Feline Aortic Thromboembolism: Recent advances and future prospects.

PRACTICAL RELEVANCE: Feline aortic thromboembolism (FATE) is commonly encountered in clinical medicine, especially in emergency situations. This often devastating syndrome usually develops secondarily to severe heart disease, and has short- and long-term consequences. CLINICAL FEATURES: The clinical presentation of FATE is consistent with peripheral ischemic neuropathy, usually in both pelvic limbs. Diagnosis is relatively straightforward, but can be assisted with Doppler ultrasound, point-of-care ultrasound or infrared thermal imaging. RECENT ADVANCES AND FUTURE PROSPECTS: Interpretation of survival rates in cats with FATE has been hampered by historically high admission euthanasia, but recent studies suggest a survival rate with supportive care of 30-40%. Moreover, with advances in post-FATE thromboprophylaxis, median survival times of over 1 year are being achieved. Future directions include use of thrombolytic agents and treatment of common FATE sequelae such as acute kidney injury and reperfusion injury. OUTLINE: This article, aimed at small animal veterinarians, including emergency practitioners, reviews key aspects of the clinical presentation, diagnosis and treatment options for FATE, with a view to guiding client and veterinarian decision-making. Three case studies are included to illustrate the practical application of information presented in the review. EVIDENCE BASE: There are limited prospective studies on FATE, although the recent literature reflects a resurgence in clinical research interest in the past few years. Advances in FATE treatment will benefit many cats and it is important that research efforts continue to identify appropriate treatment modalities.

Aneurisma aórtico torácico com trombose associada em Bugio-preto (Alouatta caraya) / Thoracic aortic aneurysm with associated thrombosis in black-and-gold howler monkey (Alouatta caraya)

O aneurisma é uma dilatação anormal e permanente das artérias, resultante do enfraquecimento da parede do vaso adelgaçamento da camada média e enfraquecimento da camada elástica. Em animais, a maioria dos casos de aneurisma tem origem idiopática e são detectados acidentalmente durante a necropsia. O objetivo deste trabalho é relatar um caso de aneurisma aórtico com trombose associada em Bugio-preto(Alouatta caraya), bem como seus aspectos patológicos. O animal era adulto, macho, pertencente ao Centro Nacional de Primatas (CENP), na cidade de Ananindeua-PA, foi encaminhado para exame necroscópico para investigação da causa mortis. No histórico do animal, não constava qualquer enfermidade. O animal apresentava bom escore de condição corporal com preservação da topografia anatômica dos órgãos. Entretanto, observou-se presença de aumento de volume localizado em aorta torácica, a 1,4 cm da base do coração. Na abertura aórtica foi observado dilatações de tamanhos variados e, no interior da maior dilatação, notou-se uma estrutura de coloração vermelho escuro, aderida, de aspecto seco e superfície áspera, medindo 1,5 cm. Aneurismas aórticos em primatas não humanos não são comuns, porém já foram reportados na literatura. O diagnóstico precoce utilizando exames complementares é importante, porém, ainda há recursos não empregados na rotina veterinária tornando ainda mais difícil o diagnóstico e prevenção. Por isso, na medicina veterinária, os aneurismas são detectados acidentalmente durante a necropsia. Com base nos achados anatomopatológicos, concluiu-se que o animal veio a óbito por trombose associada a aneurisma aórtico.

An aneurysm is an abnormal and permanent dilation of the arteries, resulting from the weakening of the vessel wall.thinning of the middle layer and weakening of the elastic layer. In animals, most cases of aneurysm are idiopathic. This paper aimed to report a case of aortic aneurysm with associated thrombosis in a black-and-gold howler monkey(Alouatta caraya), as well as its pathological aspects. The animal was an adult, male, belonging to the National Primate Center (CENP), in the city of Ananindeua-PA, that was referred for necroscopic examination to investigate the causa mortis. In the animal's history, there was no disease. The animal had a good body condition score with preservation of the anatomical topography of the organs. However, there was an increase in volume located in the thoracic aorta, 1.4 cm from the base of the heart. In the aortic opening, dilations of different sizes were observed, and inside the largest dilatation, a structure of dark red color, adhered, with a dry appearance and rough surface, measuring 1.5 cm was noted in addition to dilations of different sizes. Inside the largest cavitation, a dark red structure was observed, adhered, with a dry appearance and rough surface, measuring 1.5 cm. Aortic aneurysms in non-human primates are incommon, but have been reported in the literature. Early diagnosis using complementary exams is important, however, there are still resources not used in the veterinary routine, making diagnosis and prevention even more difficult. Therefore, in veterinary medicine, aneurysms are accidentally detected during necropsy. Based on the anatomopathological findings, it was concluded that the animal died due to thrombosis associated with an aortic aneurysm.

Stenting of the caudal aorta and aortic trifurcation for the treatment of thrombosis in 7 dogs.

BACKGROUND: Aortic and aortoiliac thrombosis in dogs causes disease and death. OBJECTIVE: To describe the procedure and outcomes for stenting the caudal aorta and aortoiliac trifurcation. ANIMALS: Seven client-owned dogs that underwent aortic/aortoiliac stenting for treatment of thrombosis. METHODS: Retrospective multi-center investigation. Medical records were reviewed for dogs that underwent stenting of the aorta or aortoiliac trifurcation between 2008 and 2020. Information collected included history, signalment, clinicopathologic data, diagnostic imaging, procedure reports, and outcomes. RESULTS: Seven dogs with an occlusive thrombus located at or near the aortic trifurcation were included. Four of 7 dogs were non-ambulatory. Hind limbs were paretic in 5 dogs, paralyzed in 1 dog, and claudication alone was noted in 1 dog. Five of the 7 dogs had protein-losing nephropathy (PLN). Of 5 dogs with PLN, 1 had protein-losing enteropathy (PLE) and controlled hypothyroidism and 1 had caudal aortic chondrosarcoma. Two dogs had no identified underlying disease. Angiography was performed before catheter directed thrombolysis and stent placement. No deaths occurred during the procedure. Postoperative complications included pain (4/7), bruising and edema (3/7), bruising only (1/7), and edema only (1/7). Median survival time (MST) of the 7 dogs was 264 days (range, 1-1053 days). Five of 7 dogs were ambulatory within 2 days of stenting and survived to discharge with a MST of 425 days (range, 208-1053 days). CONCLUSIONS AND CLINICAL IMPORTANCE: Stenting of the aorta and aortoiliac trifurcation can provide an apparently safe and effective treatment with rapid return to ambulation for some dogs with aortic thrombosis.

Surgical treatment of persistent right aortic arch with combined ligamentum arteriosum transection and esophageal diverticulum resection in three dogs.

OBJECTIVE: To describe the treatment of persistent right aortic arch (PRAA) in dogs with combined ligamentum arteriosum (LA) transection and esophageal diverticulum resection. ANIMALS: Three client owned dogs. STUDY DESIGN: Short case series. METHODS: Medical records were reviewed for clinical signs, diagnostic procedures, surgical treatment, post-operative therapies including medications and feeding regime, outcomes, and follow-up imaging. RESULTS: Esophageal resection was performed using a thoracoabdominal (TA) stapler with suture overlay. All dogs recovered well from surgery and did not experience any peri- or post-operative complications. The last follow-up was performed between 64 and 1004 days post-operatively. In all cases, regurgitation resolved and did not recur in any dogs. No dogs required medical therapy or dietary modifications. In two cases, follow-up imaging was performed that revealed marked improvement of esophageal dilation. CONCLUSION: Resection of esophageal diverticulum secondary to PRAA utilizing a TA stapler with suture overlay was technically feasible and did not seem associated with early or late complications.

Feline aortic thromboembolism: Presentation, diagnosis, and treatment outcomes of 15 cats.

Background: Feline aortic thromboembolism (FATE) is a fatal disease where a blood clot gets lodged into the aortic trifurcation. Methods: Fifteen cats with a sudden onset of hind limb paresis/paralysis, vocalization, and pain were admitted to the surgery clinic. A full case history was obtained and clinical, orthopedic, neurologic, radiographic, electrocardiographic, and echocardiographic examinations were performed for each cat. The treatment protocol included daily administration of multiple anticoagulant drugs with different mode of actions and meloxicam for 7 successive days. Prophylactic anticoagulant therapy (clopidogrel and acetylsalicylic acid) was continued for 6 months. All data were statistically analyzed and the correlation between time of admission and treatment outcome was tested using Pearson's correlation coefficient. Results: The case history and clinical, orthopedic, and neurologic examinations revealed a sudden onset of hind limb paralysis (n = 12) or paresis (n = 3) associated with vocalization and pain, absence of trauma, cold and pale paws of hind limbs (n = 13, 86.7%) or cyanosed hind paws (n = 2, 13.3%), absence of femoral pulsation, shallow and rapid open-mouth respiration (61 ± 8 breaths/minutes), hypothermia (37.9°C ± 0.6°C) and tachycardia (155 ± 12 beats/minutes), with a muffled heart sound in four cats (26.7%). Radiography revealed no abnormalities in the hind limbs, pelvis, and spines, cardiomegaly in five cats (33.3%), mild pleural effusion and vascular pattern of the lung in six cats (40%), and Valentine's heart shape in four cats (26.7%). Electrocardiography (ECG) revealed an R-wave< 0.9 mV, prolongation of QRS interval in five cats (33.3%), and conduction disturbance in four cats (26.7%). Echocardiography was consistent with hypertrophic cardiomyopathy (HCM) in five cats (33.3%). A statistically significant (p= 0.023) strong negative correlation (r= -0.6) was reported between time of admission and subsequent early treatment and recovery from clinical signs. The treatment was successful in nine cats (60%), while four cats (26.7) were euthanized and two cats (13.3%) were subjected to hind limb amputation, at the owners' requests. Conclusion: Clinical signs, radiography, ECG, and echocardiography are valuable for diagnosis of FATE. The outcome of the multiple anticoagulants therapy depends mainly upon early diagnosis and treatment within the first 6 hours from the onset of clinical signs.

Lethal acute hemorrhage from an aortoesophageal fistula following endoscopy-assisted esophageal foreign body removal in a dog.

OBJECTIVE: To describe the clinical presentation of a dog with fatal hemorrhage from an aortoesophageal fistula (AEF) immediately following endoscopic removal of an osseous esophageal foreign body. CASE SUMMARY: A 12-year-old, male mixed-breed dog presented to a university hospital with a 6-day history of gagging, hematemesis, and anorexia. Physical examination upon arrival was unremarkable. Blood work revealed leukocytosis without anemia. Thoracic radiographs from the referring veterinarian demonstrated the presence of an osseous esophageal foreign body at the level of the heart base. Subsequently, esophagoscopy was performed under general anesthesia. A triangular-shaped, osseous esophageal foreign body was visualized at the level of the heart base and successfully removed. Following its removal, a deep, nonbleeding, presumably nonperforated, esophageal ulcer was revealed. While recovering from anesthesia, the dog's condition acutely deteriorated, with absence of spontaneous respiration, severe tachycardia, hypotension, white-pale mucous membranes, and hypothermia. Severe anemia was present, with hypovolemic shock likely secondary to acute, postprocedural bleeding. Medical management included rapid packed red blood cell transfusion, crystalloid fluid therapy, and tranexamic acid. Despite initial stabilization, several hours later, the dog suffered cardiac arrest and cardiopulmonary resuscitation (CPR) was unsuccessful. At postmortem examination, a 1-mm AEF was identified on the ventral aspect of the aorta that communicated with the overlying esophagus. NEW OR UNIQUE INFORMATION PROVIDED: Aortoesophageal fistulas should be considered in any patient with severe bleeding following esophagoscopy. A history of hematemesis in a dog with an esophageal foreign body should raise suspicion of an AEF and dictate case management accordingly.

Surgical embolectomy in a cat with cardiogenic aortic thromboembolism.

A seven-year-old, spayed female, domestic longhair cat was referred for management of a sudden aortic thromboembolism (ATE). Echocardiography showed hypertrophic cardiomyopathy with severe left atrial enlargement. Ultrasonography of the abdominal aorta confirmed a large thrombus at the level of the aortic trifurcation, involving both iliac arteries. Considering the recent onset and bilateral involvement of the iliac arteries, the cat underwent emergent surgical embolectomy (SE) of the aortoiliac embolus. A standard caudal celiotomy was performed and the abdominal aorta was identified. Vessel loops with tourniquets were placed around the abdominal aorta proximal to the thrombus and on both iliac arteries distal to the thrombus. A full-thickness incision was made in the ventral surface of the aorta. The aortic thromboembolus was removed. The trifurcation was subsequently flushed with sterile saline. The SE resulted in a good outcome, with both clinical and ultrasound signs of complete reperfusion of the rear limbs within a few hours. Long-term treatment included antiplatelet drugs, furosemide and benazepril. Eighteen months after surgery, the cat was free of clinical signs, without recurrence of ATE or congestive heart failure. Based on the present case, SE could be considered as a feasible alternative to traditional conservative treatment in cats with a very recent onset of bilateral ATE.

Thrombolysis with tissue plasminogen activator (TPA) in feline acute aortic thromboembolism: a retrospective study of 16 cases.

OBJECTIVES: Thrombolytic therapy is a treatment of choice for people with acute ischemic events, but is uncommonly administered for feline aortic thromboembolism (FATE). This study reports selected clinical data and outcomes of acute FATE treated with tissue plasminogen activator (TPA). A reference group treated with current standard of care (SOC) was analyzed for comparison. METHODS: This was a retrospective study of FATE in two academic hospitals. TPA-treated cats with two or more limbs (n = 16) affected were compared with a SOC-treated group with two or more limbs affected (n = 38). A limb score based on motor function and pulse quality was calculated for each group. RESULTS: Limb score and proportion of congestive heart failure at admission was similar in both groups. Time from FATE to admission was shorter in the TPA group, with a median of 3 h (range 0-6 h) vs 6 h (range 0-48 h; P = 0.0004). The most common regimen received for TPA was 1 mg/kg over 1 h. Other treatments were similar to those of the SOC group and included analgesia, thromboprophylaxis and furosemide. Documented complications for TPA-treated cats included reperfusion injury (5/10) and acute kidney injury (AKI; 3/10). Discharge proportion rate was 44% (TPA) vs 29% (SOC; P = 0.351). There were no differences in short-term survival rate (56.2% vs 39.5%; P = 0.369), clinical improvement (56.2% vs 31%; P = 0.122), rates of reperfusion injury (50% vs 50%; P = 1.00) or AKI (30% vs 27%; P = 1.00) between the TPA-treated and SOC groups, respectively. CONCLUSIONS AND RELEVANCE: Survival and complication rates of TPA-treated cats and SOC-treated cats for acute FATE were similar.

Infrared thermography: a rapid and accurate technique to detect feline aortic thromboembolism.

Objectives The objective of this study was to evaluate the diagnostic accuracy of infrared thermography in cats with acute pelvic paralysis to differentiate feline aortic thromboembolism (FATE) from non-ischaemic conditions. Methods Thermographic images were prospectively obtained at admission from cats presented for acute bilateral pelvic paralysis. Based on the final diagnosis, cats were divided into a FATE and a control group (ischaemic and non-ischaemic related pelvic paralysis, respectively). The maximum (Tmax), minimum (Tmin) and average (Tav) temperatures were determined for each of the four limbs within a hand-drawn region of interest on the dorsal limb extremity. Temperature differences between the forelimb (non-affected) and hindlimb (affected) with the highest temperature (ΔT), with the lowest temperature (δT) and from the right and left side (RightΔT and LeftΔT, respectively) were calculated. Results The FATE and control groups included 10 and six cats, respectively. In the FATE group, right hindlimb mean Tmax (23.6°C ± 1.9), left hindlimb mean Tmax (23.6°C ± 2.2) and mean Tav (22.7°C ± 2.2) were significantly lower than in the control group (26.6°C ± 3.5 [ P = 0.042]; 26.6°C ± 2.4°C [ P = 0.024] and 25.7°C ± 2.0 [ P = 0.020], respectively). ΔT, δT, RightΔT and LeftΔT were significantly higher in the FATE group than in the control group. A cut-off value of 2.4°C for RightΔTmax and LeftΔTmax allowed discrimination between the FATE and control groups with a sensitivity of 80% and 90%, respectively, a specificity of 100% for both, a positive predictive value of 100% for both, and a negative predictive value of 75% and 86%, respectively. Conclusions and relevance A minimal difference of 2.4°C between ipsilateral affected and non-affected limbs has an excellent specificity and high sensitivity for FATE diagnosis. Infrared thermography seems to be a promising, useful, easy, non-invasive and rapid method for detecting aortic thromboembolism in cats, particularly in emergency situations.

Rosiglitazone modulates pigeon atherosclerotic lipid accumulation and gene expression in vitro.

Atherosclerosis is a major contributor to the overall United States mortality rate, primarily in the form of heart attacks and stroke. Unlike the human disease, which is believed to be multifactorial, pigeon atherosclerosis is due to a single gene autosomal recessive trait. The White Carneau (WC-As) strain develops atherosclerotic plaques without the presence of known environmental risk factors such as diet and classic predictors such as blood pressure or blood cholesterol levels. With similar parameters, the Show Racer (SR-Ar) is resistant to plaque development. Thiazolidinediones, including rosiglitazone, activate the peroxisome proliferator-activated receptor gamma (PPARγ) raising cellular sensitivity to insulin. The effect of rosiglitazone was evaluated in aortic smooth muscle cells (SMC) from these 2 pigeon breeds. Primary SMC cultures were prepared from WC-As and SR-Ar squabs. Cell monolayers, which achieved confluence in 7 d, were treated with 0 or 4 µM rosiglitazone for 24 h. Cellular lipid accumulation was evaluated by oil red O staining. Control WC-As cells had significantly higher vacuole scores and lipid content than did the SR-Ar control cells. Rosiglitazone treatment decreased WC-As lipid vacuoles significantly compared with the control cells. On the other hand, lipid vacuoles in the treated and untreated SR-Ar cells did not differ significantly. The effect of rosiglitazone on WC-As SMC gene expression was compared with control SMC using representational difference analysis. Significant transcript increases were found for caveolin and RNA binding motif in the control cells compared with the rosiglitazone-treated cells as well as cytochrome p450 family 17 subfamily A polypeptide 1 (CYP171A) in the rosiglitazone-treated cells compared with the control cells. Although rosiglitazone was selected for these experiments because of its role as a PPARγ agonist, it appears that the drug also tempers c-myc expression, as genes related to this second transcription factor were differentially expressed. Both PPARγ and c-myc appear to affect WC-As SMC gene expression, which may relate to disease development, progression, or both.

Computed tomographic and radiographic characteristics of aortic lesions in 42 dogs with spirocercosis.

Spirocerca lupi is a common cause of vomiting, regurgitation, and sudden death in dogs that live in tropical or subtropical regions. Sudden death due to aortic rupture may occur with no preceding clinical signs. The purpose of this prospective study was to compare radiographic and computed tomographic (CT) characteristics of aortic lesions in a cohort of 42 dogs with endoscopically confirmed spirocercosis. Dorsoventral and right lateral recumbent thoracic radiographic findings were compared with pre- and postcontrast thoracic CT findings. Aortic mineralization was detected using CT in 18/42 dogs (43%). Three dogs had faint diffuse aortic wall mineralization. Using CT as the reference standard, radiographs had a sensitivity and specificity of 6% and 96%, respectively, for detecting aortic mineralization. A total of 20 aortic aneurysms were detected using CT in 15/42 dogs (36%). Using CT as the reference standard, radiographs had a sensitivity and specificity of 86% and 56%, respectively, for detecting aortic aneurysms. Respiratory motion, aortic displacement by esophageal masses and Spirocerca nodules adjacent to the aorta mimicked aneurysm formation on radiographs. Aortic thrombi were seen in two dogs in postcontrast CT images. Findings from this study indicated that aortic mineralization and aneurysm formation are common in dogs with spirocercosis. Findings also supported the use of pre- and postcontrast CT as effective methods for detecting and characterizing these lesions.

Persistent right aortic arch and associated axial skeletal malformations in cats.

Persistent right aortic arch (PRAA) in cats is an uncommon vascular anomaly with clinical signs referable to oesophageal obstruction. To our knowledge no reports of axial skeletal malformations concomitant to PRAA have been reported in cats. The aim of this study is to depict a new clinical feature in cats affected by PRAA. In the study six cats with a diagnosis of vascular ring anomaly were enrolled. A complete physical examination, a neurological examination and a total body radiograph were performed on each animal. Four of the six cats showed contemporary PRAA and skeletal malformations. Additionally, for the first time, a genetic test was performed on one subject to detect DNA alterations in the homologous DiGeorge region of cat. The percentage of skeletal malformations reported in the normal population was compared with animals with PRAA and showed a higher frequency. Genetic testing failed to demonstrate a correlation between PRAA and DiGeorge genomic deletion. A review of veterinary and human diseases that presented both conditions was assessed. The few animals enrolled do not allow definitive conclusions. Further studies are required to corroborate the correlation between PRAA and axial skeletal malformations in cats.

Aortic thrombosis in dogs: 31 cases (2000-2010).

OBJECTIVE: To describe clinical signs, treatment, and outcome of aortic thrombosis in dogs. DESIGN: Retrospective case series. ANIMALS: 31 dogs with aortic thrombosis. PROCEDURES: Records were retrospectively reviewed and data collected regarding signalment, historical signs, physical examination findings, laboratory testing, definitive diagnosis, and presence of concurrent disease. RESULTS: The records of 31 dogs with clinical or postmortem diagnosis of aortic thrombosis were reviewed. Onset of clinical signs was acute in 14 (45%) dogs, chronic in 15 (48%), and not documented in 2 (6%). Femoral pulses were subjectively weak in 6 (19%) dogs and absent in 17 (55%). Frequent laboratory abnormalities included high BUN concentration (n = 13), creatinine concentration (6), creatine kinase activity (10), and D-dimer concentration (10) and proteinuria with a urine protein-to-creatinine concentration ratio > 0.5 (12). Concurrent conditions included neoplasia (n = 6), recent administration of corticosteroids (6), and renal (8) or cardiac (6) disease. Median survival time was significantly longer for dogs with chronic onset of disease (30 days; range, 0 to 959 days) than for those with acute onset of clinical signs (1.5 days; range, 0 to 120 days). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that aortic thrombosis is a rare condition in dogs and accounted for only 0.0005% of hospital admissions during the study period. The clinical signs for dogs with aortic thrombosis differed from those seen in feline patients with aortic thromboembolism. Median survival time was significantly longer for dogs with chronic disease than for dogs with acute disease. Despite treatment, outcomes were typically poor, although protracted periods of survival were achieved in some dogs.

Tubular hypoplasia of the aorta and right atrioventricular valve dysplasia in a Bulldog.

A Bulldog puppy that died at 1 day of age was presented for postmortem evaluation. Macroscopically, there was marked hypoplasia of the ascending, transverse, and proximal segments of the descending thoracic aorta and almost complete secondary thrombosis of the left ventricle causing a functional stenosis of the left atrioventricular valve. Separately, there was right atrioventricular valve dysplasia with secondary dilation of the right atrium. Microscopically, the left ventricular outflow tract was occluded by chondroid metaplasia, fibrosing recanalization of a left-ventricular thrombus, and isolated Purkinje fiber degeneration and necrosis.

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.

Surgical thrombectomy in horses with aortoiliac thrombosis: 17 cases.

REASONS FOR PERFORMING STUDY: Aortoiliac thrombosis (AIT) is a progressive vascular disease characterised by an exercise-induced hindlimb lameness. After developing a surgical technique, a follow-up study was required. OBJECTIVES: To assess the surgical results of a surgical thrombectomy in horses with AIT, a chronic arterial occlusive disease of the aorta and its caudal arteries. METHODS: Seventeen cases showed the typical signs of AIT and diagnosis was confirmed by Doppler-ultrasonography. Average age of the horses was 12 years. Seven stallions, 6 mares and 4 geldings were included. RESULTS: The thrombus was located in the left hindlimb (5 cases), the right hindlimb (9 cases) or in both hindlimbs (3 cases). Two cases were operated on both limbs with a few days between surgeries. Nine (53%) horses regained their athletic performance and 2 horses were able to work for at least 30 min without complaint, instead of the initial 5 min prior to surgery. During surgery one horse had to be subjected to euthanasia because the thrombus was too tightly attached to the arterial wall and could not be removed. Two horses were subjected to euthanasia post operatively due to severe myopathy and one due to a femoral fracture during recovery. Two reocclusions of the treated artery occurred 4 months after surgical intervention: one horse was reoperated and, due to the extent of the thrombus and quality of the arterial wall, the horse was subjected to euthanasia; the other horse was subjected to euthanasia without a second surgery. A severe complication was the appearance of AIT in the contralateral limb after surgery as result of occlusion caused by an embolus loosened by the procedure. Post anaesthetic myopathy was seen in 4 (24%) of the cases and could be so severe that euthanasia had to be considered. CONCLUSION AND POTENTIAL RELEVANCE: Surgical intervention by means of a thrombectomy in horses with AIT should be considered; 65% of the horses regained athletic activity and 53% of the operated horses in this study performed at their previous level. Adequate padding, correct positioning, prevention of intraoperative hypotension and keeping surgery time as short as possible, are important parameters to prevent post operative myopathy.

Primary intimal aortic angiosarcoma in a dog.

A primary intimal aortic angiosarcoma was diagnosed in a 4-year-old, spayed female German Shepherd that presented for complications of thromboembolic disease because of infarcts in multiple organs. On gross examination, aneurysmal dilatation of the aorta was associated with a friable, necrotic mass attached to the endothelial surface, which partially occluded the aortic lumen. On histologic examination, plump neoplastic spindle cells formed a plaque-like mass arising from the intima that merged with a large accumulation of fibrin and necrotic debris, and projected into the lumen. Neoplastic cells invaded periaortic vessels and were seen in some infarct-associated thromboemboli. Tumor cells expressed vimentin and CD31, with infrequent, patchy staining with factor VIII-related antigen; tumor cells were negative for cytokeratin and smooth-muscle actin. Aortic angiosarcoma is a rare malignancy in humans. This is the first description of a primary intimal aortic angiosarcoma in a dog, with immunohistochemical evidence of endothelial origin.

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.