Subgross investigation of vessels originating from arcus aortae in guinea-pig (Cavia porcellus)

The vessels that originate from the aortic arch were studied in 16 adult guinea-pigs. Two major vessels, the left subclavian artery and the brachiocephalic trunk, were easily identified as they were branching off from the aortic arch. The brachiocephalic trunk, at first branched off to the left common carotid artery and continued as a common trunk, which was then divided into the right subclavian artery and the right common carotid artery. The left subclavian artery branched off to the following vessels: the costacervical trunk, the internal thoracic artery, a common trunk from which the dorsal scapular artery and the vertebral artery originated, and the superficial cervical artery. The right subclavian artery branched off to the bronchoesophageal artery (in five cadavers), the caudal thyroid artery (in three cadavers) and the tracheal artery (in three cadavers) in addition to the above vessels. There were two vertebral arteries branching off to the right subclavian artery in all dissected cadavers. However, only 10 cadavers had two vertebral arteries originating from the left subclavian artery. The first vertebral artery originated from the common trunk, whereas the second vertebral artery arose from the dorsal scapular artery. The second vertebral artery entered the foramen transversarium of the seventh cervical vertebrae and anastomosed with the first vertebral artery just before entering the foramen transversarium of the sixth cervical vertebrae.     

Branching pattern of aortic arch in the Korean water deer

This study examined the branching pattern of the aortic arch and its major branches in Korean water deer (Hydropotes inermis argyropus, Heude, 1884). Silicone casts were taken from the vessels of 23 carcasses (male 14, female 9) with body weights ranging from 1.3-16.0 kg through a retrograde injection into the abdominal aorta. The findings were compared with those from other domestic ruminants. Only the brachiocephalic trunk (Bct) branched from the aortic arch in all carcasses. In 19 of the 23 cases, the Bct branched into the left subclavian artery (LSb), the left common carotid artery (LCc), and then trifurcated into the right common carotid artery (RCc), right costocervical trunk (RCct) and right subclavian artery (RSb). The subclavian artery (Sb) branched into the costocervical trunk (in left), internal thoracic artery (It), and superficial cervical artery (Sc) in that order, and continued as the axillary artery. Instead of separated carotid arteries, the bicarotid trunk from the Bct was observed in only three males and one female. Two of these males had different branching orders of the It and Sc from the Sb in one or both sides. The other male had a RCct from the RSb. The left costocervical trunk (LCct) arose from the LSb in all cases, and branched into the highest intercostal artery, the dorsal scapular artery, and the deep cervical arteries in that order, and continued as the vertebral artery. In 22 cases, the RCct branched directly from the Bct at the same point in which the RCc (or bicarotid trunk) and RSb separated. The artery branching pattern from the RCct was similar to that of the LCct. These results suggest that the Korean water deer has a Bct with different branching patterns from those of domestic ruminants.     

The right coronary artery is absent in the chinchilla (Chinchilla lanigera)

A total of 10 adult, healthy, male chinchillas (Chinchilla lanigera) were used to investigate the origin, course, and termination of the coronary arteries. Coloured latex was injected into the carotid arteries following conventional anatomical applications. In all the chinchillas examined, the left coronary artery was the single coronary artery. The right coronary artery was missing. Additionally, a small vessel originating from the cranial border of the aorta was observed in one chinchilla. The left coronary artery divided into the paraconal, interventricular and left circumflex rami. The left marginis ventricular ramus arose from the paraconal interventricular ramus in eight chinchillas, and from the left circumflex ramus in two. The ventricular and septal branches of the left coronary artery ran subepicardially at the beginning mostly parallel to the muscle fibres, also surrounded by a thin adipose tissue. It was concluded that the only left coroner artery supplied blood to the heart in the chinchilla.     

Unusual vascular ring anomaly associated with a persistent right aortic arch in two dogs

An unusual vascular ring anomaly consisting of a persistent right aortic arch and a left ligamentum arteriosum extending from the main pulmonary artery to an aberrant left subclavian artery and left aortic arch remnant complex was identified in a German shepherd dog and a great Dane. The left subclavian artery and left aortic arch remnant complex originated at the junction between the right distal aortic arch and the descending aorta and coursed dorsal to the oesophagus in a cranial direction. The attachment of the ligamentum arteriosum to the aberrant left subclavian artery was approximately 5 cm cranial to the point of origin of the aberrant left subclavian artery and left aortic arch remnant complex from the descending aorta in both dogs. This anomaly observed in both dogs is similar to an anomaly reported in humans, in which a persistent right aortic arch is found in conjunction with an aberrant left subclavian artery and a left aortic arch remnant (Kommerell's diverticulum). Surgical ligation and division of the left ligamentum arteriosum in both dogs, along with division of the left subclavian artery in the great Dane, resulted in resolution of clinical signs in both of the dogs in this report.     

The Branching Pattern of the Brachiocephalic Trunk in the Donkey (Equus asinus)

Donkeys are a member of the horse family (Equidae) and share a common ancestor. However, in morphological terms, donkeys and horses are regarded as two separate subgenus. Given variations in the branching pattern of the brachiocephalic trunk (BCT) in different species of animals and the use of donkeys in anatomy courses at colleges of veterinary medicine, we conducted this study in order to investigate the branching patterns of BCT and to describe detailed morphological information regarding donkeys. Seventeen mature donkeys were examined following euthanasia by exsanguination from the common carotid artery under general anaesthesia. Thirteen donkeys were embalmed and injected with coloured latex from BCT origin for better visualization of vessels. Four other donkeys were freshly studied without the embalming procedure. In all cases, the BCT was the only branch of the aortic arch and branched into the left subclavian (LSb) artery, the right costocervical trunk, the right subclavian (RSb) artery and the bicarotid trunk. The main branching pattern of the RSb was the costocervical trunk, the vertebral artery, the internal thoracic artery and the superficial cervical artery. The deep cervical artery branched from the costocervical trunk. The major branching pattern of the LSb was the vertebral artery, the internal thoracic artery and the superficial cervical artery. In donkeys, the external thoracic artery branches from the internal thoracic artery. Results obtained from this study indicate that BCT branching in donkeys has some similarities and differences as compared to that in horses and in the Caspian miniature horse.     

Aberrant right subclavian artery causing megaoesophagus in three cats

Three entire, domestic, shorthair male cats (age range: 3 months to 5 years) were referred because of regurgitation. Megaoesophagus attributable to aberrant right subclavian artery, originating from the aorta at the level of the fourth intercostal space, was diagnosed in all cats using thoracic radiography and CT angiography. One cat had concurrent patent ductus arteriosus with a normal aortic arch. Three‐dimensional volume‐rendered CT images were used to assess the malformations and to plan surgery for the treatment of the vascular anomalies. Different surgical approaches were used in the two kittens. The third cat was not operated. CT angiography is well suited for preoperative planning in cats with aberrant right subclavian artery alone or in combination with other vascular anomalies.     

Unusual Combination of Multiple Vascular Anomalies in a German Shepherd Puppy with Megaoesophagus

A 2‐months‐old male German shepherd puppy was referred for regurgitation and delayed growth. Radiographic and endoscopic investigations revealed a precardiac megaoesophagus and oesophageal constriction at the level of the heart base. At post‐mortem examination, a specific form of persistent right aortic arch characterized by an aberrant left subclavian artery in combination with a ligamentum arteriosum originating at the aberrant left subclavian artery (PRAA‐SA‐LA) was detected. A complete‐type persistent left cranial vena cava (PLCVC) was also observed. This is the first report describing the association between PRAA‐SA‐LA and PLCVC in a dog with megaoesophagus.     

Descriptive anatomic study of the great vessels of the heart in the capuchin monkey Cebus apella (Linnaeus, 1758)

The aim of this study was to describe the anatomy of the great vessels of the heart in capuchin monkey (Cebus apella) and to compare with those of other primates, including humans. The hearts were prepared through fixation in 10% formalin and subsequently dissected using standard techniques and instruments. The arterial and venous systems were perfused with colored latex solution via the femoral vessels. An ascending cylindrical branch with relatively great caliber was identified in the aorta artery, in addition to an aortic arch, from which three great arteries were originated, the brachiocephalic trunk, the left common carotid artery and the left subclavian artery. After a course of variable extension, the pulmonary trunk divided into right and left pulmonary arteries. The caudal vena cava was morphologically similar to that of humans, except for its association with the cardiac lobe of the right lung, whereas the cranial vena cava was formed by the two braquiocephalic veins and received the azygos vein close to right atrium. The pulmonary veins, in number of six, ended at the posterior face of the left atrium, differently from both humans and other primates. In conclusion, the morphology of the great vessels of the heart in Cebus apella was similar to that of humans and other primates, although some differences are evidenced with regards to topography and number of anatomic structures, particularly the relationship of the caudal vena cava with the cardiac lobe of the right lung and the presence of six pulmonary veins in Cebus apella.     

Unilateral shunt formation with thoracic aortic dissection in a whippet

A three‐year‐old neutered male whippet was presented with intermittent, exercise‐induced paraparesis. Femoral pulses were bilaterally absent. Neurologic examination was suggestive of a thoracolumbar myelopathy. Blood pressure measurements revealed hypotension in both pelvic limbs, hypertension in the right thoracic limb and it was immeasurable in the left thoracic limb. Echocardiography was within reference limits. A clear vascular pulsation was palpable on the right ventral abdominal wall. Computed tomographic angiography revealed a dissection of the aortic wall between the left subclavian artery and the brachiocephalic trunk with subsequent thrombus formation. A shunt between the right internal thoracic, cranial and caudal epigastric arteries to preserve blood flow to the pelvic limbs was visualized. Necropsy was declined by the owner. This is the first case report describing the formation of a unilateral vascular shunt following a thoracic aortic occlusion, which presented as exercise‐induced paraparesis .     

Anatomical anomalies and variations of main thoracic vessels in dogs: a computed tomography study

IntroductionThere is scarce information about the prevalence of anomalies and anatomical variations of the main great thoracic vessels in dogs, particularly in dogs without congenital heart disease.AnimalsThe study included 878 privately owned dogs.Material and methodsComputerized tomography (CT) thoracic studies carried out between 2011 and 2014 for a variety of reasons were reviewed. The prevalence of anomalies and anatomical variations of the aorta and vena cava, the arterial branches of the aortic arch and the main branches of the intrathoracic veins in dogs with no evidence of congenital heart disease was evaluated. Poor-quality CTs, CTs with thoracic pathology that impaired visualization or those of young dogs with clinical evidence or suspicion of congenital cardiac disease were excluded.ResultsEight hundred two CT studies were analysed. Eight dogs (1%) showed an anatomic anomaly. The most common anomaly was an aberrant retroesophageal right subclavian artery (n = 7, 0.8%). One dog showed a dilated azygos vein secondary to an interrupted vena cava. Three types of branching of the common carotid arteries were observed: both arteries arising at the same point (type I: n = 506/742; 68.2%), separated (type II: n = 212/742; 28.6%) or from a common trunk (type III: n = 24/742; 3.2%).ConclusionsMajor anatomical variations or anomalies of the main great thoracic vessels in dogs without congenital cardiac disease were rare. An aberrant retroesophageal right subclavian artery was the most common anomaly found. Three slight variations of common carotid artery branching were identified. These findings might be of relevance for surgical or catheterization procedures.     

Surgical management of an aberrant left subclavian artery originating from a left patent ductus arteriosus in a dog with a right aortic arch and abnormal branching

An increase in the availability of advanced imaging modalities has led to improved recognition of cardiovascular anomalies. Computed tomography angiography (CTA) provides a non-invasive means of acquiring 3D images with a relatively short acquisition time thereby providing essential information in regards to patient anatomy and procedure planning. The dog in this report had a right aortic arch and abnormal branching with an aberrant left subclavian artery originating from the ampulla of a left patent ductus arteriosus (PDA) that was detected with CTA. The PDA was creating a volume overload to the left side of the heart as well as contributing to the vascular ring and compression of the esophagus. Therefore, ligation and transection instead of a minimally invasive catheter-based procedure was required. This aortic arch anomaly and surgical management have not been previously reported in dogs.     

Macroanatomic investigations of the blood supply of thoracic limb of Kangal dogs

In this study, the arterial supply of the thoracic limb was investigated in Kangal dogs. Twelve adult healthy Kangal dogs of either sex were used. Latex was injected into the common carotid artery, and then the axillary artery was dissected. The axillary artery is a continuation of the subclavian artery and supplies the thoracic limb in Kangal dogs. The axillary artery gave off a deltoid branch and external thoracic, lateral thoracic, and subscapular thoracic arteries in its course along the thoracic wall. The axillary artery continues distally as the brachial artery in the arm. The brachial artery gives rise to the cranial humeral circumflex, deep brachial, bicipital, ulnar collateral, superficial brachial, transverse cubital, and common interosseus arteries. It continues as the median artery after giving off the common interosseus artery. It was observed that the deep antebrachial artery arose from the median artery at the proximal third of the forearm. In the distal third of the forearm, the median artery divided into the palmar carpal and dorsal carpal branches. The deep palmar branch of the radial artery and deep branch of the palmar branch of the caudal interosseus artery form the deep palmar arch. The median artery joined the superficial branch of the palmar branch of the caudal interosseus artery to constitute the superficial palmar arch. The radial artery and cranial interosseus artery contributed to the dorsal carpal rete. The ulnar artery contributed to the formation of the deep and superficial palmar arches.     

Persistent right aortic arch in a yearling captive wood bison (Bison bison athabascae).

An undersized, 16-mo-old, captive wood bison (Bison bison athabascae) was observed with dysphagia and postprandial regurgitation. The animal died shortly after anesthesia was initiated for diagnostic purposes. At necropsy, a persistent right aortic arch and aberrant left subclavian artery were diagnosed. The vascular ring structure around the esophagus and the trachea caused a megaesophagus with complete esophageal obstipation and ulcerative esophagitis. The aberrant left subclavian artery did not significantly compromise the esophagus. Persistence of the right aortic arch is relatively rare in ruminants and has not previously been reported in a bison.     

Angioarchitecture of collateral arteries of the aortic arch of Antillean manatee (Trichechus manatus manatus Linnaeus, 1758)

The aortic arrangement is an important structure associated with the maintenance of homeostasis. Based on this information, this study was conducted to describe the collateral arteries of the aortic arch of Antillean manatee and define the standard model for the species. Three specimens, an adult male, adult female and a male neonate, all strandings on the coast of the state of Rio Grande do Norte, Brazil, were used. The study was performed in the Laboratory of Morphophysiology of Vertebrates of the Federal University of Rio Grande do Norte, where in situ photographs were taken to demonstrate their topography. Subsequently, their hearts were removed and fixed in 10% formaldehyde and after 72 hr were dissected and analysed, obtaining schematic drawings and photographs of the vascular arrangement. The aortic arch was represented by three collateral arteries identified as the brachiocephalic trunk, left common carotid artery and left subclavian artery. This arrangement was similar to that found for other sirenians, and yet, for other mammals like hooded seal, murine, margarita island capuchin, black-handed tamarin, Mongolian gerbil and human. The morphological similarity presented in this study with different species of mammals, including humans, may contribute valuable information from an evolutionary point of view.     

Unusual vascular ring anomaly associated with a persistent right aortic arch and an aberrant left subclavian artery in German pinschers

The objective of this study was to describe a specific form of persistent right aortic arch (PRAA) in three German pinscher dogs and to analyse the mode of inheritance in the breed. This type of PRAA is characterised by a left retro-oesophageal subclavian artery in combination with a ligamentum arteriosum originating at the aberrant left subclavian artery (PRAA-SA-LA). This rare combination of anomalies has only been reported in two isolated cases in other dog breeds and the occurrence of any form of PRAA was not previously known to occur in the German pinscher. In the present study, 18 cases of this congenital anomaly were ascertained and their high degree of relatedness and inbreeding could be shown through pedigree analysis. Three of the affected dogs underwent further clinical investigations, and post-mortem examination (two cases) and findings at surgery (one case) verified the diagnosis of PRAA-SA-LA. A monogenic autosomal recessive mode of inheritance was not likely.     

Vascular ring anomaly with coarctation of the aorta in a cat

A 13-week-old, entire male domestic shorthaired cat was presented with a nine-week history of regurgitation following the ingestion of food. A diagnosis of a vascular ring anomaly with coarctation of the aorta was based on clinical signs, angiography and echocardiography. Surgical exploration via a right lateral thoracotomy confirmed the existence of a persistent right aortic arch with right ligamentum arteriosum, aortic coarctation and an aberrant left subclavian artery. Following the surgical transection of the aberrant left subclavian artery, the cat made an uneventful recovery, showing normal swallowing function with no evidence of regurgitation. Twelve months after surgery, the cat had no special dietary requirements and remained clinically normal.     

The macroanatomical investigations on the aortic arch in porcupines (Hystrix cristata)

The anatomy of aortic arch in porcupine was studied. Angiography was applied to each of the three adult porcupines (two males, one female) following the injection of latex from the abdominal aorta for the examination of aortic arch. The results indicated that three arteries arose from aortic arch in porcupine. These were truncus brachiocephalicus, arteria carotis communis sinistra and arteria subclavia sinistra. The truncus brachiocephalicus in porcupine yielded arteria subclavia dextra and arteria carotis communis dextra. Truncus bicaroticus was absent. The origin of truncus costocervicalis (right) and arteria vertebralis (right) arose from a common root. Left or right axillary arteries seemed to be a continuation of subclavian arteries. The results of this study may contribute to the data in this area of science.     

Familial aortic aneurysm in Leonberg dogs

A thoracic aortic aneurysm was diagnosed in a 6-month-old male Leonberg dog by use of radiography, transthoracic and transesophageal echocardiography, and magnetic resonance imaging. The aneurysm was associated with a twisted ascending aorta and dilatation of several other thoracic arteries (pulmonary trunk, brachiocephalic trunk, and left subclavian artery). Histologic examination of the aorta revealed cystic medial necrosis, with disruption of the elastic network, collagen fibers, and the muscle glycoprotein fibrillin-1. The dam and sire of the dog and 8 littermates were examined by use of transthoracic echocardiography. The sire and 1 male littermate also had an aneurysm of the ascending aorta. To the authors' knowledge, this is the first report of familial aortic aneurysm in dogs.     

Absent Left Main Coronary Artery with Variation in the Origin of its Branches in a South African Population

Coronary artery anomalies are traditionally classified into anomalies of origin, course and termination. One of the anomalies of origin is absence of the left main coronary artery (LMCA), where the left anterior descending (LAD), the circumflex (Cx) and the ramus medianus (RM) (when present) arteries originate directly from the left aortic sinus. The study aimed to document the prevalence of absent LMCA, discuss its possible embryogenesis and clinical relevance. A review of 407 coronary angiograms performed by cardiologists of three private hospitals in the eThekwini Municipality area of KwaZulu‐Natal, South Africa, was performed. The LMCA was absent in 9.6% (39/407) of the coronary angiograms. The LAD and Cx arteries originated directly from the left aortic sinus with a single ostium in 8.6% (35/407) and separate ostia in 1% (4/407) of the angiograms. In four of the angiograms with absent LMCA, a RM artery was recorded originating directly from the left aortic sinus in addition to the LAD and the Cx arteries. Angiographic detection of the anomalies of the coronary arteries is essential in the determination of the significance of such findings and their management.