Aorto-left atrial fistula secondary to aortic infective endocarditis in a dog with a bicuspid aortic valve.

An 11-year-old male neutered American bulldog was presented for evaluation of thrombocytopenia, acute onset of ataxia, and vomiting. A new murmur was auscultated on physical examination. Transthoracic echocardiographic examination revealed a bicuspid aortic valve, vegetative lesions on the aortic valve, and continuous shunting from the aortic root to the left atrium through an aorta to left atrial fistula. The dog was euthanized due to its guarded prognosis and critical condition. Pathological examination confirmed presence of a bicuspid aortic valve, aorto-left atrial fistula, and aortic infective endocarditis. Antemortem blood culture revealed two unusual organisms: Achromobacter xylosoxidans and Fusobacterium mortiferum.

Echocardiographic and pathologic identification of an aorto-left atrial fistula secondary to infective endocarditis in a canine patient.

A dog was presented for lameness, fever, and extreme lethargy. On physical exam, a new heart murmur, arrhythmia, and joint effusion were detected. These findings were not detected two months prior. A diagnostic work-up confirmed septic suppurative inflammation in multiple joints. Echocardiogram revealed aortic valvular endocarditis along with a communication, as a consequence of a fistula, that extended from just below the aortic sinotubular junction to the left atrial lumen. Due to a poor prognosis, humane euthanasia was elected. Necropsy and histopathology confirmed infective endocarditis of the aortic valve and an aorto-left atrial fistulous tract extending from the left coronary sinus of the aortic valve to the lumen of left atrium.

Spontaneous rupture of the right aortic sinus resulting in a sterile aorto-atrial fistula in a pet rabbit (Oryctolagus cuniculus).

Aortocardiac fistula is a broad term used to describe defects between the aorta and other cardiac chambers that can occur in humans and animals. A 1.5-year-old, 1.7 kg, male castrated Holland lop rabbit (Oryctolagus cuniculus) was presented for a two-week history of a heart murmur with corresponding cardiomegaly on radiographs. Physical examination confirmed a grade-V/VI continuous heart murmur on the right sternal border with a regular rhythm and a gallop sound. Echocardiography revealed an aortic-to-right-atrial fistula causing severe left-sided volume overload. Based on the echocardiographic findings, rupture of the right aortic sinus was suspected. Due to the poor prognosis, euthanasia was elected. On necropsy, a fistula was found connecting the right aortic sinus with the right atrium, without evidence of an inflammatory response nor evidence of an infectious etiology. The sudden onset of a heart murmur supported acquired fistulation from a ruptured aortic sinus (also known as the sinus of Valsalva), though a congenital malformation could not be completely excluded.

Liver function tests in dogs with congenital portosystemic shunts and their potential to determine persistent shunting after surgical attenuation.

Portosystemic shunts (PSS) are congenital or acquired vascular anomalies that cause blood to bypass the liver. Liver function tests, such as fasting ammonia, ammonia tolerance test, and (paired) serum bile acids, are reliable for the diagnosis of PSS in dogs. Surgical attenuation is a common treatment for congenital PSS. Following surgical attenuation, it is useful to evaluate shunt closure. In this critical review, the ability of liver function tests to determine the presence and degree of residual shunting following surgical attenuation of canine PSS is discussed. Despite the availability of several liver function tests, a single rapid, simple, cost-effective, sensitive and specific test to evaluate surgical attenuation of PSS is not available.

Percutaneous transcatheter closure of an aorto-cardiac fistula in a six-year-old Warmblood mare with atrial fibrillation.

This report describes a rare case of an aorto-cardiac fistula in a six-year-old French Warmblood mare presented with atrial fibrillation, decreased performance, ventral oedema, bounding arterial pulsation and pathological jugular venous pulse. A 2.7-cm-diameter fistula connected the right aortic sinus of Valsalva to the right atrium. Atrial fibrillation was likely due to volume overload of the right heart due to left-to-right shunting. The horse was treated by percutaneous transcatheter closure of the fistula delivered under general anaesthesia using a transarterial approach. The operation was initially successful, and clinical signs of congestive heart failure improved immediately. However, the device dislodged six days after procedure, and the general condition of the horse deteriorated quickly. A second closure attempt to deliver the occluder using a transvenous approach in the standing horse failed, and the horse was eventually euthanized. Procedural aspects and several possible risk factors for device dislodgement are discussed.

Aortocavitary fistula secondary to vegetative endocarditis in a rabbit.

A 4-year-old intact male mini lop rabbit (Oryctolagus cuniculus) was presented with a 2-week history of severe progressive lethargy. A right parasternal continuous heart murmur and an irregular rhythm were detected on physical examination. Echocardiography identified vegetative aortic and tricuspid valve (TV) endocarditis. There was an aortocavitary fistula between the right sinus of Valsalva into the right ventricle, creating a left-to-right intracardiac shunt. Based on the echocardiographic findings, it was suspected that the infection originated in the aortic valve, eroded through the periannular tissue, and secondarily infected the TV. Pleural and peritoneal effusion secondary to right-sided congestive heart failure was also found during the echocardiogram. Atrial fibrillation, conducted with a left bundle branch block morphology, was identified using electrocardiography. Necropsy findings directly correlated with the echocardiographic diagnosis; marked periodontal disease was also identified. Aerobic culture of the aortic and tricuspid vegetations resulted in significant growth of Haemophilus parainfluenzae. Haemophilus spp. belong to a group of similar gram-negative coccobacillus bacteria (HACEK group), which can act as an uncommon cause of endocarditis in humans. HACEK endocarditis is most commonly associated with oral infection and/or dental procedures in people. This is the first case report of a rabbit with periannular complications of infective endocarditis. It remains unknown whether dental disease resulted in endocarditis in this patient.

Feasibility of complete surgical ligation on 72 dogs with singular extrahepatic congenital portosystemic shunt based on portal pressure and comparison of intraoperative mesenteric portovenography.

The relation between complete or partial ligation of extrahepatic portosystemic shunting and intraoperative mesenteric portovenography (IMP) was evaluated in 72 canines. Of the 72 dogs, 55 had complete ligation and 17 underwent partial ligation of abnormal vessels. IMP allowed evaluation of the number of intrahepatic portal branches and ratio of the diameter of cranial (CrPV) and caudal main portal vein (CaPV) at the shunt location. Nearly all cases in the complete ligation group and nearly half of the cases in the partial ligation group had three or more portal vein branches. CrPV/CaPV was 0.75 ± 0.24 in the complete ligation group and 0.29 ± 0.15 in the partial ligation group. CrPV/CaPV can be an effective new method for assessing IMP.

Pneumatosis coli after partial ligation of congenital portosystemic shunt in a dog.

Pneumatosis coli is a rare intestinal disorder in dogs that is characterized by submucosal or subserosal emphysema of the colon. An 8-year-old castrated male Shih Tzu developed anorexia and hematochezia after undergoing surgery for a congenital splenophrenic shunt. Abdominal radiographic examination revealed linear radiolucency throughout the wall of the large intestine. Results of abdominal computed tomography revealed intramural gas tracking along the colon and rectum. Based on these findings, a diagnosis of pneumatosis coli was made. The dog was treated with antibiotics, but the general condition gradually deteriorated, and the dog died 6 days after the day of diagnosis. It was suspected that portal hypertension following partial ligation of congenital portosystemic shunt may have been associated with pneumatosis coli in this case.

Patent ductus arteriosus in cats (Felis catus): 50 cases (2000-2015).

OBJECTIVES: To describe signalment, clinical characteristics, diagnostic, treatment, and outcome data in a large case series of cats with patent ductus arteriosus (PDA). ANIMALS: Fifty cats with confirmed PDA. METHODS: Retrospective review of medical records from five referral veterinary hospitals for cats with PDA between 2000 and 2015. Cats were included if a PDA was visualized echocardiographically, during surgery, or on post-mortem examination. RESULTS: Median age at presentation was 6 months (range: 36 days-9.7 years; n = 50), and sex distribution was approximately equal (27 male, 23 female). Most cats did not have clinical signs (70.2%; 33/47) at the time of presentation. Murmurs were classified as continuous (55%; 22/40) or systolic (45%; 18/40). Echocardiography confirmed left-to-right shunting in 33 cats (82.5%; 33/40) and right-to-left shunting in 7 (17.5%; 7/40). Concurrent cardiac anomalies were identified in 54.5% (18/33) and pulmonary hypertension in 45.7% (16/35). Closure was pursued in 68% (34/50), and complications associated with the procedure occurred in 14.7% (5/34) of cats, including one intraoperative mortality. Long-term follow up was available in 80% (40/50) of cats. CONCLUSIONS: Cats with PDA often do not display clinical signs and may not have the characteristic physical examination findings typical of PDA in dogs. An increased prevalence of concurrent cardiac anomalies and pulmonary hypertension were found relative to previous reports. Thoracic radiographs and echocardiogram may provide the most comprehensive information for making a diagnosis and treatment recommendations. PDA closure was associated with a favorable long-term outcome in cats included in this study.

Emphysematous pyonephrosis associated with extrahepatic portosystemic shunt in a dog.

A 16-month-old intact female Maltese dog was referred for examination of depression and vomiting. Ultrasonography revealed dilated right renal pelvis containing echogenic fluid with free gas. A hyperechoic material suspected of urolith was identified in the right ureter. Computed tomography revealed emphysematous change of the right kidney associated with ureteral obstruction and extrahepatic portosystemic shunt (EHPSS). Ureteronephrectomy and surgical correction were performed for the EHPSS. Escherichia coli was isolated from pus from the right kidney. Quantitative analysis revealed that the urolith was an ammonium urate stone. After 5 months follow-up, no complication was observed. This is the first report of emphysematous pyonephrosis associated with EHPSS in a dog.

MULTIDETECTOR-ROW COMPUTED TOMOGRAPHY PATTERNS OF BRONCHOESPHAGEAL ARTERY HYPERTROPHY AND SYSTEMIC-TO-PULMONARY FISTULA IN DOGS.

Anomalies involving arterial branches in the lungs are one of the causes of hemoptysis in humans and dogs. Congenital and acquired patterns of bronchoesophageal artery hypertrophy have been reported in humans based on CT characteristics. The purpose of this retrospective study was to describe clinical, echocardiographic, and multidetector computed tomography features of bronchoesophageal artery hypertrophy and systemic-to-pulmonary arterial communications in a sample of 14 dogs. Two main vascular patterns were identified in dogs that resembled congenital and acquired conditions reported in humans. Pattern 1 appeared as an aberrant origin of the right bronchoesophageal artery, normal origin of the left one, and enlargement of both the bronchial and esophageal branches that formed a dense network terminating in a pulmonary artery through an orifice. Pattern 2 appeared as a normal origin of both right and left bronchoesophageal arteries, with an enlarged and tortuous course along the bronchi to the periphery of the lung, where they communicated with subsegmental pulmonary arteries. Dogs having Pattern 1 also had paraesophageal and esophageal varices, with the latter being confirmed by videoendoscopy examination. Authors conclude that dogs with Pattern 1 should be differentiated from dogs with other congenital vascular systemic-to-pulmonary connections. Dogs having Pattern 2 should be evaluated for underlying pleural or pulmonary diseases. Bronchoesophageal artery hypertrophy can be accompanied by esophageal venous engorgement and should be included in the differential diagnosis for esophageal and paraesophageal varices in dogs.

Aortic root disease in four horses.

Clinical findings in 4 horses with aortic root disease are described. Three of the horses had aneurysms of the right aortic sinus, and in 2 of the 3, the aneurysm ruptured, creating a fistula between the aorta and right ventricle. One of these horses had had a murmur since birth, and the aortic sinus aneurysm may have been a congenital anomaly. In a second horse, the aneurysm may have been an acquired condition that developed secondary to chronic aortic regurgitation. Another horse had a large subendocardial hematoma associated with dissection of blood from the aorta to the interventricular septum because of a tear in the aortic root near the right aortic sinus. Ventricular ectopy and signs of abdominal pain were the most common initial signs in these horses.

Mass screening of Irish wolfhound puppies for portosystemic shunts by the dynamic bile acid test.

Five hundred and sixty-six Irish wolfhound puppies aged six to 15 weeks were tested for congenital portosystemic shunts by the dynamic bile acid method. Plasma ammonia concentration was also measured in 165 of the puppies both fasting and postprandially. Nineteen puppies (3.4 per cent), nine males and 10 females, had portosystemic shunts. Smaller litters appeared to be more likely to contain affected puppies. The postprandial bile acid concentration was a reliable predictor of the presence of a shunt, with the highest concentration in a normal puppy being 38 mumol/litre and the lowest in an affected puppy being 43 mumol/litre. In contrast, fasting bile acid concentrations were normal in the majority of the affected puppies. There was considerable overlap in fasting plasma ammonia concentrations between normal and affected puppies (26 puppies, 15.8 per cent of those tested). Postprandial ammonia concentration appeared to give better separation between the two groups, apart from two individuals which produced bizarre results. It was concluded that the postprandial or dynamic bile acid test is an appropriate test for the mass screening of Irish wolfhound puppies for portosystemic shunts, and guidelines are proposed for the interpretation and follow-up of the test.

Progressive remission of portosystemic shunting in 23 dogs after partial closure of congenital portosystemic shunts.

The congenital portosystemic shunts in 23 dogs were closed partially in 18 and completely in five with a single silk ligature. The clinical results were studied and the degree of portosystemic shunting was measured by a scintigraphic method, the results being expressed as the shunt index (SI). In 17 of the dogs, the mean (sd) SI decreased from 0.92 (0.16) before surgery to 0.34 (0.25) during surgery after the attenuation of the shunt, and then to 0.10 (0.12) one month later. The dogs' venous ammonia concentration decreased from 203 (122) microM before surgery to 36 (18) one month after surgery. At the same time the clinical scores improved significantly. There were positive correlations between the SI and the general evaluation of the dogs' well-being by their owners (rs = 0.60), the ammonia concentration (rs = 0.86), and the diameter of the shunt (rs = 0.86). In the other six dogs, the intraoperative and/or postoperative SI was high. In two of them the shunt was further attenuated during a second operation, which resulted in lower SI values; in two a second small shunt was responsible for the high SI; in one multiple portosystemic shunts were found postmortem; and one dog was lost to follow-up.

Fast resolution of hypercortisolism in dogs with portosystemic encephalopathy after surgical shunt closure.

The aim of this study was to investigate whether hypercortisolism in dogs with congenital portosystemic shunts disappeared after surgical closure of the shunts concomitantly with recovery from hepatic encephalopathy. We examined 22 dogs before and four weeks after partial surgical closure of a single, large congenital portosystemic shunt (PSS). Parameters measured to characterise the basal activity of the pituitary-adrenal axis were the cortisol:creatinine (c/c) ratio in home-sampled urine and total and free cortisol in plasma. The binding characteristics of cortisol binding globulin (CBG) in pooled pre- and postoperative plasma were also determined. Ammonia and bile acid concentrations were measured in plasma to characterise the liver perfusion and function. Clinical symptoms relevant to liver function, cortisol excess, and hepatic encephalopathy were recorded semiquantitatively using a standardized questionnaire. The dogs had hypercortisolism before surgery, which had normalized four weeks later. The pre- and postoperative concentrations (means +/- SEM) were, respectively, 238+/-45 nM and 126+/-19 nM for total cortisol, 15.5+/-2.6 nM and 8.4+/-1.3 nM for free cortisol in plasma, 13.4+/-4.3 x 10(-6) and 3.9+/-0.4 x 10(-6) for c/c in urine. The pre- and postoperative Bmax values of CBG were 41 and 79, and Kd values were 3.8 and 5.5. The concentrations of ammonia were 217+/-23 microM and 32+/-3.1 microM, and of bile acids 1 10+/-33 and 11.1+/-2.0 microM, respectively. We conclude that there is a close relation between portosystemic encephalopathy and hypercortisolism in dogs with PSS and that both deviations resolve completely within four weeks of closure of the shunt.

Morphology of congenital intrahepatic portacaval shunts in dogs and cats.

The preoperative ultrasound images and biplanar operative mesenteric portograms of 28 dogs and six cats with congenital intrahepatic portacaval shunts were reviewed retrospectively. On the basis of the combined surgical, postmortem and imaging data, the shunts were classified according to their location within the liver and their shape. Thirteen dogs and four cats had a left-divisional shunt with a relatively consistent bent tubular shape that drained into the left hepatic vein. Another 13 dogs had a central-divisional shunt that took the form of a foramen between dilated portions of the intrahepatic portal vein and caudal vena cava. One cat with a central-divisional shunt had a tortuous vessel. The remaining two dogs and one cat had right-divisional shunts that were large, tortuous vessels. The morphology of a left-divisional shunt is compatible with patent ductus venosus, but the pathogenesis of central and right-divisional shunts is unknown. It is concluded that intrahepatic portacaval shunts in dogs and cats may be classified as left, central or right divisional. Ultrasound enables a preoperative morphological assessment that correlates well with the results of portography and may aid surgical planning.

Aorto-cardiac fistulas in seven horses.

This report describes the history, clinical, electrocardiographic and echocardiographic findings, treatment, outcome and post-mortem findings in seven horses with aorto-cardiac fistula. Affected horses included 5 stallions, one gelding and one mare; 2 each of the Thoroughbred, Arabian and Standardbred breeds and one Thoroughbred-cross with a mean +/- s.d. age of 12 +/- 4 years, range 6-18 years. The presenting signs were acute distress (four horses), exercise intolerance (two horses) and the lesion was detected during a routine examination in one horse. Five horses had monomorphic ventricular tachycardia on admission and one other had a history of this arrhythmia. Five horses had a characteristic continuous murmur loudest in the right fourth intercostal space. Echocardiography (six horses) and/or post-mortem examination (four horses) revealed the horses had aorto-cardiac fistulas arising from the right aortic sinus in all five horses in which the site was recorded. Two horses had ruptured aneurysmal dilatations of the aortic wall at this site. Fistulas extended into the right ventricle in four horses; the right atrium in two horses, the left ventricle in one horse, and five horses had dissecting tracts in the septal myocardium. Horses survived for periods ranging from 24 h to 4 years. Aorto-cardiac fistula should be considered in the differential diagnosis for horses presenting with acute distress, bounding arterial pulse, a right-sided continuous murmur and/or monomorphic ventricular tachycardia, particularly in middle-aged or older stallions. Echocardiography is the technique of choice for confirming the diagnosis and demonstrating accompanying cardiac changes.