Superior Vena Caval Obstruction

Key Features

• A rare disorder caused by partial or complete obstruction of the superior vena cava

• Most frequent causes

  • Neoplasms, such as lymphomas, primary malignant mediastinal tumors, or carcinoma of the lung with direct extension (over 80%)

  • Chronic fibrotic mediastinitis, either of unknown origin or secondary to tuberculosis, histoplasmosis, pyogenic infections, or drugs (especially methysergide)

  • Deep venous thrombosis

  • Aneurysm of the aortic arch

  • Constrictive pericarditis

Clinical Findings

• Swelling of the neck and face and upper extremities

• Headache

• Dizziness, stupor, syncope

• Visual disturbances

• Bending over or lying down accentuates symptoms

• Dilated anterior chest wall veins and/or collateral veins

• Facial flushing

• Brawny edema and cyanosis of the face, neck, and arms

• Cerebral and laryngeal edema

• Venous pressure

  • Elevated in the arm (often > 20 cm H₂O)

  • Normal in the leg

Diagnosis

• Venous pressure

  • Elevated (often more than 20 cm H₂O) in the arm

  • Normal in the leg

• Bronchoscopy is often performed, since lung cancer is a common cause

• Transbronchial biopsy is relatively contraindicated because of venous hypertension and the risk of bleeding

• Chest radiographs and a CT scan will define the location and often the nature of the obstructive process

• Contrast venography or magnetic resonance venography (MRV) will map out the extent and degree of the venous obstruction and the collateral circulation

• Brachial venography or radionuclide scanning following intravenous injection of technetium Tc-99m pertechnetate demonstrates a block to the flow of contrast material into the right heart and enlarged collateral veins

• These techniques also allow estimation of blood flow around the occlusion as well as serial evaluation of the response to therapy.

Treatment

• Conservative measures such as elevation of the head of the bed and lifestyle modification to avoid bending over are useful

• Occasionally, anticoagulation is needed, while thrombolysis is rarely needed

• Balloon angioplasty of the obstructed caval segment combined with stent placement

  • Procedure of choice

  • Provides prompt relief of symptoms

• Urgent treatment for neoplasm consists of

  • Cautious use of intravenous diuretics

  • Mediastinal irradiation

• Chemotherapy added for lymphoma or small-cell carcinoma

• In cases where the thrombosis is secondary to an indwelling catheter, thrombolysis may be attempted