hp_jan99_svcs

8/6/2019 hp_jan99_svcs

http://slidepdf.com/reader/full/hpjan99svcs 1/6

uperior vena cava syndrome (SVCS) was firstdescribed in l757 in a patient with a syphiliticlesion of the aorta. 1 The causes of SVCS havechanged since that time. In the 1950s, SVCS was

primarily caused by aortic aneurysm and infectionssuch as tuberculosis and fibrous mediastinitis. In the1980s and 1990s, malignant disorders have become thedominant cause of SVCS. In most patients with SVCS,primary malignancies of the mediastinum are the

causative factor. Benign disorders account for less than10% of cases of SVCS. Modern antibiotic treatment of infectious disorders is postulated to be th e cause of thechan ging e tiologies of SVCS. 2–11 This article reviews theanatomy of the superior vena cava and the pathophysi-ology, malignant and benign causes, clinical presenta-tion, and diagnosis of SVCS. Treatment and prognosisare also d iscussed.

ANATOMY OF THE SUPERIOR VENA CAVAThe superior vena cava is a thin-walled, readily com-

pressible vessel that transmits blood to th e heart at lowpressure. The superior vena cava is located in the mid-

dle mediastinum and is encircled by rigid structures,including the trachea, right bronchus, aorta, thymus,and pulmonary artery. The superior vena cava extendsapproximately 8 cm from the innominate vein to theright atrium. The distal 2 cm of the superior vena cavaare within the pericardial sac. The azygous vein entersthe superior vena cava posteriorly and is a significantvenous collateral channel. Encircling th e super ior venacava are subcarinal, perihilar, and paratracheal lymphnodes. These nodes drain the right lung and the lowerlobe of the left lung. 2– 4

PATHOPHYSIOLOGYAny pathology of the previously noted structures

produces external pressure on the superior vena cavaor internally obstructs the vessel as a result of eitherthrombosis or direct invasion by the disease process. Inaddition, enlargement of the lymph nodes may alsocompress the superior vena cava. In most cases, extrin-sic compression develops gradually and the symptomsare initially mild because collateral circulation has suffi-ciently developed. If the obstruction develops sudden-

ly, as in the case of a malignancy, the collateral circula-tion has not developed and the patient rapidly be-comes symptomatic. Thrombosis of the superior venacava may progress to involve all the major collateralvessels, and the resulting thrombosis eventually under-goes fibrosis that results in permanent occlusion of thesuperior vena cava. In this case, thrombolytic therapy isof little or n o ben efit un less the treatmen t is directed atthe p rimary cause of SVCS.

MALIGNANT AND BENIGN CAUSESMalignant Causes

The most common malignancy associated withSVCS is lung cancer, followed by lymphomas andmetastatic tumors to the med iastinum ( Table 1 ).

Lung tumors. Approximately 5% to 15% of patientswith bronchogenic carcinoma develop SVCS. The syn-drome is four times more likely to occur in patientswith right-sided tumors of the thoracic cavity. Theselesions often cause obstructive pneumonitis, which usu-ally occurs with involvement of right hilar and medi-astinal lymph nodes. Amon g the types of lung cancers,

all histologic cell types are associated with SVCS.Lymphomas and metastatic tumors. The second

group of malignancies that commonly cause SVCS arelymphomas, especially non-Hodgkin’s lymphoma. SVCSoccurs in 3% to 8% of patients with lymphoma. The lym-phoma usually originates in the anterior mediastinumand produces SVCS by external compression. Metastatictumors, more commonly breast and testicular tumors,cause SVCS in approximately 5% to 20% of patients. 2– 9

Benign CausesMany benign disorders can cause SVCS ( Table 2 ). As

noted previously, however, benign disorders accoun t forless than 10% of cases of SVCS. Benign causes of SVCSinclude thymoma, cystic hygroma, benign cystic ter-atoma, substernal thyroid goiter, dermoid cyst, andpostirradiation therapy. Infections notable for causingSVCS are tuberculosis, histoplasmosis, actinomycosis,

S

Dr. Bhimji is a Resident in Cardiac Surgery, Medical College of Georgia, Augusta, GA.

42 Hospital Physician January 1999

G r o u n d b r e a k e r s

Superior Vena Cava Syndrome

Shabir Bhimji, MD, PhD



syphilis, and pyogenic infections. In addition, theincreased current use of invasive monitoring devices,such as central lines, cardiac pacemakers, catheters fortotal parenteral nutrition, and Swan-Ganz monitoringdevices, is associated with increasing reports of throm-bosis of the superior vena cava. Finally, aneurysms of the aorta and aortic branches are occasionally responsi-ble for causing SVCS. 2– 9

CLINICAL PRESENTATIONThe typical symptoms of SVCS are most obvious

when obstructive disease is almost complete. Patientswith SVCS most often present with complaints of facialedema an d er ythema, swelling of the n eck and/ orarms, and visible dilatation of the veins in the upperextremity. Patients with SVCS may also complain of dys-pnea, persistent cough, and orthopnea. As the diseaseprogresses, the symptoms may include hoarseness, peri-orbital edema, dysphagia, headaches, dizziness, syn-cope, lethargy, and chest pain. Oth er findings mayinclude confusion and laryngeal and/ or glossal edema.

In some cases, the nerves that cross the superiormediastinum (ie, vagus and phrenic nerves) are affect-ed by SVCS. This nerve involvement can lead toho arseness and paralysis of the diaphr agm. Th esesymptoms may be worsened by positional changes suchas bending forward, stooping, or lying down. Patientswith SVCS and vagus or phrenic nerve involvementfind significant symptom relief when they are in anupright position, and many of these patients sleep in achair to avoid dyspnea.

The venous hypertension associated with SVCS cansometimes produce cerebral vessel thrombosis andhemorrhage with dire results. Of all the symptoms of SVCS, the most life-threatening complications are cere-bral or laryngeal edema. 2–10

DIAGNOSISThe diagnosis of SVCS can be made simply on ph ysi-

cal examination. In cases in which the extent of disease

B h i m j i : S u p e r i o r V e n a C a v a S y n d r o m e : p p . 4 2 – 4 6 , 6 3

Hospital Physician Janu ary 1999 43

Table 1. Malignant Causes of Superior Vena CavaSyndrome

Malignancy Histologic Subtypes

Lung cancer Small cellLarge cell

Adenocarcinoma

Undifferentiated

Lymphoma Lymphoblastic

Lymphocytic

Mixed

Nodular

Non-Hodgkin’s

Metastatic tumor Breast

Testicular

Other malignancy Kaposi’s sarcoma

Table 2. Benign Causes of Superior Vena CavaSyndrome

Infectious

Tuberculosis

Histoplasmosis

Actinomycosis

Syphilis

Pyogenic

Tumors

Cystic hygroma

Substernal goiter

Teratoma

Thymoma

Dermoid cyst

CardiacAtr ial myxoma

Pericarditis

Intrapericardial band

Mitral stenosis

Complication of central catheter

Complication of congenital heart surgery

Complication of total parenteral nutrition line

Vascular

Aortic aneurysm

Arteriovenous fistula

Polycythemia

Idiopathic thrombosis

Other causes

Sarcoidosis

Postirradiation

Mediastinal hematoma

Pneumothorax

Behçet’s disease



is minimal, the physical findings may not be prominent

and the diagnosis may be more difficult to establish.Today, establishing the underlying diagnosis and etiolo-gy of SVCS has become more important because cer-tain disorders that cause SVCS may be more amenableto specific treatment regimens. For example, small celllung carcinoma an d lymph oma respond dramatically tochemoth erapy/ irradiation, whereas thrombosis from acentral line catheter does not respond to this treat-ment. 4–12

Laboratory StudiesChest radiography. The initial diagnostic test for sus-

pected SVCS is chest radiography. Although this test is

not specific for SVCS, chest radiography may be helpfulin identifying the cause of the disorder. Findings on chestradiography that may be helpful include widening of thesuperior mediastinum, pleural effusions, and a hilar ormediastinal mass, usually on the right side ( Table 3 ).These radiologic findings usually suggest an underlyingmalignancy, whereas calcified lymph nodes may be morepredictive of granulomatous disease. However, the resultsof chest radiography may appear normal despite anobstruction in the superior vena cava. In the absence of previous catheterization or surgery, a normal result onchest radiography in a patient with SVCS is almostpathognomonic of chronic fibrous mediastinitis. 2–12

Contrast venography. The extent and site of ob-struction as well as the nature of obstruction must beidentified when SVCS is diagnosed. Identification of these features may be achieved by a number of radio-logic imaging studies. Contrast venography can provideinformation regarding th e patency of the superior venacava, the degree of superior vena cava obstruction, andthe differentiation between intrinsic and extrinsic causi-tive factors responsible for the obstruction. Contrast

venography also provides assessment of collateral vesselformation, the degree of venous distension of the neck and arms, measurement of actual venou s pressure, an dthe presence of the intern al jugular vein reflux.

Contrast venography is essential prior to planningany surgical bypass operation. Surgical bypass opera-tions are easier to accomplish when the brachiocephal-ic veins are not involved. However, if all the intra-thoracic veins are obstructed, extrathoracic bypass oper-ations can be undertaken, but the operation is moretechn ically difficult and the results are less favorable. 4

Contrast venography is also very helpful in docu-menting obstructions caused by thrombus formation.When thrombosis is present, treatmen t with fibrinolyt-ic agents (eg, urokinase, streptokinase) is pursued andrepeat venography can be used to evaluate treatmentefficacy. In the rare cases in which fresh thrombosis is

detected in the superior vena cava, thromboembolec-tomy may be an alternate method of treatment.Radionuclide venography. Radionuclide venogra-

phy can also be used to diagnose SVCS. This test is lessinvasive th an contrast venograp hy but is also less specif-ic in defining patency and flow. Radionuclide venogra-ph y may be of value in lon g-term follow-up studies.

Computed tomography scanning. Computedtomography (CT) scanning provides an effective, non-invasive evaluation of the superior vena cava and itscollateral circulation. CT scanning provides anatomicdetails of the mediastinal and thoracic organs, allowsidentification of the cause and extent of the obstruc-

tion, documents collateral circulation, provides guid-ance for percutaneous biopsies, and guides the formu-lation for radiotherapy. 2– 6

Magnetic resonance imaging. Magnetic resonanceimaging (MRI) is also used extensively in the diagnosisof SVCS, and this test is often very important in deter-mining the cause of SVCS. Although the collateral circu-lation is easier to detect by CT scan, MRI, by virtue of itsmultidimensional capabilities, shows the relationships of vessels, lymph nodes, and other mediastinal structuresbetter than the information provided by CT scanning. 2–7

Diagnostic surgery. When all other diagnostic proce-dures fail to provide information about the cause of SVCS, surgery may be the last alternative. Exploratorythoracotomy is successful in obtaining d iagnostic tissue inpatients with SVCS in virtually every case. A surgicalapproach has several advantages—surgery allows directvisualization of the underlying disease process, assess-ment of the extent of disease involvement, and accessibil-ity for tissue biopsy. However, compared to the previouslydescribed diagnostic methods, this procedure is the mostinvasive and is associated with increased risks. 2–10



Table 3. Findings on Chest Radiography in Patientswith Superior Vena Cava Syndrome

Mediastinal widening

Pleural effusion(s)

Right hilar mass

Bilateral lung infiltrates

Cardiomegaly

Calcified paratr acheal lymph nodes

Anterior mediastinal mass

Adapted with permission from Parish JM, Marschke RF Jr, Dines DE,Lee RE: Etiologic considerations in superior vena cava syndrome.Mayo Clin Proc 1981;56:407–413.



Other diagnostic techniques. Other diagnostic tech-niques used in the evaluation of SVCS include bron-choscopy, retinoscopy, cell cytology, and mediastin-oscopy. In each case, the risks of intervention, such asbleeding and perforation of the collateral circulation,should be carefully weighed against the benefits for andsafety of the patient. Today, SVCS is seldom a medicalemergency and all efforts should be made to identify theetiology. Although the specific etiology of SVCS can beobtained by tissue diagnosis in a few cases, this proce-dure may be difficult and even hazardous to the patient.

TREATMENTDepending on the underlying condition, multiple

treatment options are available for superior vena cavaobstruction. 1, 9–19 The primary treatment options includeradiation, chemotherapy, thrombolytic therapy, antico-

agulation, stents and balloon angioplasty, and surgery.Radiation

Indications. The majority of cases of SVCS arecaused by malignancy; thus, most patients receive radi-ation treatment at some point in their illness. Emer-gency radiation treatment has been administered tosome patients with life-threatening cerebral or laryn-geal edema prior to a tissue d iagnosis of malignan cy.The relief of obstructive symptoms by radiation thera-py may provide sufficient time to work up the cause of SVCS, thus allowing for more specific treatment.Radiotherapy for the treatment of a thoracic malignan-

cy or lymphoma may be appropriate, whereas radio-therapy for the treatment of an underlying thrombosisor granulomatosis causing the obstruction would beinappropriate. Therefore, delaying treatment for 1 to2 days if necessary to establish a firm tissue diagnosis isappropriate.

Dosage. Radiation treatment is initiated at high-dose fractions daily for the first few days. This treat-ment regimen is usually followed by conventional lowdaily doses. The total dose is dependent on theun der lying tumor histology. Lymphomas are general-ly treated with 3000 to 4000 cGy, whereas carcinomasrequire 4000 to 5000 cGy or more to achieve control.Lower doses of radiation treatment may be consid-ered in cases in which systemic disease is present andshort-term palliation is the goal. Because of the limit-ed tolerance of the heart and spinal cord to radiation,short duration, high-dose programs are used. Physi-cians must be aware of this dosage intensity in treat-ing patients who are receiving chemotherapeuticagents such as doxorubicin, which can enh ance rad ia-tion toxicity. 9

Response to treatment. The response to radiation inmost patients occurs within 3 to 4 days. Resolution of facial edema an d venous distension of the u pperextremities in addition to radiographic improvementoccur within 1 to 3 weeks. Radiation therapy is usuallynot effective when thrombosis is causing the occlusion,which emphasizes the importance of a complete andthorough evaluation of the venous system in the diag-nostic workup of SVCS. When radiation therapy is suc-cessful, prolonged survival has been reported, especiallyin cases in which full courses of treatment are complet-ed. Of all patients with SVCS with malignancies, 10% to20% survive more than 2 years.

Side effects. Radiation therapy is associated with anumber of complications that include persistent fever,bleeding or superior vena cava perforation at the siteof tumor invasion, nausea, vomiting, anorexia, leuko-

penia, hemoptysis, skin irritation, and esophagitis.Pulmonary or mediastinal fibrosis may also occur as alate complication. 5,8,9

ChemotherapyChemotherapy may be used as a pr imary therapy or

as an adjunct to radiotherapy for the treatment of SVCS, depending on the underlying etiology of theobstruction. The treatment of choice for SVCS causedby mediastinal lymphoma is a combination of chemo-therapy and radiotherapy.

Thrombolytic Therapy

The role of thrombolytic therapy and subsequentanticoagulation for SVCS has become increasinglyimportant within the past decade. Pericatheter throm-bosis has been demonstrated by venography in approx-imately 50% of non-anticoagulated patients with long-term cen tral venou s catheters. Depending on theacuteness or chronicity of the thrombosis, thrombolyt-ic therapy can be used. In p atients with an acute occur-rence, thrombolytic therapy can achieve excellentresults. 1

AnticoagulationPatients with SVCS are at increased risk for deep

vein thrombosis and pulmonary embolism. In patientsfor whom thrombosis is the cause of SVCS, anticoagu-lation therapy should be administered after successfulthrombolytic treatment. Once the symptoms subsideafter thrombolytic therapy, anticoagulation should bemaintained as long as the central venous catheter ispresent. Recently, low dose warfarin h as been noted tosignificantly decrease thrombosis in patients with cen-tral venous catheters. 8





Stents and Balloon AngioplastyRecent advances in interventional radiology have

contributed expandable wire stents and balloonangioplasty. These stents can be placed across thestenotic por tion of the vena cava. The stents have littlethrombogenic potential and usually remain widelypaten t withou t nar rowing for mon ths. Today, place-ment and use of stents is limited when intraluminalthrombosis is present. However, after thrombolytictherapy, stent p lacement h as been noted to be a moresuccessful approach. After stent placement, patientsexperience instantaneous relief of symptoms. Theplacement of stents is per formed under local anesthe-sia by radiologists. The placement of a stent app ears tobe suitable therapy for the palliation of the symptomsof SVCS in cases for which other therapeutic modali-ties cannot be used or are ineffective. 11 For localized

lesions, balloon angioplasty with or without stentinghas also been shown to significantly reduce the symp-toms of SVCS.

Surgical TreatmentSurgical bypass is an additional alternative to

relieve SVCS. The surgical option is usually recom-men ded to patients with ben ign disease and to only afew patients with malignancy. Patients selected forsurgery should have the venographic sign of totalsuperior vena cava obstruction associated with throm-bosis of caval branches and distension of the veins of the upper extremity. Surgery in cases of fibrosing

mediastinitis can be extremely complicated. Becauseof the gradual onset of this disorder, the collateral cir-culation is extensive and serious bleeding can occur if any of these vessels is transected. In addition, becauseof the associated venous hypertension, all the collater-al circulation is under high p ressure.

The advantages of surgery are the expeditious anddefinitive removal of the obstruction and the conve-nience of direct tissue diagnosis. Venous thrombecto-my may be indicated in select patients with catheter-induced thrombosis of the superior vena cava whenthe foreign material can be removed in addition tothe obstructing catheter. However, most data after sur-gical bypass are obtained from patients soon aftersurgery. Long-term results after surgical bypass arelacking, chiefly because most of these patients have amalignancy and their life expectancy is sho rt. 1, 11–17

Other Treatment OptionsAdditional measures used to treat SVCS include the

administration of steroids or diuretic agents and saltrestriction. Diuretic agents may provide symptomatic

relief of edema; this relief is often immediate but notlong term. Steroids are useful in the presence of respi-ratory compromise but the long-term use of steroidsmay be considered harmful because of significant sideeffects.

PROGNOSISThe prognosis of SVCS depends on the underlying

obstruction. Malignancies of the mediastinum are themost common cause of SVCS today, and the overallprognosis for these patients is poor. In p ast studies, theaverage survival time for patients with SVCS caused bymalignancies of the mediastinum has been approxi-mately 6 to 9 months. Most patients with SVCS can besuccessfully managed with medical or radiation thera-py. For patients with severe unrelenting symptomscaused by malignant disease, thrombolysis, balloon

angioplasty, and sten ting app ear to be clinically accept-able forms of therapy. Surgical bypass is primarily re-served for the few patients with persistent symptoms of SVCS secondary to a benign pathology. HP

REFERENCES1. Doty DB, Jones KW: Superior vena cava syndrome. In

Glenn’s Thoracic and Cardiovascular Surgery, 6th ed. BaueAE, Geha AS, Hammond GL, et al, eds. Stamford, CT:Appleton & Lange, 1996: 595–602.

2. Skinner DB, Alzman EW, Scannell JG: The challenge of superior vena caval obstruction. J Thorac Cardiovasc Surg1965;49:8244–8253.

3. Parish JM, Marschke RF Jr, Dines DE, Lee RE: Etiologicconsiderations in superior vena cava syndrome. MayoClin Proc 1981;56:407–413.

4. Stanford W, Doty DB: The role of venograph y andsurgery in the management of patients with superiorvena cava obstruction. Ann Thorac Surg 1986;41:158–163.

5. Perez CA, Presant CA, Van Amburg AL: Management of superior vena cava syndrome. Semin Oncol 1978;5:123–129.

6. Schraufnagel DE, Hill R, Leech JA, Pare JA: Superiorvena caval obstruction: is it a medical emergency? Am J

Med 1981;70:1169–1174.7. Yellin A, Rosen A, Reicher t N, Lieberman Y: Superior

vena cava syndrome: the myth—the facts. Am Rev Respir Dis 1990;141:1114–1118.

8. Sculier JP, Feld R: Super ior vena cava obstruction syn-drome: recommendations for management. Cancer Treat Rev 1985;12:209–218.

9. Yahalom J: Superior vena cava syndr ome. In Cancer:Principles and Practice of Oncology, 4th ed. DeVita V Jr,Hellman S, Rosenberg S, eds. Philadelphia: JB Lippin-cott, 1993:2111–2116.

10. Doty DB, Baker WH: Bypass of superior vena cava withspiral vein graft. Ann Thorac Surg 1976;22:490–493.

11. Escalante CP: Causes and man agement of super ior venacava syndrom e. Oncology (Huntingt) 1993;7:61–68.



(continued on page 63)



12. Nieto AF, Doty DB: Superior vena cava obstruction: clini-cal syndrome, etiology, and treatment. Curr Probl Cancer 1986;10:441–484.

13. Doty DB: Bypass of superior vena cava: six years’ experi-ence with spiral vein graft for obstruction of superior

vena cava due to benign and malignant disease. J ThoracCardiovasc Surg 1982;83:326–338.

14. Doty DB, Doty JR, Jones KW: Bypass of superior venacava: fifteen years’ experience with spiral vein graft forobstruction of superior vena cava caused by benign dis-ease. J Thorac Cardiovasc Surg 1990;99:889–895.

15. Bernstein EF, Knowles HJ, Saeed M: Should superiorvena caval syndrome be treated by surgery anymore?Cardiovasc Surg 1994;2:605–606.

16. Putnam JS, Uchida BT, Antonovic R, Rosch J: Super iorvena cava syndrome associated with massive thrombosis:treatment with expandable wire stents. Radiology 1988;167:727–728.

17. Kishi K, Sonomura T, Mitsuzane K, et al: Self-expandable

metallic stent therapy for superior vena cava syndrome:clinical observations. Radiology 1993;189:531–535.

18. Venugopal C, Dake MD: Intravascular stents for th etreatment of venous obstruction. Surgical Technology

International 1993;2:273–278.19. Spiro SG, Shah S, Harper PG, et al: Treatment of

obstruction of the superior vena cava by combinationchemotherapy with and without irradiation in small-cellcarcinoma of the bronchus. Thorax 1983;38:501–505.


(from page 46)


Copyright 1999 by Turner W hite Communications Inc., Wayne, PA. All rights reserved.

hp_jan99_svcs

Documents

Transcript of hp_jan99_svcs