Changes in platelet function, hemostasis, and prostaglandin expression after treatment with nonsteroidal anti-inflammatory drugs with various cyclooxygenase selectivities in dogs

Effect of experimentally induced endotoxaemia and meloxicam administration on the haemostatic system in donkeys

BACKGROUND

Endotoxaemia is a common condition in equids, frequently accompanied by alterations in haemostasis. Non-steroidal anti-inflammatory drugs, such as meloxicam, have been proven to alleviate some signs of endotoxaemia in donkeys. Neither the haemostatic response to induced endotoxaemia nor the effect of meloxicam in this regard have been described in donkeys.

OBJECTIVES

(a) To characterise the haemostatic changes in response to induced endotoxaemia in healthy donkeys, and (b) to assess the effect of meloxicam in these animals.

STUDY DESIGN

In vivo experiments.

METHODS

Endotoxaemia was induced by LPS (20 ng/kg) infusion in six healthy adult Andalusian donkeys. All animals randomly received either an IV bolus of saline solution (untreated group) or meloxicam (0.6 mg/kg) after LPS infusion (PLI), with a 1-month washout period between trials. Samples were collected at -30, 0, 30, 60, 90, 120, 180 and 360 min PLI for clotting times, antithrombin III, anti-Xa activities, platelet and fibrinogen concentrations; and at -30, 90, 180 and 360 min PLI for viscoelastography (Sonoclot).

RESULTS

LPS caused prothrombotic-specific viscoelastographic changes (short activated clot time and elongated clot rate formation) and lower antithrombin III activities compared with reference range for this species. Prolonged prothrombin times were also seen at late timepoints in the experiment. Meloxicam administration resulted in no significant differences between groups.

MAIN LIMITATIONS

Short sampling duration, only Andalusian donkeys.

CONCLUSIONS

Acute endotoxaemia induced hypercoagulability and initial signs of a consumptive coagulopathy in donkeys. Despite a more prolonged increase in anti-Xa activity, meloxicam did not ameliorate most of these haemostatic changes.

Postinjection protocols following platelet-rich plasma administration for knee osteoarthritis: A systematic review

OBJECTIVE

Platelet-rich plasma (PRP) use in treating orthopedic conditions has increased, yet evidence of its clinical efficacy is inconsistent and limited by heterogeneity in osteoarthritis (OA) severity, PRP preparations and protocols, and clinical outcome measurement. This review aims to characterize the variations in postinjection protocols in studies assessing the clinical efficacy of PRP for knee OA.

LITERATURE SURVEY

A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A literature search from database inception to February 2023 of CINAHL, MEDLINE, and EMBASE was conducted.

METHODOLOGY

Article screening, data extraction, and risk of bias assessments were completed in duplicate by two reviewers. Primary outcomes were presence/absence and timing of the following postinjection protocol components: nonsteroidal anti-inflammatory drug (NSAID) restrictions, non-NSAID analgesic and cryotherapy use, immediate knee flexion/extension, immediate rest, activity restriction, return-to-activity guidelines, and rehabilitation protocols. A descriptive analysis was used to analyze the data. Given study heterogeneity, a meta-analysis was not performed.

SYNTHESIS

A total of 187 studies were included for analysis. Half of all studies (51.9%) excluded patients due to preinjection NSAID use, most often within 5 days of blood sampling or injection. Postinjection NSAID restriction was included in 42.8% of studies, ranging from 1 to 1800 days. Few studies (19.4%) that permitted non-NSAID analgesia restricted their use prior to clinical assessments. Postinjection immediate flexion, extension, and immobilization were rarely (8.6%) mentioned. Activity restriction was included in a third of studies (35.3%), with the most frequent length of restriction being 1 day. Postinjection return-to-activity protocols were less common (20.3%), usually with a "gradual" and/or "as tolerated" recommendation. A minority of studies (16.0%) reported physical therapy protocols and the vast majority (93.3%) were home based.

CONCLUSION

Significant heterogeneity remains in post-PRP injection protocols, with unclear consensus regarding optimal recommendations and limited rationale for the protocols outlined. Further study is necessary to compare protocols directly and to determine which pre- and postinjection recommendations can result in optimal outcomes.

Pharmacologic Interventions to Immunologic and Immune-Mediated Conditions in Horses

Immunomodulators can stimulate, suppress, or regulate one or many aspects of the immune response. Use of a variety of immunostimulants, immunosuppressors, and anti-inflammatory drugs are described in horses, but the evidence supporting their efficacy is variable. Corticosteroids and nonsteroidal anti-inflammatory drugs are the best characterized immunomodulators in horses, but further study is needed to fully define their ideal dosing protocols and indications and to characterize the efficacy of other immunomodulators in equine medicine.

USE OF VISCOELASTIC COAGULATION TESTING IN MEGACHIROPTERA (PTEROPUS HYPOMELANUS AND PTEROPUS VAMPYRUS) REVEALS HIGH VARIABILITY IN CLOT KINETICS

Megachiroptera is a mammalian suborder that includes old world fruit bats. Common clinical problems among captive Megachiroptera, such as liver disease (e.g., iron storage disease), kidney disease (e.g., protein-losing nephropathy), and heart disease (e.g., dilated cardiomyopathy), carry elevated risk for hemostatic derangements. The assessment of viscoelastic coagulation assays, however, has not yet been reported in bats. The main objective of the study was to describe viscoelastography data using the Viscoelastic Coagulation Monitor (VCM) Vet in captive large flying foxes (Pteropus vampyrus) (n = 20) and variable flying foxes (Pteropus hypomelanus) (n = 10). Additional objectives were to compare viscoelastic and clotting parameters (1) between healthy P. vampyrus and P. hypomelanus bats and (2) between untreated bats and those treated with meloxicam or aspirin, and (3) to examine relationships between activated partial thromboplastin time (aPTT) and potentially homologous viscoelastic parameters clotting time (CT) and clot formation time (CFT). The results showed marked variability among clinically normal bats. The intrinsic pathway, as measured by aPTT, had prolonged times compared with most terrestrial mammals, but similar times to birds, marine mammals, and sea turtles. A search of P. vampyrus genome found stop codons present in two exons of the factor XI gene; alterations in factor XI expression would be expected to alter intrinsic coagulation. Because of the high variability, no statistically significant findings were noted in the secondary objectives. Correlation between aPTT and CT or CFT was not strong (rs = 0.406 or 0.192, respectively). The results from this study suggest that clot kinetics vary widely among Megachiroptera when using the VCM Vet with untreated blood. A prolonged intrinsic coagulation pathway, as has been found in other megachiropteran species, and activation of the extrinsic coagulation pathway during venipuncture may be responsible for the inconsistent results.

Prospective evaluation of platelet function and fibrinolysis in 20 dogs with trauma

OBJECTIVES

To determine platelet function and assess fibrinolysis in dogs following trauma using multiple electrical impedance aggregometry and a modified thromboelastographic (TEG) technique. To determine if the severity of trauma, as assessed by the Animal Trauma Triage (ATT) score and clinicopathological markers of shock, is associated with a greater degree of platelet dysfunction and fibrinolysis.

SETTING

University teaching hospital.

ANIMALS

Twenty client-owned dogs with trauma (occurring <24 h prior to admission and blood sampling) and ATT score of >4 were prospectively recruited. A control group of 10 healthy dogs was included.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Platelet function was measured using multiple electrode platelet aggregometry (MEPA) utilizing arachidonic acid, ADP, and collagen agonists. Fibrinolysis was assessed in citrated whole blood with the addition of tissue plasminogen activator (tPA; 50 U/mL) using kaolin-activated TEG. Conventional statistical analysis was performed to compare coagulation parameters between the groups and assess linear correlations. Median (interquartile range) ATT score was 5 (5-7), and 65% (n = 13) of dogs suffered polytrauma. Mean (± SD) time from trauma to blood sampling was 9 hours (± 6). Median (interquartile range) shock index and plasma lactate concentration were 1.1 (0.7-2.0, n = 16) and 2.9 mmol/L (0.9-16.0, n = 18), respectively. Four dogs did not survive to discharge (20%). There were no differences between the trauma and control group coagulation variables. A moderate negative correlation between ATT score and area under the curve for ADP was found (P = 0.043, r2  = -0.496).

CONCLUSIONS

Preliminary evaluation of platelet function measured by MEPA, and fibrinolysis measured by tPA-modified TEG, is not significantly different in this population of dogs with traumatic injury compared to healthy dogs.

Disconnect between COX-2 selective inhibition and cardiovascular risk in preclinical models

INTRODUCTION

Secondary pharmacology profiling is routinely applied in pharmaceutical drug discovery to investigate the pharmaceutical effects of a drug at molecular targets distinct from (off-target) the intended therapeutic molecular target (on-target). Data from a randomized, placebo-controlled clinical trial, the APPROVe (Adenomatous Polyp Prevention on VIOXX, rofecoxib) trial, raised significant concerns about COX-2 inhibition as a primary or secondary target, shaping the screening and decision-making processes of some pharmaceutical companies. COX-2 is often included in off-target screens due to cardiovascular (CV) safety concerns about secondary interactions with this target. Several potential mechanisms of COX-2-mediated myocardial infarctions have been considered including, effects on platelet stickiness/aggregation, vasal tone and blood pressure, and endothelial cell activation. In the present study, we focused on each of these mechanisms as potential effects of COX-2 inhibitors, to find evidence of mechanism using various in vitro and in vivo preclinical models.

METHODS

Compounds tested in the study, with a range of COX-2 selectivity, included rofecoxib, celecoxib, etodolac, and meloxicam. Compounds were screened for inhibition of COX-2 vs COX-1 enzymatic activity, ex vivo platelet aggregation (using whole blood from multiple species), ex vivo canine femoral vascular ring model, in vitro human endothelial cell activation (with and without COX-2 induction), and in vivo cardiovascular assessment (anesthetized dog).

RESULTS

The COX-2 binding assessment generally confirmed the COX-2 selectivity previously reported. COX-2 inhibitors did not have effects on platelet function (spontaneous aggregation or inhibition of aggregation), cardiovascular parameters (mean arterial pressure, heart rate, and left ventricular contractility), or endothelial cell activation. However, rofecoxib uniquely produced an endothelial mediated constriction response in canine femoral arteries.

CONCLUSION

Our data suggest that rofecoxib-related cardiovascular events in humans are not predicted by COX-2 potency or selectivity. In addition, the vascular ring model suggested possible adverse cardiovascular effects by COX-2 inhibitors, although these effects were not seen in vivo studies. These results may also suggest that COX-2 inhibition alone is not responsible for rofecoxib-mediated adverse cardiovascular outcomes.

Effectiveness of aspirin vs. clopidogrel in dogs with immune mediated haemolytic anaemia evaluated by serial thromboelastography and platelet mapping

Most dogs with immune mediated haemolytic anaemia (IMHA) are hypercoagulable, as measured by thromboelastography (TEG). Thromboelastography-platelet mapping (TEG-PM) has been used to assess platelet function in human patients treated with aspirin or clopidogrel. The aim of this study was to compare platelet thromboxane A₂-receptor inhibition (TXA_2-RI) and platelet adenosine diphosphate (ADP)-receptor inhibition (ADP-RI) as measured by TEG-PM in dogs with primary IMHA receiving aspirin or clopidogrel to determine if TEG-PM might be useful to monitor treatment. Eighteen client-owned dogs with IMHA were enroled in a prospective double blinded study. Dogs were randomised to receive aspirin or clopidogrel in addition to standard therapy. Thromboelastography was measured before, and 1 and 4 days after commencing treatment. Thromboelastography-PM was performed on days 1 and 4. Non-responders were defined as < 50 % platelet thromboxane A₂-receptor inhibition (TXA_2-RI) in the aspirin group and < 50 % platelet adenosine diphosphate (ADP)-receptor inhibition (ADP-RI) in the clopidogrel group, on day 4. Mean platelet TXA₂-RI and platelet ADP-RI were not significantly different between groups at any timepoint (P > 0.05). The overall mean percentage inhibition of TXA₂-receptor was 25 % (aspirin 33 %, clopidogrel 15 %), and of ADP-receptor was 82 % (aspirin 83 %, clopidogrel 80 %). On day 4, 6/9 dogs (66 %) in the aspirin group and 2/8 dogs (25 %) in the clopidogrel group were non-responders (P = 0.086). Two dogs defined as responders based on TEG-PM developed thromboembolism. Overall, there was no significant difference in efficacy between aspirin and clopidogrel based on measurement of receptor inhibition using TEG-PM (P > 0.05), and routine TEG was not reliable for monitoring treatment response in dogs with IMHA. In some dogs, there was a discrepancy between TEG-PM results and clinical response. Further investigation of TEG-PM use in dogs, including its usefulness to monitor treatment response and adjust treatment in individual dogs and any effect of anaemia, is warranted.

Correlation Between D-Dimer Concentrations and Thromboelastography in Dogs With Critical Illness: A Retrospective, Cross-Sectional Study

A hospital-based, retrospective, cross-sectional study was performed to assess the correlation of kaolin-activated thromboelastography (TEG) with D-dimer concentrations in 59 dogs with critical illness. Dogs were included if they had one or more serious disease detected upon performing TEG and D-dimer concentration determination based on the same blood sample. According to the coagulation index (CI), the 59 dogs were divided into two groups: a hypercoagulable state, with CI > 4 (44 dogs) and a normocoagulable state, with CI < 4 (15 dogs). Moreover, the 44 dogs with CI > 4 were divided into three sub-groups according to the disease etiology, i.e., inflammatory/tumor (I/T: 25 dogs), hemodynamic compromise (H: 11 dogs), and both conditions (I/TH: 8 dogs). The median values (interquartile ranges) of the CI and D-dimer concentration were 5.46 (4.55–6.33) and 410.25 (74.63–2206.12) in the 44 dogs with CI > 4 and 3.29 (2.92–3.75) and 1164.7 (50–2250.05) in the 15 dogs with CI < 4, respectively. The D-dimer concentration was significantly increased over the reference value in the 44 dogs with a CI > 4, particularly in dogs in the I/T group. It was also significantly increased in the 15 dogs with a CI < 4. D-dimer concentrations did not correlate with any of the TEG parameters in any of the dogs. Given this lack of correlation, the D-dimer concentration may be limited as an indicator of a possible hypercoagulable state in dogs with critical illness.

Whole blood platelet impedance aggregometry with the ROTEM platelet device: comparison of 2 anticoagulants and storage times for the establishment of canine reference intervals

The ROTEM platelet device, a point-of-care whole blood platelet impedance aggregometer, is an add-on to the rotational thromboelastometry ROTEM delta device. The latter has been validated in dogs. We examined whether canine whole blood is suited for analysis with the ROTEM platelet device using adenosine-5'-diphosphate (ADP) and arachidonic acid (ARA) as agonists for platelet activation, and if there are significant differences between sample storage times and anticoagulants used. Subsequently, we determined canine reference intervals (RIs) for the ROTEM platelet device for ADP and ARA. In a pilot study, we examined whole blood from 7 dogs after 15-min and 60-min storage of lithium-heparinized samples and 40-min and 80-min storage of hirudinized samples. Statistical analysis showed no significant differences between ROTEM platelet device results for both ADP and ARA in lithium-heparin and hirudin anticoagulated canine whole blood. Lithium-heparinized blood samples analyzed after 15-min storage had the lowest coefficient of variation. RIs were determined for heparinized whole blood samples from 49 dogs after 15 min of storage.

The use of impedance aggregometry to evaluate platelet function after the administration of DDAVP in healthy dogs treated with aspirin or clopidogrel

OBJECTIVE

To evaluate the effect of 1-Desamino-8-d-arginine vasopressin (DDAVP; desmopressin acetate) on platelet aggregation in healthy dogs receiving aspirin or clopidogrel.

ANIMALS

7 healthy staff-owned dogs.

PROCEDURES

In this randomized double-blinded crossover study, impedance aggregometry was performed on samples of lithium-heparinized whole blood samples from dogs before (T0) treatment with aspirin (1 mg/kg, PO, q 24 h for 4 days; ASP group) or clopidogrel (1 mg/kg, PO, q 24 h for 4 days; CLP group) and then before (T1) and after (T2) treatment with DDAVP (0.3 μg/kg, IV, once). There was a 14-day washout period before the crossover component. Aggregometry was performed with 4 different assays, each of which involved a different agonist reagent to stimulate platelet function: ADP, thrombin receptor activating peptide-6, arachidonic acid, or collagen type 1.

RESULTS

Median results for platelet aggregometry with agonist reagents ADP, arachidonic acid, or thrombin receptor activating peptide-6 significantly decreased between T0 and T1 for the CLP group; however, no meaningful difference in platelet aggregation was detected in the ASP group. Results for platelet aggregometry did not differ substantially between T1 and T2 regardless of treatment group or assay.

CONCLUSIONS AND CLINICAL RELEVANCE

Findings suggested that administration of DDAVP may have no effect on platelet aggregation (measured with platelet aggregometry) in healthy dogs treated with clopidogrel. Because no inhibition of platelet aggregation was detected for dogs in the ASP group, no conclusion could be made regarding the effects of DDAVP administered to dogs treated with aspirin.

The prevalence of intra-tumoral and distant thrombi, as well as tumour-cell emboli in canine neoplasia

Macroscopic thromboembolic disease has been associated with canine neoplasia, whereas prevalence studies of concurrent microthrombi and tumour-cell emboli are lacking. This retrospective study investigated microthrombi and tumour cell emboli by reviewing pathology records of dogs diagnosed with lymphoma, sarcoma, carcinoma and mast cell tumours with a concurrent description of thrombi or emboli. Pathology reports and medical records of cases with either tumour biopsies and/or post mortems with a diagnosis of neoplasia were reviewed for the presence of microthrombi, macrothrombi and/or tumour-cell emboli and the association with tumour type. Of the 28 895 canine cases in the database, 21 252 (73.5%) were antemortem biopsy specimens and 7643 were post mortems (26.5%); 2274 solid tumours were identified, 2107 (92.7%) were antemortem biopsy diagnoses and 167 (7.3%) were post mortem diagnoses. The prevalence of solid tumour types in the database (28 895 cases) was 872 (3.0%) lymphoma, 722 (2.5%) sarcoma, 455 (1.6%) carcinoma and 225 (0.8%) mast cell tumour. The prevalence of microthrombi associated with these tumours was 58/2274 (2.6%). Intra-tumoral microthrombi were reported in 53/2274 (2.3%) cases, the majority in sarcomas (37/53, 69.8%). No macrothrombi were reported. Tumour-cell emboli were identified in 39/2274 (1.7%) cases, 31/39 (79.5%) were extra-tumoral or distant emboli, and carcinoma the most commonly associated tumour (29/39; 74.4%). Microthrombi were reported in 2.6% of cases, the majority in sarcomas and tumour-cell emboli were identified in 1.7% of cases, the majority carcinomas. Prospective investigations are necessary to explore the potential clinical and prognostic implications of microthrombi and tumour-cell emboli in canine neoplasia.

SAFETY OF MULTIPLE-DOSE INTRAMUSCULAR KETOPROFEN TREATMENT IN LOGGERHEAD TURTLES (CARETTA CARETTA)

Sea turtles are frequently presented for rehabilitation with injuries for which analgesic treatment is warranted. Ketoprofen is a nonsteroidal anti-inflammatory drug (NSAID) widely used in clinical veterinary medicine for musculoskeletal pain relief. Pharmacokinetics of 2 mg/kg IM have been studied in loggerhead sea turtles (Caretta caretta) as a single and a repeated dose q24hr for 3 days. Safety of longer term administration has not been performed, however, and NSAID use carries a risk of potential complications, including gastrointestinal ulceration, kidney damage, and bleeding. The objective of the current study was to determine the effects of a 5-day course of ketoprofen on thromboelastography (TEG) and hematological (including thrombocytes) and plasma biochemical analytes in loggerheads. A secondary objective was to determine 24-hr trough concentrations of ketoprofen after 5 days of treatment. Eight loggerheads were treated with ketoprofen 2 mg/kg IM q24hr for 5 days, and TEG, hematology, and plasma biochemistry panels were performed before and at the conclusion of treatment. Eight controls were treated with an equivalent volume of saline intramuscularly. Virtually no changes were detected before and after treatment or between treatment and control groups in any of the 24 endpoints evaluated, and marginal differences were not considered clinically relevant. Plasma ketoprofen concentrations after 5 days of treatment indicated no accumulation over that duration. Ketoprofen at 2 mg/kg IM q24hr for up to 5 days in loggerheads appears safe with respect to blood clotting and blood data, although other potential effects were not evaluated.

Analgesia for Sheep in Commercial Production: Where to Next?

Simple Summary

Increasing societal and customer pressure to provide animals with ‘a life worth living’ continues to apply pressure on industry to alleviate pain associated with husbandry practices, injury and illness. Although a number of analgesic solutions are now available for sheep, providing some amelioration of the acute pain responses, this review has highlighted a number of potential areas for further research.

Abstract

Increasing societal and customer pressure to provide animals with ‘a life worth living’ continues to apply pressure on livestock production industries to alleviate pain associated with husbandry practices, injury and illness. Over the past 15–20 years, there has been considerable research effort to understand and develop mitigation strategies for painful husbandry procedures in sheep, leading to the successful launch of analgesic approaches specific to sheep in a number of countries. However, even with multi-modal approaches to analgesia, using both local anaesthetic and non-steroidal anti-inflammatory drugs (NSAID), pain is not obliterated, and the challenge of pain mitigation and phasing out of painful husbandry practices remains. It is timely to review and reflect on progress to date in order to strategically focus on the most important challenges, and the avenues which offer the greatest potential to be incorporated into industry practice in a process of continuous improvement. A structured, systematic literature search was carried out, incorporating peer-reviewed scientific literature in the period 2000–2019. An enormous volume of research is underway, testament to the fact that we have not solved the pain and analgesia challenge for any species, including our own. This review has highlighted a number of potential areas for further research.

A prospective randomized open-label trial on the comparative effects of 6% hydroxyethyl starch 130/0.4 versus polyionic isotonic crystalloids on coagulation parameters in dogs with spontaneous hemoperitoneum

OBJECTIVE

To evaluate the effects of 6% hydroxyethyl starch 130/0.4 (HES) and a polyionic isotonic crystalloid (CRYS) on standard coagulation tests and rotational thromboelastometry (ROTEM) in dogs with spontaneous hemoperitoneum (SHP).

DESIGN

Prospective randomized open-label clinical study.

SETTING

University teaching hospital.

ANIMALS

Forty-two client-owned dogs presented with SHP.

INTERVENTIONS

Dogs diagnosed with SHP and hypovolemic shock were randomly allocated to receive HES (10 mL/kg, n = 22) or CRYS (30 mL/kg, n = 20) intravenously over 20 minutes for hemodynamic stabilization.

MEASUREMENTS AND MAIN RESULTS

Parameters measured before (T₀ ) and after (T₁ ) treatment were HCT, platelet counts, prothrombin time, activated partial thromboplastin time, fibrinogen concentrations, and extrinsic activated (EXTEM), intrinsic activated (INTEM), and extrinsic activated with platelet inhibition ROTEM assays. Data were analyzed as absolute values and as the percentage change from T₀ to T₁ . No significant differences between groups were detected in any variable at T₀ , and for HCT, platelet counts, prothrombin time, activated thromboplastin time, and fibrinogen concentrations at T₁ . Clot formation time in EXTEM was significantly prolonged (P = 0.037), and maximum clot firmness was significantly decreased (P = 0.038) in the HES group compared to the CRYS group at T₁ . The percentage change in EXTEM clotting time (P = 0.012) and INTEM clot formation time (P = 0.031) was greater after HES than CRYS. Lysis indices remained at 100% for all ROTEM assays in both groups.

CONCLUSION

Compared to a 3-fold volume of CRYS, administration of HES was associated with impairment in ROTEM parameters in dogs with SHP, but no evidence of hyperfibrinolysis was detected.

Autologous Platelet-Rich Plasma Enhances the Healing of Large Cutaneous Wounds in Dogs

Platelet-rich plasma (PRP) is known to play a crucial role in skin wound healing, in both Human and Veterinary Medicine. Remarkably, until now, no studies have reported PRP treatment in subacute full-thickness skin wounds of the dog. The aim of this study was to evaluate the effects of two consecutive applications of autologous PRP, with the second application after 15 days, in 6 dogs showing large subacute skin wounds. The percentage of contraction, re-epithelialization and healing in all treated patients indicated that no complications or side effects, associated with consecutive PRP treatments, occurred in any patient and all wounds achieved complete closure and re-epithelialization. Our results suggest a positive effect of repeated autologous topical PRP treatments in large cutaneous subacute wounds of different etiology. Therefore, this PRP treatment could represent a simple, cost-effective, and valid alternative to promote healing processes in subacute large wounds cases in dogs.

Post-Procedure Protocols Following Platelet-Rich Plasma Injections for Tendinopathy: A Systematic Review

OBJECTIVE

Platelet-rich plasma (PRP) has been increasingly studied as a treatment for tendinopathy. Many factors may influence outcomes after PRP, including different protocols following administration. It was hypothesized that there would be heterogeneity in post-PRP protocols.

LITERATURE SURVEY

A systematized review of the literature on post-PRP protocols for tendinopathy was conducted using an electronic search of MEDLINE and Embase databases through September 2018.

METHODOLOGY

After duplicates were removed, English language articles involving adult patients who received PRP for tendinopathy were reviewed. Exclusion criteria included studies with fewer than 10 patients, PRP used to treat pathology other than tendinopathy, multiple protocols in one study, and surgical settings. Protocol specifics were extracted including nonsteroidal anti-inflammatory drugs (NSAID) restrictions before and after injection, postinjection restrictions on movement and weight bearing, use of orthoses, activity modifications, and postinjection rehabilitation protocols. Given limitations in the data, a meta-analysis was not performed.

SYNTHESIS

Eighty-four studies met inclusion criteria. Following PRP injection, weight-bearing restrictions were mentioned rarely (12% of protocols). Orthosis use was uncommon overall (18%) but more common in Achilles tendinopathy protocols (53%). The majority of protocols instituted a period of stretching (51%) and strengthening (54%). Stretching programs generally began 2-7 days following injection, and strengthening programs began within 2-3 weeks. Preinjection NSAID restriction was reported rarely (20%), whereas postinjection NSAID restriction was more common (56%), with a typical restriction of greater than 2 weeks (38%). Return to play or full activity was reported in 42% of protocols, most commonly at 4-6 weeks following injection.

CONCLUSION

Although the clinical effectiveness of PRP remains controversial, even less is known about the effect of post-PRP protocols, which may affect the outcomes attributed to PRP itself. No studies directly compare post-PRP protocols, and the protocols studied demonstrate substantial heterogeneity. Some consensus regarding post-PRP protocols exists, although the rationale for these recommendations is limited.

A complete cross-over design evaluating canine acceptance of Carprieve® and Rimadyl® carprofen chewable tablets in healthy dogs

Background

Osteoarthritis (OA) affects nearly 20% of all dogs greater than one year of age. Clinical signs include pain, discomfort, lameness, and ultimately lead to disability. Although there is currently no known cure, there are many therapeutic options that can slow the progression and alleviate the associated signs. There is ample supportive evidence demonstrating the efficaciousness of carprofen, a non-steroidal anti-inflammatory drug, in managing signs of OA. Since the approval of the pioneer product (Rimadyl®, Zoetis; Kalamazoo, Michigan), the United States Food and Drug Administration (FDA) has assented to several other generic, bioequivalent products. The objective of this 2 × 2 complete cross-over design was to assess the acceptance of two bioequivalent carprofen liver-flavored chewable tablets (containing 25 mg carprofen), Rimadyl® and Carprieve® (Norbrook Laboratories Limited; Newry, Northern Ireland) in 37 healthy purpose-bred dogs.

Results

Overall, 73.0% (27/37) and 70.3% (26/37) of dogs voluntarily accepted Rimadyl® and Carprieve®, respectively. Considering acceptability tests paired by individual dog, 64.9% of dogs (n = 24) voluntarily accepted both Rimadyl® and Carprieve® chewable tablets whereas 21.6% (8) of dogs denied or partially accepted both products offered. Three dogs (8.1%) fully accepted Rimadyl® but did not accept Carprieve®. Conversely, two dogs (5.4%) fully accepted Carprieve® but did not accept Rimadyl®. Canine acceptability did not significantly differ between Carprieve® and Rimadyl® carprofen chewable tablets (P = 0.65).

Conclusions

Utilizing a 2 × 2 complete cross-over design, this study provides evidence that canine acceptability of a single-dose did not differ between Carprieve® and Rimadyl® chewable tablets.

Antiinflammatory Drugs

This article reviews the mechanisms of action, clinical use, and recent scientific evidence for the use of nonsteroidal antiinflammatory drugs, grapiprant, acetaminophen (paracetamol), metamizole (dipyrone), and corticosteroids in pain management. The discussion is presented with an emphasis on the treatment of acute pain.

Correlation of rotational thromboelastometry (ROTEM) parameters with platelet count and their ability to predict thrombocytopenia in dogs

The study objectivs were to evaluate the correlation between platelet count (PLT) and rotational thromboelastometry (ROTEM) parameters and to determine ROTEM cut-off values for identification of thrombocytopenia in dogs. Medical records of 113 dogs with concurrent EXTEM (ROTEM activated by proprietary tissue factor), FIBTEM (EXTEM with added cytochalasin D) analysis and PLT were retrospectively reviewed. Signalment, treatment prior to analysis, hematocrit (HCT), EXTEM/FIBTEM maximum clot firmness (MCF_EXTEM, MCF_FIBTEM), EXTEM/FIBTEM maximum clot elasticity (MCE_EXTEM, MCE_FIBTEM) and EXTEM maximum lysis (ML_EXTEM) were extracted from patient records and ROTEM database. Delta (Δ) MCF was calculated as MCF_EXTEM-MCF_FIBTEM and ΔMCE as MCE_EXTEM-MCE_FIBTEM. The PLT was correlated to MCF_EXTEM, MCE_EXTEM, ΔMCF and ΔMCE using Spearman-Rho analysis. Correlations were further analyzed in thrombocytopenic dogs. The ability to predict thrombocytopenia was evaluated with receiver operating characteristics (ROC). Thirty-seven samples (32.7%) showed thrombocytopenia (<130 × 10⁹/L) and 19 samples (17%) severe thrombocytopenia (<60* x 10⁹/L). The PLT significantly correlated with MCF_EXTEM (r = 0.545, P < .001), MCE_EXTEM (r = 0.547, P < .001), ΔMCF (r = 0.441, P < .001) and ΔMCE (r = 0.559, P < .001). MCF_EXTEM < 49 mm, MCE_EXTEM < 93, ΔMCF <42 mm and ΔMCE <90 predicted thrombocytopenia <60 × 10⁹/L with a sensitivity of 90% and a specificity of 78% with a negative predictive value >97% for all 4 parameters. In conclusion, PLT in dogs correlated moderately but significantly with all evaluated ROTEM parameters. All parameters were able to rule out thrombocytopenia <60 × 10⁹/L with a high negative predictive value, while the sensitivity to predict thrombocytopenia was only moderate and the positive predictive value was low.

ACVIM consensus statement on the treatment of immune-mediated hemolytic anemia in dogs

Immune‐mediated hemolytic anemia (IMHA) causes severe anemia in dogs and is associated with considerable morbidity and mortality. Treatment with various immunosuppressive and antithrombotic drugs has been described anecdotally and in previous studies, but little consensus exists among veterinarians as to the optimal regimen to employ and maintain after diagnosis of the disease. To address this inconsistency and provide evidence‐based guidelines for treatment of IMHA in dogs, we identified and extracted data from studies published in the veterinary literature. We developed a novel tool for evaluation of evidence quality, using it to assess study design, diagnostic criteria, explanation of treatment regimens, and validity of statistical methods. In combination with our clinical experience and comparable guidelines for humans afflicted with autoimmune hemolytic anemia, we used the conclusions of this process to make a set of clinical recommendations regarding treatment of IMHA in dogs, which we refined subsequently by conducting several iterations of Delphi review. Additionally, we considered emerging treatments for IMHA in dogs and highlighted areas deserving of future research. Comments were solicited from several professional bodies to maximize clinical applicability before the recommendations were submitted for publication. The resulting document is intended to provide clinical guidelines for management of IMHA in dogs. These guidelines should be implemented pragmatically, with consideration of animal, owner, and veterinary factors that may vary among cases.

Use of therapeutic plasma exchange to treat nonsteroidal anti-inflammatory drug overdose in dogs

Background

Therapeutic plasma exchange (TPE) may be an effective technique for treatment of accidental nonsteroidal anti‐inflammatory drug (NSAID) overdose, but information regarding the use of this technique in veterinary medicine is currently limited.

Objectives

To evaluate the overall outcome for dogs with NSAID overdose treated with TPE and to determine if any presenting factors can predict or influence overall outcome. Secondary objectives included investigating TPE complications as well as the utility of other adjunctive treatments.

Animals

Eleven client‐owned dogs presented for NSAID overdose that received TPE. All patients also received additional supportive treatment including IV lipid infusion.

Methods

Retrospective review of medical records.

Results

Eleven cases were included in the study. Of these, the NSAID ingested was ibuprofen in 6 (54.5%), naproxen in 4 (36.4%), and deracoxib in 1 (9.1%). All dogs survived to discharge with 3 (27.3%) developing acute kidney injury during hospitalization. A larger initial dose of NSAID ingested was associated with a higher maximum serum creatinine concentration during hospitalization (P = .04) and larger change in serum creatinine concentration from baseline (P = .02). Six dogs (54.5%) developed complications associated with TPE. The use of other treatments did not affect the overall outcome.

Conclusions and Clinical Importance

We identified TPE as an effective treatment for NSAID overdose with good outcomes despite high doses of NSAID ingestion in dogs treated with a single TPE treatment. Complications were common but did not affect the final outcome. Therapeutic plasma exchange should be considered in patients presenting for high‐dose NSAID ingestion.

Bronchoalveolar lavage hemosiderosis in dogs and cats with respiratory disease

BACKGROUND

Hemosiderophages can be found in bronchoalveolar lavage samples and have been reported in association with a wide range of respiratory and cardiovascular disorders in cats and humans.

OBJECTIVES

This study aimed to retrospectively evaluate the presence of hemosiderin in canine and feline bronchoalveolar lavage (BAL) samples. It also aimed to examine the association of BAL hemosiderin with signalment, clinical signs, and historical disease prior to BAL, with prior transthoracic fine-needle aspiration (FNA), with bronchoalveolar lavage duration, and with cytologic interpretation.

METHODS

The medical records of dogs and cats with respiratory disease that underwent BAL between 2007 and 2016 were reviewed. Appropriate medical information and BAL results were available from 171 dogs and 34 cats. Cases were assigned to four disease categories based on BAL cytologic findings: pneumonia, inflammatory disease, neoplasia, or normal airways. The degree of hemosiderosis was classified based on a semi-quantitative scoring scale. Exact logistic regression analysis was used to evaluate the relationship between risk factors and the presence of BAL hemosiderosis on cytology.

RESULTS

Hemosiderin was identified in 13/171 (7.6%) canine samples and 18/34 (52.9%) feline samples. Cats were 13.33 times more likely to have pulmonary hemosiderosis on bronchoalveolar lavage cytology compared with dogs (P < 0.001). Increased respiratory rates, prolonged bronchoalveolar lavage times, concurrent transthoracic FNAs, and cytologic diagnoses were associated with an increased risk of hemosiderosis in dogs. No specific risk factors associated with pulmonary hemosiderosis in cats were identified.

CONCLUSIONS

Hemosiderosis is more common in BAL samples from cats than from dogs and is associated with a diverse range of disease conditions.

Thrombin-antithrombin complex measurement using a point-of-care testing device for diagnosis of disseminated intravascular coagulation in dogs

Reference interval for thrombin-antithrombin complex (TAT) level was determined using an in-house TAT measurement device, and its validity for diagnosis of disseminated intravascular coagulation (DIC) was evaluated in dogs. One hundred and two clinically healthy dogs and 247 diseased dogs with conditions that potentially caused DIC were recruited in the study. Six diagnostic testing for DIC were evaluated in diseased dogs and the diseased dogs were categorized into five groups depending on abnormal findings. TAT was measured in all study animals and between-group differences were evaluated. TAT level was positively associated with severity of DIC. There were no significant differences in TAT levels among clinically healthy dogs, diseased dogs without any abnormal finding and diseased dogs with one abnormal finding in the DIC diagnostic testing. TAT levels in groups with two or more abnormal findings were significantly higher than clinically healthy dogs. Reference interval of TAT level for clinically healthy dogs was ≤ 0.25 ng/ml. Validity of using TAT for early detection of DIC was evaluated. In-house TAT measurement was suggested to be a clinically relevant and useful tool for early detection of canine DIC.

Use of a Cyclooxygenase-2 Inhibitor Does Not Inhibit Platelet Activation or Growth Factor Release From Platelet-Rich Plasma

BACKGROUND

It remains unestablished whether use of cyclooxygenase (COX)-2 inhibitors impairs platelet activation and anabolic growth factor release from platelets in platelet-rich plasma (PRP).

PURPOSE

The purpose of this study was to assess the effects of a COX-2 inhibitor on platelet activation and anabolic growth factor release from canine PRP when using a clinically applicable PRP activator and to determine whether a 3-day washout would be sufficient to abrogate any COX-2 inhibitor-related impairment on platelet function.

STUDY DESIGN

Controlled laboratory study.

METHODS

Ten healthy dogs underwent blood collection and PRP preparation. Dogs were then administered a COX-2 inhibitor for 7 days, after which PRP preparation was repeated. The COX-2 inhibitor was continued for 4 more days and PRP preparation performed a third time, 3 days after discontinuation of the COX-2 inhibitor. Immediately after PRP preparation, the PRP was divided into 4 aliquots: 2 unactivated and 2 activated using human γ-thrombin (HGT). One activated and 1 unactivated sample were assessed using flow cytometry for platelet expression of CD62P and platelet-bound fibrinogen using the canine activated platelet-1 (CAP1) antibody. The 2 remaining samples were centrifuged and the supernatant assayed for transforming growth factor-β1 (TGF-β1), platelet-derived growth factor-BB (PDGF-BB), and thromboxane B2 (TXB2) concentrations. Differences in platelet activation and TGF-β1, PDGF-BB, and TXB2 concentrations over the 3 study weeks were evaluated using a 1-way repeated-measures ANOVA, and comparisons between activated and unactivated samples within a study week were assessed with paired t tests.

RESULTS

There were no statistically significant ( P > .05) effects of the COX-2 inhibitor on percentage of platelets positive for CD62P or CAP1 or on concentrations of TGF-β1, PDGF-BB, or TXB2. All unactivated samples had low levels of activation or growth factor concentrations and significantly ( P < .05) greater activation and growth factor concentrations in HGT-activated samples.

CONCLUSION

This COX-2 inhibitor did not impair platelet activation, growth factor release, or TXB2 production in this canine PRP when using HGT as an activator. Studies are warranted to determine whether COX-2 inhibitors affect platelet activation and growth factor release from human PRPs.

CLINICAL RELEVANCE

These results suggest that there is no need to withhold a COX-2 inhibitor before PRP preparation, particularly if thrombin is going to be used to activate the PRP. This is clinically relevant information because many patients who are candidates for PRP therapy for treatment of musculoskeletal injury are also using COX-2 inhibitors.

Prevalence of and risk factors for intraoperative gastroesophageal reflux and postanesthetic vomiting and diarrhea in dogs undergoing general anesthesia

OBJECTIVE

To determine the prevalence of intraoperative gastroesophageal reflux (GER) and postanesthetic vomiting and diarrhea, and to evaluate risk factors associated with these gastrointestinal disorders (GID) in dogs undergoing general anesthesia.

DESIGN

Prospective observational study.

SETTING

University teaching hospital.

ANIMALS

Two hundred thirty-seven client-owned dogs undergoing general inhalant anesthesia for diagnostic or surgical purposes.

INTERVENTIONS

None MEASUREMENTS AND MAIN RESULTS: Patient, surgical, and anesthetic variables, and postanesthetic treatments administered in the immediate postanesthesia period were evaluated in relation to GID using univariate and multivariate logistic regression analysis (P < 0.05). Seventy-nine of the 237 (33.4%) dogs developed GID during the perianesthetic period. The prevalences of GER, vomiting, and diarrhea were 17.3%, 5.5%, and 10.5%, respectively. Intraabdominal surgery (P = 0.016; odds ratio [OR] 2.82, 95% confidence interval [CI]: 1.21-6.62), changes in body position (P = 0.003; OR 3.17, 95% CI: 1.47-6.85), and length of anesthesia (P = 0.052; OR 1.006, 95% CI: 1.000-1.013) were associated with GER. Changes in the ventilation mode during surgery (P = 0.011; OR 6.54, 95% CI: 1.8-23.8), length of anesthesia (P = 0.024; OR 1.001, 95% CI: 1.001-1.020), and rescue synthetic colloid support due to hypotension (P = 0.005; OR 6.9, 95% CI: 1.82-26.3) were positively associated with postanesthetic vomiting. On the contrary, dogs that received acepromazine as premedication were significantly less likely (P < 0.019; OR 12.3, 95% CI: 1.52-100) to vomit. Finally, length of anesthesia, changes in body position, changes in ventilation mode, or hypoxemia during the procedure tended to increase the risk (univariate model) of diarrhea during the recovery phase.

CONCLUSIONS

GID are common in dogs undergoing general anesthesia. Duration and characteristics of the procedure, anesthetic management, and changes in certain patient variables are significant risk factors for the presence of GID in the perioperative period.

In vitro canine platelet aggregation caused by Dirofilaria immitis extract

Platelet function hyper-activity has been reported in Dirofilaria immitis (heartworm, HW)-infected dogs. Although the mechanism of increased platelet hyper-activity has not yet been elucidated, it is suggested to be mediated by unknown factors, which may be related to adult HW components. This study aims to determine whether adult male HW whole body extract induces canine platelet aggregation in vitro. The results indicate that HW extract caused an aggregation of canine platelets in a concentration-dependent manner. This aggregation ability of the HW extract was not mediated by the adenosine diphosphate receptor. In addition, the mechanisms of aggregation did not require cyclooxygenase-dependent pathways, and the aggregating activity of substances contained in the HW extract was heat stable; therefore, the active substances may be different from collagen. Furthermore, the platelet aggregating activity remained within the molecular weight (MW)≥100,000 fraction obtained by ultrafiltrating the HW extract. In contrast, the MW <100,000 fraction also had a platelet aggregation ability, but the aggregation pattern was reversible and the maximum extent decreased, compared with the MW≥100,000 fraction response. Our experiments have been conducted using a whole body extract from adult HWs to determine with certainty the aggregating activity of HW elements on canine platelets. More studies are necessary to evaluate the effects of the metabolic products released from live adult worms in pulmonary arteries and the symbiont bacterium Wolbachia-derived antigens on canine platelet aggregation.

Comparison of the effects of a balanced crystalloid-based and a saline-based tetrastarch solution on canine whole blood coagulation and platelet function

OBJECTIVE

To evaluate the effects of a 6% hydroxyethyl starch (130/0.42) solution in either a buffered, electrolyte-balanced (HES-BAL), or a saline (HES-SAL) carrier solution on canine platelet function and whole blood coagulation.

DESIGN

Prospective, randomized study.

SETTING

University teaching hospital.

ANIMALS

Thirty-seven client-owned dogs undergoing general anesthesia for arthroscopy or imaging studies.

INTERVENTIONS

Dogs received a 15 mL/kg intravenous bolus of HES-SAL (n = 13), HES-BAL (n = 14), or a modified Ringer's solution (n = 10) over 30-40 minutes. Coagulation was analyzed using a Platelet Function Analyzer-100 (closure time [Ct_PFA ]), and whole blood thromboelastometry (ROTEM) with extrinsically (ex-tem and fib-tem) and intrinsically (in-tem) activated assays, which assessed clotting time (CT), clot formation time (CFT), maximal clot firmness (MCF), and lysis index (LI). Coagulation samples were assayed prior to fluid administration (T0), and 5 minutes (T1), and 3 hours (T2) following fluid bolus administration, respectively.

RESULTS

Both HES solutions resulted in impaired platelet function as indicated by a significant prolongation of Ct_PFA at T1 as compared to T0, but which resolved by T2. An IV bolus of Ringer's solution did not alter platelet function. In both HES groups, whole blood coagulation was significantly impaired at T1 as indicated by a significant increase in in-tem CFT, and a significant decrease in ex-tem, in-tem, and fib-tem MCF compared to T0. Furthermore, a significant increase in ex-tem CFT at T1 compared to T0 was found in the HES-SAL group. With the exception of in-tem MCF after HES-BAL, these effects were not present at T2. No significant differences were found in Ct_PFA or any ROTEM variable at any time point between HES-SAL and HES-BAL.

CONCLUSION

Administration of a single bolus of 15 mL/kg 6% HES 130/0.42 results in significant but short-lived impairment of canine platelet function and whole blood coagulation, regardless of carrier solution.

Concentrations of thromboxane metabolites in feline urine

OBJECTIVE To determine the predominant thromboxane (TX) metabolite in urine of healthy cats, evaluate whether the method of sample collection would impact concentration of that metabolite, and propose a reference interval for that metabolite in urine of healthy cats. ANIMALS 17 cats (11 purpose-bred domestic shorthair cats, 5 client-owned domestic shorthair cats, and 1 client-owned Persian cat). PROCEDURES All cats were deemed healthy on the basis of results for physical examination, a CBC, serum biochemical analysis, urinalysis, and measurement of prothrombin time and activated partial thromboplastin time. Voided and cystocentesis urine samples (or both) were collected. Aliquots of urine were stored at -80°C until analysis. Concentrations of TXB₂, 11-dehydroTXB₂, and 2,3 dinorTXB₂ were measured with commercially available ELISA kits. Urinary creatinine concentration was also measured. RESULTS 11-dehydroTXB₂ was the most abundant compound, representing (mean ± SD) 59 ± 18% of the total amount of TX detected. In all samples, the concentration of 11-dehydroTXB₂ was greater than that of 2,3 dinorTXB₂ (mean, 4.2 ± 2.7-fold as high). Mean concentration of 11-dehydroTXB₂ for the 17 cats was 0.57 ± 0.47 ng/mg of creatinine. A reference interval (based on the 5% to 95% confidence interval) of 0.10 to 2.1 ng of 11-dehydroTXB₂/mg of creatinine was proposed for healthy cats. CONCLUSIONS AND CLINICAL RELEVANCE In this study, 11-dehydroTXB₂ was the major TX metabolite in feline urine. Measurement of this metabolite may represent a noninvasive, convenient method for monitoring in vivo platelet activation in cats at risk for thromboembolism.

Effects of Firocoxib, Flunixin Meglumine, and Phenylbutazone on Platelet Function and Thromboxane Synthesis in Healthy Horses

OBJECTIVE

Determine the effects of nonsteroidal anti-inflammatory drugs (NSAID) on platelet function and thromboxane synthesis immediately after drug administration and following 5 days of NSAID administration in healthy horses.

STUDY DESIGN

Randomized cross-over study.

ANIMALS

Healthy adult horses (n=9; 6 geldings and 3 mares).

METHODS

Horses received either flunixin meglumine (1.1 mg/kg IV every 12 hours), phenylbutazone (2.2 mg/kg IV every 12 hours), or firocoxib (loading dose of 0.27 mg/kg IV on day 1, then 0.09 mg/kg IV every 24 hours for 4 days) for a total of 5 days. Blood samples were collected prior to drug administration (day 0), 1 hour after initial NSAID administration (day 1), and then 1 hour post-NSAID administration on day 5. Platelet function was assessed using turbidimetric aggregometry and a platelet function analyzer. Serum thromboxane B₂ concentrations were determined by commercial ELISA kit. A minimum 14 day washout period occurred between trials.

RESULTS

At 1 hour and 5 days postadministration of firocoxib, flunixin meglumine, or phenylbutazone, there was no significant effect on platelet aggregation or function using turbidimetric aggregometry or a platelet function analyzer. There was, however, a significant decrease in thromboxane synthesis at 1 hour and 5 days postadministration of flunixin meglumine and phenylbutazone that was not seen with firocoxib.

CONCLUSION

Preoperative administration of flunixin meglumine, phenylbutazone, or firocoxib should not inhibit platelet function based on our model. The clinical implications of decreased thromboxane B₂ synthesis following flunixin meglumine and phenylbutazone administration are undetermined.

Evaluation of platelet function using multiple electrode platelet aggregometry in dogs with septic peritonitis

OBJECTIVE

To assess platelet function via multiple electrode platelet aggregometry (MEPA) in dogs with septic peritonitis and in healthy dogs. The secondary aim was to determine if there is prognostic significance to changes in platelet function observed in septic dogs.

DESIGN

Prospective, observational cohort study conducted from January 2012 to March 2014.

SETTING

University teaching hospital.

ANIMALS

Twenty dogs with septic peritonitis and 23 healthy dogs.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

MEPA using arachidonic acid, adenosine diphosphate, and collagen (COL) as agonists was measured within 24 hours of diagnosis of sepsis. Compared to healthy dogs, platelet aggregation was reduced in dogs with septic peritonitis for all agonists (P < 0.01). Overall mortality rate was 40%. MEPA in response to COL was significantly reduced in nonsurvivors compared to survivors (P = 0.019). Using receiver-operating characteristic curve statistics, a COL-activated MEPA less than 43.5 aggregation units had a sensitivity and specificity of 85.7% and 90.9%, respectively, for predicting nonsurvival in dogs with septic peritonitis.

CONCLUSIONS

Circulating platelets from dogs with septic peritonitis have diminished aggregation in response to multiple platelet agonists. MEPA may serve as an assessment tool for illness severity in this patient population.

Evaluation of the relationship between clinical variables and thromboelastographic findings in dogs with protein-losing nephropathy

OBJECTIVE

To determine whether hypercoagulability in proteinuric dogs, defined by thromboelastography (TEG), is related to the degree of proteinuria, presence of systemic arterial hypertension, presence of hypoalbuminemia, or reduced antithrombin activity.

DESIGN

Prospective study of client-owned dogs. Data collected from each patient included signalment, body weight, urine protein-to-creatinine ratio (UPC), serum albumin concentration, TEG values, noninvasive arterial blood pressure, and AT activity. Hypercoagulability was diagnosed by TEG and odds ratios for other measurements were assessed by univariate logistic regression.

SETTING

Urban referral center and teaching hospital.

ANIMALS

Seventy-six dogs with protein-losing nephropathy (PLN) based on UPC, diagnosed between Oct 2009 and Oct 2012.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The prevalence of hypercoagulability was 89%. No statistically significant associations were detected between hypercoagulability and UPC, serum albumin, noninvasive blood pressure, or AT activity (all P > 0.05). The prevalence of thromboembolism was 6.6%.

CONCLUSIONS

Hypercoagulability was prevalent in dogs with PLN but could not be predicted based upon the presence or degree of proteinuria, systemic arterial hypertension, hypoalbuminemia, or low AT activity. The prevalance of thromboembolism was low in this population with PLN.

Presumptive intraperitoneal envenomation resulting in hemoperitoneum and acute abdominal pain in a dog

OBJECTIVE

To describe the clinical features, diagnostic findings, treatment, and outcome of a dog with acute abdominal pain and hemoperitoneum secondary to a presumptive intraperitoneal (IP) snakebite.

CASE SUMMARY

A 10-month-old castrated male mixed-breed dog was evaluated for suspected snake envenomation. The dog presented recumbent and tachycardic with signs of severe abdominal pain. Two cutaneous puncture wounds and hemoperitoneum were discovered during evaluation. Ultrasonographic examination revealed communication of the wounds with the peritoneal cavity. The dog was treated with supportive care, parenteral analgesia, packed red blood cell and fresh frozen plasma transfusions, crotalid antivenom, and placement of an IP catheter to provide local analgesia. The dog recovered fully and was discharged 5 days after initial presentation.

NEW OR UNIQUE INFORMATION PROVIDED

To our knowledge, this is the first report of IP envenomation accompanied by hemorrhage treated with continuous IP analgesia in the veterinary literature.

Evaluation of systemic absorption and renal effects of topical ophthalmic flurbiprofen and diclofenac in healthy cats

OBJECTIVE

To investigate systemic absorption and renal effects of topically applied ophthalmic flurbiprofen and diclofenac in healthy cats.

ANIMALS STUDIED

Twelve domestic shorthair cats.

PROCEDURES

Cats were randomly assigned to two treatment groups (n = 6) and administered one drop (approximately 40 μL) of either flurbiprofen 0.03% or diclofenac 0.1% in both eyes four times daily (6 am, 12 pm, 6 pm, and 12 am) for 14 days. Blood samples were collected on days 0, 4, 8, 14, 16, and 17 and analyzed by liquid chromatography and mass spectrometry for flurbiprofen and diclofenac plasma concentrations. A complete blood count (CBC), serum chemistry, and urinalysis were analyzed at the beginning of the study (Day 0) and at the end of topical drug administration (Day 15).

RESULTS

Both drugs demonstrated systemic absorption. Flurbiprofen was detected (mean ± SD) at day 4 (237 ± 65 ng/mL), day 8 (396 ± 91 ng/mL), day 14 (423 ± 56 ng/mL), day 16 (350 ± 66 ng/mL), and day 17 (270 ± 62 ng/mL), and diclofenac was detected (mean ± SD) at day 4 (130 ± 44 ng/mL), day 8 (131 ± 25 ng/mL), day 14 (150 ± 36 ng/mL), and sporadically on day 16 [corrected]. Flurbiprofen plasma concentration decreased slowly over 48 h after the last dose. No clinically significant abnormalities were noted in the serum blood urea nitrogen, creatinine, or urine specific gravity at the end of topical drug administration compared to the beginning of the study.

CONCLUSIONS

Flurbiprofen and diclofenac were systemically absorbed after topical administration four times daily to both eyes of healthy cats. Flurbiprofen reached higher plasma concentrations compared to diclofenac.

Assessment of coagulation utilizing thromboelastometry in dogs undergoing orthopedic surgery

OBJECTIVE

To evaluate blood coagulation using thromboelastometry in dogs following orthopedic surgery.

DESIGN

Longitudinal observational study.

SETTING

University veterinary teaching hospital.

ANIMALS

Thirty-four adult client-owned dogs.

MEASUREMENTS AND MAIN RESULTS

Dogs undergoing elective or emergency orthopedic surgery had whole blood collected before (T0), at 24 hours (T1), and 1 week (T2) after surgery. Whole blood from each dog was collected by jugular venipuncture using a 20-Ga needle and minimum venous stasis. The blood was placed into tubes containing 3.8% trisodium citrate (1 part citrate: 9 parts blood) and rested at 37°C. Coagulation was evaluated by means of thromboelastometry using the in-TEM, ex-TEM, and fib-TEM assays. Statistically significant increases (P < 0.05) in maximum clot firmness (MCF) from T0 to T1 in the in-TEM and fib-TEM profiles (both P = 0.0001), from T0 to T2 in the in-TEM, ex-TEM, and fib-TEM profiles (P = 0.012, P = 0.037, and P = 0.0001, respectively), and from T1 to T2 in the fib-TEM profile (P = 0.039) were noted. The α angle increased from T0 to T2 in the in-TEM and ex-TEM profiles (P = 0.019 and P = 0.036, respectively). All results were, however, within the institutional reference ranges.

CONCLUSIONS

In this study, unlike the hypercoagulability observed in human orthopedic patients, a hypercoagulable state as measured by thromboelastometry did not develop in dogs following orthopedic surgery.

Evaluation of coagulation in dogs with partial or complete extrahepatic biliary tract obstruction by means of thromboelastography

OBJECTIVE

To characterize in vitro coagulation status in a cohort of dogs with extrahepatic biliary tract obstruction (EHBO) and to evaluate these patients for hypercoagulability by means of thromboelastography.

DESIGN

Prospective cohort study. Animals-10 dogs with EHBO and 19 healthy control dogs.

PROCEDURES

Partial or complete EHBO was confirmed via exploratory celiotomy. Venous blood samples were collected for evaluation of prothrombin time (PT) and activated partial thromboplastin time (APTT); fibrinogen and D-dimer concentrations; protein C and antithrombin activities; and factor VII, VIII, and XI coagulant activities in plasma as well as thromboelastography in whole blood. Thromboelastography variables were measured from the thromboelastography tracing, and a coagulation index was calculated. Thromboelastography results were compared with those of healthy control dogs previously evaluated by the same laboratory.

RESULTS

Hypercoagulability was diagnosed in all dogs with EHBO on the basis of a high coagulation index. Thromboelastography variables, including maximal amplitude, α-angle, and coagulation index, were significantly higher, and K (clot formation time) and R (reaction time) were significantly lower in these dogs than in control dogs. All dogs with EHBO had PT and APTT within respective reference ranges. Plasma D-dimer and fibrinogen concentrations were above reference ranges in 8 and 7 dogs, respectively, and protein C and antithrombin activities were below reference ranges in 3 and 1 dogs, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

In vitro hypercoagulability was commonly detected in dogs with naturally occurring EHBO. The traditional view of EHBO as a disease that causes hypocoagulability may need to be reconsidered.

Intravenous administration of desmopressin acetate to reverse acetylsalicylic acid-induced coagulopathy in three dogs

BACKGROUND

Acetylsalicylic acid (ie, aspirin) administration inhibits platelet aggregation in dogs and is associated with increased perioperative blood loss and transfusion requirements in people. Desmopressin acetate (DDAVP) is used to control or prevent bleeding in dogs with type 1 von Willebrand disease and is also widely reported in the human literature as an emergency antithrombotic reversal agent.

KEY FINDINGS

Three dogs undergoing surgery for intervertebral disc disease had marked prolongations in buccal mucosal bleeding time (BMBT) after aspirin administration. DDAVP was given intravenously preoperatively and achieved prompt reversal of the prolongation in BMBT. None of the dogs experienced intraoperative bleeding complications.

SIGNIFICANCE

IV DDAVP corrected prolongations in BMBT in dogs given aspirin and should be considered in dogs requiring prompt reversal of aspirin-induced coagulopathies to reduce the risk of bleeding complications.

Systematic review of nonsteroidal anti-inflammatory drug-induced adverse effects in dogs

The aim of this systematic review was to identify, assess, and critically evaluate the quality of evidence of nonsteroidal anti-inflammatory drug (NSAID)-induced adverse effects in dogs. Original prospective studies published in peer-reviewed journals in English (1990-2012) that reported data on the safety of NSAIDs administration in dogs were searched. For each study, design type (I, II, III, or IV) and assessment of quality (+, Ø, -) were rated. For each drug, quantity and consistency rating (***, **, *) and strength of evidence (high, moderate, low, or extremely low) were identified and evaluated. The strength of evidence was defined in terms of how applicable and relevant the conclusions were to the target population. Sixty-four studies met the inclusion criteria. Thirty-five (55%) research studies and 29 (45%) clinical trials were identified. A high strength of evidence existed for carprofen, firocoxib, and meloxicam; moderate for deracoxib, ketoprofen, and robenacoxib; and low for etodolac. Quality and consistency rating were as follows: carprofen (***/***), deracoxib (**/***), etodolac (*/unable to rate), firocoxib (***/**), ketoprofen (**/***), meloxicam (***/***), and robenacoxib (**/**), respectively. Adverse effects were detected in 35 studies (55%) and commonly included vomiting, diarrhea, and anorexia. Three studies (5%) reported a power analysis related to adverse effects of ≥80%. In randomized, placebo-controlled, blinded studies (n = 25, 39%), the incidence of adverse effects was not statistically different between treated and control dogs. Finally, most studies were not appropriately designed to determine the safety of NSAIDs, and involved a healthy nongeriatric population of research dogs.

Evaluation of inflammatory and hemostatic surgical stress responses in male cats after castration under general anesthesia with or without local anesthesia

OBJECTIVE

To characterize acute inflammatory and hemostatic surgical stress responses following castration in cats and to evaluate whether the addition of local anesthesia to the anesthetic protocol attenuates these responses.

ANIMALS

39 male cats.

PROCEDURES

Cats undergoing castration were randomly assigned to 2 groups: both groups underwent surgery with general anesthesia, and 1 group additionally received a local anesthetic (lidocaine [2.0 mg/kg in total, divided intratesticularly and SC]) prior to incision. Blood samples were collected after anesthetic induction (baseline) and 1, 5, and 24 hours later. Thromboelastography and coagulation variables (activated partial thromboplastin time [aPTT] and prothrombin time [PT]) were analyzed; fibrinolysis was assessed with plasma D-dimer concentrations. The acute-phase response was evaluated via measurement of plasma fibrinogen and serum amyloid A (last time point, 28 hours) concentrations. Hematologic variables were analyzed at baseline and 1, 5, and 24 hours later.

RESULTS

Evidence of hemostatic and inflammatory activation after surgery was detected in both groups. Maximum amplitude and G (global clot strength) were significantly increased at 24 hours, and significant, but not clinically relevant, decreases were detected in aPTT at 5 and 24 hours and in PT at 24 hours, compared with baseline values. Serum amyloid A concentrations were significantly higher at 24 and 28 hours than at baseline, and plasma fibrinogen concentration was significantly increased at 24 hours; WBC and RBC counts and Hct were significantly increased at multiple time points. No differences between groups were detected for any variables.

CONCLUSIONS AND CLINICAL RELEVANCE

Castration appeared to induce hypercoagulability and an acute-phase inflammatory response in cats. Local anesthesia with lidocaine did not attenuate this response.

Multicenter randomized prospective clinical evaluation of meloxicam administered via transmucosal oral spray in client-owned dogs

The clinical safety and efficacy of a transmucosal oral spray (TMOS) formulation of meloxicam was evaluated for the control of pain and inflammation associated with osteoarthritis in dogs. A total of 280 client-owned dogs were enrolled at fourteen veterinary clinics: there were 187 dogs in the meloxicam TMOS group and 93 in the placebo control group. Dogs received placebo or treatment spray once daily for twenty-eight days. Improvement in signs of osteoarthritis was measured using client-specific outcome measures (CSOM) made at days 14 and 28 and veterinary assessments of lameness and pain on palpation made at day 28. A significantly higher number of dogs in the meloxicam TMOS group were treatment successes at 28 days (72.6%) compared with the placebo group (46.9%), based on CSOM scores. Total CSOM scores were significantly lower in the meloxicam TMOS-treated group compared with the placebo group at both 14 and 28 days. Differences between treatment groups were not observed in veterinary assessments. Gastrointestinal effects of meloxicam were observed in some animals. Meloxicam TMOS was found to be safe and effective in dogs for the control of pain and inflammation associated with osteoarthritis.

Effects of oral prednisone administration with or without ultralow-dose acetylsalicylic acid on coagulation parameters in healthy dogs

OBJECTIVE

To determine the effects of oral prednisone administration with or without ultralow-dose acetylsalicylic acid on coagulation parameters in healthy dogs and to assess intraindividual variation in thromboelastography results.

ANIMALS

14 healthy research dogs and 10 healthy client-owned dogs.

PROCEDURES

In a randomized controlled trial, research dogs underwent thromboelastography twice (3 days apart), and intraindividual variation in test results was calculated. Dogs were given prednisone (2 mg/kg/d, PO) plus acetylsalicylic acid (0.5 mg/kg/d, PO) or prednisone (2 mg/kg/d, PO) plus a placebo for 14 days, after which thromboelastography and other tests were repeated. Differences from preadministration (baseline) test results between and within groups were compared. In a separate trial, client-owned dogs also underwent thromboelastography twice 2 days apart to assess intraindividual variation in untreated dogs.

RESULTS

Intraindividual variation in thromboelastography results for research dogs was ≤ 10% for maximum amplitude (MA) and α angle. In the research dogs, MA and fibrinogen values significantly increased from baseline, whereas percentage lysis 30 minutes after attainment of the MA as well as antithrombin activity significantly decreased within each group. In the dogs that received prednisone plus a placebo, percentage lysis 60 minutes after attainment of the MA was significantly lower than at baseline. For all parameters for research dogs, there was no difference between groups for change from baseline. Intraindividual variation in findings for client-owned dogs was similar to the variation for research dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

Prednisone administration resulted in hypercoagulability in healthy dogs as indicated by an increase in MA and plasma fibrinogen concentration and a decrease in antithrombin activity. Concurrent ultralow-dose acetylsalicylic acid use had no effect on measured thromboelastography values. The high intraindividual variation in some thromboelastography parameters may preclude routine use of this technique in clinical practice.

Potential adverse effects of omega-3 Fatty acids in dogs and cats

Fish oil omega-3 fatty acids, mainly eicosapentaenoic acid and docosahexaenoic acid, are used in the management of several diseases in companion animal medicine, many of which are inflammatory in nature. This review describes metabolic differences among omega-3 fatty acids and outlines potential adverse effects that may occur with their supplementation in dogs and cats with a special focus on omega-3 fatty acids from fish oil. Important potential adverse effects of omega-3 fatty acid supplementation include altered platelet function, gastrointestinal adverse effects, detrimental effects on wound healing, lipid peroxidation, potential for nutrient excess and toxin exposure, weight gain, altered immune function, effects on glycemic control and insulin sensitivity, and nutrient-drug interactions.

Cyclooxygenase expression and platelet function in healthy dogs receiving low-dose aspirin

BACKGROUND

Low-dose aspirin is used to prevent thromboembolic complications in dogs, but some animals are nonresponsive to the antiplatelet effects of aspirin ("aspirin resistance").

HYPOTHESIS/OBJECTIVES

That low-dose aspirin would inhibit platelet function, decrease thromboxane synthesis, and alter platelet cyclooxygenase (COX) expression.

ANIMALS

Twenty-four healthy dogs.

METHODS

A repeated measures study. Platelet function (PFA-100 closure time, collagen/epinephrine), platelet COX-1 and COX-2 expression, and urine 11-dehydro-thromboxane B(2) (11-dTXB(2)) were evaluated before and during aspirin administration (1 mg/kg Q24 hours PO, 10 days). Based on prolongation of closure times after aspirin administration, dogs were divided into categories according to aspirin responsiveness: responders, nonresponders, and inconsistent responders.

RESULTS

Low-dose aspirin increased closure times significantly (62% by Day 10, P < .001), with an equal distribution among aspirin responsiveness categories, 8 dogs per group. Platelet COX-1 mean fluorescent intensity (MFI) increased significantly during treatment, 13% on Day 3 (range, -29.7-136.1%) (P = .047) and 72% on Day 10 (range, -0.37-210%) (P < .001). Platelet COX-2 MFI increased significantly by 34% (range, -29.2-270%) on Day 3 (P = .003) and 74% (range, -19.7-226%) on Day 10 (P < .001). Urinary 11-dTXB(2) concentrations significantly (P = .005, P < .001) decreased at both time points. There was no difference between aspirin responsiveness and either platelet COX expression or thromboxane production.

CONCLUSIONS AND CLINICAL IMPORTANCE

Low-dose aspirin consistently inhibits platelet function in approximately one-third of healthy dogs, despite decreased thromboxane synthesis and increased platelet COX expression in most dogs. COX isoform expression before treatment did not predict aspirin resistance.