ACVIM consensus statement on the treatment of immune thrombocytopenia in dogs and cats.

Management of immune thrombocytopenia (ITP) in dogs and cats is evolving, but there are no evidence-based guidelines to assist clinicians with treatment decisions. Likewise, the overall goals for treatment of ITP have not been established. Immunosuppressive doses of glucocorticoids are the first line treatment, but optimal treatment regimens beyond glucocorticoids remain uncertain. Additional options include secondary immunosuppressive drugs such as azathioprine, modified cyclosporine, and mycophenolate mofetil, usually selected based on clinician preference. Vincristine, human IV immunoglobulin (hIVIg), and transfusion of platelet or red blood cell-containing products are often used in more severe cases. Splenectomy and thrombopoietin receptor agonists are usually reserved for refractory cases, but when and in which patient these modalities should be employed is under debate. To develop evidence-based guidelines for individualized treatment of ITP patients, we asked 20 Population Intervention Comparison Outcome (PICO) format questions. These were addressed by 17 evidence evaluators using a literature pool of 288 articles identified by a structured search strategy. Evidence evaluators, using panel-designed templates and data extraction tools, summarized evidence and created guideline recommendations. These were integrated by treatment domain chairs and then refined by iterative Delphi survey review to reach consensus on the final guidelines. In addition, 19 non-PICO questions covering scenarios in which evidence was lacking or of low quality were answered by expert opinion using iterative Delphi surveys with panelist integration and refinement. Commentary was solicited from multiple relevant professional organizations before finalizing the consensus. The rigorous consensus process identified few comparative treatment studies, highlighting many areas of ITP treatment requiring additional studies. This statement is a companion manuscript to the ACVIM Consensus Statement on the Diagnosis of Immune Thrombocytopenia in Dogs and Cats.

Effect of institutional antimicrobial stewardship guidelines on prescription of critically important antimicrobials for dogs and cats.

BACKGROUND: Veterinary hospital antimicrobial stewardship (AMS) guidelines might help combat antimicrobial resistance (AMR). OBJECTIVES: Determine the conditions and types of infection for which antimicrobial drugs (AMDs) deemed critically important (CIA) by the World Health Organization (WHO) were prescribed and assess the effect of hospital AMS guidelines on adherence to International Society for Companion Animal Infectious Diseases published guidelines for the treatment of superficial bacterial folliculitis, respiratory tract disease and urinary tract infection in these cases. ANIMALS: Dogs and cats managed at an academic veterinary hospital from 1/21 to 6/21 and 9/21 to 6/22. METHODS: Prescriptions of cephalosporins (third or fourth generation), glycopeptides, macrolides/ketolides, polymyxins, and quinolones were identified. Data on culture and susceptibility (C/S) testing and previous AMD exposure were collected. Frequencies were compared between time periods using Fisher's exact test with Bonferroni corrections. RESULTS: In animals prescribed ≥1 WHO-CIA AMD, fluoroquinolones were the most frequently prescribed WHO-CIA class in dogs (567/1724, 32.9%) and cats (192/450, 42.7%). No animals were prescribed carbapenems, dihydrofolate reductase inhibitors/sulfonamides, or polymyxins. No cats were prescribed aminoglycosides or amphenicols. Institutional guidelines were followed in 57.8% (324/561) cases. The most frequent causes of nonadherence were failure to perform C/S testing 46.0% (109/237) and unnecessary use of a higher-tier AMD 43.0% (102/237). Bacterial C/S testing was more frequently performed after AMS guideline institution (59.7% vs. 46.8%, P = 0.0006). CONCLUSIONS AND CLINICAL IMPORTANCE: Adherence to published guidelines remained poor despite an increase in C/S testing. There were no changes in the frequencies of confirmed infections, positive cultures or AMD resistance between time periods.

Defining sepsis in small animals.

OBJECTIVE: To discuss the definitions of sepsis in human and veterinary medicine. DESIGN: International, multicenter position statement on the need for consensus definitions of sepsis in veterinary medicine. SETTING: Veterinary private practice and university teaching hospitals. ANIMALS: Dogs and cats. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Sepsis is a life-threatening condition associated with the body's response to an infection. In human medicine, sepsis has been defined by consensus on 3 occasions, most recently in 2016. In veterinary medicine, there is little uniformity in how sepsis is defined and no consensus on how to identify it clinically. Most publications rely on modified criteria derived from the 1991 and 2001 human consensus definitions. There is a divergence between the human and veterinary descriptions of sepsis and no consensus on how to diagnose the syndrome. This impedes research, hampers the translation of pathophysiology insights to the clinic, and limits our abilities to optimize patient care. It may be time to formally define sepsis in veterinary medicine to help the field move forward. In this narrative review, we present a synopsis of prior attempts to define sepsis in human and veterinary medicine, discuss developments in our understanding, and highlight some criticisms and shortcomings of existing schemes. CONCLUSIONS: This review is intended to serve as the foundation of current efforts to establish a consensus definition for sepsis in small animals and ultimately generate evidence-based criteria for its recognition in veterinary clinical practice.

A prospective cohort study to identify clinical diagnostic and prognostic markers of primary immune thrombocytopenia in dogs.

BACKGROUND: Primary immune thrombocytopenia (pITP) in dogs presents a diagnostic challenge, and clinical markers of severity are lacking. OBJECTIVES: Identify clinicopathologic features that differentiate pITP from secondary ITP (sITP) and markers related to bleeding severity, transfusion, and survival of dogs with pITP. ANIMALS: Ninety-eight thrombocytopenic dogs (58 pITP and 40 sITP). METHODS: Client-owned dogs with platelet counts <50 000/µL were enrolled in a prospective, multi-institution cohort study. History and treatment information, through a maximum of 7 days, was recorded on standard data forms. Bleeding severity was scored daily using a bleeding assessment tool (DOGiBAT). At-admission blood samples were collected for CBC, biochemistry, C-reactive protein concentration, and coagulation panels, and to measure platelet surface-associated immunoglobulin G (PSAIg) and expression of platelet membrane proteins and phospholipids. Dogs with evidence of coincident disease were classified as sITP. RESULTS: No definitive pITP diagnostic test was found. However, pITP cases were characterized by lower platelet counts, D dimer concentrations, and platelet membrane protein expression than sITP cases. Differentiation between pITP and sITP was further enhanced using logistic regression modeling combining patient sex, coagulation profile, platelet count, D dimer, and PSAIg. A second model of pITP severity indicated that low hematocrit and high BUN concentration were associated with non-survival. Low hematocrit at admission, but not platelet count or DOGiBAT score, was associated with transfusion. CONCLUSIONS AND CLINICAL IMPORTANCE: Pending validation studies, models constructed from at-admission clinicopathologic findings may improve differentiation of pITP from sITP and identify the most severe pITP cases at the time of presentation.

Prevalence of antibiotic use for dogs and cats in United States veterinary teaching hospitals, August 2020.

BACKGROUND: Awareness of prescribing practices helps identify opportunities to improve antibiotic use (AU). OBJECTIVES: To estimate AU prevalence in dogs and cats in U.S. veterinary teaching hospitals (VTHs) and identify antibiotic drugs commonly prescribed, indications for use, and evidence of bacterial infection. ANIMALS: Medical record data were collected from dogs and cats examined at 14 VTHs. METHODS: Data were collected from VTH medical records of dogs and cats examined by primary care, urgent care, emergency and critical care, internal medicine, and surgery services on a single day during August 13-September 3, 2020. Data included signalment; clinical service; inpatient or outpatient status; clinical conditions; diagnostic tests; evidence of bacterial infection; intended reason for AU; name and route of antibiotics prescribed. RESULTS: Of 883 dogs and cats, 322 (36.5%) were prescribed at least 1 antibiotic. Among 285 antibiotics administered systemically intended for treatment of infection, 10.9% were prescribed without evidence of infection. The most common class of antibiotics presribed for systemic administration was potentiated penicillin for dogs (115/346, 33.3%) and cats (27/80, 33.8%). For dogs and cats, first-generation cephalosporins (93/346, 26.9% and 11/80, 13.8%, respectively) and fluoroquinolones (51/346, 14.7% and 19/80, 23.8%, respectively) was second or third most-prescribed. Common AU indications included skin, respiratory, and urinary conditions, and perioperative use. CONCLUSIONS AND CLINICAL IMPORTANCE: Collaborative data collection provides a sustainable methodology to generate national AU prevalence estimates and bring attention to areas requiring additional research and detailed data collection. These efforts can also identify practice improvement opportunities in settings where future veterinarians are trained.

Increased thrombin activatable fibrinolysis inhibitor activity is associated with hypofibrinolysis in dogs with sepsis.

Introduction: Disorders of coagulation are well-recognized in dogs with sepsis, but data regarding fibrinolysis disorders are limited. We aimed to characterize fibrinolysis in dogs with sepsis compared to healthy controls. We hypothesized that dogs with sepsis would be hypofibrinolytic, and that hypofibrinolysis would be associated with non-survival. Methods: This was a prospective observational cohort study. We enrolled 20 client-owned dogs with sepsis admitted to the Cornell University Hospital for Animals and 20 healthy pet dogs. Coagulation and fibrinolytic pathway proteins including antiplasmin activity (AP), antithrombin activity (AT), thrombin activatable fibrinolysis inhibitor activity (TAFI), D-dimer concentration, fibrinogen concentration, and plasminogen activity were measured and compared between groups. Overall coagulation potential, overall fibrinolysis potential, and overall hemostatic potential were calculated from the curve of fibrin clot formation and lysis over time. Results: Compared to healthy controls, dogs with sepsis had lower AT (P = 0.009), higher AP (P = 0.002), higher TAFI (P = 0.0385), and higher concentrations of fibrinogen (P < 0.0001) and D-dimer (P = 0.0001). Dogs with sepsis also had greater overall coagulation potential (P = 0.003), overall hemostatic potential (P = 0.0015), and lower overall fibrinolysis potential (P = 0.0004). The extent of fibrinolysis was significantly negatively correlated with TAFI. No significant differences were observed between survivors and non-survivors. Discussion: Dogs with sepsis were hypercoagulable and hypofibrinolytic compared to healthy dogs, suggesting potential utility of thromboprophylaxis in this patient population. The association between high TAFI and low overall fibrinolysis potential might provide a potential mechanism for this hypofibrinolysis.

Apolipoprotein A1 and serum amyloid A in dogs with sepsis and septic shock.

Introduction: Apolipoprotein-A1 (Apo-A1) acts as a negative acute phase protein (APP) during inflammatory states, and has a potential prognostic value in people and dogs with sepsis. The aim of this retrospective study was to investigate the association of serum Apo-A1 concentration with disease severity, multiorgan dysfunction syndrome (MODS) and outcome in a population of dogs with sepsis, and to assess its correlation with major canine APPs. Methods: Ninety-nine dogs with uncomplicated sepsis (n = 78) or septic shock (n = 21) were included. The serum concentration of Apo-A1, C-reactive protein (CRP) and serum amyloid A (SAA) were recorded, alongside the canine acute patient physiologic and laboratory evaluation fast (APPLEfast) score and the presence of MODS. Results: Dogs with septic shock had significantly lower serum Apo-A1 concentrations (106.3 ± 22.7 mg/dl; reference interval: 123.0-142.3 mg/dl), higher APPLEfast score (30, 13-38) and greater frequency of MODS (67%) compared to those with uncomplicated sepsis (117.9 ± 19.3 mg/dl; 25, 6-33 and 8%, respectively) (P = 0.0201; P = 0.0005; P < 0.0001, respectively). Similarly, dogs with MODS had significantly lower serum Apo-A1 concentrations (104.1 ± 4.6 mg/dl) and higher APPLEfast score values (31, 13-38) compared to those without MODS (118.32 ± 2.1 mg/dl and 26, 6-33, respectively) (P = 0.0050 and P = 0.0038, respectively). Conversely, neither CRP nor SAA were different between these groups. No difference in serum APPs concentrations was detected between survivors and non-survivors. Significant negative correlations were detected between serum Apo-A1 and SAA (P = 0.0056, r = -0.277), and between serum Apo-A1 and the APPLEfast score (P = 0.0027, r = -0.3). In this population, higher values of the APPLEfast score and the presence of MODS were independently associated with a higher risk of death. Discussion: Our study shows that Apo-A1 is a useful biomarker of sepsis severity in dogs, since it is decreased in those with septic shock and MODS. Further prospective investigations are deemed to evaluate the applicability of Apo-A1 to predict sepsis course and response to treatment in septic dogs.

2022 Update of the Consensus on the Rational Use of Antithrombotics and Thrombolytics in Veterinary Critical Care (CURATIVE) Domain 6: Defining rational use of thrombolytics.

OBJECTIVES: To systematically review available evidence and establish guidelines related to the use of thrombolytics for the management of small animals with suspected or confirmed thrombosis. DESIGN: PICO (Population, Intervention, Control, and Outcome) questions were formulated, and worksheets completed as part of a standardized and systematic literature evaluation. The population of interest included dogs and cats (considered separately) and arterial and venous thrombosis. The interventions assessed were the use of thrombolytics, compared to no thrombolytics, with or without anticoagulants or antiplatelet agents. Specific protocols for recombinant tissue plasminogen activator were also evaluated. Outcomes assessed included efficacy and safety. Relevant articles were categorized according to level of evidence, quality, and as to whether they supported, were neutral to, or opposed the PICO questions. Conclusions from the PICO worksheets were used to draft guidelines, which were subsequently refined via Delphi surveys undertaken by the Consensus on the Rational Use of Antithrombotics and Thrombolytics in Veterinary Critical Care (CURATIVE) working group. RESULTS: Fourteen PICO questions were developed, generating 14 guidelines. The majority of the literature addressing the PICO questions in dogs is experimental studies (level of evidence 3), thus providing insufficient evidence to determine if thrombolysis improves patient-centered outcomes. In cats, literature was more limited and often neutral to the PICO questions, precluding strong evidence-based recommendations for thrombolytic use. Rather, for both species, suggestions are made regarding considerations for when thrombolytic drugs may be considered, the combination of thrombolytics with anticoagulant or antiplatelet drugs, and the choice of thrombolytic agent. CONCLUSIONS: Substantial additional research is needed to address the role of thrombolytics for the treatment of arterial and venous thrombosis in dogs and cats. Clinical trials with patient-centered outcomes will be most valuable for addressing knowledge gaps in the field.

Identifying potential biomarkers and therapeutic targets for dogs with sepsis using metabolomics and lipidomics analyses.

Sepsis is a diagnostic and therapeutic challenge and is associated with morbidity and a high risk of death. Metabolomic and lipidomic profiling in sepsis can identify alterations in metabolism and might provide useful insights into the dysregulated host response to infection, but investigations in dogs are limited. We aimed to use untargeted metabolomics and lipidomics to characterize metabolic pathways in dogs with sepsis to identify therapeutic targets and potential diagnostic and prognostic biomarkers. In this prospective observational cohort study, we examined the plasma metabolomes and lipidomes of 20 healthy control dogs and compared them with those of 21 client-owned dogs with sepsis. Patient data including signalment, physical exam findings, clinicopathologic data and clinical outcome were recorded. Metabolites were identified using an untargeted mass spectrometry approach and pathway analysis identified multiple enriched metabolic pathways including pyruvaldehyde degradation; ketone body metabolism; the glucose-alanine cycle; vitamin-K metabolism; arginine and betaine metabolism; the biosynthesis of various amino acid classes including the aromatic amino acids; branched chain amino acids; and metabolism of glutamine/glutamate and the glycerophospholipid phosphatidylethanolamine. Metabolites were identified with high discriminant abilities between groups which could serve as potential biomarkers of sepsis including 13,14-Dihydro-15-keto Prostaglandin A2; 12(13)-DiHOME (12,13-dihydroxy-9Z-octadecenoic acid); and 9-HpODE (9-Hydroxyoctadecadienoic acid). Metabolites with higher abundance in samples from nonsurvivors than survivors included 3-(2-hydroxyethyl) indole, indoxyl sulfate and xanthurenic acid. Untargeted lipidomic profiling revealed multiple sphingomyelin species (SM(d34:0)+H; SM(d36:0)+H; SM(d34:0)+HCOO; and SM(d34:1D3)+HCOO); lysophosphatidylcholine molecules (LPC(18:2)+H) and lipophosphoserine molecules (LPS(20:4)+H) that were discriminating for dogs with sepsis. These biomarkers could aid in the diagnosis of dogs with sepsis, provide prognostic information, or act as potential therapeutic targets.

Effect of antimicrobial administration on fecal microbiota of critically ill dogs: dynamics of antimicrobial resistance over time.

BACKGROUND: Multidrug resistance in companion animals poses significant risks to animal and human health. Prolonged antimicrobial drug (AMD) treatment in animals is a potential source of selection pressure for antimicrobial resistance (AMR) including in the gastrointestinal microbiota. We performed a prospective study of dogs treated for septic peritonitis, pyometra, or bacterial pneumonia and collected repeated fecal samples over 60 days. Bacterial cultures and direct molecular analyses of fecal samples were performed including targeted resistance gene profiling. RESULTS: Resistant Escherichia coli increased after 1 week of treatment (D1:21.4% vs. D7:67.9% P < 0.001) and returned to baseline proportions by D60 (D7:67.9% vs D60:42.9%, P = 0.04). Dogs with septic peritonitis were hospitalized significantly longer than those with pneumonia or pyometra. Based on genetic analysis, Simpson's diversity index significantly decreased after 1 week of treatment (D1 to D7, P = 0.008), followed by a gradual increase to day 60 (D1 and D60, P = 0.4). Detection of CTX-M was associated with phenotypic resistance to third-generation cephalosporins in E. coli (OR 12.1, 3.3-68.0, P < 0.001). Lincosamide and macrolide-resistance genes were more frequently recovered on days 14 and 28 compared to day 1 (P = 0.002 and P = 0.004 respectively). CONCLUSION: AMR was associated with prescribed drugs but also developed against AMDs not administered during the study. Companion animals may be reservoirs of zoonotic multidrug resistant pathogens, suggesting that veterinary AMD stewardship and surveillance efforts should be prioritized.

2022 Update of the Consensus on the Rational Use of Antithrombotics and Thrombolytics in Veterinary Critical Care (CURATIVE) Domain 1- Defining populations at risk.

OBJECTIVES: To expand the number of conditions and interventions explored for their associations with thrombosis in the veterinary literature and to provide the basis for prescribing recommendations. DESIGN: A population exposure comparison outcome format was used to represent patient, exposure, comparison, and outcome. Population Exposure Comparison Outcome questions were distributed to worksheet authors who performed comprehensive searches, summarized the evidence, and created guideline recommendations that were reviewed by domain chairs. The revised guidelines then underwent the Delphi survey process to reach consensus on the final guidelines. Diseases evaluated in this iteration included heartworm disease (dogs and cats), immune-mediated hemolytic anemia (cats), protein-losing nephropathy (cats), protein-losing enteropathy (dogs and cats), sepsis (cats), hyperadrenocorticism (cats), liver disease (dogs), congenital portosystemic shunts (dogs and cats) and the following interventions: IV catheters (dogs and cats), arterial catheters (dogs and cats), vascular access ports (dogs and cats), extracorporeal circuits (dogs and cats) and transvenous pacemakers (dogs and cats). RESULTS: Of the diseases evaluated in this iteration, a high risk for thrombosis was defined as heartworm disease or protein-losing enteropathy. Low risk for thrombosis was defined as dogs with liver disease, cats with immune-mediated hemolytic anemia, protein-losing nephropathy, sepsis, or hyperadrenocorticism. CONCLUSIONS: Associations with thrombosis are outlined for various conditions and interventions and provide the basis for management recommendations. Numerous knowledge gaps were identified that represent opportunities for future studies.

Serial evaluation of thoracic radiographs and acute phase proteins in dogs with pneumonia.

BACKGROUND: Acute phase proteins (APP) may guide treatment of pneumonia in dogs but correlations with radiographic abnormalities are poorly characterized. OBJECTIVES: Develop a thoracic radiographic severity scoring system (TRSS), assess correlation of radiographic changes with APP concentrations, and compare time to APP and radiograph normalization with duration of antimicrobials treatment. ANIMALS: Sixteen client-owned dogs, 12 with aspiration pneumonia, and 4 with community-acquired pneumonia. METHODS: Concentrations of C-reactive protein (CRP), serum amyloid A (SAA), and haptoglobin were measured on days 1, 3, 7, 14, 28, and 60 and orthogonal 2-view thoracic radiographs were obtained on days 1, 7, 14, 28, and 60. Treatment was clinician-guided and blinded to APP concentrations. Radiographic severity scores were assigned by blinded, randomized retrospective review by 2 board-certified radiologists with arbitration by a third radiologist. RESULTS: Median (interquartile range [IQR]) time to normalization of CRP (7 days [7-14]) and SAA concentrations (7 days [7-14]) were shorter than antimicrobial treatment duration (17.5 days [14.5-33.5]; P = .001 and .002, respectively) and TRSS normalization (14 days [8.8-52], P = .02 and .02, respectively). The CRP and SAA concentrations were positively correlated with TRSS (CRP rs , 0.643; SAA rs , 0.634; both P < .0001). Both CRP and SAA identified normal thoracic radiographs area under the curve (AUC) 0.873 and 0.817, respectively, both P < .0001. Interobserver agreement for TRSS assignment was moderate (κ, .499; P < .0001). CONCLUSION AND CLINICAL IMPORTANCE: Concentrations of CRP and SAA normalized before radiographic resolution and before clinicians discontinued antimicrobial treatment. The CRP and SAA concentrations may guide duration of antimicrobial treatment for dogs with pneumonia.

Clinical features and posttreatment monitoring of dogs administered rivaroxaban (2018-2020): 19 cases.

OBJECTIVE: To describe a population of sick dogs administered rivaroxaban monitored with a rivaroxaban-calibrated anti-Xa activity assay (aXa). DESIGN: Descriptive retrospective study. SETTING: Two veterinary teaching hospitals. ANIMALS: Client-owned dogs administered rivaroxaban and monitored with aXa from January 2018 to January 2020 were eligible for study. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Medical records were reviewed and 19 dogs with a variety of underlying disease processes were identified. Rivaroxaban was administered to 12 of 19 dogs (63%) with confirmed thrombosis, 4 of 19 dogs (21%) with a strong clinical suspicion of thrombosis, and in 3 of 19 dogs (16%) with no current evidence of thrombosis. The median rivaroxaban dose administered was 0.96 mg/kg/day (0.62-1.58 mg/kg/day), with 15 of 19 dogs (79%) receiving rivaroxaban once daily. Clopidogrel was concurrently administered to 11 of 19 dogs (58%). Complete or partial thrombus resolution was identified in 5 of 12 (42%) and 3 of 12 (25%) dogs, respectively. Rivaroxaban appeared safe, with only 1 of 19 dogs (5%), concurrently administered clopidogrel, developing evidence of mild hematuria. Posttreatment monitoring revealed that 8 of 19 dogs (42%) had aXa below the target (aXa range of 150-250 ng/ml associated with effective treatment and prevention of venous thrombosis in people). The remaining 3 to 19 dogs (16%) achieved this range, and 8 of 19 dogs (42%) exceeded the range. No significant relationship between the initial rivaroxaban dose administered and the corresponding aXa result was identified. There were also no significant differences in baseline clinicopathological variables in dogs in which aXa fell within or outside this range. CONCLUSIONS: aXa was most commonly measured in dogs receiving rivaroxaban with confirmed or suspected thrombosis. Dogs in this study received a range of rivaroxaban dosages and attained variable aXa values that were not directly correlated with dosage.

Acute phase protein response and changes in lipoprotein particle size in dogs with systemic inflammatory response syndrome.

BACKGROUND: Improved methodology to measure acute phase proteins and determination of lipoprotein particle-size distribution (PSD) could be clinically useful in dogs with systemic inflammatory processes. OBJECTIVES: Evaluate an immunoturbidometric assay for serum amyloid A (SAA) and lipoprotein PSD in dogs with sepsis, nonseptic systemic inflammation, and in healthy controls. Correlate dyslipidemic changes with SAA and C-reactive protein (CRP) concentrations. ANIMALS: Twenty-five dogs with sepsis, 15 dogs with nonseptic systemic inflammation, and 22 healthy controls. METHODS: Prospective, case-control study. Variables included SAA, CRP, and electrophoretic subfractionation of high- and low-density lipoproteins (HDL, LDL). Continuous variables were compared using ANOVA or Kruskal-Wallis tests with linear regression or Spearman's rank correlation used to assess relationships between variables. RESULTS: Median SAA and CRP concentrations were greater in dogs with sepsis (SAA 460 mg/L, interquartile range [IQR] 886 mg/L; CRP 133.2 mg/L, IQR 91.6 mg/L) and nonseptic inflammation (SAA 201 mg/L, IQR 436 mg/L; CRP 91.1 mg/L, IQR 88.6 mg/L) compared to healthy dogs (SAA 0.0 mg/L, IQR 0.0 mg/L; CRP 4.9 mg/L, IQR 0.0 mg/L) P < .0001. A cutoff of >677.5 mg/L SAA was 43.2% sensitive and 92.3% specific for sepsis. Low-density lipoprotein was higher in dogs with sepsis 29.6%, (mean, SD 14.6) compared to 14.4% (mean, SD 5.6) of all lipoproteins in healthy controls (P = .005). High-density lipoprotein was not associated with CRP but was negatively correlated with SAA (rs -0.47, P < .0001). Subfractions of LDL and HDL differed between groups (all P < .05). CONCLUSIONS AND CLINICAL IMPORTANCE: Measurement of SAA using the immunoturbidometric assay evaluated in this study and lipoprotein PSD in dogs with inflammation might help distinguish septic from nonseptic causes of inflammation.

Preliminary evaluation of a flow cytometric assay with microsphere controls for the detection of platelet-bound antibodies in canine immune thrombocytopenia.

BACKGROUND: Canine immune thrombocytopenia (ITP) ranges from a mild to severe bleeding disorder, and platelet counts do not reliably predict clinical disease course. The detection of platelet autoantibodies may further define the disease phenotype, but variability in assay configurations and a lack of well-characterized controls limit the diagnostic utility of anti-platelet antibody assays. OBJECTIVES: We aimed to develop control reagents to facilitate the characterization of canine platelet surface-associated immunoglobulin (PSAIg) in flow cytometric assays. METHODS: Silica microspheres were coated with canine IgG and IgM to assess the reactivity of goat and rabbit origin anti-canine immunoglobulin reagents. They were also used as positive controls in the PSAIg assay. Preliminary assay evaluation and determination of sample stability used PRP isolated from seven healthy dogs and 26 dogs newly diagnosed with thrombocytopenia. RESULTS: Blood sample stability was established for up to a 48-hour storage time. The conjugated positive control microspheres demonstrated stable fluorescent labeling over a 2-year observation period. Rabbit and goat origin anti-dog IgM fluorescent antibody labels reacted nonspecifically with canine IgG. Rabbit origin anti-dog IgG antibody demonstrated greater class specificity for canine IgG than a goat origin antibody. Thrombocytopenic dogs had a broad range of membrane-bound immunoglobulin. Median PSAIgG for dogs with primary or secondary ITP (18.4%, 34.1%, respectively) were significantly higher than controls (3.8%, P < .05). CONCLUSIONS: The described assay reagents and procedures provide positive controls and allow consistent thresholding to define a positive test result, suitable for any flow cytometer. A rabbit anti-dog IgG fluorescent label demonstrated specificity for canine IgG and was useful for the detection of PSAIgG in thrombocytopenic dogs.

Serial analysis of blood biomarker concentrations in dogs with pneumonia, septic peritonitis, and pyometra.

BACKGROUND: Prolonged antimicrobial drug (AMD) treatment is associated with antimicrobial resistance development. Biomarker measurement may aid treatment decision-making. OBJECTIVES: Investigate temporal changes in blood biomarker concentrations in dogs undergoing treatment for pulmonary and intra-abdominal infections; compare time to biomarker concentration normalization with duration of clinician-directed AMD treatment. ANIMALS: Forty-two client-owned dogs with pneumonia (n = 22), septic peritonitis (n = 10), or pyometra (n = 10). METHODS: Plasma concentrations of C-reactive protein (CRP), serum amyloid A (SAA), haptoglobin, procalcitonin, nucleosomes, cell-free DNA (cfDNA), high-mobility group box-1 (HMGB1), CC-motif chemokine ligand-2 (CCL2), CXC-motif chemokine ligand-8 (CXCL8), and keratinocyte chemoattractant-like (KC-Like) were quantitated in samples collected on days 1, 3, 7, 14, 28, and 60. Treatment was directed by clinicians blinded to biomarker concentrations. RESULTS: Concentrations of CCL2, CRP, and KC-Like were maximal on D1, concentrations of SAA, cfDNA, HMGB1, and nucleosomes were maximal on D3 and haptoglobin concentrations were maximal on D7. These maximal concentrations were significantly different from those on D60. Concentrations of CRP and SAA decreased by 80% from peak and into respective reference intervals before AMDs were discontinued. For CRP, the median (interquartile range [IQR]) times to 20% peak and normal were 7 (6-9) and 7 (6-12) days, respectively, and for SAA they were 4 (4, 5) and 6 (5-8) days, respectively, compared to a median (IQR) duration of AMD prescribing of 16 (12-23) days (all P < .0001). CONCLUSIONS AND CLINICAL IMPORTANCE: Biomarker concentrations normalized within 7 to 14 days. Serial measurements of CRP and SAA might aid identification of disease resolution and could help guide AMD prescription decision-making.

Prospective investigation of factors associated with success on the American College of Veterinary Emergency and Critical Care certification examination (2016-2018).

OBJECTIVE: To assess the association of candidate attributes and residency training factors with success on the American College of Veterinary Emergency and Critical Care (ACVECC) board certification examination and to develop multivariable models of first-attempt success. DESIGN: Prospective survey-based study. SETTING: Post-assessment ACVECC examination candidates. ANIMALS: None. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Comprehensive surveys were distributed to ACVECC examination candidates in 2016 to 2018 after completion of their assessments, but prior to publication of examination results. Unique anonymous candidate identification numbers were used to match survey responses to outcome data from the office of the ACVECC Executive Secretary. After curation to retain only the first response from each candidate, there were 97 unique candidate responses available for analysis. Univariate analyses identified multiple factors associated with first-attempt success and multiple differences between academic and private practice residency programs. Multivariable logistic regression modeling suggested that 5 factors were independently associated with first-attempt success on the ACVECC examination, specifically younger age, more weeks of study prior to the examination, training at a facility with more ACVECC Diplomates, training at a facility with more ACVECC residents, and having no requirement to manage both Emergency Room (ER) and Critical Care (CC) cases simultaneously. CONCLUSIONS: Numerous resident and training center factors are associated with success in the ACVECC board certification examination. Residents and training centers might be able to use these data to enhance training, but caution must be exercised because these data are associative only.

Pharmacokinetics, pharmacodynamics and safety evaluation of 5,5'-methylenebis(2-acetoxybenzoic acid) in dogs following intravenous administration.

Complement-mediated intravascular hemolysis occurs in canine immune-mediated hemolytic anemia (IMHA). Complement inhibitors might enhance treatment of this disease. Dimers of acetylsalicylic acid such as 5,5'-methylenebis(2-acetoxybenzoic acid) (DAS) have been reported to inhibit complement. This study aimed to characterize the pharmacokinetics and safety profile of a single 3 mg/kg IV dose of DAS in 6 healthy mixed-breed dogs. Serum concentrations of DAS and its primary metabolites were measured by liquid chromatography-tandem mass spectrometry at baseline and at 5, 10 and 30 min, and 1, 2, 4, 6, 8, 12, 18 and 24 h post-administration. Additional blood samples were collected 7 and 14 days after drug administration. Complete blood counts, serum chemistry panels, C-reactive protein measurements, coagulation testing and cytokine analyses were used for safety monitoring. Following IV administration of 3 mg/kg DAS, the estimated mean maximum plasma concentration was 54,709 ng/mL. Pharmacokinetic modeling suggested that DAS was eliminated with a half-life value of 8.1 h, equivalent to a clearance of 6.93 L/hr kg and a volume of distribution of 56 mL/kg. Plasma concentrations of the metabolites were measured rapidly (within 15-60 min for M1 and M2 respectively). Overall, the relative exposure to M1 and M2 suggest significant biotransformation of DAS occurred, but DAS was the most abundant circulating species. No adverse clinical reactions were noted following DAS administration and safety studies suggested DAS caused no inflammatory response or coagulation disturbance. Further clinical evaluation of DAS is warranted.

Pharmacokinetics and Biologic Activity of Apixaban in Healthy Dogs.

Thrombosis is common in critically ill dogs and causes considerable morbidity and mortality. The direct factor Xa inhibitor apixaban is safe, efficacious, and convenient in humans. This study aimed to determine the pharmacokinetics (PK), bioactivity, protein binding, and bioavailability of apixaban following intravenous (IV) and oral (PO) administration to healthy dogs. Six healthy, adult, mixed-breed dogs were administered apixaban 0.18 mg/kg IV and then following a minimum 2-week washout period administered apixaban 0.2 mg/kg PO. Dogs were monitored using an apixaban-calibrated anti-Xa bioassay, prothrombin time (PT) and activated partial thromboplastin time (aPTT) and tissue-factor thromboelastography (TF-TEG). Plasma apixaban concentrations were measured using liquid chromatography-tandem mass spectrometry. Concentration-time plots were constructed, and PK modeling performed using compartmental methods. Administration of IV and PO apixaban was well-tolerated. Following IV administration, mean half-life was 4.1 h, and volume of distribution was 177 ml/kg. Apixaban was highly protein bound (98.6%). Apixaban concentrations and anti-Xa activity were highly correlated (R2 0.994, P < 0.0001). Intravenous apixaban significantly prolonged PT at time points up to 1 h, and aPTT at time points up to 0.25 h post-administration. Coagulation times were positively correlated with apixaban concentrations (PT R2 0.599, P < 0.0001; aPTT R2 0.430, P < 0.0001) and TF-TEG R-time was significantly prolonged 0.25 h post-administration. Following oral administration, mean bioavailability was 28.4%, lag time was 2 h, time to Cmax was 5 h and the apparent elimination half-life was 3.1 h. Oral apixaban significantly prolonged PT at 4, 6, and 8 h but aPTT and TF-TEG were not consistently affected by oral apixaban. Apixaban concentrations are best monitored using anti-Xa activity. Future studies should determine PK and bioactivity of other doses using commercial tablets and following multidose administration and establish safe, effective dosing ranges in sick dogs.