AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Background

Superior vena cava syndrome (SVCS) is obstruction of blood flow through the superior vena cava (SVC). It is a medical emergency and most often manifests in patients with a malignant disease process within the thorax. A patient with SVCS requires immediate diagnostic evaluation and therapy.

William Hunter first described the syndrome in 1757 in a patient with syphilitic aortic aneurysm. In 1954, Schechter reviewed 274 well-documented cases of SVCS reported in the literature; 40% of them were due to syphilitic aneurysms or tuberculous mediastinitis. In more recent times, these infections have gradually decreased as the primary cause of SVC obstruction. Lung cancer is now the underlying process in approximately 70% of the patients with SVCS.

Pathophysiology

The SVC is the major drainage vessel for venous blood from the head, neck, upper extremities, and upper thorax. It is located in the middle mediastinum and is surrounded by relatively rigid structures such as the sternum, trachea, right bronchus, aorta, pulmonary artery, and the perihilar and paratracheal lymph nodes. It extends from the junction of the right and left innominate veins to the right atrium, a distance of 6-8 cm. It is a thin-walled, low-pressure, vascular structure. This wall is easily compressed as it traverses the right side of the mediastinum.

Obstruction of the SVC may be caused by neoplastic invasion of the venous wall associated with intravascular thrombosis or, more simply, by extrinsic pressure of a tumor mass against the relatively fixed thin-walled SVC. Postmortem examinations reveal that complete SVC obstruction is the result of intravascular thrombosis in combination with extrinsic pressure. Incomplete SVC obstruction more often is secondary to extrinsic compression without thrombosis.

An obstructed SVC initiates collateral venous return to the heart from the upper half of the body through 4 principal pathways. The first and most important pathway is the azygous venous system, which includes the azygous vein, the hemiazygous vein, and the connecting intercostal veins. The second pathway is the internal mammary venous system plus tributaries and secondary communications to the superior and inferior epigastric veins. The long thoracic venous system, with its connections to the femoral veins and vertebral veins, provides the third and fourth collateral routes, respectively.

Despite these collateral pathways, venous pressure is almost always elevated in the upper compartment if obstruction of the SVC is present. Venous pressure as high as 200-500 cm H₂O has been recorded in patients with severe SVCS.

Frequency

United States

SVCS develops in 5-10% of patients with a right-sided malignant intrathoracic mass lesion. In 1969, Salsali and Cliffton observed SVCS in 4.2% of 4960 patients with lung cancer; 80% of the tumors inducing SVCS were of the right lung. In 5 large series of small cell lung cancer, 9-19% of patients demonstrated SVCS. In 1987, Armstrong and Perez found SVCS in 1.9% of 952 patients with lymphoma.

Mortality/Morbidity

• Survival in patients with SVCS depends mainly on the course of the underlying disease. No mortality, per se, results directly from mild venous congestion.
• In patients with benign SVCS, life expectancy is unchanged.
• If SVCS is secondary to a malignant process, patient survival correlates with the histology of the tumor. Patients with signs and symptoms of laryngeal and cerebral edema have the most life-threatening manifestations of this syndrome and are in danger of sudden death. Clinical observations show that approximately 10% of patients with a bronchogenic carcinoma and 45% of patients with lymphoma treated with irradiation live at least 30 months. In contrast, patients with untreated malignant SVCS survive only approximately 30 days.

Race

The frequency of SVCS in different races depends largely on the frequency of lung cancer and lymphomas in these populations.

Sex

• Malignant causes of SVCS are most commonly observed in males because of the high incidence of lung cancer in this population.
• In contrast, no sex difference is observed in cases related to benign causes.

Age

• Malignant causes of SVCS are predominantly observed in individuals aged 40-60 years.
• Benign causes account for most of the cases diagnosed in individuals aged 30-40 years.
• Obstruction of the SVC in the pediatric age group is rare and has a different etiologic spectrum.

CLINICAL

Section 3 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

History

• Early in the clinical course, partial SVC obstruction may be asymptomatic, but more often, minor symptoms and signs are overlooked.
• As the syndrome advances toward total SVC obstruction, the classic symptoms and signs become more obvious.
• • Dyspnea is the most common symptom and is observed in 63% of patients with SVCS.
  • Other symptoms include facial swelling, head fullness, cough, arm swelling, chest pain, dysphagia, orthopnea, distorted vision, hoarseness, stridor, headache, nasal stuffiness, nausea, and light-headedness.

Physical

• The characteristic physical findings of SVCS include venous distension of the neck and chest wall, facial edema, upper extremity edema, mental changes, plethora, cyanosis, papilledema, stupor, and even coma.
• Bending forward or lying down may aggravate the symptoms and signs.

Causes

• More than 80% of cases of SVCS are caused by malignant mediastinal tumors.
• • Bronchogenic carcinomas account for 75-80% of all these cases, with most of these being small-cell carcinomas.
  • Non-Hodgkin lymphoma (especially the large cell type) represents 10-15% of cases.
• Causes of SVCS appear similar to the relative incidence of primary lung and mediastinal tumors.
• Rare malignant diagnoses include Hodgkin disease, metastatic cancers, primary leiomyosarcomas of the mediastinal vessels, and plasmocytomas.
• Nonmalignant conditions causing SVCS include mediastinal fibrosis; vascular diseases such as aortic aneurysm, vasculitis, and arterial-venous fistulas; infections such as histoplasmosis, tuberculosis, syphilis, and actinomycosis; benign mediastinal tumors such as teratoma, cystic hygroma, thymoma, and dermoid cyst; cardiac causes, such as pericarditis and atrial myxoma; and thrombosis related to the presence of central vein catheters.

DIFFERENTIALS

Section 4 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Other Problems to be Considered

Aortic aneurysm

WORKUP

Section 5 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Imaging Studies

• Patients presenting with overt SVCS may be diagnosed by means of physical examination alone. However, subtle presentations require diagnostic imaging. Chest radiography may reveal a widened mediastinum or a mass in the right side of the chest. Only 16% of the patients studied by Parish and colleagues in 1981 had normal findings on chest radiography.
• CT has the advantage of providing more accurate information on the location of the obstruction and may guide attempts at biopsy by mediastinoscopy, bronchoscopy, or percutaneous fine-needle aspiration.
• • It also provides information on other critical structures such as the bronchi and the vocal cords.
  • The additional information is necessary because the involvement of these structures requires prompt action for relief of pressure.
• MRI has not been sufficiently investigated, but it appears promising.
• • It has several potential advantages over CT scanning, including the fact that it provides images in several planes of view and allows direct visualization of blood flow. Furthermore, MRI does not require iodinated contrast material.
  • Disadvantages may include increased scanning time with attendant problems in patient compliance and increased cost.
• Invasive contrast venography is the most conclusive diagnostic tool.
• • It precisely defines the etiology of obstruction.
  • It is especially important if surgical management is being considered for the obstructed vena cava.
• Radionuclide technetium-99m venography is an alternative minimally invasive method of imaging the venous system. Although images obtained by this method are not as well defined as those achieved with contrast venography, they demonstrate potency and flow patterns.
• Gallium single-proton emission CT scanning may be of value in select cases.

Procedures

• Most patients with SVCS present before the primary diagnosis is established.
• Controversy often arises in the treatment of a patient with SVCS in regard to the need for pathologic confirmation of malignancy before the start of therapy.
• Treatment without an established diagnosis should be initiated only in patients with rapidly progressive symptoms or those in whom multiple attempts to obtain a tissue diagnosis have been unsuccessful.
• Fortunately, relatively noninvasive measures establish the diagnosis in a high percentage of patients with SVCS.
• • Sputum cytologic results are diagnostic in 68% of the cases, whereas biopsy of a palpable supraclavicular node is positive in 87%.
  • Bronchoscopy has a 60% success rate, while thoracotomy is 100% successful.
  • Open biopsy is rarely needed for diagnosis.

TREATMENT

Section 6 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical Care

The goals of SVCS management are to relieve symptoms and to attempt cure of the primary malignant process. Only a small percentage of patients with a rapid-onset SVC obstruction are at risk for life-threatening complications.

• Patients with clinical SVCS often gain significant symptomatic improvement from conservative treatment measures, including elevation of the head of the bed and supplemental oxygen.
• Emergency treatment is indicated when brain edema, decreased cardiac output, or upper airway edema is present. Corticosteroids and diuretics are often used to relieve laryngeal or cerebral edema, although documentation of their efficacy is questionable.
• Radiotherapy has been advocated as a standard treatment for most patients with SVCS. It is used as the initial treatment if a histologic diagnosis cannot be established and the clinical status of the patient is deteriorating; however, recent reviews suggest that SVCS obstruction alone rarely represents an absolute emergency that requires treatment without a specific diagnosis.
  • The fractionation schedule of radiation usually includes 2-4 large initial fractions of 300-400 cGy, followed by conventional fractionation of 150-200 cGy daily, to a total dose of 3000-5000 cGy. The radiation dose depends on tumor size and radioresponsiveness. The radiation portal should include a 2-cm margin around the tumor.
  • During irradiation, patients improve clinically before objective signs of tumor shrinkage are evident on chest radiography. Radiation therapy palliates SVC obstruction in 70% of patients with lung carcinoma and in more than 95% with lymphoma.
• In patients with SVCS secondary to non–small-cell carcinoma of the lung, radiotherapy is the primary treatment. The likelihood of patients benefiting from such therapy is high, but the overall prognosis of these patients is poor.
• Chemotherapy may be preferable to radiation for patients with chemosensitive tumors.
• • In 1983, Maddox and associates reported on 56 patients with small-cell lung cancer who presented with SVCS. Correction of SVCS was obtained in 9 (56%) of 16 patients treated with radiation therapy alone, in 23 (100%) of 23 given chemotherapy, and in 5 (83%) of 6 who received combined therapy.
  • The most extensive experience in SVCS management secondary to non-Hodgkin lymphoma is reported from the M.D. Anderson cancer center. Patients were treated with chemotherapy alone, chemotherapy combined with radiation therapy, or radiation therapy alone. All patients achieved complete relief of SVCS symptoms within 2 weeks of the institution of any type of treatment. No treatment modality appeared to be superior in achieving clinical improvement.
• When SVCS is due to thrombus around a central venous catheter, patients may be treated with antifibrinolytics (eg, streptokinase, urokinase, recombinant tissue-type plasminogen activator) or anticoagulants (eg, heparin, oral anticoagulants). Removal of the catheter, if possible, is another option, and it should be combined with anticoagulation to avoid embolization.
• In a 1988 report, Adelstein et al discuss prophylaxis against embolic events in the presence of a SVC obstruction in the management of 25 patients with malignant SVCS.
• Ten patients were retrospectively reviewed after having been diagnosed clinically without venography and treated without anticoagulation. Five thromboembolic complications occurred, 2 of which proved fatal.
• Fifteen patients were prospectively evaluated by means of angiography and then treated with anticoagulants. Angiographic evidence of intraluminal subclavian vein or SVC thrombosis was found in 5 of these patients, and no thromboembolic complications occurred.
• Of the 20 patients who were ultimately given anticoagulation therapy, 2 had fatal intracranial hemorrhages.
• The authors suggested the need for randomized prospective trials if the role of venography and anticoagulation in this syndrome is to be determined.

Surgical Care

• Surgical bypass of the SVC may be a useful way to palliate symptoms in carefully selected patients.
• • Indications to proceed with such procedure are much less clear.
  • For the most part, these are patients with advanced intrathoracic disease amenable only to palliative therapy (ie, after failure of radiation therapy and chemotherapy).
• SVC stenting can provide rapid symptomatic relief within few days in most patients with SVCS.
• • SVC stenting may provide relief of severe symptoms for patients while the histological diagnosis of the malignancy causing the obstruction is being actively pursued.
  • Stenting may also be indicated in patients in whom chemotherapy or radiation has failed.
  • Some literature recommends stenting as first-line treatment to be performed early in the management of SVCS.

Consultations

• Thoracic surgeon
• Hematologist/oncologist
• Radiation therapist
• Interventional radiologist

MEDICATION

Section 7 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

The goals of pharmacotherapy are to reduce morbidity and to prevent complications.

Drug Category: Corticosteroids

The agents reduce swelling in patients with cerebral or laryngeal edema.

Drug Category: Thrombolytics

The potential benefits of thrombolytics for the treatment of pulmonary embolism include fast dissolution of physiologically compromising pulmonary emboli, quickened recovery, prevention of recurrent thrombus formation, and rapid restoration of hemodynamic disturbances. For deep vein thrombosis, lysis of the thrombus can prevent pulmonary embolism and permanent pathologic changes, such as venous valvular dysfunction and postphlebitic syndrome.

Drug Category: Anticoagulants

In SVCS, these agents are used mainly to prevent pulmonary embolism from SVC thrombus.

FOLLOW-UP

Section 8 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Further Inpatient Care

• Admit the patient to the hospital if symptoms of SVCS are moderate-to-severe and/or when a patient requires the administration of thrombolytic therapy or anticoagulation.

Further Outpatient Care

• Instruct patients to use supportive measures, such as elevation of the head of the bed.
• Carefully monitor the patient's symptoms and the adverse effects of the administered treatment. Patients should notify the physician immediately if any change in symptoms occurs.

In/Out Patient Meds

• Oxygen supplementation may be provided if needed.
• Antiemetics may be provided as needed to prevent nausea and vomiting.
• For those patients started on steroids, taper steroids slowly, depending on the patient's condition.

Transfer

• Transfer may be required for further diagnostic evaluation and surgical intervention.

Complications

• Complications include laryngeal edema, cerebral edema, decreased cardiac output with hypotension, and pulmonary embolism (when an associated thrombus is present).

Prognosis

• The survival of patients with SVCS depends mainly on the course of the underlying disease.
• Untreated patients and those not responding to treatment survive approximately 30 days.

MISCELLANEOUS

Section 9 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical/Legal Pitfalls

• Failure to establish the correct diagnosis and the underlying etiology
• Failure to initiate immediate treatment
• Failure to recognize a thrombus in the SVC
• Failure to consult a medical oncologist and radiation therapist
• Failure to expeditiously diagnose and appropriately manage heparin-related complications
• • In particular, one must monitor platelet count and be vigilant should a rapid decline in platelets occur. This suggests the possibility of platelet-induced thrombocytopenia syndrome (white clot syndrome). This rare syndrome may lead to extremity gangrene and life-threatening venous thromboembolism.
  • Management requires urgent discontinuation of heparin and urgent evaluation by a hematologist for appropriate pharmacotherapy.
  • Vascular surgical evaluation may also be indicated.

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

• Abner A. Approach to the patient who presents with superior vena cava obstruction. Chest. Apr 1993;103(4 Suppl):394S-397S. [Medline].
• Adelstein DJ, Hines JD, Carter SG. Thromboembolic events in patients with malignant superior vena cava syndrome and the role of anticoagulation. Cancer. Nov 15 1988;62(10):2258-62. [Medline].
• Armstrong BA, Perez CA, Simpson JR. Role of irradiation in the management of superior vena cava syndrome. Int J Radiat Oncol Biol Phys. Apr 1987;13(4):531-9. [Medline].
• Davis SR, King HS, Le Roux I. Superior vena cava syndrome caused by an intrathoracic plasmacytoma. Cancer. Sep 15 1991;68(6):1376-9. [Medline].
• Maddox AM, Valdivieso M, Lukeman J. Superior vena cava obstruction in small cell bronchogenic carcinoma. Clinical parameters and survival. Cancer. Dec 1 1983;52(11):2165-72. [Medline].
• Parish JM, Marschke RF, Dines DE. Etiologic considerations in superior vena cava syndrome. Mayo Clin Proc. Jul 1981;56(7):407-13. [Medline].
• Perez CA, Presant CA, Van Amburg AL. Management of superior vena cava syndrome. Semin Oncol. Jun 1978;5(2):123-34. [Medline].
• Perez-Soler R, McLaughlin P, Velasquez WS. Clinical features and results of management of superior vena cava syndrome secondary to lymphoma. J Clin Oncol. Apr 1984;2(4):260-6. [Medline].
• Roswit B, Kaplan G, Jacboson HG. The superior vena cava obstruction syndrome in bronchogenic carcinoma; pathologic physiology and therapeutic management. Radiology. Nov 1953;61(5):722-37. [Medline].
• Salsali M, Cliffton EE. Superior vena caval obstruction in carcinoma of lung. N Y State J Med. Nov 15 1969;69(22):2875-80. [Medline].
• Scarantino C, Salazar OM, Rubin P. The optimum radiation schedule in treatment of superior vena caval obstruction: importance of 99mTc scintiangiograms. Int J Radiat Oncol Biol Phys. Nov-Dec 1979;5(11-12):1987-95. [Medline].
• Schechter MM. The superior vena cava syndrome. Am J Med Sci. 1954;227:46-56. [Medline].
• Smayra T, Otal P, Chabbert V. Long-term results of endovascular stent placement in the superior caval venous system. Cardiovasc Intervent Radiol. Nov-Dec 2001;24(6):388-94. [Medline].
• Thony F, Moro D, Witmeyer P. Endovascular treatment of superior vena cava obstruction in patients with malignancies. Eur Radiol. 1999;9(5):965-71. [Medline].
• Urban T, Lebeau B, Chastang C. Superior vena cava syndrome in small-cell lung cancer. Arch Intern Med. Feb 8 1993;153(3):384-7. [Medline].
• Weiss KS, Zidar BL, Wang S. Radiation-induced leiomyosarcoma of the great vessels presenting as superior vena cava syndrome. Cancer. Sep 15 1987;60(6):1238-42. [Medline].
• Yim CD, Sane SS, Bjarnason H. Superior vena cava stenting. Radiol Clin North Am. Mar 2000;38(2):409-24. [Medline].

Article Last Updated: Aug 10, 2005