Aortic and iliac thrombosis in six dogs

Ultrasonographic findings of abdominal thrombosis in dogs

ABSTRACT This retrospective case series study describes the clinical and vascular ultrasound findings of 26 dogs diagnosed with abdominal thrombosis. Images were selected based on the detection of intravascular echogenic thrombus or the absence of vascular flow on color Doppler, confirmed by surgery or necropsy. Images were acquired using the Mylab 40 model, with linear and microconvex multifrequency probes. All the reports were evaluated along with the corresponding images by a veterinary diagnostic imaging radiologist. The ultrasonographic aspects evaluated were echogenicity (92.3%), anechogenicity (7.7%), vascularization (11.5%), mineralization (15.4%), and recanalization (7.7%) of the thrombosis. The vascular and hemodynamic findings were dilation of the affected vein (57.7%), total occlusion of blood flow (30.8%), presence of turbulent flow (65.38%), and visualization of smoke signal (blood flow detected as moving echogenic points in dynamic bidimensional mode) (11.5%). Neoplasms (19 cases) and nephropathies (13 cases) were the most common clinical conditions in the affected dogs. Eleven cases of vascular invasion due to adrenal neoplasms were identified. The results indicate that the vascular ultrasound examination is an important method for diagnosis, as 23 of the 26 cases did not show any clinical signs of thrombosis.

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

OBJECTIVES

To expand the number of conditions and interventions explored for their associations with thrombosis in the veterinary literature and to provide the basis for prescribing recommendations.

DESIGN

A population exposure comparison outcome format was used to represent patient, exposure, comparison, and outcome. Population Exposure Comparison Outcome questions were distributed to worksheet authors who performed comprehensive searches, summarized the evidence, and created guideline recommendations that were reviewed by domain chairs. The revised guidelines then underwent the Delphi survey process to reach consensus on the final guidelines. Diseases evaluated in this iteration included heartworm disease (dogs and cats), immune-mediated hemolytic anemia (cats), protein-losing nephropathy (cats), protein-losing enteropathy (dogs and cats), sepsis (cats), hyperadrenocorticism (cats), liver disease (dogs), congenital portosystemic shunts (dogs and cats) and the following interventions: IV catheters (dogs and cats), arterial catheters (dogs and cats), vascular access ports (dogs and cats), extracorporeal circuits (dogs and cats) and transvenous pacemakers (dogs and cats).

RESULTS

Of the diseases evaluated in this iteration, a high risk for thrombosis was defined as heartworm disease or protein-losing enteropathy. Low risk for thrombosis was defined as dogs with liver disease, cats with immune-mediated hemolytic anemia, protein-losing nephropathy, sepsis, or hyperadrenocorticism.

CONCLUSIONS

Associations with thrombosis are outlined for various conditions and interventions and provide the basis for management recommendations. Numerous knowledge gaps were identified that represent opportunities for future studies.

Case Report: Non-traumatic Unilateral Forelimb Arterial Thrombosis Associated With Hyperadrenocorticism in a Dog

A 16-year-old spayed female Pomeranian dog was presented to the hospital with an acute onset of pain and non-weight-bearing lameness in the right forelimb. On physical examination, knuckling, coolness, pain, and cyanosis were observed in the affected forelimb. Peripheral blood glucose concentration and body surface temperature differed between the right and left forelimbs. Hypercoagulable thromboelastographic results and increased D-dimer levels were suggestive of thrombus. Accordingly, recombinant tissue plasminogen activator (rtPA) was administered intravenously. Prompt clinical improvements (including restored warmth of the affected limb) occurred, and rtPA was discontinued after two shots administered 2 h apart owing to concerns of bleeding side effects. The dog was discharged 6 days after admission, and outpatient treatment with clopidogrel was continued for the prevention of re-thrombosis. Following patient stabilization, further examinations for underlying diseases of hypercoagulability were conducted; hyperadrenocorticism (HAC) was diagnosed, and oral trilostane therapy was thus administered. Eight weeks later, the patient regained normal mobility. Finally, in the present canine patient with arterial thrombosis, thrombolysis with rtPA successfully improved clinical symptoms and the following administration of clopidogrel inhibited the formation of additional thrombus.

Brachial artery thrombosis in a dog causing monoparesis mimicking nerve sheath tumor

There are few differential diagnoses for non‐orthopedic thoracic limb lameness in adult dogs aside from nerve tumors and disk‐associated nerve compression; this report introduces another etiology. A 9‐year‐old male castrated mixed dog presented with an episodic history of nonweight‐bearing thoracic limb lameness. Additional clinical signs included an atrophied thoracic limb with cool paw pads and painful axillary region. Magnetic resonance imaging, computed tomography, ultrasound, and exploratory surgery confirmed a chronic thrombus of the right brachial artery. No underlying cause for the thrombus was identified. The dog has been successfully managed on long‐term rivaroxaban and clopidogrel. Follow‐up ultrasound of the thrombus suggested early remodeling.

[Trichinella induced polymyositis with unilateral lameness in a dog]

A 9-year-old Cairn Terrier was presented for a right thoracic limb lameness of 3-month duration resistant to anti-inflammatory pain treatment. Blood chemistry revealed a highly elevated creatine kinase activity. An orthopedic or vascular etiology of the lameness was excluded by radiographs, computed tomography, and magnetic resonance imaging. Further workup for a neurologic or muscular etiology by electromyography, nerve conduction velocity measurement, and histology of muscle as well as nerve biopsies identified the cause of the lameness. Histology revealed a pyogranulomatous, necrotizing myositis with parasites of the species Trichinella. Furthermore different developmental stages of fungi were detected which were identified as Mucor sp. Treatment with albendazole and itraconazole significantly improved the patient's clinical signs.

Outcome and treatments of dogs with aortic thrombosis: 100 cases (1997-2014)

Background

Aortic thrombosis (ATh) is an uncommon condition in dogs, with limited understanding of risks factors, outcomes, and treatments.

Objectives/Hypothesis

To describe potential risk factors, outcome, and treatments in dogs with ATh.

Animals

Client‐owned dogs with a diagnosis of ATh based on ultrasonographic or gross necropsy examination.

Method

Multicentric retrospective study from 2 academic institutions.

Results

One hundred dogs were identified. Anti‐thrombin diagnosis, 35/100 dogs were nonambulatory. The dogs were classified as acute (n = 27), chronic (n = 72), or unknown (n = 1). Fifty‐four dogs had at least one comorbidity thought to predispose to ATh, and 23 others had multiple comorbidities. The remaining 23 dogs with no obvious comorbidities were classified as cryptogenic. Concurrent illnesses potentially related to the development of ATh included protein‐losing nephropathy (PLN) (n = 32), neoplasia (n = 22), exogenous corticosteroid administration (n = 16), endocrine disease (n = 13), and infection (n = 9). Dogs with PLN had lower antithrombin activity than those without PLN (64% and 82%, respectively) (P = .04). Sixty‐five dogs were hospitalized with 41 subsequently discharged. Sixteen were treated as outpatient and 19 euthanized at admission. In‐hospital treatments varied, but included thrombolytics (n = 12), alone or in combination with thrombectomy (n = 9). Fifty‐seven dogs survived to discharge. Sixteen were alive at 180 days. Using regression analysis, ambulation status at the time of presentation was significantly correlated with survival‐to‐discharge (P < .001).

Conclusions/Clinical Importance

Dogs with ATh have a poor prognosis, with nonambulatory dogs at the time of presentation having worse outcome. Although the presence of comorbid conditions associated with hypercoagulability is common, an underlying cause for ATh was not always identified.

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.

Consensus on the Rational Use of Antithrombotics in Veterinary Critical Care (CURATIVE): Domain 2-Defining rational therapeutic usage

OBJECTIVES

To systematically review available evidence to determine when small animals at risk of thrombosis should be treated with antiplatelet agents and anticoagulants, which antiplatelet and anticoagulant agents are most effective, and when multimodal therapy is indicated.

DESIGN

Standardized, systematic evaluation of the literature, categorization of relevant articles according to level of evidence (LOE) and quality (Good, Fair, or Poor), and development of consensus on conclusions via a Delphi-style survey for application of the concepts to clinical practice. 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

Databases searched included Medline via PubMed and CAB abstracts. Twelve Population Intervention Comparison Outcome questions were devised and generated corresponding worksheets investigating indications for use of antithrombotic drugs in small animals. Seventy-eight studies were reviewed in detail. Most studies assessed were experimentally controlled laboratory studies in companion animals (56 LOE 3) with smaller numbers of LOE 2 (1), LOE 4 (5), LOE 5 (6), and LOE 6 (4) studies assessed. Only 5 randomized controlled clinical trials were identified (LOE 1, Good-Fair). The 12 worksheets generated 21 guidelines with 17 guideline statements that were refined during 3 rounds of Delphi surveys. A high degree of consensus was reached across all guideline recommendations during the Delphi process.

CONCLUSIONS

Overall, systematic evidence evaluations generated 2 strong recommendations, 19 weak recommendations (formulated as suggestions), 9 situations where the evidence was insufficient to make strong recommendations, and 8 situations where no relevant evidence was retrieved to aid guideline generation. Numerous significant knowledge gaps were highlighted by the evidence reviews undertaken, indicating the need for substantial additional research in this field.

Vascular surgery of aortic thrombosis in a dog using Fogarty maneuver - technical feasibility

Aortic thromboembolism is a rare and life‐threatening disease in dogs. This report aims to describe the successful surgical treatment by use of a Fogarty Thrombectomy Catheter in an 8‐year‐old patient. The postsurgical intensive care therapy to prevent ischemia‐reperfusion syndrome is specified, despite poor outcome in our case (owner elected euthanasia).

Multicenter evaluation of signalment and comorbid conditions associated with aortic thrombotic disease in dogs

OBJECTIVE To assess signalment and concurrent disease processes in dogs with aortic thrombotic disease (ATD). DESIGN Retrospective case-control study. ANIMALS Dogs examined at North American veterinary teaching hospitals from 1985 through 2011 with medical records submitted to the Veterinary Medical Database. PROCEDURES Medical records were reviewed to identify dogs with a diagnosis of ATD (case dogs). Five control dogs without a diagnosis of ATD were then identified for every case dog. Data were collected regarding dog age, sex, breed, body weight, and concurrent disease processes. RESULTS ATD was diagnosed in 291 of the 984,973 (0.03%) dogs included in the database. The odds of a dog having ATD did not differ significantly by sex, age, or body weight. Compared with mixed-breed dogs, Shetland Sheepdogs had a significantly higher odds of ATD (OR, 2.59). Protein-losing nephropathy (64/291 [22%]) was the most commonly recorded concurrent disease in dogs with ATD. CONCLUSIONS AND CLINICAL RELEVANCE Dogs with ATD did not differ significantly from dogs without ATD in most signalment variables. Contrary to previous reports, cardiac disease was not a common concurrent diagnosis in dogs with ATD.

Thromboelastographic monitoring of the effect of unfractionated heparin in healthy dogs

OBJECTIVE

To characterize the correlation between thromboelastography (TEG) variables using strong activators and anti-Xa (AXa) activity in healthy dogs administered subcutaneous unfractionated heparin (UFH).

DESIGN

Prospective experimental study.

SETTING

University research facility.

ANIMALS

Eight adult random-source male dogs.

INTERVENTION

Dogs were randomized to receive subcutaneous UFH at 200, 250, or 300 IU/kg every 8 hours for a total of 10 injections. Blood samples were collected at time 0 (preheparin) and 3, 6, and 8 hours after the 1st (Day 1) and 10th (Day 4) UFH injection.  After the 8-hour blood sample was obtained on day 4, a 100 IU/kg IV bolus of UFH was administered and an additional blood sample was collected 1 hour later (hour 9). AXa activity, activated partial thromboplastin time (aPTT), and TEG (with up to 5 activators) were performed at each time point.  Modes of activation for TEG included  recalcified (Ca), Ca with heparinase (CaH), CaH and tissue factor 1:3600 (CTF3600H), Ca with tissue factor 1:100 (CTF100), and RapidTEG. Spearman rank correlations were calculated for each of the aforementioned parameters and the AXa activity. P-values were corrected for multiple comparisons with a Bonferroni correction.

MEASUREMENTS AND MAIN RESULTS

Significant correlations were found between AXa activity and the TEG R values generated with CTF100 (R = 0.83, P ≤ 0.0001) and RapidTEG (R = 0.90, P < 0.0001), as well as both forms of aPTT measurement (R = 0.86 and 0.84, P < 0.0001).

CONCLUSIONS

This study demonstrates that TEG variables derived using robust activation correlate with AXa activity as well as aPTT and have the potential to be used for monitoring UFH therapy in healthy dogs.  Future studies are warranted to evaluate its diagnostic utility in critically ill animals.

Surgical Removal of a Canine Aortic Thromboembolism Secondary to Pancreatitis

A 7-year-old castrated male Pomeranian was evaluated on emergency for diagnostic work-up and treatment for acute nonpainful paraparesis. The neurologic examination suggested a L4-S3 myelopathy, but physical examination revealed lack of femoral pulses and rectal hypothermia, as well as a grade II/VI systolic heart murmur, so ischemic neuromyopathy was suspected. Clinicopathologic analysis revealed increased muscle enzymes and proteinuria. Abdominal ultrasonography confirmed aortic thromboembolism (ATE), and surgical histopathology diagnosed necrotizing pancreatitis. Surgical aortic thrombectomy was performed, and antithrombotic therapy was instituted. Pancreatitis was treated supportively. The dog was discharged to the owners after 10 days of hospitalization. Recheck examination 6 weeks after initial presentation revealed a normal neurologic examination and normal femoral pulses. The patient has had no further bouts of pancreatitis and remains neurologically normal 5 years after initial presentation. Canine ATE is relatively rare compared to the feline counterpart. Directed therapy for feline ATE is often not recommended, as underlying conditions are oftentimes ultimately fatal. Underlying etiologies for canine ATE include cardiovascular disease and endocrinopathies, but canine ATE secondary to pancreatitis has not yet been reported. Surgical removal of aortic thromboembolus should be considered as curative for pelvic limb dysfunction in the canine patient without a terminal underlying disease.

Peripheral and central venous blood glucose concentrations in dogs and cats with acute arterial thromboembolism

Background

Acute limb paralysis because of arterial thromboembolism (ATE) occurs in cats and less commonly in dogs. ATE is diagnosed based on physical examination findings and, occasionally, advanced imaging.

Hypothesis/Objectives

Peripheral, affected limb venous glucose concentration is decreased in ATE, whereas its systemic concentration is within or above reference interval.

Animals

Client‐owned cats and dogs were divided into 3 respective groups: acute limb paralysis because of ATE (22 cats and 9 dogs); acute limb paralysis secondary to orthopedic or neurologic conditions (nonambulatory controls; 10 cats and 11 dogs); ambulatory animals presented because of various diseases (ambulatory controls; 10 cats and 9 dogs).

Methods

Prospective observational, clinical study. Systemic and local (affected limb) blood glucose concentrations were measured. Their absolute and relative differences (ΔGlu and %ΔGlu, respectively) were compared among groups.

Results

ΔGlu and %ΔGlu were significantly higher in the ATE cats and dogs groups, compared to both of their respective controls (P < .0001 and P < .001, respectively). No significant differences were observed between the control groups. Receiver operator characteristics analysis of ΔGlu and %ΔGlu as predictors of ATE had area under the curve of 0.96 and 0.99 in cats, respectively, and 1.00 and 1.00, in dogs, respectively. ΔGlu cutoffs of 30 mg/dL and 16 mg/dL, in cats and dogs, respectively, corresponded to sensitivity and specificity of 100% and 90% in cats, respectively, and 100% in dogs.

Conclusions and Clinical Importance

ΔGlu and %ΔGlu are accurate, readily available, diagnostic markers of acute ATE in paralyzed cats and dogs.

Diseases associated with thrombosis

Coagulation abnormalities are commonly encountered in critical illness. Traditionally, clinically relevant coagulation disorders have consisted mostly of bleeding associated with advanced stages of disseminated intravascular coagulation or toxin ingestion. However, advances in critical care have highlighted hypercoagulability as a clinically relevant state that must be recognized and treated to optimize the chances of a positive outcome. Retrospective studies of dogs with confirmed thrombosis in varying locations have identified populations most likely to experience hypercoagulable states. Diseases most frequently complicated by thrombosis include immune-mediated disease, neoplasia, systemic inflammation and sepsis, cardiac disease, protein-losing states, and infectious diseases. In this report, the existing retrospective studies will be discussed along with a review of specific disease processes that predispose to a hypercoagulable state. Studies targeting those populations most at risk for thrombotic complications are necessary for better understanding the need for prophylactic anticoagulant therapy.

Aortic thrombosis in dogs: presentation, therapy, and outcome in 26 cases

OBJECTIVES

The pathogenesis and presentation of aortic thrombosis (AT) in dogs is not well characterized and an effective antithrombotic therapy for AT in dogs has not been identified. Our goal is to report the clinical presentation and results of therapies in dogs with AT.

ANIMALS

Twenty-six client-owned dogs.

METHODS

Retrospective review of medical records of dogs diagnosed with AT between 2003 and 2010.

RESULTS

Twenty-six dogs had an apparent primary mural aortic thrombus. None had structural heart disease at diagnosis. Twenty dogs were ambulatory with varying degrees of pelvic limb dysfunction. Duration of ambulatory dysfunction was 7.8 weeks (range 1 day-52 weeks). A majority of dogs (58%) had no concurrent conditions at diagnosis. Fourteen dogs were treated with a standard warfarin protocol for a median period of 22.9 months (range 0.5-53 months). Ambulatory function improved in all dogs treated with warfarin. Time until clinical improvement was 13.9 days (range 2-49 days). Dogs treated with warfarin did not become non-ambulatory, die or undergo euthanasia related to AT, or have a known serious hemorrhagic event.

CONCLUSIONS

The pathogenesis of AT in dogs is distinct from that of aortic thromboembolism (ATE) in cats. Aortic thrombosis in dogs is more likely to involve local thrombosis in the distal aorta with embolization to the arteries of the pelvic limb resulting in chronic progressive ambulatory dysfunction. Chronic warfarin administration is well-tolerated and appears to be an effective short-term and long-term therapy for dogs with AT.

Mesenteric Vascular Thrombosis Associated with Disseminated Abdominal Visceral Hemangiosarcoma in a Cat

An adult castrated male cat was evaluated because of a 4 day history of lethargy and partial anorexia. Physical examination revealed abdominal pain with a palpable fluid wave. Cytologic and biochemical analyses of peritoneal effusion were suggestive of septic peritonitis. On surgical exploration of the abdomen, the mesenteric vessels had no palpable pulses and they contained gross thromboses. The intestines were white with no visible peristalsis. Necropsy findings included disseminated, poorly differentiated hemangiosarcoma throughout the abdomen. Mesenteric arterioles contained fibrin thrombi. To the author's knowledge, no previous reports exist of complete mesenteric vascular thrombosis associated with disseminated abdominal visceral hemangiosarcoma in a cat.

Thromboembolic Conditions, Aetiology Diagnosis and Treatment in Dogs and Cats

In veterinary medicine, thrombo-embolism (TE) is an under-appreciated medical condition that requires immediate recognition. Since TE is multifactorial and its mode of presentation may vary, veterinarians face great difficulties in making a definitive diagnosis in a timely manner. In addition, most of the underlying conditions that give rise to TE are life-threatening and an aggressive diagnostic and therapeutic approach is required. Not only does the diagnosis and treatment of this condition require the collaboration of many specialties, the costs of therapy can be excessive with a high risk of recurrence. As such, owners have to be thoroughly informed before the therapy commences. While TE has been well-characterized in humans and is associated with significant morbidity and mortality, little information of similar quality is available in veterinary medicine. In addition, TE in animals is distinct from its human counterpart and we cannot simply adapt what is known from human clinical trials. With the promise of improvements in imaging modalities that improve our diagnostic capabilities, the window of opportunity to treat TE increases. This article focuses on aetiology, clinical presentation, diagnosis, and treatment of dogs and cats affected by TE.

Pneumothorax secondary to pulmonary thromboembolism in a dog

OBJECTIVE

To describe a case of spontaneous pneumothorax secondary to pulmonary thromboembolism possibly associated with pituitary dependent hyperadrenocorticism.

CASE SUMMARY

A 7-year-old spayed female Collie weighing 26 kg was referred for evaluation of spontaneous pneumothorax. An exploratory thoracotomy was performed and revealed 2 lung lobes to be diffusely hemorrhagic and they were resected. Histologic examination of multiple sections documented diffuse thromboembolism. A 2-3 cm thrombus was visualized distal to the bifurcation of the pulmonary artery during an echocardiographic examination postoperatively. The dog was discharged to the owner after recovery from surgery. The thrombus had resolved at the 4-week recheck examination. Diagnosis of pituitary dependent hyperadrenocorticism was confirmed based on follow-up endocrine testing.

NEW OR UNIQUE INFORMATION PROVIDED

This is the first report of pulmonary thromboembolism causing spontaneous pneumothorax in the dog.

Distal abdominal aortic thrombosis diagnosed by three-dimensional contrast-enhanced magnetic resonance angiography

Contrast enhanced magnetic resonance angiography (MRA) can provide noninvasive relatively rapid three-dimensional high-detailed vascular images over large anatomic areas. There are few descriptions of the use of contrast-enhanced MRA in veterinary patients. This is a report illustrating the use of contrast-enhanced MRA to localize the full extent of distal aortic, external iliac, and femoral artery thrombi confirmed surgically in four dogs. Distal aorta contrast-enhanced MRA was anatomically accurate in detecting the full extent of thrombi involving the aorta, external iliac and femoral arteries in these four canine patients. This procedure can provide important information for surgery.

Cushing's disease complicated with thrombosis in a dog

Thrombosis is a potential complication of hyperadrenocorticism (HAC) in dogs. An 8-year-old male Beagle diagnosed with pituitary-dependent HAC had complicated with thrombosis in the caudal vena cava and abdominal aorta, which was treated by hypophysectomy and antithrombotic therapy. After hypophysectomy, hypercortisolemia disappeared and the general condition was also significantly improved. Ultrasonography after hypophysectomy revealed that the thrombus remained in the abdominal aorta, but the thrombus in the caudal vena cava had disappeared. However 692 days after the hypophysectomy, the dog had an acute onset of dyspnea and died. Postmortem examination revealed the presence of thrombi in the abdominal aorta and the pulmonary artery. Observations from this case show that HAC dogs must be attention to thrombosis.

IMAGING DIAGNOSIS?AORTIC THROMBOEMBOLISM ASSOCIATED WITH SPIROCERCOSIS IN A DOG

An 8-year-old neutered female Rhodesian Ridgeback developed acute, nonneurological right pelvic limb lameness. Femoral pulsation was poor, and oscillometric blood pressure measurements between the two pelvic limbs differed markedly. A caudal aortic right external iliac embolus was detected sonographically. Radiographically, there was a caudal esophageal mass and thoracic vertebral spondylitis typical of spirocercosis. Using CT-angiography, a caudal thoracic aortic aneurysm with a mural thrombus was detected. The dog recovered following heparin and aspirin therapy but signs recurred 7 months later. Subsequently, the patient improved on treatment and remains asymptomatic. This report illustrates the value of CT-angiography in detecting aortic thrombosis in dogs with spirocercosis.

Normal morphometry of the thoracic aorta in the german shepherd dog: a computed tomographic study

Computed tomographic images of the thoracic aorta of 14 German shepherd dogs were examined in order to determine the morphometry of the thoracic aorta. Examinations were carried out in the transverse plane at both intervertebral and mid-vertebral levels of each thoracic vertebra between T(5) and T(13). The dorsoventral and transversal diameters as well as cross-section area of the thoracic aorta were measured. The widest transversal diameter was observed at T(4-5), whereas the largest dorsoventral diameter was detected at T(5). The maximum cross-section area was detected at T(4-5). When dorsoventral and transversal diameters were compared between males and females, the aortic diameter was found to be smaller in males than in females. Although the shape of the thoracic aorta was transversal oval in the majority of the examined females, the shape of the thoracic aorta was dorsoventral oval in the majority of the males. There were significant differences between all levels measured for transversal (P < 0.001), dorsoventral (P < 0.001) diameters and cross-section area (P < 0.001) of the thoracic aorta. And there was a significant correlation between the three parameters examined. However, the correlation coefficient was highest in females.

Thromboembolic Therapies in Dogs and Cats: An Evidence-Based Approach

In veterinary medicine, we are forced to make use of less than ideal "evidence," such as extrapolation from experimental studies in dogs and cats without naturally occurring diseases and from clinical trials in other species (particularly human clinical trials), as well as limited information gained from veterinary clinical experience, small clinical trials, case studies, and anecdotal reports. In this article, specific treatment recommendations are made for each of the common thromboembolic conditions seen in dogs and cats. These recommendations are made with the important caveat that, to date, such suggested therapeutic approaches are based on limited evidence.

Aortic and iliac thrombosis associated with angiosarcoma of skeletal muscle in a dog

A seven-year-old, neutered male greyhound was presented with a history of episodic shifting hindlimb lameness and pain. Ischaemic necrosis of areas of the hindlimb digits and skin and a firm swelling within the medial right thigh musculature were found on physical examination. Investigation demonstrated thrombosis of the terminal aorta and right external iliac artery with ischaemic necrosis of muscular and dermal tissue distal to the sites of thrombosis. The dog was euthanased due to poor prognosis. Necropsy findings were of a poorly differentiated invasive sarcoma of the skeletal muscle of the proximal right hindlimb, thrombosis of the aorta and right external iliac artery and secondary renal glomerulopathy. Immunohistochemistry of the neoplastic tissue indicated angiosarcoma based on expression of CD31 and factor VIII-related antigen. Thrombosis was considered likely to be due to systemic hypercoagulability because of the presence of altered flow characteristics and endothelial damage in the vascular tumour bed. Aortoiliac thrombosis, paraparesis and hindlimb ischaemia are unusual sequelae of angiosarcoma in the dog.

Aortic thromboembolism associated with Spirocerca lupi infection

A 2-year-old male castrated Cavalier King Charles Spaniel was presented with paraplegia, cold caudal extremities and lack of femoral pulses. A 2cm long thrombus occluding the aortic trifurcation and a 3cm long abdominal aortic aneurysm with a thrombus were detected by ultrasonographic examination. The clinical and ultrasonographic findings were consistent with aortic thromboembolism. Anti-thrombotic and vasodilative therapy was not helpful and the dog was euthanized 3 days after the onset of paraplegia. A thrombus in the aortic trifurcation, multiple thoracic and abdominal aneurysms and a distal mediastinal esophageal granuloma containing Spirocera lupi worms were found on necropsy. The abdominal aortic aneurysms formed by S. lupi larval migration are believed to be responsible for the formation of the thrombus that occluded the aortic trifurcation. This is the first report of aortic thromboembolism associated with S. lupi infection.

Haemangiosarcoma of the urinary bladder in a dog

Haemangiosarcoma of the urinary bladder is reported in a dog. The bladder mass was detected incidentally during physical examination. Partial cystectomy with unilateral ureteroneocystostomy were performed to remove the tumour en bloc. Necrosis of the urinary bladder was diagnosed 10 days postoperatively and the dog was euthanased.