Pulmonic stenosis caused by single coronary artery in dogs: four cases (1965-1984)

Single right coronary artery (CA) associated with pulmonic stenosis was found in 3 English Bulldogs and a Boxer, suggesting a genetic predisposition for the associated anomalies. The left main coronary branch arose from the single right CA, encircled the pulmonic root over hypoplastic pulmonic valves at the level of the obstruction, and appeared to be the primary cause of underlying pulmonic stenosis. Patch-graft surgery to relieve pulmonic stenosis caused death in 1 dog when the unrecognized anomalous CA was served during the procedure. The anomalous left CA was detectable by use of angiocardiography in all 4 dogs and was recognized before surgery in 2 of them. In 1 dog, a right ventricle-to-pulmonary trunk-bridging conduit was implanted to improve outflow from the right side of the heart.     

Congenital cardiac disease in dogs

Pulmonic stenosis is caused by a malformed pulmonic valve, stricture of the right ventricular outflow tract or stricture of the pulmonary artery. English Bulldogs, Beagles, Samoyeds, Fox Terriers and Chihuahuas are predisposed. Clinical signs in severely affected dogs include exercise intolerance, stunting, dyspnea, syncope and ascites. Auscultation reveals a high-frequency, crescendo-decrescendo murmur during systole, loudest over the left side of the thorax, near the sternal cardiac border. An ECG may reveal a right-axis deviation of greater than 120 degrees, S waves in leads I, II and III, deep S waves in CV6LL, CV6LU and V10, Q waves deeper than 0.5 mv in leads II, III and AVF, and positive T waves in lead V10. Plain film LAT thoracic radiographs reveal an elevated carina, increased sternal contact of the heart, loss of the cranial cardiac waist and a widened cardiac silhouette, with normal pulmonary vasculature. A DV projection reveals an inverted "D" shape of the right ventricle and a pulmonary artery bulge. A nonselective angiocardiogram reveals poststenotic dilation of the main pulmonary artery. Treatment involves surgical correction of the stenosis.     

Tricuspid atresia in a foal

An Arabian crossbred foal was examined because of a suspected congenital cardiac anomaly. There was a grade V/V crescendo-decresendo holosystolic murmur and thrill in the left 4th intercostal space. The foal was slightly cyanotic and polycythemic. Electrocardiography suggested left ventricular hypertrophy. Angiography and cardiac and vascular pressure recordings led to a diagnosis of pulmonic stenosis. The foal died after cardiac bypass and corrective surgery. Postmortem examination revealed an enlarged right atrium, atresia of the tricuspid orifice, a large, fenestrated patent foramen ovale, eccentric left ventricular hypertrophy, and a large interventricular septal defect. The right ventricle had a small lumen and a relatively thick wall. There was valvular and supravalvular pulmonic stenosis, with poststenotic dilatation of the pulmonary artery. A single coronary artery originated from the anterior sinus of the aorta.     

Non‐electrocardiographic‐gated computed tomographic angiography can be used to diagnose coronary artery anomalies in Bulldogs with pulmonary valve stenosis

Coronary artery anomalies have been reported in Bulldogs and present an increased risk when performing balloon valvuloplasty. Identification of coronary anomalies has been reported using multidetector‐row computed tomographic (MDCT) angiography with electrocardiographic gating. However, the utility of non‐electrocardiographic‐gated 16‐row computed tomographic for MDCT for the identification of coronary artery anatomy or anomalies to the authors’ knowledge has not been fully investigated. The purpose of this study was to evaluate the feasibility of non‐electrocardiographic‐gated computed tomographic (CT) angiography to identify coronary anomalies in Bulldogs with pulmonary valve stenosis. In this prospective, observational study, Bulldogs with echocardiographically diagnosed pulmonary valve stenosis, an echocardiographically derived transpulmonic pressure gradient >70 mm Hg, and a clinician recommendation for balloon valvuloplasty were included. Anesthetized dogs underwent a 16‐row MDCT non‐electrocardiographic‐gated CT angiography. A board‐certified veterinary radiologist and board‐certified veterinary cardiologist reviewed the CT angiography studies and identified the coronary artery anatomy. When normal coronary artery anatomy was detected on CT angiography, a right ventricular outflow tract fluoroscopic angiogram was performed and evaluated during levophase to confirm normal coronary anatomy prior to balloon valvuloplasty. Dogs with coronary anomalies noted on CT angiography were recovered from anesthesia and balloon valvuloplasty was not performed. All dogs (10/10; 100%) had interpretable images from the non‐electrocardiographic‐gated CT angiography. Coronary anomalies were identified in six dogs based on non‐electrocardiographic‐gated CT angiography, five with type R2A anomaly and one had a single left coronary ostium. Four dogs had normal coronary anatomy based on non‐electrocardiographic‐gated CT angiography. Balloon valvuloplasty was performed without incident in these four dogs. We conclude that non‐electrocardiographic‐gated CT angiography represents a noninvasive method for diagnosing coronary anomalies in Bulldogs with pulmonary valve stenosis.     

A case of valvular pulmonic stenosis and an aberrant coronary artery in a Brittany spaniel

Valvular pulmonic stenosis and aberrancy of the right coronary artery with subsequent subvalvular stenosis was found on echocardiographic evaluation of a 9-month-old Brittany spaniel. Previous echocardiography at 4 mo of age revealed the pulmonic stenosis; however, the aberrant coronary artery only became apparent during the second evaluation.     

Coronary arteries of the roe deer (Capreolus capreolus; Linnaeus 1758) heart

A study of the coronary arteries of the roe deer heart was performed on 21 hearts of animals of both sexes and various ages. The roe deer heart is supplied by two arteries: the left coronary artery and the right coronary artery. The left coronary artery arises from the left aortic sinus and forms a short common trunk. The left coronary artery reaches the coronary groove, then divides into the paraconal interventricular branch and the circumflex branch. The circumflex branch gives off several branches to the left ventricle wall and terminates in the subsinuosal interventricular groove as the subsinuosal interventricular branch. The right coronary artery is less pronounced than the left coronary artery. It arises from the right aortic sinus and enters the coronary groove as the right circumflex branch. We found the left arterial cone branch in 75% and the right arterial cone branch in 80% of the cases investigated. The coronary arteries of the heart run subepicardially. In 9 cases we found muscular bridges over the coronary arteries, mostly on the paraconal interventricular branch. In conclusion we affirm the left type of the arterial vascularisation in the roe deer heart.     

Unexpected death in an adult dog with anomalous origin of the left coronary artery from the pulmonary trunk

A two-year-old female miniature poodle died unexpectedly while romping with its owner. Anomalous origin of the left coronary artery from the left pulmonic sinus was discovered at necropsy. Histologically, the right ventricle was unremarkable, but multifocal to coalescing necrosis and fibrosis occurred in the myocardium and endocardium of the left ventricle. Medial hypertrophy of small muscular pulmonary arteries was observed in the lung. The cardiac lesions were similar to those of children with anomalous origin of the left coronary artery from the pulmonary trunk. Pulmonary hypertension, which is suggested by the pulmonary arterial medial hypertrophy, could have increased left ventricular myocardial perfusion and delayed the ischemic myocardial damage that resulted in the death of this dog.     

Pulmonic stenosis in the dog: 29 cases (1975-1984)

In a retrospective study of 29 dogs with congenital pulmonic stenosis, we evaluated the clinical, radiographic, angiocardiographic, and cardiac catheterization data. Eighteen dogs had no clinical signs of disease and were referred for evaluation of a previously detected cardiac murmur, 5 dogs had congestive right-sided heart failure, and 5 dogs were examined for exercise intolerance or syncope. Dogs with heart failure tended to be older than dogs without clinical signs of heart failure (19.3 months vs 12 months). All dogs had radiographic or electrocardiographic evidence of right ventricular enlargement. Poststenotic dilatation of the main pulmonary artery and apparent pulmonary undercirculation were observed frequently on survey radiographs. Isolated pulmonic valve dysplasia, representing a range of angiographic pulmonic valve abnormalities, was evident in 88% of the available 26 angiographic studies, whereas subvalvular stenosis was uncommon and observed in only 2 dogs. Muscular hypertrophy of the right ventricular infundibulum and supraventricular crest were observed in 96% and 25% of the angiocardiograms, respectively. Poststenotic dilatation of the main pulmonary artery was observed in every dog. A ratio between the width of the main pulmonary artery and the valve annulus was useful in identifying pulmonic stenosis and distinguishing this anomaly from other congenital malformations. The degree of poststenotic dilatation did not appear to be related to the severity of the systolic pressure gradient, which ranged from 20 to 228 mm of Hg (mean, 93 mm of Hg).(ABSTRACT TRUNCATED AT 250 WORDS)     

Pulmonary artery dissection following balloon valvuloplasty in a dog with pulmonic stenosis

A 3-month-old, 9.9 kg, male pit bull cross was referred for evaluation of collapse. A left basilar systolic heart murmur graded V/VI and a grade IV/VI right basilar systolic heart murmur were ausculted. Echocardiography showed severe pulmonic stenosis characterized by annular hypoplasia, leaflet thickening, and leaflet fusion. After 1 month of atenolol therapy, a pulmonic valve balloon valvuloplasty procedure was performed, and the intra-operative right ventricular pressure was reduced by 43%. Echocardiography, performed the following day, showed apparent rupture of a pulmonary valve leaflet and a membranous structure within the pulmonary artery consistent with a dissecting membrane. Short-term follow-up has shown no apparent progression of the pulmonary artery dissection and the patient remains free of clinical signs.     

Balloon Valvuloplasty for Treatment of Pulmonic Stenosis in English Bulldogs with an Aberrant Coronary Artery

Background: English Bulldogs (EB) with pulmonic stenosis (PS) sometimes have an aberrant coronary artery (CA) type R2A encircling the pulmonary artery (PA). Balloon valvuloplasty (BV) is treatment of choice for severe PS, but is considered to be contraindicated in dogs with aberrant CA. Hypothesis: Conservative BV in EB with aberrant CA is safe and improves clinical signs and quality of life. Animals: Four client‐owned EB with severe PS were retrospectively reviewed/analysed. Methods: Retrospective study: Case records, echocardiography, BV, and follow‐up investigations of EB diagnosed with severe PS and treated with BV were reviewed. The ratios of PA to aortic (Ao) velocity time integral (VTI) were calculated to assess progression/improvement of PS. Results: An aberrant CA was confirmed on angiography in all EB. Conservative BV was performed, using a balloon of the size of the PA annulus or smaller (0.6–1 × PA annulus size). All dogs survived the procedure, but only a mild reduction in pressure gradient was achieved. There was an improvement in PA to Ao VTI in 3 of 4 dogs (P≤ .017), which were free of evidence of congestive heart failure (CHF) 5, 10, and 15 months after BV. One dog that had right‐sided CHF when BV was performed died due to progressive right‐sided CHF within 3 months. Conclusions: Conservative BV in EB might be safe and might improve quality and quantity of life.     

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.     

Rudimentary Coronary Artery in Syrian Hamsters (Mesocricetus auratus)

Congenital underdevelopment of one or more main branches of the coronary arteries has been reported in man, but not in non-human mammals. In man, this defective coronary artery arrangement may cause myocardial ischaemia and even sudden death . The main goal of this study was to describe the coronary artery distribution patterns associated with the presence of a markedly underdeveloped (rudimentary) coronary artery in Syrian hamsters. Moreover, an attempt was made to explain the morphogenesis of these patterns, according to current knowledge on coronary artery development. Eleven affected hamsters belonging to a laboratory inbred family were examined by means of internal casts of the heart, great arterial trunks and coronary arteries. The aortic valve was tricuspid (normal) in seven hamsters and bicuspid in the other four. A rudimentary coronary artery arose from the right side of the aortic valve in four specimens, from the left side of the aortic valve in a further three, and from the dorsal aortic sinus in the remaining four. In all cases, a second, well-developed coronary artery provided for all the coronary blood flow. Except for the existence of a rudimentary coronary artery, the present anomalous coronary artery distribution patterns are similar to coronary artery patterns reported in Syrian hamsters, dogs and humans in association with a solitary coronary ostium in aorta. We suggest that an unusual prolonged time interval in the development of the embryonic coronary stems might be a key factor in the formation of coronary arteries displaying significantly dissimilar developmental degrees.     

Left coronary aneurysmal dilation and subaortic stenosis in a dog

A 6-month-old German shepherd dog was referred for evaluation of a cardiac murmur.Upon physical examination, the auscultated heart rate was 120 beats/min, and a grade IV/VI systolic heart murmur with a point of maximal intensity over the left heart base radiating up the neck was heard. The standard echocardiographic examination showed subaortic stenosis and an anechoic tubular structure extending from the sinus of Valsalva to the left ventricular posterior wall. Aneurysmal left coronary artery (CA) was confirmed by angiography. The dog was euthanized and post-mortem examination showed severe dilatation of the proximal left CA and confirmed the subaortic stenosis. Histopathology did not demonstrate abnormalities in the walls of the CA, aorta or pulmonary artery.The exact cause of the CA aneurysmal dilation remains unknown. Subaortic stenosis, elevated coronary vascular resistance or a congenital anomaly may have contributed to the dilation.To our knowledge, coronary aneurysmal dilation has never been described in dogs. Standard echocardiography provides reliable information on coronary anatomy.     

The arrangement of the coronary artery trunks is subject to inheritance factors: A study in Syrian hamsters

The concept that anatomical variations in the coronary artery tree might be influenced by genes is relatively old. However, empirical evidence on the effect of genotype on the coronary morphology is still scarce. In the Syrian hamster, there is a septal coronary artery which arises from the left or from the right coronary artery and supplies most of the interventricular septum. The aim was to decide whether the anatomical origin of the septal artery is subject to inheritance factors. Overall, 483 internal casts of the heart and coronary arteries were examined. All the hamsters included in this study had normal coronary arteries. The results of 74 crosses were compared statistically to seek for any significant difference between the phenotypes of the offspring and the phenotypes of the parents. The left septal artery was over‐represented in the offspring of crosses between parents having both a left septal artery (p < .01), while the right septal artery was over‐represented in the offspring of crosses between parents, one with a right and the other with a left septal artery (p < .001), and, more markedly, in the offspring of crosses between parents both with a right septal artery (p < .001). These results are the first to reveal that the coronary artery pattern is influenced by genetic factors, at least in its proximal portion with regard to the aorta.     

Use of 3D printer technology to facilitate surgical correction of a complex vascular anomaly with esophageal entrapment in a dog

A 10 week old female intact Staffordshire terrier was presented with a total of five congenital cardio-thoracic vascular anomalies consisting of a patent ductus arteriosus (PDA) with an aneurysmic dilation, pulmonic stenosis, persistent right aortic arch, aberrant left subclavian artery and persistent left cranial vena cava. These abnormalities were identified with a combination of echocardiogram and computed tomography angiography (CTA). The abnormalities were associated with esophageal entrapment, regurgitation, and volume overload of the left heart with left atrial and ventricular enlargement. A 2 cm diameter aneurysmic dilation at the junction of the PDA, right aortic arch and aberrant left subclavian artery presented an unusual surgical challenge and precluded simple circumferential ligation and transection of the structure. A full scale three dimensional model of the heart and vasculature was constructed from the CTA and plasma sterilized. The model was used preoperatively to facilitate surgical planning and enhance intraoperative communication and coordination between the surgical and anesthesia teams. Intraoperatively the model facilitated spatial orientation, atraumatic vascular dissection, instrument sizing and positioning. A thoracoabdominal stapler was used to close the PDA aneurysm prior to transection. At the four-month postoperative follow-up the patient was doing well. This is the first reported application of new imaging and modeling technology to enhance surgical planning when approaching correction of complex cardiovascular anomalies in a dog.     

Arrhythmogenic right ventricular cardiomyopathy in Bulldogs: Evaluation of clinical and histopathologic features,progression, and outcome in 71 dogs (2004–2016)

ObjectivesThis study aimed to characterize the clinical and histopathological features of arrhythmogenic right ventricular cardiomyopathy (ARVC) in English Bulldogs, American Bulldogs, and Bulldog-type mixed breed dogs and assess affected Bulldogs for a striatin gene mutation previously reported in Boxers with ARVC.AnimalsSeventy-one Bulldogs fit the inclusion criteria. Genetic analysis was performed on five dogs. Cardiac post-mortem evaluations were performed on two dogs.MethodsMedical records from a single veterinary cardiology group (CVCA) were retrospectively evaluated. Tissue and blood samples were submitted for histopathological analysis and genetic testing in select patients.ResultsPresenting complaints included syncope (38%), arrhythmia (81.7%), or murmur (34.2%) documented on examination. On presentation, congestive heart failure (CHF) was diagnosed in 22 (31%) dogs, and 58 (81.7%) had ventricular arrhythmias. On bivariable analyses, the two-dimensional (2D) left atrial-to-aortic root ratio (LA:Ao) was the only prognostic variable significantly associated with survival time. Dogs with 2D LA:Ao below the mean (1.41) had longer median survival to all-cause mortality (12 months; 95% confidence interval [CI] six–15 months) than those with 2D LA:Ao above the mean (four months; 95% CI two–six months; p=0.0384). Most dogs (54%) died from cardiac disease, with 42.1% experiencing sudden death. The median time from diagnosis to cardiac death was four months.ConclusionsArrhythmogenic right ventricular cardiomyopathy affects Bulldogs with both arrhythmogenic and dilated-type phenotypes. Despite variable arrhythmia severity and predominantly right-sided involvement in many dogs, an increase in left atrial size was the only significant predictor of mortality in this sample of dogs.     

Separate origin of the main components of the left coronary artery in Syrian hamsters (Mesocricetus auratus)

This study describes a rare congenital coronary artery anomaly in the Syrian hamster; namely, the separate origin of the obtuse marginal and left circumflex arteries which are the main components of the left coronary artery. The hearts of nine affected animals were examined by means of a corrosion-cast technique and histology. The hamsters belonged to a laboratory inbred family with a high incidence of coronary artery anomalies and bicuspid aortic valve. The aortic valve was tricuspid in three hamsters and bicuspid in the other six hamsters. In all cases, the right coronary artery was normal, whereas the left coronary artery main trunk was absent. The present anomalous coronary artery patterns could be classified into two main entities: (i) ectopic origin of the obtuse marginal artery from the right aortic sinus or from the right coronary artery, with the left circumflex artery arising from the left side of the aortic valve; and (ii) ectopic origin of both the obtuse marginal artery from the right aortic sinus or from the right coronary artery and left circumflex artery from the dorsal aortic sinus. In all cases, the obtuse marginal artery coursed to the right side of the heart through the ventral wall of the right ventricular outflow tract. When the left circumflex artery arose from the dorsal aortic sinus, it formed an acute angle with the aortic wall. This report seems to be the first to describe the separate origin of the main components of the left coronary artery in a non-human mammalian species. In man, the congenital coronary artery and aortic valve defects reported herein may entail the risk of clinical complications. However, none of the affected hamsters showed signs of disease.     

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) in four calves

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA), or Bland-White-Garland syndrome, is a rare congenital malformation described in children and adults. In this condition, the left coronary artery, which normally originates from the left coronary sinus in the aorta, instead originates from the pulmonary trunk, which results in retrograde flow of blood away from the myocardium into the lower-pressure pulmonary artery. Myocardial hypoxic-ischemic injury results in cardiac dysfunction, failure, and eventually in patient death if not surgically repaired. This report describes gross and microscopic findings in 4 beef calves with ALCAPA. All the calves had a history of being found dead with few or no premonitory signs, 2 shortly after sudden strenuous exercise. Gross necropsy lesions suggestive of heart failure included cardiomegaly with atrial and ventricular dilation and/or ventricular hypertrophy, and hepatomegaly. Dissection of each heart revealed the origin of the left coronary artery arising in the pulmonary trunk above the anterior cusp of the pulmonic valve. No degeneration; mineralization; and fiber loss, with replacement by fibrous connective tissue, predominantly in the left ventricular papillary muscle and the interventricular septum. Changes observed in the liver and lungs, including hepatomegaly, sinusoidal congestion, centrilobular fibrosis, and pulmonary congestion, edema, and intra-alveolar pigment-laden macrophages were consistent with heart failure.     

The 1st balloon valvuloplasty: an historical note

Balloon valvuloplasty (BV) is currently the treatment of choice for pulmonic stenosis in humans and dogs. Before permission was obtained to attempt the 1st BV in a child in 1982, the safety and efficacy of the procedure were tested in 1980 in an English Bulldog with spontaneous pulmonic stenosis. A fatal outcome would have caused indefinite postponement of BV in human patients, a procedure that currently benefits over 25,000 patients a year worldwide. This article describes the initial test procedure and its fortunate outcome in spite of unrecognized coronary anomalies in the bulldog. A small balloon was used in the test procedure, and fatal disruption of the anomalous left coronary artery (CA) did not occur as it has in several bulldogs since that time.