Superior vena cava syndrome is a form of vessel obstruction that occurs as a result of mechanical compression or due to thrombosis. Symptoms include facial edema, dyspnea, cough, neck distension, hoarseness and dysphagia, while severe cases may present with coma and severe respiratory distress. The diagnosis can be made clinically, but imaging studies are recommended for confirmation. Treatment depends on the underlying cause.
Symptoms of SVCS depend on the severity and rapidness of vessel pathology. Most common symptoms include a sense of fullness in the head, neck and facial swelling, dyspnea, chest pain, cough, dysphagia and distended upper extremities . Tachycardia, hoarseness, stridor, respiratory distress and cerebral edema with ischemia and herniation may be encountered in severe cases. Physical examination can reveal distended neck veins, edema of the upper extremities, while various neurological deficits may be encountered.
Because SVCS can mimic various conditions, including pericarditis, heart failure, myocardial infarction (if symptoms appear abruptly) and ischemic stroke, the diagnostic workup should start with a full physical examination and proper patient history. Information about comorbidities, history of previous surgical procedures and underlying diseases such as malignant tumors (which may not be diagnosed yet, in which case a high clinical suspicion is necessary) should be obtained in full, whereas physical examination may provide key details in making the diagnosis. These tools, however, may only make an initial diagnosis that needs to be confirmed with imaging studies. Plain radiography may reveal the presence of a tumor, but CT, venography, or MR angiography are recommended methods in confirming the diagnosis . If a tumor is suspected, biopsy with subsequent histopathological evaluation is necessary to determine the subtype. Through these methods, the exact cause may be determined, after which appropriate treatment can be instated.
Management of patients initially necessitates supportive measures. Cyanosis and respiratory distress mandates adequate supplementation of oxygen and assisted ventilation in severe cases, while rest, fluid administration, use of diuretics and glucocorticoids is shown to be of great benefit for patients. . The mainstay of therapy, however, is identification and treatment of the underlying cause. In the setting of thrombosis, anticoagulant and thrombolytic therapy consisting of either warfarin or heparin is effective , whereas removal of central venous catheters and pacemakers should be considered. Infectious pathogens such as histoplasmosis and tuberculosis require intensive antifungal and antibiotic therapy, respectively. As tumors are the most common cause, appropriate staging of the tumor and adequate therapy consisting of surgery, radiation and/or chemotherapy are vital in eliminating the mass that compresses the superior vena cava. Various techniques for isolated management of SVCS have been described across many studies, with endovascular approaches being recommended as first-line therapy . Insertion of vascular endoprostheses and resection and reconstruction of the venous vessel using autologous tissue are some of the most successful   .
The prognosis of patients with SVCS directly depends on the underlying cause. If malignancy triggers SVCS, overall prognosis is poor. Studies have established that SVCS is a predictor of poor outcome in patients suffering from non-small cell lung cancer . On the other hand, central venous catheter-induced thrombosis can be resolved quickly, which is why identifying the cause as soon as possible may significantly improve the outcome .
SVCS was initially described more than 250 years ago , and numerous causes have been described in literature. Studies have shown two pathologic events: extraluminal mechanical compression of the vein that causes narrowing of the vessel lumen and thrombosis . Malignant tumors, most frequently bronchogenic carcinoma, but also lymphoma, chondrosarcoma , melanoma and breast cancer are responsible for approximately 85% of all SVCS cases, while mediastinal metastases and enlarged lymph nodes may also compress the superior vena cava . Non-malignant causes are much more uncommon and comprise about 15% of cases. Infectious pathogens such as tuberculosis and histoplasmosis, thymomas, aortic aneurysms, mediastinal fibrosis (that may be a consequence of histoplasmosis), as well as central venous and pacemaker catheters are causative agents in approximately 15% of patients . Recent reports, however, suggest that benign causes may be responsible for up to 40% of cases, primarily because of increasing use of central venous catheters and pacemakers that can lead to thrombosis .
Because of the underlying etiologies, SVCS is established to be most common in males between 50-70 years of age with either primary or metastatic tumors of the mediastinum . Certain studies have established that approximately 15,000 individuals develop SVCS in the United States every year . Advanced malignant disease is the single most important risk factor for SVCS, but several other have been established. Right-sided tumors, due to anatomical proximity to the vessel, are more likely to cause SVCS . Placement of central venous catheters , as well as implantation of cardiac pacemakers are significant risk factors for SVCS as these methods induce hypercoagulable states that lead to obstruction.
Under physiological conditions, venous blood from the head, upper thorax and the arms drain into the superior vena cava, which eventually terminates in the right atrium, making it one of the most important venous vessels in the body. It is tightly enclosed in the anterior superior mediastinum by several structures , including the sternum, the trachea, right mainstem bronchus, thoracic aorta, and both perihilar and paratracheal lymph nodes. In most cases, SVCS stems from either mechanical extraluminal compression by a malignant tumor or thrombosis . In case of compression, narrowing of the vessel lumen occurs, while thrombosis reduces the diameter through which blood can pass, both eventually elevating venous pressures. As a compensatory mechanism, the body redistributes circulation to tributaries of the superior vena cava, such as the azygous vein, in the attempt to reduce vessel overload. As the underlying cause is not resolved, however, severe compression or occlusion eventually triggers the onset of symptoms.
Timely diagnosis of the underlying cause may significantly reduce the rate of SVCS appearance, but directed preventive strategies may be aimed at regular screening of patients who are at risk, such as those with malignant tumors that are known to induce this vascular phenomenon, but also those with central venous catheters and pacemakers.
Superior vena cava syndrome (SVCS) is a clinical entity in which mechanical obstruction of the superior vena cava leads to reduced blood flow. In up to 85% of all cases, SVCS stems from mechanical compression by malignant tumors, while other etiologies include mediastinal fibrosis, use of cardiac pacemakers and central venous catheters that predispose patients to thrombosis . Bronchogenic carcinoma is by far the most common tumor, followed by small-cell carcinomas, non small-cell carcinomas, lymphomas and various other . The superior vena cava is responsible for drainage of the upper portions of the thorax, the arms and the endocranium. In the setting of mechanical compression or thrombosis, there is an increased load on the accessory veins, including vertebral, internal mammary and the thoracic venous system, but the azygous vein is the single most important collateral branch . Eventually, increased venous pressure develops and various symptoms may appear depending on the progression and severity of obstruction. Facial edema, dyspnea, cough, dysphagia together with neck and upper extremity distension are most frequently reported . Severe cases present with hoarseness, laryngeal edema and neurological deficits . Physical examination may reveal distended neck veins, tachycardia, swelling of the face and upper extremities, whereas patients suffering from severe forms may develop respiratory distress, altered mental state, seizures and coma . Although the diagnosis can be made based on clinical criteria, imaging studies such as computed tomography (CT), magnetic resonance imaging (MRI), MR angiography, venography and even plain radiography may be used to confirm the diagnosis and the underlying cause. Since tumors are the most common cause of obstruction, biopsy with subsequent histopathological examination is required to determine the exact tumor subtype. Treatment is aimed at resolving the cause. Radiation, surgery and chemotherapy are used in the case of malignancy, while supportive measures include oxygen therapy and use of diuretics, thrombolytic agents and corticosteroids .
Superior vena cava syndrome (SVCS) is a condition in which one of the most important veins, the superior vena cava, is either mechanically compressed or affected by thrombosis, leading to impaired blood flow and appearance of various symptoms. This vein collects blood from the entire head and neck, as well as the upper extremities and the upper part of the chest that reaches the right atrium, from where it travels to the lungs, back to the heart and into the circulation through the aorta. The most common cause of SVCS is a malignant tumor, comprising about 85% of all cases, with lung cancer being the most common type of malignancy. The presence of a tumor causes compression of the vessel and narrows the lumen through which blood can pass. Thrombosis due to placement of central venous catheters (often instated in intensive care patients and many other) or pacemakers can also trigger SVCS, as thromb formation impedes normal blood flow. To compensate for reduced blood flow, the body attempts to redistribute blood via several tributaries of the superior vena cava, but eventually, symptoms such as head and neck swelling, breathing difficulties and chest pain appear. In severe cases, voice changes due to swelling of the larynx, tachycardia and neurological changes may be observed, which requires immediate treatment and identification of the underlying cause. To make a presumptive diagnosis, physical examination can reveal distended neck veins, cyanosis (blue discoloration of the skin due to impaired oxygen delivery of the heart) and swelling of the upper extremities, but imaging techniques such as X-ray, computed tomography (CT scan), venography and a specific form of magnetic resonance imaging (MRI), MR angiography, can be used. If a tumor is suspected, biopsy of the mass is necessary to determine the exact subtype. Treatment depends on the underlying cause, but supportive measures consisting of oxygen therapy, administration of anticoagulants, diuretics, corticosteroids and fluid replenishment are recommended. Surgery, radiation and chemotherapy are used in managing malignant tumors, while various surgical procedures for vessel repair have been described. The condition itself may not be of significant risk for patients, but the underlying diagnosis is cancer in the vast majority of cases, which is why poor outcomes are observed. This condition is most commonly seen in males between 50-70 years and about 15,000 Americans are diagnosed every year with SVCS. For these reasons, screening of patients that are already diagnosed with lung cancer, as well as those that have established risk factors may be an effective treatment strategy in reducing the burden of this condition.