Mediastinal Vascular Anomalies Causing Tracheal and Esophageal Compression and Obstruction in Childhood

Over an 11-year period, 22 children have been operated upon at the Hospital for Sick Children, Toronto, for vascular compression of the trachea and esophagus. Thirteen had a double aortic arch; three, a right aortic arch and left ligamentum arteriosum; three, an anomalous innominate artery; and one, an aberrant right subclavian artery. An unusual case of right aortic arch, aberrant left subclavian artery and left ligamentum arteriosum is reported for the first time. One child with an anomalous left pulmonary artery producing emphysema of the right lung is also described. One death occurred during the process of intubation, and three patients died postoperatively despite tracheotomy. These children were in serious condition, and the importance of rigid preoperative and postoperative care, avoiding tracheotomy if possible, is emphasized.     

Anomalous origin of the right subclavian artery in a marmoset (Callithrix jacchus).

Anomalous right subclavian artery in a one-day-old marmoset (Callithrix jacchus) is reported. The anomalous vessel originated with the left subclavian artery from a short trunk off the arch of the aorta, then passed posterior to the esophagus, indenting it.     

Loss of Gbx2 results in neural crest cell patterning and pharyngeal arch artery defects in the mouse embryo

Several syndromes characterized by defects in cardiovascular and craniofacial development are associated with a hemizygous deletion of chromosome 22q11 in humans and involve defects in pharyngeal arch and neural crest cell development. Recent efforts have focused on identifying 22q11 deletion syndrome modifying loci. In this study, we show that mouse embryos deficient for Gbx2 display aberrant neural crest cell patterning and defects in pharyngeal arch-derived structures. Gbx2(-/-) embryos exhibit cardiovascular defects associated with aberrant development of the fourth pharyngeal arch arteries including interrupted aortic arch type B, right aortic arch, and retroesophageal right subclavian artery. Other developmental abnormalities include overriding aorta, ventricular septal defects, cranial nerve, and craniofacial skeletal patterning defects. Recently, Fgf8 has been proposed as a candidate modifier for 22q11 deletion syndromes. Here, we demonstrate that Fgf8 and Gbx2 expression overlaps in regions of the developing pharyngeal arches and that they interact genetically during pharyngeal arch and cardiovascular development.     

Coronary artery anomalies and aortic valve morphology in the Syrian hamster

In the Syrian hamster, anomalies in the origin of the left coronary artery are significantly associated with the bicuspid condition of the aortic valve. In this species, bicuspid aortic valves are expressions of a trait, the variation of which takes the form of a phenotypic continuum, ranging from a tricuspid aortic valve with no commissural fusion to a bicuspid aortic valve with the aortic sinuses located in ventrodorsal orientation and devoid of any raphe. The intermediate stages of the continuum are represented by tricuspid aortic valves with a more or less extensive fusion of the ventral commissure and bicuspid aortic valves with a more or less developed raphe located in the ventral aortic sinus. The present study was designed to decide whether there is a gap between tricuspid and bicuspid aortic valves regarding the incidence of coronary artery anomalies, or whether this incidence varies according to the different tricuspid and bicuspid morphotypes of the continuum. The study was carried out in Syrian hamsters belonging to a single inbred family with a high incidence of tricuspid aortic valves with fusion of the ventral commissure, bicuspid aortic valves, and anomalies in the origin of the left coronary artery, i.e. single right coronary artery ostium in aorta, anomalous origin of the left coronary artery from the pulmonary artery, and anomalous origin of the left coronary artery from the dorsal aortic sinus. The specimens were examined by means of a stereomicroscope and, in several cases, scanning electron microscopy was also used. The relationships between anomalous coronary artery patterns and aortic valve morphologies were tested using a logistic regression model. The results obtained indicate that there is no discontinuity between tricuspid and bicuspid aortic valves regarding the incidence of coronary artery anomalies. The probability of occurrence of anomalous coronary artery patterns increases continuously according to the deviation degree of the aortic valve from its normal (tricuspid) design. The present findings suggest that in the Syrian hamster, the morphogenetic mechanisms involved in the formation of congenital anomalous aortic valves and anomalies in the origin of the left coronary artery, respectively, are strongly related from an aetiological viewpoint.     

Management of a right aberrant subclavian artery during complex hybrid stent-graft procedures: a rare and complex issue

A 76-year-old man with an ascending arch and proximal descending aortic aneurysm underwent a complex aortic replacement through a sternotomy with ligation of a right aberrant subclavian artery (RASA) distal to the right vertebral artery. The second-stage procedure was performed with a stent-graft deployed within the elephant trunk. At 6- and 12-month follow-up, the RASA was opacified by the patent right vertebral artery. Under ultrasound guidance, the patient's RASA stump was occluded by coils. Management of an RASA during complex hybrid stent-graft procedures is discussed.     

Ethyl alcohol-induced cardiovascular malformations in the chick embryo

Chick embryos incubated for 72-80 hours were exposed to various volumes (0.20-0.40 m1/egg) of 50% ethyl alcohol. Examination of embryos at day 14 of incubation showed that higher doses of ethanol decreased the survival rate of embryos compared with control embryos. Three major categories of cardiovascular malformations were observed in this study: intracardiac anomalies characterized primarily by isolated ventricular septal defect, ventricular septal defect with overriding aorta, double outlet right ventricle or common aorticopulmonary trunk; aortic arch anomalies; and subclavian artery anomalies. Frequencies of embryos with intracardiac anomalies were equal to or greater than 64.8% in the six groups exposed to ethanol. Administration of ethanol also induced high frequencies of embryos with subclavian artery anomalies (11.2-89.1%). Absence or hypoplasia of the right and/or left secondary subclavian artery was commonly associated with persistence of the corresponding primary subclavian artery. Bilateral absence and/or hypoplasia of the secondary subclavian arteries was more common than unilateral anomalies, whereas absence of the left secondary subclavian artery was more commonly observed than an absent right secondary subclavian artery. No embryos in the two control groups combined (n = 94) demonstrated aortic arch or subclavian artery anomalies.     

The aberrant retroesophageal right subclavian artery

Two cases with arteria lusoria were found at 278 routine dissections. These arteria arise as the last branches of the aortic arch and have a retroesophageal position. At the crossing point, the esophagus narrows due to the groove caused by the artery. The appearance of this malposition is the consequence of the perturbation in the organo-genesis of the right dorsal aorta and fourth branchial artery. The aberration can lead to disphagia lusoria.     

A rare form of persistent right aorta arch in linkage disequilibrium with the DiGeorge critical region on CFA26 in German Pinschers

Persistent right aortic arch (PRAA) is a congenital vascular ring anomaly common in several dog breeds. In German Pinscher, the disorder is characterized by a left retroesophageal subclavian artery in combination with a ligamentum arteriosum originating at the aberrant left subclavian artery (PRAA-SA-LA). In this study, we genotyped 38 microsatellite markers on canine chromosome 26 (CFA26) in German Pinschers and tested them for linkage and association. We found a chromosome-wide significantly linked genomic region on CFA26, which corresponds to the human DiGeorge syndrome critical region (DGCR). Therefore, we analyzed sequences from 13 genes of DGCR and the canine t-box gene TBX1. We identified a total of 26 polymorphisms in German Pinschers. Three of these SNPs located within TBX1 and one in the mitochondrial ribosomal protein L40 gene (MRPL40) were associated with the PRAA-SA-LA phenotype in German Pinscher. Despite linkage and association between PRAA-SA-LA and the canine DGCR, none of these mutations appeared responsible for PRAA-SA-LA. As the orthologue human region on HSA22q11.2 is known for high susceptibility to genomic rearrangements, we suspect that in German Pinschers, chromosomal aberrations might cause PRAA-SA-LA.     

Abnormal development of cardiovascular systems in rat embryos treated with bisdiamine

Administration of N,N'-bis(dichloroacetyl)-1,8-octamethylenediamine, bisdiamine, in pregnant Donryu rats on day 10 of gestation induces a high incidence of cardiovascular anomalies in fetuses. Bisdiamine administration induced aplasia of the sixth aortic arch artery, with both the right and left primitive pulmonary arteries being directly linked to the truncus, and resulting in four types of malformation of pulmonary arteries (PAs). When two primitive PAs shared a single root, the consequence was either pulmonary trunk hypoplasia, as is seen in tetralogy of Fallot, or type I persistent truncus arteriosus (PTA) as classified by Collet and Edwards. When root portions of two PAs did not fuse, either type II or type III PTA resulted. In controls, the right dorsal aorta (DA) between the right seventh intersegmental artery (IA) and the site where both DAs fuse degenerated and the left aortic arch (AA) and the right subclavian artery (SA) were formed. Bisdiamine administration induced two additional types of vascular anomalies. In one of these, the right DA between the right 4AA and the right 7IA degenerated and a left AA accompanied by an aberrant right SA resulted. In the other type, the left DA between the left 4AA and the left 7IA degenerated and a right AA accompanied by an aberrant left SA resulted. These results indicate that administration of bisdiamine induces malformation in the great blood vessels by disturbing persistency and degeneration of aortic arch arteries and DAs.     

Thoracic aorta dissection associated with aberrant right subclavian artery: treatment with endovascular stent-graft placement

Dissecting aneurysm is the condition produced by separation of the layers of the arterial wall by circulating blood. Although rare, the coexistence of aortic dissection and aberrant right subclavian artery may be catastrophic. In this study we report the endovascular treatment of a patient with thoracic aorta dissection associated with aberrant right subclavian artery. Aortic clamping proximal to the left subclavian artery in a patient with an aberrant right subclavian artery slows or eliminates flow to both vertebral arteries. Endovascular repair eliminates the complications associated with aortic clamping during surgical repair in the presence of an aberrant right subclavian artery; therefore, it should be considered the treatment of choice in this situation.     

Anomalous right coronary artery originating from the left sinus of Valsalva in a Yucatan minipig

A 39.2-kg, castrated male Yucatan minipig (Sus scrofa domestica) was presented for enrollment in a coronary artery study. Angiography revealed an anomalous right coronary artery originating from the left sinus of Valsalva. The left anterior descending, left circumflex, and anomalous right coronary arteries were implanted with metallic stents without complications. The minipig remained on the study for 3 mo until it reached its predetermined study endpoint, during which time it showed no clinical signs of disease. Histologic examination of the implanted coronary arteries revealed no differences between the normal (left anterior descending and left circumflex arteries) and the anomalous right coronary artery. Swine are important models for coronary research. Although several cases of anomalous human coronary arteries have been documented, the current case is the first report of a coronary artery anomaly in a minipig.     

Incidence of anomalous origin of coronary artery in 1879 Chinese adults on dual-source CT angiography

Background and Objective. Dual-source CT (DSCT) has been used to detect coronary artery anomalies. The purpose of this study was to assess the incidence of anomalous origin of the coronary artery in Chinese adults. Methods. We summarised all patients who underwent DSCT coronary angiography (CTCA) from December 2006 to February 2008, and data of anomalous origin of the coronary artery in Chinese adults were recorded. Results. 1879 patients underwent CTCA during that period; 24 patients with an anomalous origin of the coronary artery were detected, giving an incidence of 1.3%. Fifteen patients had an anomalous origin of the right coronary artery (12 from left coronary sinus, 3 high takeoff), eight patients had an anomalous origin of the left coronary artery (LCA from posterior sinus of Valsalva in three cases, LCX from the right coronary sinus, LCX from RCA, high takeoff, LCA from right coronary sinus, and single coronary artery in one case, respectively), and one patient had an anomalous origin of both coronary arteries (high takeoff). Conclusion. The incidence of anomalous origin of the coronary artery in Chinese adults in this study is 1.3%. DSCT can clearly visualise the anomalous origin and course of the coronary artery and is a useful screening modality. (Neth Heart J 2010;18:466-70.)     

Disruption of the Hoxa3 homeobox gene results in anomalies of the carotid artery system and the arterial baroreceptors

Homeobox gene Hoxa3 is expressed in the third pharyngeal arch and pouch and is required for development of the third arch artery in addition to the thymus, parathyroid gland and carotid body. We therefore statistically analyzed malformations of the carotid artery system in Hoxa3 homozygous mutant mice, in comparison with wild-type and heterozygous littermates. To identify the carotid artery system, red carbon ink was injected, or vascular casts were made by injection of Mercox resin and observed by scanning electron microscopy. Furthermore, innervation of the carotid sinus and baroreceptor regions in the aortic arch and right subclavian artery were studied in the Hoxa3 null mutants having an abnormal carotid artery system by immunohistochemistry with TuJ1 and protein gene product (PGP) 9.5 antibodies, which recognize nerve fibers and neurons. The common carotid artery of Hoxa3 homozygous mutants was absent or very short and therefore the internal and external carotid artery arose from a more proximal level than those of wild types. The baroreceptor innervation, however, persisted in the mutants, although vascular targets were changed. These results indicate that Hoxa3 gene is crucial for the formation of the common carotid artery and the null mutant mice are the first useful animal models to show that the third arch arteries on both sides specifically degenerate but the fourth and sixth arch arteries are normal.     

Origin of the left anterior descending coronary artery from the pulmonary artery: An unusual cause of angina in a middle-aged woman

A 48-year-old woman was admitted to our institution with angina pectoris and a systolic murmur. At cardiac catheterization, she was found to have an anomalous origin of the left anterior descending coronary artery from the pulmonary trunk. There was also an associated atrial septal defect and a bicuspid aortic valve.     

Surgical management of chronic occlusive disease of the aortic arch vessels and vertebral arteries.

Occlusive disease of the aortic arch vessels is relatively rare and often missed initially. Of 41 patients treated surgically for this condition over a 10-year period 38 had arteriosclerotic lesions, 2 had symptoms secondary to vasculitis (Takayasu''s arteritis) and 1 had a radiation injury to a subclavian artery. In 22 cases the left subclavian artery was involved; the right subclavian and innominate arteries were the next most commonly affected. Only four vertebral stenoses were treated. Most patients presented with a combination of arm and hindbrain ischemia that was shown radiologically to be associated with a subclavian steal syndrome, but in some only isolated arm symptoms or severe vertigo alone was experienced. There was a difference in blood pressure between the arms of at least 20 mm Hg in 88% of the patients. The treatment for 28 patients was creation of a carotid-subclavian bypass, for 6 the placement of a bypass graft from the ascending aorta to the subclavian or carotid artery or both, for a 3 a subclavian endarterectomy and for 4 vertebral angioplasty. There were no operative deaths, and 90% of the grafts were patent 1 to 72 months later. however, only 30 (73%) of the patients were asymptomatic and 9 (22%) had improved.     

Variations in the extracranial origin of the human vertebral artery

The aim of this study is to demonstrate a case of a cadaver in which both left and right vertebral arteries had an abnormal origin. On the left, the artery arose directly from the arch of the aorta. On the right, a double-originating vertebral artery was seen. The literature on the variations of the artery is reviewed and a detailed morphometric study of the artery was carried out because of its importance for neurosurgeons.     

A quantitative histological study of the aortic nerve and the aortic body in the buffalo (Bubalus bubalis)

In the buffalo, the left aortic nerve ramifies in the periarterial connective tissue between the ventral surface of the aortic arch and the truncus pulmonalis. The right aortic nerve ramifies over the dorsal and right aspects of the aorta ascendens near its origin. The histograms of myelinated fibres of both left and right aortic nerve are distinctly unimodal with peak around 4-6 micron (64.2-67.8%). The left aortic body is situated in the periarterial connective tissue between the ventral surface of the aortic arch and the truncus pulmonalis, while the right aortic body is located in the tunica adventitia of the dorsal and right aspects of the aorta ascendens near its origin. The greatest sagittal section area of the left aortic body is 0.102 +/- 0.009 mm2 and that of the right aortic body is 0.041 +/- 0.002 mm2. The organ is highly vascular. The mean size of the glomus cells from the left aortic body is 7.68 +/- 0.9 micron x 9.37 +/- 0.13 micron (short diameter x long diameter), whereas the corresponding value for the right aortic body is 7.84 +/- 0.14 micron x 9.86 +/- 0.21 micron; and their density values are (11,417 +/- 301.7)/mm2 and (9,839 +/- 213.3)/mm2 respectively.     

Blunt Traumatic Aortic Injury of Right Aortic Arch in a Patient with an Aberrant Left Subclavian Artery

Right-sided aortic arch (RAA) is a rare congenital developmental variant present in about 0.1 percent of the population. This anatomical anomaly is commonly associated with congenital heart disease and complications from compression of mediastinal structures. However, it is unknown if patients are at a higher risk of blunt thoracic aortic injury (BTAI). We report a case of a 20-year-old man admitted to the hospital after being hit by an automobile. Computed tomographic scan revealed an RAA with an aberrant left subclavian artery originating from a Kommerell’s diverticulum. A pseudo-aneurysm was also seen along the aortic arch. A diagnosis of blunt traumatic aortic injury was made. The patient was successfully treated with a 26mm Vascutek hybrid stentgraft using the frozen elephant trunk technique.A literature review of the pathophysiology of BTAI was performed to investigate if patients with right-sided aortic arch are at a higher risk of suffering from BTAI. Results from the review suggest that although theoretically there may be a higher risk of BTAI in RAA patients, the rarity of this condition has prevented large studies to be conducted. Previously reported cases of BTAI in RAA have highlighted the possibility that the aortic isthmus may be anatomically weak and therefore prone to injury. We have explored this possibility by reviewing current literature of the embryological origins of the aortic arch and descending aorta.     

Variations in coronary artery anatomy: Normal versus abnormal

We offer a comprehensive classification of coronary artery anomalies, together with angiographic examples of each entity. Minimal requirements for normality include the following criteria: (1) the dual aortic origin is from right and left coronary ostia; (2) the course of the right coronary artery follows the right atrioventricular groove; (3) the course of the left coronary artery follows the left atrioventricular groove and anterior interventricular groove; (4) the posterior descending branch originates from either the right or left coronary artery; (5) the major coronary branches flow epicardially; and (6) the coronary arteries terminate at the myocardial capillary level. This conception of "normal" coronary arteries has determined the classification of abnormalities presented here. Early and correct diagnosis of anomalies that may compromise the myocardial blood supply is stressed, and possible surgical solutions are offered. Selective coronary angiography is the technique of choice for precise visualization of the coronary artery system.     

A rare origin of the superior thyroid artery

In the course of a classroom dissection of a negro male (height: 167 cm; weight: 56.8 kg), and anomalous right superior thyroid artery was noted. It arose from the common carotid artery 27 mm proximal to the bifurcation into external and internal carotids. Previous reports indicate that the incidence of origin of the superior thyroid from the common carotid or its bifurcation varies from 5 to 45%, depending on the population sampled. Moreover, a low origin is more common in females than males, and appears approximately twice as often on the left as on the right. Previous reports also indicate that the origin is only very rarely more than 1 cm proximal to the bifurcation, only one case having been reported of an origin 25 mm proximal. The present case appears to be the most proximal origin so far recorded, and the first far proximal origin in negroes. The implications of such a low origin for surgical approach to the thyroid are considerable.