Double-sided superior vena cava: developmental considerations associated with the thymic veins / Vena cava superior de doble cara: consideraciones de desarrollo asociadas con las venas tímicas

SUMMARY: The superior vena cava is usually located only on the right side, but persistence of the left superior vena cavais observed in about 0.3 to 0.5 % of adults. A routine dissection of the cadaver of a 91-year-old Japanese female, whose cause of death was sepsis due to cholecystitis, was performed at Nagasaki University and revealed a double-sided superior vena cava. On the right side, the superior vena cava opened to the right atrium, while on the left, it opened into the extended coronary sinus. Veins in the left head, neck and upper limb regions joined to form the persistent left superior vena cava, with eventual drainage into the expanded coronary vein. An anastomosing branch occurred between each superior vena cava, and two thymic veins opened to the anastomosing branch. The azygos vein in the azygos venous system opened into the right superior vena cava, whereas a hemi-azygos vein opened into the azygos vein. The accessory hemi-azygos vein also opened into the azygos vein and opened cranially into the left superior vena cava. The left supreme intercostal vein also opened into the left superior vena cava. Several studies have reported a persistent left superior vena cava and the various considerations for its occurrence. Here, we propose a new hypothesis for the embryonic development of the persistent left superior vena cava with the thymic vein. This hypothesis essentially states that the left brachiocephalic vein fails to mature due to inadequate venous return from the thymic vein during the embryonic period, and the left superior vena cava then remains to maintain venous return from the left head, neck and upper limb. We also discuss the clinical significance of the persistent left superior vena cava.

RESUMEN: Usualmente la vena cava superior se localiza solo en el lado derecho, sin embargo en aproximadamente 0,3 a 0,5 % de los adultos se observa la persistencia de la vena cava superior izquierda. En la Universidad de Nagasaki se realizó una disección de rutina del cadáver de una mujer japonesa de 91 años, cuya causa de muerte fue sepsis debido a una colecistitis. El cuerpo presentaba una vena cava superior doble. En el lado derecho, la vena cava superior llegaba al atrio derecho, mientras que en el lado izquierdo drenaba al seno coronario. Las venas de las regiones de la cabeza, el cuello y del miembro superior izquierdo formaban la vena cava superior izquierda persistente, con drenaje hacia la vena coronaria. Se observó una rama anastomótica entre cada vena cava superior y dos venas tímicas drenaban a la rama anastomótica. La vena ácigos drenaba a la vena cava superior derecha, mientras que una vena hemiácigos drenaba a la vena ácigos. La vena hemiácigos accesoria también drnaba en la vena ácigos y cranealmente lo hacia la vena cava superior izquierda. La vena intercostal suprema izquierda drenaba en la vena cava superior izquierda. Varios estudios han informado una vena cava superior izquierda persistente y las diversas consideraciones para su aparición. Aquí, proponemos una nueva hipótesis para el desarrollo embrionario de la vena cava superior izquierda persistente con la vena tímica, que esencialmente establece que la vena braquiocefálica izquierda no se dearrolla debido a un retorno venoso inadecuado de la vena tímica durante el período embrionario, y se mantiene la vena cava superior izquierda para el retorno venoso de la cabeza, el cuello y el miembro superior izquierdo. Además se informa de la importancia clínica de la persistencia de la vena cava superior izquierda.

Crosse aortique droite et lobe de la veine d'Azygos : une association extrêmement rare

Le lobe de la veine d'Azygos et la crosse aortique droite, représentent chacun une variante anatomique extrêmement rare dont le diagnostic pris isolément est simple à la radiographie thoracique. En revanche le diagnostic radiographique de leur association peut être un challenge. Nous rapportons un cas de lobe de la veine d'Azygos méconnu à la radiographie pulmonaire en incidence de face, en présence d'une crosse aortique droite

Clinical Significance of Extraluminal Compressions according to the Site of the Esophagus

BACKGROUND/AIMS: Differentiation of an extraluminal compression from a true subepithelial tumor (SET) in the esophagus by using endoscopy alone is often difficult. EUS is known as the best method for differentiating an extraluminal compression from a true SET. Extraluminal compression in the esophagus is occasionally observed, but its clinical significance has been rarely reported. Therefore, we aimed to evaluate the clinical significance of extraluminal compression in the esophagus according to the location of the lesion. MATERIALS AND METHODS: Sixty-one patients were diagnosed as having an extraluminal compression in the esophagus by using EUS between January 2006 and March 2014. Some patients underwent chest computed tomography for accurate diagnosis. RESULTS: The extraluminal compression was located at the mid-esophagus in 26 cases, lower esophagus in 22 cases, and upper esophagus in 13 cases. Of the 61 cases, 55 were caused by normal structures and 6 were caused by pathological lesions. The causes of the normal structures were the aorta, vertebra, trachea, left main bronchus, azygos vein, and diaphragm. The causes of the pathological lesions were engorged vessels and calcified lymph nodes. The posterior wall was the most frequent location of the extraluminal compression. However, the lesions in the anterior and right walls showed a higher frequency of pathological lesions than those in other sites. CONCLUSIONS: If the extraluminal compression is found in the anterior and right walls of the esophagus, more careful evaluation should be performed considering the high frequency of pathological lesions in the site.

Anatomical variations of the azygos venous system: classification and clinical relevance / Variaciones anatómicas del sistema venoso ácigos: clasificación y relevancia clínica

The azygos venous system is highly variable in terms of its origin, course, communications, tributaries and termination of the associated veins: this study aimed to classify these anatomical variations. Thirty Thiel-embalmed cadavers aged 48­98 years (18 female, 12 male) were examined. The vertebral level of termination and diameter of the azygos, hemiazygos, accessory hemiazygos and the left superior intercostal veins were determined, as well as the termination level of the right superior intercostal vein. The azygos system was classified into 3 types; primitive (type 1), transitional (type 2) and unicolumnar (type 3). Type 2 was further divided into 5 subgroups (A to E) according to the number of retroaortic communications. Type one was observed in 3 % (n=1), type 2 in 87 % (n=26) and type 3 in 10 % (n=3) of specimens. The vertebral level of termination of the azygos, hemiazygos, accessory hemiazygos, right superior intercostal and left superior intercostal veins were between T2 and T3, T6 and T10, T5 and T9, T2 and T4, and T2 and T4 respectively. Identification and understanding these variations are important during preoperative radiological investigations and surgical procedures, especially spinal surgery between T7 and T12 using a left thoracotomy approach, to avoid injuries which may lead to postoperative hematomas.

El sistema venoso ácigos es muy variable en función de su origen, comunicaciones, afluentes y terminación de venas asociadas. Este estudio tuvo como objetivo clasificar las variaciones anatómicas relacionadas con el sistema venoso ácigos. Se examinaron treinta cadáveres embalsamados con la técnica de Thiel, con edades comprendidas entre 48-98 años (18 mujeres, 12 hombres). Se determinó el nivel vertebral de terminación y el diámetro de las venas ácigos, hemiácigos, hemiácigos accesoria e intercostales superiores izquierdas, así como el nivel de terminación del lado derecho de la vena intercostal superior. El sistema ácigos se clasificó en 3 tipos; primitivo (tipo 1), de transición (tipo 2) y unicolumnar (tipo 3). El tipo 2 se dividió en 5 subgrupos (A a E) de acuerdo con el número de comunicaciones retroaórticas. El tipo 1 se observó en 3 % (n = 1), el tipo 2 en 87 % (n = 26) y tipo 3 en 10 % (n = 3) de las muestras. El nivel vertebral de terminación de las venas ácigos, hemiácigos, hemiácigos accesoria, intercostal derecho superior e intercostales superiores izquierda se presentaron entre T2 y T3, T6 y T10, T5 y T9, T2 y T4 y T2 y T4, respectivamente. La identificación y comprensión de estas variaciones anatómicas son importantes durante las investigaciones radiológicas preoperatorias y de los procedimientos quirúrgicos, especialmente en cirugía de columna vertebral, entre los niveles T7 y T12, utilizando un abordaje de toracotomía izquierda, para evitar lesiones que pueden conducir a hematomas postoperatorios.

Pre-aortic inter-azygos veins: two case reports / Venas interácigos pre-aórticas: reporte de dos casos

This report describes two cases of multiple anomalies associated with the azygos venous system. In Case 1, the hemiazygos vein drained the 9th to 11th left posterior intercostal veins. At T9 vertebral level, the interazygos vein passed obliquely and anterior to the aorta to drain into the azygos vein on the right. In Case 2, the common venous trunk formed by the accessory hemiazygos and hemiazygos veins passed anterior to the aorta to drain into the azygos vein at T9 vertebral level. These findings represent pre-aortic inter-azygos veins, which is a rare variation of the azygos venous system. Pre-aortic inter-azygos veins can mimic pathologies such as enlarged lymph nodes, tumors and aneurysms leading to misinterpretation of radiographs, computerized tomography and magnetic resonance scans. Surgeons need to be aware of this type of variation so as to avoid injury of any anomalous passing venous vessels.

Este informe describe dos casos de múltiples anomalías asociadas con el sistema venoso ácigos. En el caso 1, la vena ácigos drena las 9 y 11 venas intercostales posteriores izquierdas. A nivel de la 9 vértebra torácica, la vena interácigos pasó oblicuamente y anterior a la aorta para drenar en la vena ácigos del lado derecho. En el caso 2, el tronco venoso común formado por las venas hemiácigos accesoria y hemiácigos pasaron anterior a la aorta para drenar en la vena ácigos a nivel de la 9 vértebra torácica. Estos resultados representan venas interácigos pre-aórticas, que es una rara variación del sistema venoso ácigos. Las venas interácigos pre-aórticas pueden imitar patologías, como agrandamiento de nódulos linfáticos, tumores y aneurismas que conducen a una mala interpretación de las exploraciones por radiografías, tomografía computarizada y resonancia magnética. Los cirujanos deben ser conscientes de estos tipos de variaciones para evitar lesionarlos.

Extracorporeal Membrane Oxygenation Cannula Malposition in the Azygos Vein in a Neonate with Right-Sided Congenital Diaphragmatic Hernia / 대한구급학회지

Malposition of the extracorporeal membrane oxygenation (ECMO) venous cannula in the azygos vein is not frequently reported. We hereby present such a case, which occurred in a neonate with right-sided congenital diaphragmatic hernia. Despite ECMO application, neither adequate flow nor sufficient oxygenation was achieved. On the cross-table lateral chest radiograph, the cannula tip was identified posterior to the heart silhouette, which implied malposition of the cannula in the azygos vein. After repositioning the cannula, the target flow and oxygenation were successfully achieved. When sufficient venous flow is not achieved, as in our case, clinicians should be alerted so they can identify the cannula tip location on lateral chest radiograph and confirm whether malposition in the azygos vein is the cause of the ineffective ECMO.

Complicated Azygos Vein Aneurysm in an Infant Presenting with Acute Pulmonary Thromboembolism

Azygos vein aneurysm is a rare cause of mediastinal mass. Most cases present as an incidental finding on imaging modalities, but in few cases the thrombosis in the aneurysm leads to pulmonary thromboembolism, which may require surgical resection. We present a case where, for the first time, a case of a complicated azygos vein aneurysm was diagnosed in infancy, which required surgical resection.

A Case of Azygos Vein Thombosis Associated with Transient Antiphospholipid Syndrome in Urinary Tract Infection with Escherichia coli

A 73-year-old female with diabetes admitted for treatment of an intertrochanter fracture of the femur and a urinary tract infection (UTI) with Escherichia coli developed thrombosis in her right azygos vein, which was thought to be associated with antiphospholipid and immunoglobulin M anticardiolipin antibodies. After antibiotic therapy, antiphospholipid antibody was undetectable, and a repeat chest computed tomography showed complete resolution of the azygos vein thrombosis. A wide variety of infections can be associated with thrombotic events in patients with transient antiphospholipid syndrome (APS), and this case serves as a reminder that the possibility of transient APS should be considered in patients with venous thrombosis in the setting of a UTI.

Extracorporeal Membrane Oxygenation Cannula Malposition in the Azygos Vein in a Neonate with Right-Sided Congenital Diaphragmatic Hernia / 대한중환자의학회지

Malposition of the extracorporeal membrane oxygenation (ECMO) venous cannula in the azygos vein is not frequently reported. We hereby present such a case, which occurred in a neonate with right-sided congenital diaphragmatic hernia. Despite ECMO application, neither adequate flow nor sufficient oxygenation was achieved. On the cross-table lateral chest radiograph, the cannula tip was identified posterior to the heart silhouette, which implied malposition of the cannula in the azygos vein. After repositioning the cannula, the target flow and oxygenation were successfully achieved. When sufficient venous flow is not achieved, as in our case, clinicians should be alerted so they can identify the cannula tip location on lateral chest radiograph and confirm whether malposition in the azygos vein is the cause of the ineffective ECMO.

Heart Transplantation in a Patient with Left Isomerism

We report the case of a 37-year-old man who suffered from biventricular failure due to left isomerism, inferior vena cava interruption with azygos vein continuation, bilateral superior vena cava, double outlet of right ventricle, complete atrioventricular septal defect, pulmonary stenosis, and isolated dextrocardia. Heart transplantation in patients with systemic venous anomalies often requires the correction and reconstruction of the upper & lower venous drainage. We present a case of heart transplantation in a patient with left isomerism, highlighting technical modifications to the procedure, including the unifocalization of the caval veins and reconstruction with patch augmentation.

Course of major paravertebral vessels and the positional relationship to the vertebral bodies in healthy Chinese subjects: a CT-based study / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Several studies, including those done in China, report that paravertebral vascular injury during posterior spinal surgery can greatly harm patients, though it is a relatively rare complication. However, few studies have examined their course and anatomic relationship to the spine. The aim of this study was to measure the course of the major paravertebral vessels and their positional relationships to the vertebral bodies in Chinese subjects using computed tomography.</p><p><b>METHODS</b>We studied a total of fifty subjects who underwent thoracolumbar computed tomography from T1-S1 at our institution. We measured the theoretical distance, actual distance, theoretical angle, and actual angle of the paravertebral vessels at each thoracolumbar intervertebral disc.</p><p><b>RESULTS</b>The paravertebral artery actual angle at T4-L4 ranged from -11.41 to 79.75° and the actual distance from 16.98 to 52.53 mm. The actual angle of the inferior vena cava at L1-L5 intervertebral disc ranged from -40.75 to 34.50° and the actual distance from -36.63 to 61.69 mm. There was no significant difference in the actual angle of the paravertebral vein or in the actual distance in the thoracic segments according to gender (P > 0.05). However, the actual distance in the lumbar segments were significantly different according to gender (P < 0.05).</p><p><b>CONCLUSIONS</b>The major paravertebral vessels' course is closer to the mid-sagittal plane as they move posterior along the vertebrae, and the actual distance of the paravertebral artery and azygos vein increase, while the actual distance of the inferior vena cava decreases. The course of the lumbar paravertebral vessels varies, especially at L4/L5, and may be more prone to intraoperative injury in female subjects.</p>

Mesoesophagus and other fascial structures of the abdominal and lower thoracic esophagus: a histological study using human embryos and fetuses / 대한해부학회지

A term "mesoesophagus" has been often used by surgeons, but the morphology was not described well. To better understand the structures attaching the human abdominal and lower thoracic esophagus to the body wall, we examined serial or semiserial sections from 10 embryos and 9 fetuses. The esophagus was initially embedded in a large posterior mesenchymal tissue, which included the vertebral column and aorta. Below the tracheal bifurcation at the fifth week, the esophagus formed a mesentery-like structure, which we call the "mesoesophagus," that was sculpted by the enlarging lungs and pleural cavity. The pneumatoenteric recess of the pleuroperitoneal canal was observed in the lowest part of the mesoesophagus. At the seventh week, the mesoesophagus was divided into the upper long and lower short parts by the diaphragm. Near the esophageal hiatus, the pleural cavity provided 1 or 2 recesses in the upper side, while the fetal adrenal gland in the left side was attached to the lower side of the mesoesophagus. At the 10th and 18th week, the mesoesophagus remained along the lower thoracic esophagus, but the abdominal esophagus attached to the diaphragm instead of to the left adrenal. The mesoesophagus did not contain any blood vessels from the aorta and to the azygos vein. The posterior attachment of the abdominal esophagus seemed to develop to the major part of the phrenoesophageal membrane with modification from the increased mass of the left fetal adrenal. After postnatal degeneration of the fetal adrenal, the abdominal esophagus might again obtain a mesentery. Consequently, the mesoesophagus seemed to correspond to a small area containing the pulmonary ligament and aorta in adults.

Stroke after percutaneous transhepatic variceal obliteration of esophageal varix in Caroli syndrome / 소아과

Here we present the case of an 11-year-old female patient diagnosed with Caroli syndrome, who had refractory esophageal varices. The patient had a history of recurrent bleeding from esophageal varices, which was treated with endoscopic variceal ligation thrice over a period of 2 years. However, the bleeding was not controlled. When the patient finally visited the Emergency Department, the hemoglobin level was 4.4 g/dL. Transhepatic intrajugular portosystemic shunt was unsuccessful. Subsequently, the patient underwent percutaneous transhepatic variceal obliteration. Twenty hours after this procedure, the patient complained of aphasia, dizziness, headache, and general weakness. Six hours later, the patient became drowsy and unresponsive to painful stimuli. Lipiodol particles used to embolize the coronary and posterior gastric veins might have passed into the systemic arterial circulation, and they were found to be lodged in the brain, kidney, lung, and stomach. There was no abnormality of the portal vein on portal venography, and blood flow to the azygos vein through the paravertebral and hemiazygos systems was found to drain to the systemic circulation on coronary venography. Contrast echocardiography showed no pulmonary arteriovenous fistula. Symptoms improved with conservative management, and the esophageal varices were found to have improved on esophagogastroduodenoscopy.

Implante de eletrodo em veia ázigos: uma opção terapêutica para limiar de desfibrilação elevado / Azygos vein lead implantation: a therapeutic option for elevated defibrillation threshold

A avaliação do limiar de desfibrilação (DFT) durante o implante do cardioversor-desfibrilador (CDI) é uma etapa relevante do procedimento, uma vez que, em até 16% dos pacientes, podemos encontrar elevados DFT. Relatamos o caso de um paciente portador de cardiomiopatia dilatada (CMPD) idiopática submetido a implante de CDI biventricular. Durante o procedimento, apresentou elevado DFT e se mostrou resistente às modalidades terapêuticas usuais. Optamos pelo implante de eletrodo de desfibrilação em veia ázigos, com resolução do quadro.

The evaluation of the defibrillation threshold (DFT) during the implantation of a cardioverter-defibrillator (ICD) is an important stage of the procedure, as a high DFT can be found in up to 16% of patients. We report a patient with idiopathic dilated cardiomyopathy (DCM) submitted to a biventricular ICD implantation. During the procedure, the patient showed a high DFT and showed to be resistant to usual therapeutic modalities. We opted for the azygos vein defibrillation lead implantation, with good resolution.

Anatomic variation of thorax drainage: absence of accessory hemiazygos vein

Formed by the azygos, hemiazygos and accessory hemiazygos veins, this system is responsible for the venous drainage of the thorax and partially of the abdomen. Abnormalities of this system are not uncommon, and many are referred to in literature. The complete agenesis of the accessory hemyazigos vein is associated with complete regression of the left posterior cardinal vein or atrophy of the left subcardinal vein. The reported case consists of the complete absence of the accessory hemiazygos vein, culminating in the drainage of the 4th, 5th, 6th, 7th and 8th left posterior intercostal veins directly into the azygos vein of a male cadaver. The importance of the theme is due to the necessity of recognizing patterns and frequencies of these variations when facing procedures addressing the mediastinum or the major vessels.

Reconstruction of cavopulmonary pathway for the patient with persistent arteriovenous malformations due to offset flow from hepatic vein

The hypoxemia caused by arteriovenous malformations after cavopulmonary shunt in patients with heterotaxy, an interrupted inferior vena cava and single ventricle physiology have been treated by incorporation of hepatic vein flow into the pulmonary circulation. However, some patients have persistent arteriovenous malformations because of offset hepatic venous flow to one pulmonary artery. Various approaches have been used to change offset flow to achieve balanced hepatic flow to the lungs in this patient population. This case report highlights the challenges that may be associated with anastomosis of the azygos vein to the inferior vena cava at the level of the diaphragm and illustrates an alternative technique to direct hepatic venous blood into an affected lung with arteriovenous malformations. The redirection of hepatic venous flow to the affected pulmonary artery resulted in resolution of symptoms within months of surgery

Endoscopic ultrasonography in patients with chronic liver disease: a case control study

The portal system and azygos vein are the main drainage systems during portal hypertension. This study aims to compare the diameter of these veins by endoscopic ultrasonography [EUS] in patients with and without chronic liver disease [CLD]. During one year, patients with CLD enrolled as the study group. Patients who underwent EUS for other reasons during the same period served as controls. In cases with CLD, we assessed the relationship between degrees of hepatic dysfunction [Child-Pugh class], history of variceal bleeding, presence of hyponatremia, thrombocytopenia, and endoscopic grading of varices with the sizes of the portal, splenic, and azygos veins on EUS. During the study period, there were 63 patients [20 females and 43 males] with CLD and 85 control subjects [42 females and 43 males] enrolled. The mean ages of cases was 45.60 +/- 14 years and controls was 48.5 +/- 15 years. The most common cause of CLD was post-necrotic cirrhosis due to hepatitis B virus. Patients with CLD had significantly higher mean portal, splenic, and azygos vein diameters than the control group [p < 0.001]. With azygos, portal, and splenic vein diameters of 10, 11 and 9 mm, sensitivity for the diagnosis of portal hypertension was 66%, 71%, and 66%, while specificity was 94%, 99% and 99%, respectively. Splenic and portal vein dilation, and thrombocytopenia significantly correlated with variceal bleeding [p < 0.05]. EUS allows for the collection of valuable quantitative data from the portal system, the diagnosis of portal hypertension, and follow up of patients with CLD

Posterior Nutcracker Syndrome Associated with Interrupted Left Inferior Vena Cava with Azygos Continuation and Retroaortic Right Renal Vein

Various anatomic anomalies have been considered the causes of nutcracker syndrome (NCS). Posterior NCS refers to the condition, in which vascular narrowing was secondary to the compression of the retroaortic left renal vein while it is crossing between the aorta and the vertebral column. Here, we report an unusual case of posterior NCS associated with a complicated malformation of the interrupted left inferior vena cava with azygos continuation and retroaortic right renal vein, diagnosed by both color Doppler ultrasonography and CT angiography.

A Case of Septic Azygos Vein Embolism Caused by Staphylococcus aureus Bacteremia / 결핵및호흡기질환

A Septic embolism is a type of embolism infected with bacteria containing pus. These may become dangerous if dislodged from their original location. Embolisms of this type in the azygos vein are potentially fatal. The diagnosis of septic azygos vein embolism is difficult, so rapid diagnosis and treatment is important to avoid complications. Generally, treatment is enough for appropriate antibiotic therapy without anticoagulant therapy. We report a case of staphylococcal septic embolism in the azygos vein, which was discovered in a 51-year-old man exhibiting chest pain, dyspnea and fever. The patient was treated with antibiotic therapy alone without the use of anticoagulants.