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

Platelet hyperresponsiveness and increased platelet-neutrophil aggregates in dogs with myxomatous mitral valve disease and pulmonary hypertension

BACKGROUND

Pulmonary hypertension (PH) in dogs with myxomatous mitral valve disease (MMVD) is caused by increased pulmonary venous pressure. Thrombosis, vascular remodeling, and vasoconstriction mediated by platelets could exacerbate PH.

HYPOTHESIS

Dogs with PH will exhibit a hypercoagulable state, characterized by increased platelet activation, platelet-leukocyte, and platelet-neutrophil aggregate formation.

ANIMALS

Eleven dogs (≥3.5 kg) diagnosed with MMVD and PH and 10 dogs with MMVD lacking PH.

METHODS

Prospective cohort ex vivo study. All dogs underwent echocardiographic examination, CBC, 3-view thoracic radiographs, and heartworm antigen testing. Severity of PH and MMVD were assessed by echocardiography. Viscoelastic monitoring of coagulation was assessed using thromboelastography (TEG). Platelet activation and platelet-leukocyte/platelet-neutrophil interactions were assessed using flow cytometry. Plasma serotonin concentrations were measured by ELISA.

RESULTS

Unstimulated platelets from dogs with MMVD and PH expressed more surface P-selectin than MMVD controls (P = .03). Platelets from dogs with MMVD and PH had persistent activation in response to agonists. The number of platelet-leukocyte aggregates was higher in dogs with MMVD and PH compared with MMVD controls (P = .01). Ex vivo stimulation of whole blood resulted in higher numbers of platelet-neutrophil aggregates in dogs with MMVD and PH (P = .01). Assessment of hypercoagulability based on TEG or plasma serotonin concentrations did not differ between groups.

CONCLUSION AND CLINICAL IMPORTANCE

Platelet hyperresponsiveness and increased platelet-neutrophil interaction occur in dogs with MMVD and PH, suggesting that platelets play a role of in the pathogenesis of PH. Clinical benefits of antiplatelet drugs in dogs with MMVD and PH require further investigation.

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.

Retrospective analysis of immunosuppressive and anti-thrombotic protocols in nonassociative immune mediated hemolytic anemia in dogs

BACKGROUND

Evidence supporting the effectiveness of therapeutic protocols for nonassociative immune-mediated hemolytic anemia (na-IMHA) is weak.

HYPOTHESIS/OBJECTIVES

Investigate the efficacy of various drugs in na-IMHA.

ANIMALS

Two hundred forty-two dogs.

METHODS

Multi-institutional retrospective study (2015-2020). Immunosuppressive effectiveness was determined by time to packed cell volume (PCV) stabilization and duration of hospitalization through analysis by mixed model linear regression. Occurrence of disease relapse, death, and antithrombotic effectiveness, were analyzed using mixed model logistic regression.

RESULTS

Use of corticosteroids vs a multi-agent protocol had no effect on time to PCV stabilization (P = .55), duration of hospitalization (P = .13), or case fatality (P = .06). A higher rate of relapse (P = .04; odds ratio: 3.97; 95% confidence interval [CI]: 1.06-14.8) was detected in dogs receiving corticosteroids (11.3%) during follow-up (median: 28.5 days, range: 0-1631 days) compared to multiple agents (3.1%) during follow up (median: 47.0 days, range: 0-1992 days). When comparing drug protocols, there was no effect on time to PCV stabilization (P = .31), relapse (P = .44), or case fatality (P = .08). Duration of hospitalization was longer, by 1.8 days (95% CI: 0.39-3.28 days), for the corticosteroid with mycophenolate mofetil group (P = .01) compared to corticosteroids alone. Use of clopidogrel vs multiple agents had no effect on development of thromboses (P ≥ .36).

CONCLUSIONS AND CLINICAL IMPORTANCE

Addition of a second immunosuppressive agent did not alter immediate outcome measures but might be associated with a reduction in relapse. Use of multiple antithrombotic agents did not reduce incidence of thrombosis.

Long-term follow-up of portal vein thrombosis in an American Cocker Spaniel with lobular dissecting hepatitis: a case report

BACKGROUND

Lobular dissecting hepatitis (LDH) is a rare form of canine liver cirrhosis that may be accompanied by portal hypertension in American Cocker Spaniels. In human patients with liver cirrhosis, portal vein thrombosis (PVT) is a common complication. However, PVT has not been reported in dogs with LDH. Herein, we describe the long-term follow-up of PVT in an American Cocker Spaniel with LDH.

CASE PRESENTATION

An 8-year-old neutered male American Cocker Spaniel presented with a 1-month history of severe abdominal effusion. The dog was histopathologically diagnosed with LDH and treated with low-dose prednisolone on day 14. On day 115, computed tomography angiography (CTA) confirmed the presence of a thrombus in the portal vein. Therefore, the dog was subcutaneously administered with the anticoagulant dalteparin, and low-dose prednisolone was continued. As a follow-up for PVT, CTA examinations were performed on days 207, 515, 886, and 1168, and the dog's antithrombin and D-dimer levels were measured. Following anticoagulant therapy, the dog was confirmed to have gradually increased antithrombin activity and decreased D-dimer concentrations. In addition, although the thrombus was confirmed to be in the same area of the portal vein system by CTA, atrophy and increased CT values due to organization were observed during the follow-up period. The dog's condition remained stable without clinical signs until day 1112 when it developed hepatic encephalopathy. The dog died on day 1208. On postmortem examination, histopathologically, the liver showed marked bile duct hyperplasia and fibrosis with chronic thrombus in the portal vein.

CONCLUSIONS

This case demonstrated that low-dose glucocorticoid combined with dalteparin allowed long-term follow-up of PVT in an American Cocker Spaniel with LDH.

Case Report: Mineralized Pulmonary Artery Thrombi in Two Dogs Treated for Meningoencephalitis of Unknown Origin

Meningoencephalitis of unknown origin (MUO) is a relatively common and very serious canine neurologic condition, which is typically associated with a poor long term prognosis despite treatment. This case series chronicles two dogs diagnosed with MUO who were treated with long term corticosteroids and cytosine arabinoside and lived well-beyond the typical survival time for this condition. Both eventually succumbed to respiratory signs associated with mineralized thrombi in their pulmonary arteries. Adverse effects from the two drugs used for treatment are reviewed in order to propose a possible mechanism to explain how long term use of these medications could result in such a phenomenon.

Effects of clopidogrel and prednisone on platelet function in healthy dogs

Background

Glucocorticoids cause hypercoagulability, but it is unknown if they counteract clopidogrel's antiplatelet effects.

Hypothesis/Objectives

Determine the effects of clopidogrel and prednisone on platelet function.

Animals

Twenty‐four healthy dogs.

Methods

Double‐blinded, placebo‐controlled randomized trial. Platelet function was evaluated using a platelet function analyzer and impedance aggregometry (days 0, 14, and 28) for dogs treated with placebo, clopidogrel (2‐3 mg/kg/d), prednisone (2 mg/kg/d), or prednisone with clopidogrel PO for 28 days. Results were categorized as nonresponder versus responder (platelet function analyzer), and inadequate, ideal, or excessive response (aggregometry). Results were compared using mixed model, split‐plot repeated measures analysis of variance and generalized estimating equation proportional odds models. P < .05 was considered significant.

Results

Closure times differed by treatment (F [3, 20] = 10.5; P < .001), time (F [2, 40] = 14.3; P < .001), and treatment‐by‐time (F [6, 40] = 3.4; P = .01). Area under the curve (AUC) differed by treatment (F [3, 20] = 19.6; P < .001), time (F [2, 40] = 35.4; P < .001), and treatment‐by‐time (F [6, 40] = 13.5; P < .001). Based on closure times, 5/6 dogs each in the clopidogrel and prednisone/clopidogrel groups were responders. All dogs in the prednisone/clopidogrel group were overcontrolled based on AUC (days 14 and 28), whereas 5/6 (day 14) and 2/6 (day 28) dogs treated with clopidogrel were overcontrolled. Compared to clopidogrel, dogs receiving prednisone/clopidogrel were 11 times (P = .03) more likely to have an excessive response.

Conclusions and Clinical Importance

Administration of clopidogrel/prednisone increases platelet dysfunction in healthy dogs.

Effects of Aspirin and Prednisone on Platelet Function and Thromboxane Synthesis in Healthy Dogs

Glucocorticoid administration is a risk factor for thromboembolism in hypercoagulable dogs, and it is unknown if aspirin counteracts glucocorticoid-induced hypercoagulability. The objective was to determine the effects of sustained aspirin and prednisone administration on platelet function and thromboxane synthesis. Our hypothesis was that aspirin would consistently inhibit platelet function and thromboxane synthesis when administered with or without prednisone. In 24 healthy dogs, platelet aggregometry and urine 11-dehydro-thromboxane-B₂ (11-dTXB₂)-to-creatinine ratios were measured on days 0, 14, and 28. Dogs were administered placebos, aspirin (2 mg/kg/d), prednisone (2 mg/kg/d), or prednisone/aspirin combination therapy PO for 28 days in a randomized double-blinded study. Aspirin response was based on a >25% reduction in platelet aggregation compared to pre-treatment values. Results were compared using mixed model, split-plot repeated measures ANOVAs. P < 0.05 was considered significant. AUC differed significantly by time [F_(2,40) = 10.2, P < 0.001] but not treatment or treatment-by-time. On day 14, 2 dogs were aspirin responders (aspirin, 1; placebo, 1). On day 28, 3 dogs were aspirin responders (aspirin, 2; prednisone/aspirin, 1). Urine 11-dTXB₂-to-creatinine ratios differed significantly by group [F_(3,20) = 3.9, P = 0.024] and time [F_(2,40) = 8.7, P < 0.001), but not treatment-by-time. Post-hoc analysis revealed significant differences between aspirin and placebo groups (P=0.008), aspirin and prednisone/aspirin groups (P = 0.030), and placebo and prednisone groups (P = 0.030). In healthy dogs, sustained aspirin, prednisone, and combination therapy do not inhibit platelet aggregation, and when used as individual therapies, aspirin and prednisone decreased thromboxane synthesis. Additional studies using varied platelet function methodologies in hypercoagulable dogs are necessary.

Primary immune-mediated haemolytic anaemia: a retrospective long-term study in 61 dogs

OBJECTIVES

The objective of this study is to describe the course of disease of dogs with primary immune-mediated haemolytic anaemia (pIMHA) with an observation period longer than 90 days in regard to clinical signs, laboratory results and treatment response.

MATERIAL AND METHODS

Clinical records between January 2003 and December 2011 were reviewed. Diagnosis of pIMHA was based on the presence of haemolytic anaemia with a packed cell volume of <0.35 L/L, a positive Coombs' test and/or erythrocyte agglutination, spherocytosis and exclusion of an underlying disease. Included were dogs which could be monitored for more than 90 days after initial presentation.

RESULTS

Sixty-one dogs with pIMHA were included. The initial packed cell volume ranged from 0.08 to 0.30 L/L (median 0.16). Immunosuppressive treatment included prednisolone in all the cases; 32 dogs successively received cyclosporine (28), cyclophosphamide (5), leflunomide (2) or human intravenous immunoglobulins (2) in addition. In 33/61 dogs, the drugs were discontinued 67-3372 days (median 334) after beginning of therapy; in 28 dogs, the drug dosage was reduced, but not discontinued until the end of the study. Three dogs developed immune-mediated thrombocytopenia (days 132, 156 and 680). The observation period ranged from 96 to 4147 days (median 628). A total of 22.9% (14/61) of the dogs developed a relapse after 94-3972 days (median 517). Five dogs were euthanased due to a relapse after 96-1188 days (median 628).

CLINICAL SIGNIFICANCE

Long-term prognosis in dogs with pIMHA is favourable. However, a relapse can occur after many years. Relapse was the most common cause of death in dogs with pIMHA that survive more than 90 days.

American College of Veterinary Emergency and Critical Care (ACVECC) Consensus on the Rational Use of Antithrombotics in Veterinary Critical Care (CURATIVE) guidelines: Small animal

OBJECTIVES

To systematically review available evidence and establish guidelines related to the risk of developing thrombosis and the management of small animals with antithrombotics.

DESIGN

Standardized, systematic evaluation of the literature (identified by searching Medline via PubMed and CAB abstracts) was carried out in 5 domains (Defining populations at risk; Defining rational therapeutic use; Defining evidence-based protocols; Refining and monitoring antithrombotic therapies; and Discontinuing antithrombotic therapies). Evidence evaluation was carried out using Population, Intervention, Comparison, Outcome generated within each domain questions to address specific aims. This was followed by categorization of relevant articles according to level of evidence and quality (Good, Fair, or Poor). Synthesis of these data led to the development of a series of statements. Consensus on the final guidelines was achieved via Delphi-style surveys. Draft recommendations were presented at 2 international veterinary conferences and made available for community assessment, review, and comment prior to final revisions and publication.

SETTINGS

Academic and referral veterinary medical centers.

RESULTS

Over 500 studies were reviewed in detail. Worksheets from all 5 domains generated 59 statements with 83 guideline recommendations that were refined during 3 rounds of Delphi surveys. A high degree of consensus was reached across all guideline recommendations.

CONCLUSIONS

Overall, systematic evidence evaluations yielded more than 80 recommendations for the treatment of small animals with or at risk of developing thrombosis. Numerous significant knowledge gaps were highlighted by the evidence reviews undertaken, indicating the need for substantial additional research in this field.

Consensus on the Rational Use of Antithrombotics in Veterinary Critical Care (CURATIVE): Domain 1-Defining populations at risk

OBJECTIVES

Thrombosis is a well-recognized phenomenon in dogs and cats with a significant impact on morbidity and mortality. Despite growing awareness of thrombosis and increased use of antithrombotic therapy, there is little information in the veterinary literature to guide the use of anticoagulant and antiplatelet medications. The goal of Domain 1 was to explore the association between disease and thrombosis in a number of conditions identified as potential risk factors in the current veterinary literature, 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. Revised guidelines then underwent the Delphi survey process to reach consensus on the final guidelines. Diseases evaluated included immune-mediated hemolytic anemia, protein-losing nephropathy, pancreatitis, glucocorticoid therapy, hyperadrenocorticism, neoplasia, sepsis, cerebrovascular disease, and cardiac disease.

SETTINGS

Academic and referral veterinary medical centers.

RESULTS

Of the diseases evaluated, a high risk for thrombosis was defined as dogs with immune-mediated hemolytic anemia or protein-losing nephropathy, cats with cardiomyopathy and associated risk factors, or dogs/cats with >1 disease or risk factor for thrombosis. Low or moderate risk for thrombosis was defined as dogs or cats with a single risk factor or disease, or dogs or cats with known risk factor conditions that are likely to resolve in days to weeks following treatment.

CONCLUSIONS

Documented disease associations with thrombosis provide the basis for recommendations on prescribing provided in subsequent domains. Numerous knowledge gaps were identified that represent opportunities for future study.

Comparative pathophysiology and management of protein-losing enteropathy

Protein‐losing enteropathy, or PLE, is not a disease but a syndrome that develops in numerous disease states of differing etiologies and often involving the lymphatic system, such as lymphangiectasia and lymphangitis in dogs. The pathophysiology of lymphatic disease is incompletely understood, and the disease is challenging to manage. Understanding of PLE mechanisms requires knowledge of lymphatic system structure and function, which are reviewed here. The mechanisms of enteric protein loss in PLE are identical in dogs and people, irrespective of the underlying cause. In people, PLE is usually associated with primary intestinal lymphangiectasia, suspected to arise from genetic susceptibility, or “idiopathic” lymphatic vascular obstruction. In dogs, PLE is most often a feature of inflammatory bowel disease (IBD), and less frequently intestinal lymphangiectasia, although it is not proven which process is the true driving defect. In cats, PLE is relatively rare. Review of the veterinary literature (1977‐2018) reveals that PLE was life‐ending in 54.2% of dogs compared to published disease‐associated deaths in IBD of <20%, implying that PLE is not merely a continuum of IBD spectrum pathophysiology. In people, diet is the cornerstone of management, whereas dogs are often treated with immunosuppression for causes of PLE including lymphangiectasia, lymphangitis, and crypt disease. Currently, however, there is no scientific, extrapolated, or evidence‐based support for an autoimmune or immune‐mediated mechanism. Moreover, people with PLE have disease‐associated loss of immune function, including lymphopenia, severe CD4+ T‐cell depletion, and negative vaccinal titers. Comparison of PLE in people and dogs is undertaken here, and theories in treatment of PLE are presented.

Treatment Outcome of 22 Dogs With Masticatory Muscle Myositis (1999-2015)

Medical records of dogs diagnosed with masticatory muscle myositis (MMM) at Ryan Veterinary Hospital of the University of Pennsylvania during a period of 17 years (from 1999 to 2015) were reviewed. Twenty-two dogs were included in this retrospective case series study. Immunosuppressive doses of prednisone were prescribed to all dogs. Twenty dogs had full recovery of masticatory function. The mean (SD) improvement in the vertical mandibular range of motion (vmROM) was 5.3 (3.1) cm during the first 4 weeks of treatment (weeks 1-4) and 2.8 (2.2) cm during the subsequent 8 weeks (weeks 5-12). The vmROM continued to improve for several more months. Six dogs had a relapse, but the clinical signs were more severe in dogs when no longer receiving prednisone compared to dogs still on prednisone at the time of relapse. When diagnosed and treated appropriately, MMM has a good prognosis with relatively quick return to masticatory function. Early discontinuation of prednisone therapy should be avoided. Approximately 1 year of therapy is recommended prior to discontinuing the medication. Educating the client about how to perform muscle palpation, determine vmROM at home, recognize signs of pain, and notice behavioral changes may help in the early detection of relapses.

Effects of immunosuppressive agents on the hemostatic system in normal dogs

Background

In dogs, the effects of immunosuppressive medications on hemostasis are not well known.

Hypothesis/Objectives

The objective was to determine the effects of immunosuppressive medications on primary and secondary hemostasis. Our hypothesis was that cyclosporine and prednisone would increase markers of hypercoagulability and thromboxane synthesis, while azathioprine, mycophenolate mofetil, and leflunomide would have minimal effects on hemostasis.

Animals

Eight healthy dogs.

Methods

A randomized, cross‐over study used aggregometry, the PFA‐100 platelet function analyzer, viscoelastometry, platelet count, and prothrombin and activated partial thromboplastin times to evaluate hemostasis during the administration of prednisone, azathioprine, cyclosporine, mycophenolate mofetil, and leflunomide for 1 week each at standard oral doses. Urine 11‐dehydro‐thromboxane‐B₂ (11‐dTXB₂) and 6‐keto‐prostaglandin‐F_1α (6‐keto‐PGF_1α) concentrations, normalized to urine creatinine concentration, were measured.

Results

The aggregometry amplitude decreased from 51 ± 21 to 27 ± 14 (P = .002) during leflunomide treatment (ADP activation), but there were no differences in amplitude (P = .240) for any medications when platelets were activated with collagen. For all medications, there were no significant differences in viscoelastometry indices (ACT, P = .666; ClotRate, P = .340; and platelet function, P = .411) and platelet count (P = .552). Compared with pretreatment values, urinary 11‐dTXB₂‐to‐creatinine ratio increased (P = .001) after drug administration (from 3.7 ± 0.6 to 5.6 ± 1.1). Cyclosporine was associated with an increase (P < .001) in the 6‐keto‐PGF_1α‐to‐creatinine ratio (from 10.3 ± 4.6 to 22.1 ± 5.3).

Conclusions and Clinical Importance

Most immunosuppressive drugs do not enhance platelet function or coagulation in healthy dogs, suggesting that these medications might not predispose hypercoagulable dogs to thromboembolism. The results of our study need to be correlated with the clinical outcomes of hypercoagulable dogs.

Bilateral Vertebral Venous Sinus Thrombosis Causing Cervical Spinal Cord Compression in a Dog

A 10-year-old male neutered mixed breed dog was evaluated for cervical hyperesthesia and tetraparesis. Magnetic resonance imaging of the brain and cervical spinal cord identified an extradural compressive lesion over the body of C2 caused by marked dilation of the vertebral venous sinuses. Following intravenous contrast administration both vertebral sinuses had heterogeneous contrast enhancement consistent with incomplete thrombi formation. An abdominal ultrasound also showed a distal aortic thrombus. A definitive cause for the thrombi formation was not identified, but the patient had several predisposing factors which may have contributed. The patient was treated with a combination of warfarin, clopidogrel, and enoxaparin as well as analgesics. Within 48 h of initiation of warfarin therapy, the tetraparesis and hyperesthesia were markedly improved. Repeat abdominal ultrasound 3 weeks after discharge showed reduction in size of aortic thrombus. Neurologic function remained normal for 6 weeks following initiation of treatment. Seventy-four days following initial diagnosis the patient rapidly declined and passed away at home. Necropsy was declined. This is the first report of vertebral venous sinus enlargement leading to spinal cord compression and tetraparesis in a dog. Additionally, warfarin in combination with clopidogrel and enoxaparin appeared to be a safe and effective treatment for the suspected thrombi reported in this case. Vertebral sinus enlargement secondary to thrombi should be considered as a differential diagnosis in patients presenting with tetraparesis and cervical hyperesthesia.

Thromboembolism in Dogs with Protein-Losing Enteropathy with Non-Neoplastic Chronic Small Intestinal Disease

Dogs with protein-losing enteropathy (PLE) are suggested to be at increased risk of developing thromboembolic events. However, with some exceptions, there are very few reports of thromboembolism in such dogs. This multicentre retrospective observational study describes a case series of thromboembolism (TE) in eight dogs with PLE secondary to non-neoplastic, chronic small intestinal disease. Seven dogs had poorly controlled PLE when the thromboembolic event occurred. Pulmonary thromboembolism (PTE) occurred in six dogs, while one dog developed splenic vein thrombosis and another had concurrent splenic vein and aortic TE. Six dogs died, all with PTE. Antithrombin activity was decreased in one of two dogs in which it was measured. Serum cobalamin and folate concentrations were measured in three dogs and cobalamin was subnormal in all three. Serum magnesium, measured in two dogs, was low in both. Dogs with uncontrolled chronic small intestinal disease and PLE are at risk for developing serious life-threatening TE, mostly PTE.

Evaluation of the safety and tolerability of rivaroxaban in dogs with presumed primary immune-mediated hemolytic anemia

OBJECTIVE

To evaluate the safety and tolerability of rivaroxaban (RIV), an oral direct factor Xa inhibitory drug, in dogs with presumed primary immune-mediated hemolytic anemia (pIMHA).

DESIGN

Prospective, multicenter, positive-controlled, unblinded clinical trial. Client-owned dogs were enrolled between October 2012 and March 2014.

SETTING

Private referral centers.

ANIMALS

Twenty-four client-owned dogs with pIMHA. Enrolled dogs were randomized in 2 treatment groups to receive by mouth RIV or clopidogrel (CL) and low-dose aspirin (LDA). All dogs were monitored for 90 days from the enrollment in the study.

INTERVENTIONS

Enrolled dogs were given a standardized immunosuppressive protocol and RIV or CL and LDA.

MEASUREMENTS AND MAIN RESULTS

There was no identifiable adverse drug reaction, evidence of hemorrhage, significant prolongation of prothrombin time or activated partial thromboplastin time, or increase in transfusion requirements associated with RIV therapy compared to CL and LDA in dogs with pIMHA. There was no significant difference between treatment groups with respect to thrombotic events, survival rates to discharge, at 1 month and 3 months from diagnosis.

CONCLUSIONS

This study suggests that RIV at a median dose of 0.89 mg/kg by mouth once daily was safe and well tolerated in a small group of dogs with presumed pIMHA able to tolerate oral medications and treated with a standardized immunosuppressive treatment protocol. Conclusions regarding the relative efficacy of RIV as compared to CL and LDA cannot be made due to the small size of the treatment groups and because pharmacodynamic effects were not assessed.

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.