Systemic to pulmonary venous communication (right-to-left shunt) in superior vena cava obstruction demonstrated by spiral CT

Insights Into Endovascular Management of Superior Vena Cava Obstructions

Superior vena cava obstruction results from any limitation of blood flow through the superior vena cava. Circulation to the heart may persist through various collateral vessels whose development depends on the level of obstruction. Depending on the level and degree of occlusive disease, the severity of clinical symptoms may vary considerably, up to lethal. Etiologies have changed dramatically in recent years, mainly due to the increasing use of intravascular devices. However, guidelines for treatment are lacking, and various options are available. Endovascular therapies developed considerably in recent years, may offer a rapid improvement in symptoms and proved to be safe. However, knowledge and selection of appropriate techniques are essential to venous angioplasty, involving specific tools to guarantee satisfying outcomes. This review aims to discuss the particular venous anatomy of the upper body, the physiopathology of superior vena cava obstruction, and specificities of endovascular treatment compared with other management options.

Systemic-to-pulmonary venous shunt in a patient with non-Hodgkin lymphoma: A case report and review of the literature

We describe a case of a systemic-to-pulmonary venous shunt secondary to superior vena cava obstruction in a patient with newly diagnosed non-Hodgkin lymphoma. This rare condition manifested with symptoms of dyspnea and hypoxemia that were out of proportion to the pleural effusion diagnosed on chest imaging. Standard treatment of such rare collateral plexuses is observation. However, it is important for clinicians to be cognizant that in rare cases such plexuses can lead to right-to-left shunt complications such as embolism.

Vanishing bone metastases--a pitfall in the interpretation of contrast enhanced CT in patients with superior vena cava obstruction

We describe a previously unreported case of vertebral marrow enhancement owing to collateral circulation in a patient with superior vena cava obstruction. Failure to recognise this phenomenon led to the misdiagnosis of sclerotic bone metastases.

Haemodynamic findings on cardiac CT in children with congenital heart disease

In patients with congenital heart disease, haemodynamic findings demonstrated on cardiac CT might provide useful hints for understanding the haemodynamics of cardiac defects. In contrast to morphological features depicted on cardiac CT, such haemodynamic findings on cardiac CT have not been comprehensively reviewed in patients with congenital heart disease. This article describes normal haemodynamic phenomena of cardiovascular structures and various abnormal haemodynamic findings with their mechanisms and clinical significance on cardiac CT in patients with congenital heart disease.

Embolization of a symptomatic systemic to pulmonary (right-to-left) venous shunt caused by fibrosing mediastinitis and superior vena caval occlusion

Paradoxical embolization can occur when a right-to-left shunt allows a venous thromboembolus to escape filtration by the lungs. Venous collateral pathways draining into the left heart incited by superior vena cava obstruction are a rare acquired right-to-left shunt. Herein, the authors report on a case of transient ischemic attack in a patient with vena caval occlusion secondary to histoplasmosis-related fibrosing mediastinitis, with subclavian vein thrombosis and a right-to-left extracardiac shunt diagnosed with echocardiography. Despite the complexity of the collateral network, this shunt was successfully eradicated with coil embolization.

Infraphrenic collaterals in malignant superior vena cava obstruction

We present three cases of malignant superior vena cava obstruction demonstrating infraphrenic venous collaterals, one of which showed intense focal hepatic enhancement on computed tomographic scan. Infraphrenic venous collaterals and focal liver enhancement are uncommon but specific computed tomographic features of superior vena cava obstruction.

Establishment of a rabbit model of superior vena cava obstruction

OBJECTIVE

To explore a method of establishing a rabbit model of superior vena cava obstruction (SVCO) by injecting VX2 tumor cell suspension transcutaneously under ultrasound guidance.

METHODS

A suspension of VX2 tumor cells was prepared under sterile conditions. Fifteen adult healthy New Zealand White rabbits were enrolled in the experiment. Under ultrasound guidance, about 0.1 ml of the living tumor cell suspension was transcutaneously injected in front of the anterior wall of the right superior vena cava (SVC). The lumen, wall, blood flow of SVCs and adjacent tissues were examined with gray-scale and color Doppler ultrasonography, every 3 days starting from the 9th day after injection. Meanwhile, CT scanning and digital subtraction angiography (DSA) were also performed. The rabbits were dissected immediately after death and tissue samples were collected for pathologic examination.

RESULTS

Fourteen out of 15 rabbits developed tumors that were located close to SVCs and/or SVCs cavity, which was shown by ultrasonography. The diameters of the tumors were 80.7 +/- 4.3 mm. These tumors grew close to SVCs area and resulted in compression and infiltration of SVCs. CT scanning and DSA confirmed the establishment of the SVCO model. The achievement rate of the SVCO model was 93.3%. No rabbit died of complications.

CONCLUSION

A method of establishing a rabbit SVCO model by injecting VX2 tumor cell suspension under ultrasonographic guidance was established successfully, and it proved to be simple, effective and repeatable. The imaging characteristics of this model are in good accordance with those of SVCO in patients.

[Abnormality of hepatic perfusion secondary to superior vena cava obstruction: three case reports]

The aim of this study was to evaluate the altered flow dynamics of liver perfusion that can be observed during superior vena cava obstruction. Through the description of three case reports of patients with SVC obstruction, the authors discuss the different collateral pathways used that result in systemic portal venous shunting creating this altered flow dynamics and their appearance in computed tomography.

Thoracic venous anatomy multidetector row CT evaluation

Two-dimensional CT angiography provides much information of the systemic and pulmonary thoracic veins. The combination of MDCT and volume-rendering techniques postprocessing provides higher-quality data sets and a method fully to harness the potential for image display and interpretation. Although this may not radically alter sensitivity for detection of systemic or pulmonary venous pathology it does provide a more comprehensive and sophisticated evaluation through volume acquisition and interpretation.

Collateral pathways in superior vena caval obstruction as seen on CT

PURPOSE

Collateral venous pathways occurring with superior vena cava (SVC) obstruction were examined based on CT scans obtained from the thoracic inlet to the pubic symphysis. Similarities and variations from the prior classification scheme were analyzed.

METHOD

A retrospective review of our database resulted in a cohort comprising 21 CT scans from 19 patients. The location and frequency of each collateral pathway and the level of the SVC obstruction were tabulated. An accepted classification scheme was applied to the collateral patterns in each case. Additional and atypical features were noted.

RESULTS

Fifteen common collateral veins were found that could be grouped into one to four collateral pathways. Unusual shunts, including hepatic parenchymal and pulmonary pathways, were found. Thirteen cases (62%) varied from the standard classification owing to different occlusion levels or presence of other collaterals. No statistically significant relationship between the level of occlusion and the number of collateral pathway groups was found. The most common abdominal collateral veins were those along the liver surface (52.3% of cases), although 18 patients (94.7%) had at least one collateral vein visible in the abdomen.

CONCLUSION

The spectrum of venous collateral formations as seen on thoracoabdominal CT scans often includes collaterals at or below the level of the diaphragm, including intrahepatic shunts. Many collateral patterns found in this series could not be classified with the existent classification scheme.

Systemic to pulmonary venous shunt in superior vena cava occlusion

This report describes systemic-to-pulmonary venous connections at the pleural level resulting from superior vena cava occlusion. The interval development of new venous collaterals within a 3-year period represents an advanced manifestation of SVC occlusion in this patient with a history of pleural disease. In this case, progressive venous thrombosis caused by underlying hypercoaguability led to the development of collaterals in unusual sites, including systemic-to-pulmonary venous shunting, and resulting in progressive cyanosis and death.