Thoracoscopic thoracic duct ligation and thoracoscopic pericardectomy for treatment of chylothorax in dogs.

OBJECTIVE: To report the use of thoracoscopic thoracic duct ligation (TDL) and pericardectomy for treatment of chylothorax. STUDY DESIGN: Case series. ANIMALS: Dogs with chylothorax (n=12). METHODS: Dogs with secondary or idiopathic chylothorax had thoracoscopy performed in sternal recumbency through 3 portals in the caudal right hemithorax for TDL and were then repositioned in dorsal recumbency for pericardectomy. Portals were placed in the 5th and 7th intercostal spaces of the right hemithorax with 1 transdiaphragmatic portal in the right paraxiphoid position. Follow-up was performed by recheck examination or telephone interview to determine outcome. RESULTS: Seven dogs (58%) had idiopathic chylothorax; 6 dogs (85.7%) had complete resolution of their effusion, whereas only 2 of the 5 nonidiopathic dogs (40%) had complete resolution. CONCLUSIONS: Thoracoscopy is minimally invasive, provides excellent observation, and allows for ligation of the thoracic duct in the caudal thorax. Patients with idiopathic chylothorax may have a better prognosis after TDL and pericardectomy than dogs with nonidiopathic chylothorax. CLINICAL RELEVANCE: Thoracoscopy for ligation of the thoracic duct and pericardectomy is an acceptable surgical technique for treatment of chylothorax.

Mortality rate and prognostic factors for dogs with severe anaphylaxis: 67 cases (2016-2018).

OBJECTIVE: To determine mortality rates for dogs with severe anaphylaxis and identify potential prognostic factors. ANIMALS: 67 dogs with suspected anaphylaxis graded as severe. PROCEDURES: Dogs were classified on the basis of outcome as survivors and nonsurvivors. Medical records were reviewed, and data were extracted including signalment, examination findings, time to hospital admission from onset of clinical signs, CBC results, serum biochemical analysis results, coagulation testing results, and findings on abdominal ultrasonography. Initial treatment within the first 6 hours after hospital admission was recorded for analysis, specifically including the use of epinephrine, diphenhydramine, corticosteroids, antimicrobials, fresh-frozen plasma, and supplemental dextrose. RESULTS: The overall mortality rate was 14.9% (10/67) for dogs with anaphylaxis graded as severe. Serum phosphorus concentration and prothrombin time (PT) were significantly higher in nonsurvivors, compared with survivors. Nonsurvivors had lower presenting body temperatures than survivors. Serum phosphorus concentration ≥ 12.0 mmol/L, hypoglycemia within 6 hours after hospital admission, high PT value, concurrently high PT and partial thromboplastin time (PTT) values > 50% above the reference range limit, and the need for supplemental dextrose were associated with death. The incidences of coagulopathy and peritoneal effusion were unexpectedly high (85.2% and 65.5% of dogs, respectively) but were not indicative of survival. CONCLUSIONS AND CLINICAL RELEVANCE: Despite the poor presenting clinical condition seen in dogs with severe anaphylaxis, the rate of survival with treatment was fairly high. Coagulopathy and the presence of peritoneal effusion were common findings in dogs with severe anaphylaxis. Serum phosphorus concentration ≥ 12.0 mmol/L, high PT value, concurrent increases of PT and PTT values > 50% above reference range limits, hypoglycemia within 6 hours after hospital admission, and the need for supplemental dextrose were associated with death.

Consensus on the Rational Use of Antithrombotics in Veterinary Critical Care (CURATIVE): Domain 5-Discontinuation of anticoagulant therapy in small animals.

OBJECTIVES: To systematically evaluate the evidence supporting the timing and mechanisms of permanent or temporary discontinuation of antiplatelet or anticoagulant medications in small animals DESIGN: Standardized, systematic evaluation of the literature, categorization of relevant articles according to level of evidence and quality (poor, fair, or good), and development of consensus on conclusions via a Delphi-style survey for application of the concepts to clinical practice. SETTINGS: Academic and referral veterinary medical centers. RESULTS: Databases searched included Medline via PubMed and CAB abstracts. Two specific courses of inquiry were pursued, one focused on appropriate approaches to use for small animal patients receiving antiplatelet or anticoagulant drugs and requiring temporary discontinuation of this therapy for the purposes of invasive procedures (eg, surgery), and the other aimed at decision-making for the complete discontinuation of anticoagulant medications. In addition, the most appropriate methodology for discontinuation of heparins was addressed. CONCLUSIONS: To better define specific patient groups, a risk stratification characterization was developed. It is recommended to continue anticoagulant therapy through invasive procedures in patients at high risk for thrombosis that are receiving anticoagulant therapy, while consideration for discontinuation in patients with low to moderate risk of thrombosis is reasonable. In patients with thrombosis in whom the underlying cause for thrombosis has resolved, indefinite treatment with anticoagulant medication is not recommended. If the underlying cause is unknown or untreatable, anticoagulant medication should be continued indefinitely. Unfractionated heparin therapy should be slowly tapered rather than discontinued abruptly.

Effects of ketamine, diazepam, and their combination on intraocular pressures in clinically normal dogs.

OBJECTIVE: To evaluate the effects of ketamine, diazepam, and the combination of ketamine and diazepam on intraocular pressures (IOPs) in clinically normal dogs in which premedication was not administered. ANIMALS: 50 dogs. PROCEDURES: Dogs were randomly allocated to 1 of 5 groups. Dogs received ketamine alone (5 mg/kg [KET5] or 10 mg/kg [KET10], IV), ketamine (10 mg/kg) with diazepam (0.5 mg/kg, IV; KETVAL), diazepam alone (0.5 mg/kg, IV; VAL), or saline (0.9% NaCl) solution (0.1 mL/kg, IV; SAL). Intraocular pressures were measured immediately before and after injection and at 5, 10, 15, and 20 minutes after injection. RESULTS: IOP was increased over baseline values immediately after injection and at 5 and 10 minutes in the KET5 group and immediately after injection in the KETVAL group. Compared with the SAL group, the mean change in IOP was greater immediately after injection and at 5 and 10 minutes in the KET5 group. The mean IOP increased to 5.7, 3.2, 3.1, 0.8, and 0.8 mm Hg over mean baseline values in the KET5, KET10, KETVAL, SAL, and VAL groups, respectively. All dogs in the KET5 and most dogs in the KETVAL and KET10 groups had an overall increase in IOP over baseline values. CONCLUSIONS AND CLINICAL RELEVANCE: Compared with baseline values and values obtained from dogs in the SAL group, ketamine administered at a dose of 5 mg/kg, IV, caused a significant and clinically important increase in IOP in dogs in which premedication was not administered. Ketamine should not be used in dogs with corneal trauma or glaucoma or in those undergoing intraocular surgery.

Cardioversion of atrial fibrillation in a dog with structural heart disease using an esophageal-right atrial lead configuration.

Atrial fibrillation is a common arrhythmia in dogs with structural cardiac disease and can result in significant clinical signs. Several methods of electrical cardioversion of atrial fibrillation have been described. Biphasic transthoracic cardioversion of atrial fibrillation in dogs with naturally occurring heart disease has been described in veterinary medicine and has been shown to be highly successful. In humans and research animals intracardiac and transesophageal cardioversion of atrial fibrillation has been described as an alternative to transthoracic cardioversion. While transesophageal cardioversion is very successful in humans and research animals, this technique has not been previously described in a clinical patient with naturally occurring heart disease in veterinary medicine. This report describes the use of transesophageal cardioversion in a dog with atrial fibrillation and structural cardiac disease. Cardioversion was unsuccessful using two electrodes positioned within the esophagus. Cardioversion of atrial fibrillation to normal sinus rhythm was successfully achieved and maintained using one electrode positioned within the esophagus and one electrode positioned within the right atrium using a synchronized monophasic shock of 50 J.

Systematic evaluation of evidence on veterinary viscoelastic testing part 5: Nonstandard assays.

OBJECTIVE: To systematically examine the evidence on nontraditional uses of viscoelastic coagulation monitoring in veterinary species. DESIGN: Standardized, systematic evaluation of the literature, categorization of relevant articles according to level of evidence and quality, and development of consensus on conclusions for application of the concepts to clinical practice. SETTING: Academic and referral veterinary medical centers. RESULTS: Databases searched included Medline, CAB abstracts, and Google Scholar. CONCLUSIONS: Nontraditional assays identified included thrombelastography (TEG)-PlateletMapping (PM), functional fibrinogen assessment, and rapid-TEG (r-TEG). Direct veterinary evidence was found for only the ADP-activated PM, which appears to generate valid data in dogs but not cats or horses. Arachidonic acid activated PM shows high variability and requires further assessment and validation in veterinary species. Functional fibrinogen assays may be performed in veterinary species but may require modification due to species differences in response to abciximab. While tissue factor (TF)-activated TEG has been well described in the veterinary literature, the specific r-TEG assay has not been assessed, but presumably would be effective for generating TEG tracings and values for maximum amplitude and angle in shorter periods of time than some traditional assays.

Update on disseminated intravascular coagulation: when to consider it, when to expect it, when to treat it.

Disseminated intravascular coagulation (DIC) spans a continuum in which clinical signs can range from a prothrombotic to a hemorrhagic phenotype, with some patients suffering from both concurrently. DIC is always caused by an underlying condition, with most cases linked to systemic inflammation or infection. Numerous factors contribute to the development of DIC, including aberrations in endothelial function, and altered levels of endogenous procoagulant, anticoagulant, and fibrinolytic factors. Excessive thrombin generation, or failure to localize thrombin production, is the unifying theme throughout this broad condition. DIC can be described as overt or nonovert, each with varying degrees of severity. The ability to concisely define and diagnose such a broad condition has proven challenging, especially in veterinary medicine, where interspecies differences result in phenotypic variability. In most patients, DIC is recognized when a patient experiences noteworthy hematologic changes, such as a drop in circulating platelet count in concert with a 20% to 30% prolongation in the activated partial thromboplastin time. Similar to diagnosing, proven benefits of any particular therapy are difficult to identify. Despite these difficulties, therapy can be optimized with an understanding of the underlying pathology(ies). With appropriate care and a committed owner/veterinary team, patients with DIC can have a favorable outcome.

Effects of rest temperature, contact activation, and sample technique on canine thrombelastography.

OBJECTIVE: To determine the effects of rest temperature, contact activation (CA), and sample collection technique on thrombelastography (TEG) using canine whole blood. DESIGN: Prospective, experimental study. SETTING: University-based research facility. ANIMALS: Twelve healthy, adult, mixed-breed dogs. INTERVENTIONS: Blood was collected by jugular venipuncture. Tubes containing 3.2% sodium citrate, with and without 75 µg/mL corn trypsin inhibitor (CTI), were filled by vacuum. Samples rested for 30 minutes at 3 temperatures: 37°C, room temperature (RT, 20-22°C), or warmed to 37°C 5 minutes prior to analysis (prewarmed). Samples were analyzed at 37°C. CTI-treated samples were analyzed with and without 1:50,000 tissue factor (TF) as activator. Six dogs were also tested similarly using a needle/syringe collection technique. MEASUREMENT AND MAIN RESULTS: Prewarmed samples exhibited greater MA compared to RT (55.5 ± 7.2 mm vs. 53.5 ± 6.0, P< 0.05), while 37°C samples exhibited a steeper angle (56.7 ± 10.4°C vs. 52.4 ± 8.6°C) and greater MA (55.9 ± 7.5 mm vs. 53.5 ± 6.0 mm) than RT samples (both P< 0.05). CTI-treated samples were hypocoagulable (R time 45 min [7.5-56.8 min], angle 8.2°C [5.1-42.5°C], MA 29.2 ± 9.7 mm, P< 0.001), with TF activation returning all but the angle (42.5 ± 7.6°C) to values similar to citrated samples (angle = 56.7 ± 10.4°C, P = 0.017). Collection using a syringe/needle method revealed a shorter R time for prewarmed samples only (R time 4.7 ± 0.7 min, vs. 5.6 ± 0.8 min for vacuum-collected samples, P = 0.008). CONCLUSIONS: Even in the absence of exogenous activators, CA has an impact on canine TEG results. The effects of rest temperatures and sample collection technique on TEG appear to be minimal.

Sonoclot evaluation of whole blood coagulation in healthy adult dogs.

OBJECTIVE: To establish a standard protocol for analysis of canine whole blood and generate reference intervals for healthy dogs using the Sonoclot analyzer, and to compare Sonoclot values to standard and viscoelastic coagulation tests. DESIGN: Prospective study. SETTING: Veterinary University research facility and teaching hospital. ANIMALS: Twelve healthy random source dogs and 52 healthy dogs from the general veterinary school population. INTERVENTIONS: Blood sampling for viscoelastic coagulation testing. MEASUREMENTS AND MAIN RESULTS: Blood was collected from 12 healthy adult dogs by jugular venipuncture. After a rest period at room temperature of 30, 60, or 120 minutes, 340 µL of citrated blood was added to 20 µL of 0.2 M CaCl(2) in 1 of 2 cuvette types warmed to 37° C. Cuvettes contained a magnetic stir-bar with glass beads (gbACT+) or only a magnetic stir-bar (nonACT). Reference interval samples were collected from 52 healthy adult dogs and analyzed in duplicate. The ACT, CR, and PF were not affected by duration of rest period for either cuvette type. ACT variability was decreased when using gbACT+ cuvettes (P < 0.05). In normal dogs reference intervals (mean ± 2 SD) using gbACT+ cuvettes were: ACT 56.0-154.0 seconds, CR 14.85-46.0, and PF 2.1-4.05. ACT correlated to TEG R-time, K-time, and angle, while CR correlated with all TEG parameters. Fibrinogen correlated with ACT, CR, and PF. Sonoclot did not correlate with other common coagulation tests. CONCLUSIONS: Sonoclot provides viscoelastic evaluation of canine whole blood coagulation and correlated to several TEG parameters and fibrinogen. A standard protocol and reference intervals were established.

Spontaneous echocardiographic contrast in three dogs.

OBJECTIVE: To describe the clinical presentation and outcome in 3 dogs with spontaneous echocardiographic contrast (SEC). CASE OR SERIES SUMMARY: SEC was identified in 3 dogs with concurrent hyperfibrinogenemia. The dogs were diagnosed with different underlying conditions including infective endocarditis of the mitral valve (Case 1), presumptive Evan's syndrome (Case 2), and presumptive sepsis (Case 3). Various therapies were used in each case directed at their underlying condition, in addition to thromboprophylaxis that were based upon a perceived risk of thromboembolic disease. The 3 dogs in this series survived to discharge and had good outcome during the follow-up period, which ranged from 3 weeks to 7 months. NEW OR UNIQUE INFORMATION PROVIDED: SEC is considered a marker for thromboembolic disease in people and can occur in dogs in the absence of significant cardiomegaly. SEC in these 3 dogs may be related to the documented hyperfibrinogenemia. Further investigation is warranted to determine whether dogs with SEC are at an increased risk for thromboembolic complications.