The association of a retroesophageal right subclavian artery, a right-sided terminating thoracic duct, and a left vertebral artery of aortic origin: anatomical and clinical considerations

The findings in a cadaver demonstrated: (a) an aberrant retroesophageal right subclavian artery (RRSA); (b) a thoracic duct (Th.d.) terminating at the junction of the right internal jugular and subclavian veins ('venous angle'), and (c) a left vertebral artery (LVA) of aortic origin. The origin of the RRSA from the aortic arch was distal and medial to the left subclavian artery and it reached the upper extremity by crossing posterior to the esophagus. The Th.d. ran a normal retroesophageal course in the mediastinum, until it was intercepted by the anomalous subclavian artery. At this level the Th.d. was deflected towards the right and, accompanied by the anomalous artery, reached the right venous angle. The LVA arose from the aortic arch between the left common carotid and the left subclavian arteries, and ascended to the transverse foramen of C6. The practical importance of associations in general is discussed, and the special diagnostic and surgical significance of the RRSA and Th.d. is stressed.     

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.     

Hybrid repair of a very late, post-aortic coarctation surgery thoracic aneurysm: a case report

ABSTRACT: INTRODUCTION: Local aneurysms after surgical repair of coarctation of the aorta occur mainly in patients surgically treated by Dacron patch plasty during adulthood. The management of these patients is always problematic, with frequent complications and increased mortality rates. Percutaneous stent-graft implantation avoids the need for surgical reintervention. CASE PRESENTATION: We report a case involving the hybrid treatment by stent-graft implantation and transposition of the left subclavian artery to the left common carotid artery of an aneurysmal dilatation of the thoracic aorta that occurred in a 64-year-old Caucasian man, operated on almost 40 years earlier with a Dacron patch plasty for aortic coarctation. Our patient presented to our facility for evaluation with back pain and shortness of breath after minimal physical effort. A physical examination revealed stony dullness to percussion of the left posterior thorax, with no other abnormalities. The results of chest radiography, followed by contrast-enhanced computed tomography and aortography, led to a diagnosis of giant aortic thoracic aneurysm. Successful treatment of the aneurysm was achieved by percutaneous stent-graft implantation combined with transposition of the left subclavian artery to the left common carotid artery. His post-procedural recovery was uneventful. Three months after the procedure, computed tomography showed complete thrombosis of the excluded aneurysm, without any clinical signs of left lower limb ischemia or new onset neurological abnormalities. CONCLUSIONS: Our patient's case illustrates the clinical outcomes of surgical interventions for aortic coarctation. However, the very late appearance of a local aneurysm is rather unusual. Management of such cases is always difficult. The decision-making should be multidisciplinary. A hybrid approach was considered the best solution for our patient.     

Computational analysis of type II endoleaks in a stented abdominal aortic aneurysm model

Insertion of a stent-graft into an aneurysm to form a new (synthetic) blood vessel and prevent the weakened artery wall from rupture is an attractive surgical intervention when compared to traditional open surgery. However, focusing on a stented abdominal aortic aneurysm (AAA), post-operative complications such as endoleaks may occur. An endoleak is the net influx of blood during the cardiac cycle into the cavity (or sac) formed by the stent-graft and the AAA wall. A natural endoleak source may stem from one or two secondary branches leading to and from the aneurysm, labeled types IIa and IIb endoleaks. Employing experimentally validated fluid-structure interaction solvers, the transient 3-D lumen and cavity blood flows, wall movements, pressure variations, maximum wall stresses and migration forces were computed for types IIa and IIb endoleaks. Simulation results indicate that the sac pressure caused by these endoleaks depends largely on the inlet branch pressure, where the branch inlet pressure increases, the sac pressure may reach the systemic level and AAA-rupture is possible. The maximum wall stress is typically located near the anterior-distal side in this model, while the maximum stent-graft stress occurs near the bifurcating point, in both cases, due to local stress concentrations. The time-varying leakage rate depends on the pressure difference between AAA sac and inlet branch. In contrast, the stent-graft migration force is reduced by type II endoleaks because it greatly depends on the pressure difference between the stent-graft and the aneurysm cavity.     

Aortic dissection presenting as acute lower extremity ischemia: report of a case

Although not common, acute leg ischemia is an important element in the clinical presentation of a patient with aortic dissection. This report describes a case of aortic dissection in which the main feature at presentation was acute right leg ischemia. The angiography showed right common iliac artery and external iliac artery occlusion. Diagnosis was made by clinical evaluation and angiography. Embolectomy was then attempted immediately but failed. Aortic dissection was highly suspected and confirmed by emergency computed tomography. Fortunately, the patient had good recovery. Aortic dissection is potentially lethal if misdiagnosed or if recognition is delayed. As such, aortic dissection should be considered in the differential diagnosis.     

Flow patterns in an endovascular stent-graft for abdominal aortic aneurysm repair

Endovascular exclusion of the abdominal aortic aneurysm (AAA) has been carried out in selected patients during the past decade. The deployment of a complex multicomponent endovascular device in an aneurysmal aorta may alter the local haemodynamics and lead to thrombosis and intimal hyperplasia development. The aim of this in vitro study was to investigate the flow patterns using flow visualisation and laser Doppler anemometry in a commercial bifurcated stent-graft. Two configurations of the stent-graft, endo-stent and exo-stent, were investigated in an idealised planar AAA model. The flow structures in the main trunk in both configurations of the stent-graft are three-dimensional with complex secondary structures. However, these flow structures were not entirely caused by the stent-graft. The stent struts in the endo-stent configuration cause localised alteration in the flow pattern but the overall flow structures were not significantly affected. Low velocity regions in the main trunk and flow separation in the stump region and the curved segment of the iliac limbs were observed. These areas are associated with thrombosis in the clinical situation. Improvements in the design of endovascular devices may remove these areas of unfavourable flow patterns and lead to better clinical performance.     

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.     

Endovascular treatment of a blunt thoracic aortic laceration due to thoracolumbar spine fracture

A 36-year-old woman sustained an aortic laceration at the level of the diaphragmatic hiatus owing to a displaced thoracolumbar spine fracture (TLS). We herein report the first case of aortic trauma secondary to a TLS fracture treated with a thoracic stent-graft.     

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.     

颈性眩晕中医证型与经颅超声脑动脉血流检测结果的相关性分析

摘要 目的：分析颈性眩晕中医证型与经颅超声脑动脉血流检测结果的相关性。方法：选取2021年5月-2023年5月收治颈性眩晕患者作为研究对象,根据不同中医证型分为痰湿中阻组、肝阳上亢组、肝肾阴虚组和气血亏虚组,每组各纳入20例;并另选取健康体检患者30例作为对照组,均给予多普勒超声检查。分析不同中医证型者与对照组者多普勒超声检查特征与脑动脉血流变化[左右椎动脉、基底动脉及大脑中动脉收缩期峰值血流速度（VS）、平均血流速度(Vm)、舒张期峰值血流速度(Vd)及搏动指数(PI)]。结果：痰湿中阻组、肝肾阴虚组和气血亏虚组左右椎动脉、基底动脉及大脑中动脉VS均低于对照组（P＜0.05）;肝阳上亢组左右椎动脉、基底动脉及大脑中动脉VS均高于对照组（P＜0.05）;不同中医证型组间VS比较,肝阳上亢组＞痰湿中阻组＞肝肾阴虚组＞气血亏虚组;痰湿中阻组左右椎动脉、基底动脉均高于对照组（P＜0.05）,大脑中动脉Vm均低于对照组（P＜0.05）;肝阳上亢组左右椎动脉、基底动脉及大脑中动脉Vm均高于对照组（P＜0.05）;肝肾阴虚组左右椎动脉、基底动脉及大脑中动脉Vm均低于对照组（P＜0.05）;气血亏虚组大脑中动脉Vm均低于对照组（P＜0.05）,左右椎动脉、基底动脉Vm和对照组无显著性差异（P>0.05）;不同中医证型组间Vm比较,肝阳上亢组＞痰湿中阻组＞气血亏虚组＞肝肾阴虚组;痰湿中阻组左右椎动脉、基底动脉Vd均低于对照组（P＜0.05）,大脑中动脉Vd均高于对照组（P＜0.05）;肝阳上亢组左右椎动脉、基底动脉及大脑中动脉Vd均低于对照组（P＜0.05）;肝肾阴虚组左右椎动脉及大脑中动脉Vd均低于对照组（P＜0.05）,基底动脉Vd和对照组无差异（P＞0.05）;气血亏虚组左右椎动脉Vd均低于对照组（P＜0.05）,基底动脉Vd和对照组无差异（P＞0.05）,大脑中动脉Vd均高于对照组（P＜0.05）;不同中医证型组间Vd比较,气血亏虚组＞痰湿中阻组＞肝肾阴虚组＞肝阳上亢组;痰湿中阻组和气血亏虚组左右椎动脉、基底动脉及大脑中动脉PI均低于对照组（P＜0.05）;肝阳上亢组和肝肾阴虚组左右椎动脉、基底动脉及大脑中动脉PI均高于对照组（P＜0.05）;不同中医证型组间PI比较,肝阳上亢组＞肝肾阴虚组＞痰湿中阻组＞气血亏虚组。结论：不同中医证型的眩晕患者会出现不同程度脑动脉血流动力学异常,且不同组间存在差异,通过经颅多普勒超声检查,可以对眩晕中医证型提供参考价值。     

Dacron Patch Aortoplasty of Thoracic Aortic Pseudoaneurysm due to Penetrating Atherosclerotic Ulcer

We report the case of a patient with severe diffuse peripheral vascular disease, coronary artery disease, congestive heart failure, and gastrointestinal bleeding with a pseudoaneurysm of descending thoracic aorta who underwent successful Dacron patch aortoplasty. She was not a candidate for stent-graft repair because of poor access. Using a partial occluding clamp, the pseudoaneurysm was excised and the aorta repaired with a 3.5-cm Dacron patch. She was discharged home in 7 days and has successfully undergone stenting of the left subclavian artery and right and left carotid endarterectomy.     

Fluid-structure interaction effects on sac-blood pressure and wall stress in a stented aneurysm

An aneurysm is a local artery ballooning greater than 50% of its nominal diameter with a risk of sudden rupture. Minimally invasive repair can be achieved by inserting surgically a stent-graft, called an endovascular graft (EVG), which is either straight tubular curved tubular or bifurcating. However post-procedural complications may arise because of elevated stagnant blood pressure in the cavity, i.e., the sac formed by the EVG and the weakened aneurysm wall In order to investigate the underlying mechanisms leading to elevated sac-pressures and hence to potentially dangerous wall stress levels and aneurysm rupture, a transient 3-D stented abdominal aortic aneurysm model and a coupled fluid-structure interaction solver were employed. Simulation results indicate that, even without the presence of endoleaks (blood flowing into the cavity), elevated sac pressure can occur due to complex fluid-structure interactions between the luminal blood flow, EVG wall, intra-sac stagnant blood, including an intra-luminal thrombus, and the aneurysm wall. Nevertheless, the impact of sac-blood volume changes due to leakage on the sac pressure and aneurysm wall stress was analyzed as well. While blood flow conditions, EVG and aneurysm geometries as well as wall mechanical properties play important roles in both sac pressure and wall stress generation, it is always the maximum wall stress that is one of the most critical parameters in aneurysm rupture prediction. All simulation results are in agreement with experimental data and clinical observations.     

Capacities of angiography in the imaging of abnormal changes in the cerebral arteries

The study was based on the angiographic examination of 233 patients with prior subarachnoidal hemorrhage. Angiographic study was performed using the Seldinger technique by contrasting both carotid and vertebral arteries. Twenty-three patients in whom arterial aneurysm had been detected by digital subtraction angiography underwent 3D angiography. The authors improved a procedure during which a contrast agent was manually injected into the internal carotid or vertebral artery, by using a 20-ml disposal syringe with controlled maximum developed pressure and flow increase rate up to 2.0 ml/sec for 4-5 sec during rotary scanning and the administration of the radiocontrast medium was stopped when an image appeared on the monitor at 190 degrees (190.0, 200.0) C-arm rotation. This procedure could decrease significantly the volume of the administered contrast agent from 18 to 8 (8.0, 10.0) ml and reduce the time of radiation exposure from 6 to 4 (4.0, 5.0) sec. The improved angiographic modes for the right vertebral and right carotid artery could visualize pathological changes in these arteries and establish a relationship, namely: due to degenerative dystrophic processes of the cervical spine there is a tendency for higher pathological changes in the vertebral arteries with an increased stage of osteochondrosis in the cervical spine (R = 0.95; p = 0.014).     

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.     

On RASA

Relative Apparent Synapomorphy Analysis (RASA) was recently proposed as a way to measure phylogenetic signal, choose "optimal" outgroups, find long branches, and eliminate long-branch attraction. In this paper it is shown with simple examples that RASA has several problems. The null regression model used by RASA to measure phylogenetic signal does not have a straightforward relation to phylogenetic information. RASA detects long branches, but does not discriminate between long branches that mislead an analysis and those that do not. Rooted RASA, which is used for "optimal outgroup analysis," is shown to be an inappropriate measure of "+esiomorphy content".     

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.     

Effects of major endoleaks on a stented abdominal aortic aneurysm

Insertion of a stent-graft into an aneurysm, especially abdominal aortic aneurysms (AAAs), is a very attractive surgical intervention; however, it is not without major postoperative complications, such as endoleaks. An endoleak is the transient accumulation of blood in the AAA cavity, which is formed by the stent-graft and AAA walls. Of the four blood pathways, a type I endoleak constitutes the major one. Thus, focusing on both proximal and distal type I endoleaks, i.e., the minute net influx of blood past the attachment points of a stent-graft into the AAA cavity, the transient three-dimensional interactions between luminal blood flow stent-graft wall, leakage flow, and AAA wall are computationally simulated. For different type I endoleak scenarios and inlet pressure wave forms, the impact of type I endoleaks on cavity pressure, wall stress, and stent-graft migration force is analyzed. The results indicate that both proximal type I-a and distal type I-b endoleaks may cause cavity pressures close to a patient's systemic pressure; however, with reduced pulsatility. As a result, the AAA-wall stress is elevated up to the level of a nonstented AAA and, hence, such endoleaks render the implant useless in protecting the AAA from possible rupture. Interestingly enough, the net downward force acting on the implant is significantly reduced; thus, in the presence of endoleaks, the risk of stent-graft migration may be mitigated.     

A role for p120 RasGAP in thymocyte positive selection and survival of naive T cells

Activation of the Ras small GTP-binding protein is necessary for normal T cell development and function. However, it is unknown which Ras GTPase-activating proteins (RasGAPs) inactivate Ras in T cells. We used a T cell-specific RASA1-deficient mouse model to investigate the role of the p120 RasGAP (RASA1) in T cells. Death of CD4(+)CD8(+) double-positive thymocytes was increased in RASA1-deficient mice. Despite this finding, on an MHC class II-restricted TCR transgenic background, evidence was obtained for increased positive selection of thymocytes associated with augmented activation of the Ras-MAPK pathway. In the periphery, RASA1 was found to be dispensable as a regulator of Ras-MAPK activation and T cell functional responses induced by full agonist peptides. However, numbers of naive T cells were substantially reduced in RASA1-deficient mice. Loss of naive T cells in the absence of RASA1 could be attributed in part to impaired responsiveness to the IL-7 prosurvival cytokine. These findings reveal an important role for RASA1 as a regulator of double-positive survival and positive selection in the thymus as well as naive T cell survival in the periphery.     

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.     

Limitations of relative apparent synapomorphy analysis (RASA) for measuring phylogenetic signal.

In this paper we use hypothetical and empirical data matrices to evaluate the ability of relative apparent synapomorphy analysis (RASA) to measure phylogenetic signal, select outgroups, and identify terminals subject to long-branch attraction. In all cases, except for equal character-state frequencies, RASA indicated extraordinarily high levels of phylogenetic information for hypothetical data matrices that are uninformative regarding relationships among the terminals. Yet, regardless of the number of characters or character-state frequencies, RASA failed to detect phylogenetic signal for hypothetical matrices with strong phylogenetic signal. In our empirical example, RASA indicated increasing phylogenetic signal for matrices for which the strict consensus of the most parsimonious trees is increasingly poorly resolved, clades are increasingly poorly supported, and for which many relationships are in conflict with more widely sampled analyses. RASA is an ineffective approach to identify outgroup terminal(s) with the most plesiomorphic character states for the ingroup. Our hypothetical example demonstrated that RASA preferred outgroup terminals with increasing numbers of convergent character states with ingroup terminals, and rejected the outgroup terminal with all plesiomorphic character states. Our empirical example demonstrated that RASA, in all three cases examined, selected an ingroup terminal, rather than an outgroup terminal, as the best outgroup. In no case was one of the two outgroup terminals even close to being considered the optimal outgroup by RASA. RASA is an ineffective means of identifying problematic long-branch terminals. In our hypothetical example, RASA indicated a terminal as being a problematic long-branch terminal in spite of the terminal being on a zero-length branch and having no possibility of undergoing long-branch attraction with another terminal. RASA also failed to identify actual problematic long-branch terminals that did undergo long-branch attraction, but only after following Lyons-Weiler and Hoelzer's (1997) three-step process to identify and remove terminals subject to long-branch attraction. We conclude that RASA should not be used for any of these purposes.