Therese E. O'Toole

Identification of hypercoagulability in dogs with primary immune-mediated hemolytic anemia by means of thromboelastography

OBJECTIVE To evaluate whole blood hemostasis by means of thromboelastography in dogs with primary immune-mediated hemolytic anemia (IMHA) to determine whether these dogs had evidence of hypercoagulability prior to the administration of immunosuppressant medications, blood transfusion products, or anticoagulant agents. DESIGN Evaluation study. ANIMALS 11 client-owned dogs admitted to a teaching hospital for management of primary IMHA and 20 clinically normal dogs. PROCEDURES Citrated whole blood samples were obtained from all dogs for performance of kaolin-activated thromboelastography. Citrated plasma was harvested from blood samples of dogs with IMHA for plasma-based coagulation testing, including activated partial thromboplastin time, prothrombin time, D-dimer concentration, fibrinogen concentration, and antithrombin activity. RESULTS Compared with control dogs, dogs with primary IMHA had evidence of hypercoagulability as indicated by a significantly lower median (range) clot formation time (0.8 seconds [0.8 to 2.0 seconds] vs 1.9 seconds [1.3 to 3.8 seconds]), higher median angle (76.1° [59.2° to 84.6°] vs 64.0° [45.4° to 71.0°]), higher median maximum amplitude (75.9 mm [66.3 to 86.3 mm] vs 55.7 mm [49.9 to 63.6 mm]), and higher median clot strength (15,000 dyne/cm(2) [9,900 to 31,400 dyne/cm(2)] vs 6,100 dyne/cm(2) [4,900 to 8,700 dyne/cm(2)]). CONCLUSIONS AND CLINICAL RELEVANCE Dogs with primary IMHA had hypercoagulability as demonstrated by thromboelastography at the time of initial diagnosis and prior to treatment. Such hypercoagulability may be a precursor to clinically evident thrombosis as a complication of the disease process.

Portal Vein Thrombosis in 33 Dogs: 1998–2011

BACKGROUND Portal vein thrombosis (PVT) has been reported infrequently in dogs. OBJECTIVES To characterize the presentation, associated disease conditions, and outcome in dogs with PVT. ANIMALS Client-owned dogs with a diagnosis of PVT and a complete medical record. METHODS Records were retrospectively analyzed for presentation, history, physical examination, clinicopathologic data, diagnostic imaging, treatment, and outcome. RESULTS Thirty-three dogs were included. Common clinical signs were vomiting, diarrhea, abdominal pain, ascites, and signs of hypovolemic shock. Associated disease conditions included hepatic (14/33), neoplastic (7/33), immune (5/33), and infectious (4/33) diseases, protein-losing nephropathy (3/33), hyperadrenocorticism (2/33), protein-losing enteropathy (1/33), and pancreatitis (1/33). Fourteen dogs were receiving glucocorticoids at the time of diagnosis. Twenty-nine dogs had at least 1 predisposing condition for venous thrombosis, and 11 had 2 or more. Thrombocytopenia (24/33), increased liver enzyme activity (23/33), and hypoalbuminemia (20/33) were common laboratory abnormalities. Clinical syndromes at the time of PVT diagnosis included shock (16/33), systemic inflammatory response syndrome (SIRS), (13/33) and disseminated intravascular coagulation (3/33). Twenty-four dogs had acute and 9 had chronic PVT. Multiple thrombi were found in 17/33 dogs. Nineteen dogs survived to discharge. Dogs treated with anticoagulant therapy were more likely, whereas those with acute PVT, multiple thromboses or SIRS were less likely to survive. CONCLUSIONS AND CLINICAL IMPORTANCE Hepatic disease is a common pre-existing condition in dogs with PVT. PVT should be considered in dogs with risk factors for venous thrombosis presenting with abdominal pain, ascites, and thrombocytopenia. Studies evaluating anticoagulant therapy in the management of PVT are warranted.

Use of human immunoglobulin in addition to glucocorticoids for the initial treatment of dogs with immune-mediated hemolytic anemia

OBJECTIVE To determine the utility of human intravenous immunoglobulin (hIVIG) for the initial treatment of canine immune-mediated hemolytic anemia (IMHA). DESIGN Blinded, randomized, clinical trial. SETTING Veterinary teaching hospital. ANIMALS Twenty-eight, client-owned dogs with primary IMHA. INTERVENTIONS At enrollment, after diagnosis of IMHA, dogs were randomly assigned to receive either hIVIG or placebo, in a blinded fashion. For the next 14 days, all dogs received glucocorticoids as the sole immunosuppressant agent. All dogs received low-molecular-weight heparin as an anticoagulant. D-dimer concentrations were evaluated at the beginning and end of the study protocol to monitor for thromboembolic complications. MEASUREMENTS AND MAIN RESULTS Twenty-five of 28 dogs (89%) were discharged from the hospital. Thirteen of those received hIVIG and 12 received placebo. Twenty-four dogs (86%) were alive 14 days after enrollment, and of these 13 received hIVIG and 11 received placebo. D-dimer concentrations were elevated in 86% of all dogs at the time of diagnosis. CONCLUSIONS For initial treatment of dogs with IMHA, the addition of hIVIG to corticosteroid treatment did not improve initial response, nor did it shorten hospitalization.

Use of mycophenolate mofetil as a rescue agent in the treatment of severe generalized myasthenia gravis in three dogs

OBJECTIVE To describe the use of IV and oral mycophenolate mofetil (MMF) as adjunctive therapy in 3 dogs with severe generalized myasthenia gravis. CASE SERIES SUMMARY Three dogs suffering from severe generalized myasthenia gravis as confirmed by acetylcholine antibody titers were treated with MMF as part of their treatment regimens. All 3 dogs had radiographic evidence of megaesophagus and suffered from severe regurgitation. Each dog was initially treated with pyridostigmine and supportive agents. When clinical remission was not achieved, IV MMF was administered to all dogs. Signs of clinical remission were apparent within 48 hours and all dogs were later maintained on oral MMF following resolution of regurgitation. NEW OR UNIQUE INFORMATION PROVIDED This is the first report of the use of IV MMF as adjunctive treatment in dogs with severe generalized myasthenia gravis. Outcome was favorable in all 3 dogs and no adverse effects were noted from the MMF.

Portal Vein Thrombosis in Cats: 6 Cases (2001–2006)

BACKGROUND Portal vein thrombosis (PVT) in cats is sparsely reported. PURPOSE OF STUDY To evaluate the clinical signs and diseases associated with PVT in cats. ANIMALS 6 client-owned cats. METHODS Medical records for cats with a portal vein thrombus diagnosed on abdominal ultrasound or at necropsy were reviewed. Signalment, historical data, underlying disorders, clinical findings, clinicopathologic and histopathologic data, diagnostic imaging findings, treatment, and outcome were recorded. RESULTS All 6 cats identified with PVT also had hepatic disease. Evidence of a congenital portosystemic shunt was present in 3/6 cats. Two cats had primary or metastatic hepatic neoplasia. One cat had acute cholangitis, acute pancreatitis, and locally extensive acute centrilobular hepatic necrosis. Two cats were suspected to have acute thrombi and 4 cats had chronic thrombi. CONCLUSION AND CLINICAL SIGNIFICANCE PVT might be an important concurrent finding in cats with hepatic disease.

Risk factors for perioperative death in dogs undergoing splenectomy for splenic masses: 539 cases (2001–2012)

OBJECTIVE To determine the perioperative mortality rate, causes of death, and risk factors for perioperative death in dogs undergoing splenectomy for splenic mass lesions. DESIGN Retrospective case series. ANIMALS 539 dogs. PROCEDURES Medical records of dogs that underwent splenectomy for known splenic masses were reviewed. Perioperative mortality rate and causes of death were determined. Associations between potential prognostic factors and perioperative death were evaluated by multivariable logistic regression analysis. RESULTS 41 of 539 (7.6%) dogs died during the perioperative period. Thrombotic and coagulopathic syndromes and uncontrolled bleeding from metastatic lesions were the most common causes of death. Of the variables selected for multivariable analysis, platelet count at admission, whether PCV at admission was < 30%, and development of ventricular arrhythmias during surgery were significantly associated with outcome. For each decrease in platelet count of 10,000 platelets/μL, odds of death increased by approximately 6%. For dogs with PCV < 30%, odds of death were approximately twice those for dogs with PCV ≥ 30%, and for dogs that developed intraoperative arrhythmias, odds of death were approximately twice those for dogs that did not. CONCLUSIONS AND CLINICAL RELEVANCE Marked preoperative thrombocytopenia or anemia and development of intraoperative ventricular arrhythmias were identified as risk factors for perioperative death in dogs with splenic masses. The risk of death may be limited by efforts to prevent thrombotic and coagulopathic syndromes and to control all sources of intra-abdominal hemorrhage.

Transfusion practices for treatment of dogs undergoing splenectomy for splenic masses: 542 cases (2001–2012)

OBJECTIVE To describe transfusion practices for treatment of dogs undergoing splenectomy for splenic masses. DESIGN Retrospective case series. ANIMALS 542 client-owned dogs. PROCEDURES Medical records of dogs that underwent splenectomy for splenic masses at 2 referral institutions were reviewed. Variables of interest were compared between dogs that did and did not undergo transfusion. Multiple logistic regression analysis was performed to assess associations of transfusion with death during hospitalization and with 30- and 180-day survival rates. RESULTS Transfusions were administered to 240 of 542 (44%) dogs; packed RBCs were the most frequently administered blood product. On admission, dogs that subsequently received transfusions had higher mean illness severity score, heart rate, respiratory rate, blood lactate concentration, and prothrombin time, with lower mean PCV, platelet count, serum total solids and albumin concentrations, and base deficit than dogs that did not receive transfusions. Hemoperitoneum and malignancy, especially hemangiosarcoma, were more common in the transfusion group. Overall, 500 of 542 (92%) dogs survived to discharge. Dogs that received transfusions had higher odds of death or euthanasia while hospitalized and lower odds of surviving to 30 or 180 days after hospital discharge than dogs that did not. CONCLUSIONS AND CLINICAL RELEVANCE Evidence of shock, anemia, and hypocoagulability were apparent triggers for the decision to perform blood transfusion in dogs undergoing splenectomy for splenic masses and were likely attributable to hemoperitoneum and related hypovolemia. Dogs undergoing transfusion more commonly had malignant disease and had greater odds of poor long-term outcome, compared with dogs that did not undergo transfusion.

Transfusion practices for treatment of dogs hospitalized following trauma: 125 cases (2008–2013)

OBJECTIVE To describe transfusion practices for treatment of dogs hospitalized because of traumatic injuries. DESIGN Retrospective case series. ANIMALS 125 client-owned dogs. PROCEDURES Medical records of dogs that sustained trauma and were hospitalized for ≥ 24 hours after emergency stabilization were reviewed. Admission characteristics and transfusion-specific data were assessed. Receiver operating characteristic curves were plotted to evaluate diagnostic utility of PCV and serum total solids concentration as predictors of transfusion in the study population. RESULTS 45 of 125 (36%) dogs received transfusions. Packed RBCs were the most commonly administered blood product (42/45 [93%]). Common reasons for transfusion included perioperative hemodynamic support and treatment of shock or worsening anemia. Dogs that underwent transfusion had higher mean heart rate, blood lactate concentration, and animal trauma triage scores, with lower mean PCV, serum total solids concentration, and rectal temperature at admission than dogs that did not undergo transfusion. Total solids concentration and PCV at admission were specific but insensitive predictors of subsequent transfusion. Most (109/125 [87%]) dogs survived to hospital discharge. Significantly fewer dogs that had transfusions survived, compared with dogs that did not have transfusions. Seven of 10 dogs that received massive transfusions survived to discharge. CONCLUSIONS AND CLINICAL RELEVANCE Apparent clinical triggers for the decision to perform blood transfusion in dogs hospitalized following traumatic injury included evidence of shock or worsening anemia on admission and requirement for perioperative hemodynamic optimization. Although dogs that received transfusions had a lower survival rate than dogs that did not, this was likely attributable to greater severity of injuries in the transfusion group.