Multi-detector computed tomography of an aortic dissection in a cat

Presumed renal arterial aneurysm in a cat

A 3-year-old cat was presented for an abdominal ultrasound examination with apathy and anemia. The US revealed the enlargement of the left kidney with a hypoechoic subcapsular thickening. An abnormal, tortuous vessel was visible in the medulla with arterial flow on pulsed-wave Doppler examination. The CT examination confirmed the ultrasound findings and a presumptive diagnosis of the intraparenchymal renal aneurysm was made. Four days later, the cat presented again with a worsening of its condition. The US features were suggestive for that of an aneurysm rupture.

Annuloaortic ectasia in a four-month-old male Newfoundland dog: long-term follow-up and immunofluorescent study

A 4 month-old, 14.8 kg, male Newfoundland dog was presented for cardiovascular evaluation following detection of a heart murmur. Echocardiography revealed enlargement of the sinuses of Valsalva and marked, diffuse dilation of the ascending aorta (annuloaortic ectasia, AAE), with mild/equivocal subaortic stenosis (SAS). The dog was monitored over the duration of its lifetime, with serial echocardiograms performed at 5, 6, and 8 months and 1, 2, 3, 4, 8, and 10 years demonstrating persistent, diffuse dilation of the ascending aorta. The dog lived until it was 10 years old and died of metastatic carcinoma. Postmortem examination confirmed AAE and mild SAS. Hematoxylin and eosin and Weigert van Gieson stains were used to compare the ascending aorta to the descending aorta and left subclavian artery, and to compare aortic samples to those of three control dogs. Histopathologic evaluation revealed mild medial degeneration in the ascending aorta of all four dogs. Immunofluorescent microscopy was used for determining the deposition of proteins known to play a role in aortic aneurysms in humans: fibrillin-1 (FBN1), latent transforming growth factor beta binding protein 4 (LTBP4) and fibronectin. The ascending aorta of the AAE case demonstrated reduced deposition of FBN1, indicating that its loss may have contributed to aortic dilation. Diffuse, primary ascending aortic dilation is uncommonly reported in dogs; when it is, it carries a poor prognosis. This case provides an important example of marked dilation of the ascending aorta in a dog that lived with no associated adverse effects for 10 years.

Echocardiographic changes in the shape and size of the aortic cusps in dogs with confirmed systemic hypertension

Systemic hypertension (SH) in dogs typically occurs secondary to renal disease, diabetes mellitus, hyperadrenocorticism, malignant adrenal tumors, or various medications. Echocardiography performed on people with SH has shown asymmetric dilation of the sinuses at the level of the aortic valves, previously undescribed in canine patients. The objective of this retrospective case-control study was to determine if there was a difference in size and shape of the aortic cusps at the level of the sinus of Valsalva in dogs with SH compared to dogs with normal blood pressure. We reviewed echocardiographic findings in 74 dogs with SH and 37 dogs with normal blood pressure (NBP), defined as less than 150 mmHg. Systemic hypertension was classified as mild (150-159 mm Hg), moderate (160-179 mm Hg), or severe (greater than 180 mm Hg). There was a significant difference (P < .001) in the mean size of the aorta cusps at the level of the sinuses in 67 of 74 dogs with SH and none of 37 dogs with NBP. Of the 74 dogs with SH, 70 had left ventricular hypertrophy (18 asymmetric, 15 concentric, and 37 eccentric). Additionally, there was aortic root dilatation in 15 dogs, aortic insufficiency in 21, mitral regurgitation in 50, and left atrial enlargement in 71. The standard deviation of the three cusp measurements between the dogs with SH and dogs with NBP had a sensitivity of 92% and specificity of 97% for diagnosis of SH. Asymmetric size of the aortic cusps on echocardiography is therefore a reliable indicator of SH in dogs.

Aortic dissection in four cats: clinicopathological correlations

Aortic dissection (AD) is characterized by bleeding within the aortic wall or a tear in the intimal layer of the aortic wall, resulting in the passage of blood from the aortic lumen into the tunica media. In cases of AD, a floating, intimal flap in the aortic lumen divides the lumen into a true portion, with flow present, and a false portion, with no flow. We describe a series of 4 cats with AD of the ascending aorta and moderate aortic insufficiency. Three cats had an acute onset of clinical signs with pericardial effusion and cardiac tamponade, whereas one cat showed a chronic onset without pericardial effusion. Detailed gross and histopathological characterization is available for two cats, which revealed the typical features of AD. One cat also showed connective tissue abnormalities, microscopically resembling Marfan-like syndrome. Concomitant detection of hypertrophic cardiomyopathy in 2 cats represents a novel finding in the veterinary literature. Feline AD is generally associated with systemic hypertension. In all the cats of this case series, blood pressure was normal at presentation, although systemic hypertension before the acute dissection cannot be ruled out. In humans, hypotension is more common with AD of the ascending aorta, so the anatomical location could also play a role in cats. Hypertrophic cardiomyopathy in cats could have been a potential trigger of AD through shear stress. Transthoracic echocardiography, as herein demonstrated, can be considered as a rapid, non-invasive and useful method for the diagnosis of dissection at the level of the ascending aorta.

AORTIC ANEURYSM, DISSECTION, AND RUPTURE IN SIX BILE-FARMED BEARS

Across China and Southeast Asia, over 17,000 bears are currently farmed for bile, predominantly for traditional Chinese medicines. Bears on farms in China are cage confined and undergo repeated daily bile extraction facilitated by surgically implanted catheters or gallbladder fistulas. Numerous health problems have been reported in bile-farmed bears including peritonitis, abdominal hernias, and extraction site abscessation. Between 2009 and 2014, five Asiatic black bears ( Ursus thibetanus) and one Asiatic black/Eurasian brown bear ( Ursus arctos arctos) hybrid, rescued from the bear bile industry in China, died from ruptured and/or dissecting aortic aneurysm. Medical records were reviewed and two bears exhibited no clinical signs prior to death. In four bears, clinical findings varied and included increased stereotypic behavior prior to death, epistaxis, retinal lesions, dysphagia, weight loss, and acute onset of hyporexia. On postmortem examination, hemopericardium with dissection and/or rupture of the ascending aorta and left ventricular wall hypertrophy were present in all cases. No evidence of infectious disease, connective tissue disorders, or congenital cardiac disease was identified. Based on these observations screening thoracic radiography was performed on all bears at the rescue center and aortic dilation was identified in 73 of 134 (54.5%) bile-extracted bears. To the authors' knowledge, aortic aneurysm, rupture, and/or dissection have not been previously reported in any bear species and the high prevalence in this population of bears suggests an association with bile-farming practices. Future studies are needed to investigate the etiopathogenesis of this condition to aid in early diagnosis and improved management of bears being rescued from bile farms across Asia.

ACVIM consensus statement: Guidelines for the identification, evaluation, and management of systemic hypertension in dogs and cats

An update to the 2007 American College of Veterinary Internal Medicine (ACVIM) consensus statement on the identification, evaluation, and management of systemic hypertension in dogs and cats was presented at the 2017 ACVIM Forum in National Harbor, MD. The updated consensus statement is presented here. The consensus statement aims to provide guidance on appropriate diagnosis and treatment of hypertension in dogs and cats.

ISFM Consensus Guidelines on the Diagnosis and Management of Hypertension in Cats

Practical relevance: Feline hypertension is a common disease in older cats that is frequently diagnosed in association with other diseases such as chronic kidney disease and hyperthyroidism (so-called secondary hypertension), although some cases of apparent primary hypertension are also reported. The clinical consequences of hypertension can be severe, related to 'target organ damage' (eye, heart and vasculature, brain and kidneys), and early diagnosis followed by appropriate therapeutic management should help reduce the morbidity associated with this condition. Clinical challenges: Despite being a common disease, routine blood pressure (BP) monitoring is generally performed infrequently, probably leading to underdiagnosis of feline hypertension in clinical practice. There is a need to: (i) ensure BP is measured as accurately as possible with a reproducible technique; (ii) identify and monitor patients at risk of developing hypertension; (iii) establish appropriate criteria for therapeutic intervention; and (iv) establish appropriate therapeutic targets. Based on current data, amlodipine besylate is the treatment of choice to manage feline hypertension and is effective in the majority of cats, but the dose needed to successfully manage hypertension varies between individuals. Some cats require long-term adjuvant therapy and, occasionally, additional therapy is necessary for emergency management of hypertensive crises. Evidence base: These Guidelines from the International Society of Feline Medicine (ISFM) are based on a comprehensive review of the currently available literature, and are aimed at providing practical recommendations to address the challenges of feline hypertension for veterinarians. There are many areas where more data is required which, in the future, will serve to confirm or modify some of the recommendations in these Guidelines.

Vasa Vasorum Arteriopathy: Relationship With Systemic Arterial Hypertension and Other Vascular Lesions in Cats

The vasa vasorum is a delicate network of small arterioles that supplies nutrients to the adventitia and outer media of large arteries. In humans, dysfunction of the vasa vasorum contributes to the pathogenesis of aortic dissection and atherosclerosis. Twenty-four cats from 1 to 18 years of age were prospectively evaluated. Cases were divided into 3 cohorts—with systemic hypertension, without systemic hypertension, and uncertain. Histologic sections of the aorta and main pulmonary artery, as well as sections of kidney and lung, were blindly examined by 2 pathologists. The severity of vasa vasorum arteriopathy was compared to the presence of renal arteriosclerosis, aortic medial degeneration, subintimal fibroplasia of the main pulmonary artery, and blood pressure. We found that vasa vasorum arteriopathy correlated strongly with hypertensive status, degree of renal arteriosclerosis, and lesions in the great vessels. The positive predictive value of a severe vasa vasorum score for systemic hypertension was 84.6%. Lesions of vasa vasorum arteriopathy were predictive of renal arteriosclerosis with 100% sensitivity and 64.7% specificity. The positive predictive value of a severe vasa vasorum score for the presence of aortic lesions was 69.2% vs 91.6% for lesions in the main pulmonary artery. The vasa vasorum appears to be an important responder to systemic hypertension in cats, and arteriopathy of this vascular bed has significant implications for the integrity of the great vessels.

Pulmonary artery dissection in eight dogs with patent ductus arteriosus

OBJECTIVES

To describe a series of dogs with pulmonary artery dissection and patent ductus arteriosus (PDA).

ANIMALS

Eight dogs.

METHODS

Retrospective case series.

RESULTS

Pulmonary artery dissection was diagnosed in 8 dogs, 3 were Weimaraners. Four dogs presented in left-sided congestive heart failure, 4 presented for murmur evaluation and without clinical signs, and 1 presented in right-sided congestive heart failure. In 7 dogs the dissection was first documented concurrent with a diagnosis of uncorrected PDA. In the other dog, with pulmonary valve stenosis and PDA, the dissection was observed on autopsy examination 17 months after balloon pulmonary valvuloplasty and ductal closure. Median age at presentation for the 7 dogs with antemortem diagnosis of pulmonary artery dissection was 3.5 years (range, 1.5-4 years). Three dogs had the PDA surgically ligated, 2 dogs did not undergo PDA closure, 1 dog failed transcatheter occlusion of the PDA with subsequent surgical ligation, 1 dog underwent successful transcatheter device occlusion of the PDA, and 1 dog had the PDA closed by transcatheter coil delivery 17 months prior to the diagnosis of pulmonary artery dissection. The 2 dogs that did not have the PDA closed died 1 and 3 years after diagnosis due to heart failure.

CONCLUSIONS

Pulmonary artery dissection is a potential complication of PDA in dogs, the Weimaraner breed may be at increased risk, presentation is often in mature dogs, and closure of the PDA can be performed and appears to improve outcome.