Superior Vena Cava Syndrome

Obstruction of the superior vena cava (SVC) may occur as an acute or subacute process producing a syndrome with characteristic features including facial edema and plethora, dilation of chest wall and neck veins, and mild to moderate respiratory difficulty. SVC syndrome is usually due to a neoplastic process, predominantly lung carcinoma, with a disproportionate number having small cell histology; non-Hodgkin lymphoma and metastatic tumors are the next most common. SVC syndrome can be iatrogenic; it is increasingly seen as a complication of a central venous catheter, pacemaker leads or cardiac surgery. Diagnosis is based on clinical findings. Contrast enhanced computed tomography scanning helps identify the etiology and collateral flow, and is the most helpful study to guide treatment. Venography with a small dose of contrast material can be safely accomplished to define the exact location of caval obstruction and routes of collateral flow. Treatment of an identified mass before histologic diagnosis is rarely justified unless prior diagnosis is established. Methods used to define histology are sputum cytology, thoracentesis, endobronchial ultrasound with and without bronchoscopy, lymph node biopsy, percutaneous biopsy, and video-assisted mediastinoscopy or thoracotomy; these techniques are considered quite safe. Radiation therapy with or without chemotherapy is a preferred treatment in most malignant causes of SVC syndrome. Percutaneously placed, self-expanding intravascular stents provide an option or adjunct to other procedures in the palliative treatment of patients (usually with malignant disease). Angioplasty alone or in combination of self-expanding intravascular stents, and bypass surgery, is used for treatment of benign SVC obstruction.