a) Obstruction below azygous vein
· Azygous - hemiazygous, lumbar veins to IVC
b) Obstruction above azygous vein
· Venous collateral in neck to azygous to SVC
c) Obstruction includes azygous vein
· Internal mammary, paraspinous, esophageal and subcutaneous vein to IVC
d) Cerebral decompression through a single jugular vein via midline intracranial venous sinuses
a) Extrinsic compression of SVC
· Gradual SVC obstruction
b) Invasion of SVC
· Obstruction develops rapidly
c) Thrombosis of SVC
· Acute obstruction
d) Venous hypertension and lymphatic obstruction - all empty into the subclavian veins
a) Benign 10%
· Inflammatory - histoplasmosis, idiopathic fibrosing mediastinitis
· Iatrogenic - pacemaker electrode, hyperalimentation or other CV line
b) Malignant 90%
· Bronchogenic, epidermoid 65-80%
· Small cell 12-30%
· Lymphoma 12-20%
· Swelling face, neck, arms
· Shortness of breath, orthopnea, cough and chest pain suggest upper airway obstruction
· Hoarseness, stridor, tongue swelling, nasal congestion
· Headaches, syncope and lethargy are caused by cerebral edema from venous hypertension
· Symptoms worse lying down, bending forward
· Symptoms of cerebral or laryngeal edema is associated witha reduced life expectancy of about 6 weeks, demanding urgent intervention
· Caval obstruction may be the life-limiting problem of patients with underlying malignancy
a) Chest x-ray
· Right hilar mass - bronchogenic carcinoma
· Anterior mediastinal mass - lymphoma
· Calcification - histoplasmosis
b) Simultaneous bilateral arm venogram
· Defines obstruction and collateral circulation
· Identifies thrombus
c) Computerized axial tomography
· Assessment of mediastinum
· Determine patency of jugular veins
· Directed needle biopsy
· Since most cases due to malignancy, nearly all patients receive radiation
· 80-90% relieved of SVC Syndrome
· 50% of patients relapse
· Relapse occurs in benign disease as well; although collaterals develop, thrombosis will continue to propogate and occlude these collaterals over time
· Chemotherapy for lymphomas and small cell carcinoma
· Diuretics and corticosteroids reduce cerebral edema
· Anticoagulants in selected cases to prevent clot propagation
· Thrombolytic therapy for selected acute thrombosis
· Severe SVC Syndrome associated with thrombosis of caval tributaries and inadequate collateral circulation
· SVC bypass with composite autogenous vein grafts or PTFE 6-12 months after onset in benign causes or for palliation in malignant causes with severe or acute onset SVC syndrome