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Acquired Diseases of the Systemic Veins
Definition
Acquired disease of the systemic veins entails obstruction—partial or complete—of the major veins of the thorax. Veins of surgical importance are the superior and inferior venae cavae (SVC and IVC). Left and right brachiocephalic veins, including the jugular-subclavian vein confluence, are major tributaries of the SVC and may be considered collectively with conditions of the SVC. Congenital anomalies of the venae cavae and axillary vein conditions such as effort thrombosis are not considered in this chapter. Obstruction results from extrinsic compression, direct invasion by disease processes, or thrombosis. SVC syndrome is the result of venous hypertension in the head, neck, and arms caused by SVC obstruction.
Historical Note
William Hunter described the first recorded case of SVC syndrome in 1757 in a patient with syphilitic aneurysm of the aorta. SVC obstruction was due to compression by the aneurysm. William Osler described SVC compression in his classic text of 1892: “Along the convex border of the ascending part [of the aorta], aneurism frequently develops, and may grow to a large size.… In this situation the sac is liable indeed to compress the superior vena cava, causing engorgement of the vessels of the head and arm.” William Stokes’ text of 1853 described SVC obstruction and noted the more frequent occurrence with cancer: “As an indication of intrathoracic tumour, an extensively varicose state of the superficial veins of the neck and thorax is probably less frequent in aneurismal than in cancerous disease.… The superior cava may be adherent to the tumour, and become narrowed, not only by pressure, but by adhesion of its internal surfaces.” Gomes and Hufnagel reviewed cases of SVC obstruction reported before 1975. Data from more than 90 publications, including 1980 cases reported in the literature since 1934, were reviewed by Ahmann in 1984. The clinical problem was reviewed by Nieto and Doty in 1986.
The first successful bypass operations for SVC obstruction by Klassen and colleagues in 1951 and Bricker and McAfee in 1952 were performed using autologous femoral vein grafts. In 1965, Hanlon and Danis used other large veins to replace or bypass the SVC, employing variously the femoral, subclavian, and jugular veins. In 1962, Benvenuto and colleagues constructed a composite panel graft from pieces of saphenous vein for replacing the SVC. The operative approach to relieve venous obstruction up to 1970 was reviewed by Haimovici and colleagues. They concluded that autologous veins are preferable for venous replacement. All reported experimental and clinical experiences with vena cava replacement or bypass up to 1974 were reviewed by Scherck and colleagues. A number of conduits had been tried, including autologous, homologous, and heterologous vein, aorta, and various synthetic materials. These authors concluded that autologous vein grafts of nearly the same size as the SVC were most likely to remain patent. To obtain such a large autologous vein usually requires a large vein from elsewhere in the body, with resultant venous drainage problems, or constructing a composite graft from a smaller vein.
Synthetic grafts are attractive because of their convenience and availability and because of the variety of sizes available. In 1973, Effeney and colleagues reported successful bypass of the SVC using polyester grafts. In 1977, Avasthi and Moghissi used a polyester graft interposed between the brachiocephalic vein on the left side and right atrial appendage to bypass the obstructed SVC. Thrombosis of polyester grafts limited success of the procedure. Expanded polytetrafluoroethylene (PTFE) was used successfully as a venous replacement conduit in experimental venous operations in dogs. Hiratzka and colleagues showed that PTFE and polyester were equally poor venous substitute conduits in the experimental setting, and that they did not approach the effective patency of autologous vein grafts. Reichle and colleagues suggested that this was because autologous vein grafts have a living endothelial surface even after initial endothelial desquamation, whereas prosthetic graft inner surfaces are composed of collagen matrix. Nevertheless, success using PTFE grafts has been reported. Antiplatelet-adhesive drugs may be of benefit in maintaining patency of PTFE grafts. Dartevelle and colleagues reported that 12 of 13 PTFE grafts used to replace the SVC were patent an average of 24 months after operation.
Composite vein grafts constructed from the saphenous or external jugular veins, in paneled or longitudinal fashion, have been used clinically for SVC bypass or replacement (both techniques are discussed in detail later in this chapter). In 1974, Chiu and colleagues reported constructing a composite vein graft from the external jugular vein, which was matched to the size of the SVC. The donor vein was opened longitudinally and wrapped in spiral fashion around a tubular stent of approximately the same size as the SVC. Vein edges were then sutured together to form the conduit. The graft occluded in the initial three experiments in dogs. After that, however, 10 consecutive grafts remained patent for up to 15 months. This report prompted successful application of this technique in humans by Doty and Baker in 1976. Successful percutaneous balloon dilatation of the SVC in a child was reported by Rocchini and colleagues in 1982. In 1986, Sherry and colleagues reported successful dilatation of an SVC stricture caused by pacemaker electrodes in an adult. In 1987, Rosch and colleagues used an expandable wire stent to treat SVC obstruction caused by malignant disease that recurred after extensive radiation therapy.
Morphology And Pathogenesis
Morphology
Superior Vena Cava
The SVC is located in the middle mediastinum and is surrounded by relatively rigid structures including the trachea, right bronchus, aorta, pulmonary trunk, and perihilar and paratracheal lymph nodes. It is thin walled, compliant, and easily compressible. Pressure within it is low. The SVC originates as the confluence of right and left brachiocephalic veins and extends for a distance of 6 to 8 cm to the right atrium. It is inside the pericardial sac for the distal several cm of its course. The azygos vein is the only major venous channel that enters the SVC; it enters posteriorly just above the pericardial reflection and is an important venous collateral pathway.
Collateral Circulation
SVC obstruction stimulates formation of extensive venous collateral circulation ( Fig. 28-1 ). The azygos vein is the only major venous channel that enters the SVC and is the most important collateral pathway. When SVC obstruction is located caudad to a patent azygos vein, there is retrograde flow through the azygos and hemiazygos veins to the lumbar veins below the diaphragm and to the IVC. When obstruction is cephalad to the patent azygos vein, collateral veins in the neck allow blood flow to enter the azygos system and continue directly into the distal SVC below the obstruction. When connection of the azygos vein to the SVC is involved in the obstruction, more complex and varied pathways must develop to drain the upper body. One prominent system consists of the internal thoracic veins, which connect to superior and inferior epigastric veins and subsequently to the IVC by way of the external iliac veins. Lateral thoracic veins drain to thoracoepigastric veins; eventually, blood may enter the femoral veins. Paraspinous veins form a collateral network that connects to the IVC via lumbar veins. The esophageal venous network also can decompress the thorax via the left gastric vein to the portal system. This pathway is not very important unless esophageal varicosities develop, and only rarely are these associated with bleeding into the gastrointestinal tract. Subcutaneous veins are a particularly important means of bringing blood flow from the upper body to below the diaphragm via the IVC.
Despite extensive collateral circulation that may develop, venous pressure in the SVC as high as 200 to 500 cm of water has been recorded. Cerebral venous decompression may be provided through a single internal jugular vein, because the veins of the right and left sides of the brain are in continuity through midline venous sinuses. Superior and inferior sagittal sinuses drain the cerebral hemispheres to the confluence of sinuses that communicate through transverse and sigmoid sinuses to either internal jugular vein. The cavernous venous sinuses also connect both sides of the brain to either internal jugular vein. Cerebral venous drainage, therefore, may remain adequate.
Pathogenesis
SVC obstruction may be caused by a spectrum of malignant ( Table 28-1 ) and benign ( Box 28-1 ) conditions. Disease in any adjacent anatomic structures may contribute to SVC syndrome. The common causes of SVC obstruction have changed over the past 50 years. In 1949, the most common were thoracic malignancy (33%), aortic aneurysm (30%), and chronic granulomatous mediastinitis (19%). Up until 1962, approximately 25% were due to benign disease ; between 1969 and 1979, that proportion decreased to 3%. Currently, malignancies account for the majority of cases. Iatrogenic causes such as indwelling catheters are becoming more frequent, and an increasing number of infectious causes are being reported in immunosuppressed patients.
Table 28-1
Malignant Causes of Superior Vena Cava Syndrome a
| n | % | |
|---|---|---|
| Bronchogenic Carcinoma | 170 | 83 |
| Undifferentiated | 19 | |
| Epidermoid | 41 | |
| Small cell | 51 | |
| Large cell | 22 | |
| Adenocarcinoma | 23 | |
| Unclassified | 14 | |
| Lymphoma | 22 | 11 |
| Lymphoblastic | 4 | |
| Lymphocytic | 6 | |
| Histiocytic | 5 | |
| Mixed | 4 | |
| Hodgkin disease | 1 | |
| Unclassified | 2 | |
| Metastatic | 11 | 5 |
| Other | 3 | 1 |
| Kaposi sarcoma | 1 | |
| Thymic | 2 |
Box 28-1
Benign Causes of Superior Vena Cava Syndrome a
a Data from Mahajan.
-
Mediastinitis (60%-70%)
-
Idiopathic
-
Histoplasmosis
-
Postradiation therapy
-
Other:
-
Tuberculosis
-
Actinomycosis
-
Syphilis
-
Sarcoidosis
-
Pyogenesis
-
Silicosis
-
-
Benign tumor:
-
Thymoma
-
Teratoma (benign)
-
Substernal thyroid goiter
-
Cystic hygroma
-
Benign Causes
Reviews from Mayo Clinic and Cleveland Clinic reported mediastinal granulomatous disease resulting in fibrosing mediastinitis as a prominent cause of benign SVC obstruction. The most common etiologic agent is histoplasmosis, which causes a caseating granulomatous process in mediastinal lymph nodes that compresses, fibroses, and contracts around the SVC and may result in secondary thrombosis. Fibrosing mediastinitis resulting from radiation therapy can be progressive and involve the SVC years after radiation treatment has been completed.
Iatrogenic causes have been increasing in importance because of increased use of invasive intravenous procedures such as cardiac pacemaker electrodes, central venous and pulmonary artery catheters, hyperalimentation and chemotherapy catheters, and extracorporeal membrane oxygenation. Mazzetti and colleagues reviewed pacemaker electrodes as a cause and found four cases of SVC obstruction among 2600 patients followed in a pacemaker clinic. They also reviewed 37 cases reported in the literature and concluded that prevalence of this complication is likely lower than 1 in 1000. A more recent publication identified 104 patients from a review of 74 different publications. Williard and colleagues reported the Memorial Sloan-Kettering Cancer Center experience with thrombosis of long-term vascular access. Occurrence of thrombosis of access catheters placed through the SVC was 7%, compared with 19% for catheters placed through the IVC. About half the thromboses involved just the catheter; the other half involved the blood vessel through which the catheter was introduced.
In infants, substantial morbidity is associated with chronic central venous access catheters. In the series of Swaniker and Fonkalsrud, IVC occlusion occurred in 4.5% and SVC occlusion in 11% of 510 infants having 756 central venous catheters placed for parenteral nutrition. Head and neck swelling developed in all with SVC occlusion, pleural effusions developed in 50%, and two infants died. Thrombosis of the SVC around these catheters is especially troublesome when they are required for permanent life support and cannot be conveniently removed. In addition, thrombosis frequently follows the entire intravascular course of the catheter and thus is extensive, involving the major SVC venous tributaries. SVC thrombosis can be an important complication after extracorporeal membrane oxygenation. Zreik and colleagues reported 7 of 60 neonates (12%; CL 7%-18%) had either complete or partial SVC obstruction. Other benign causes include benign tumor, vascular aneurysm, a variety of cardiac and pulmonary diseases, and mediastinal hematomas.
Malignant Causes
Intrathoracic malignancy now accounts for more than 90% of SVC obstructions, with bronchogenic carcinoma responsible for 67% to 82%. SVC syndrome develops in 3% to 15% of patients with bronchogenic carcinoma. Bronchogenic carcinoma cell type associated with SVC obstruction appears to be somewhat variable, which may in part be related to difference in tumor classification schemes used by different investigators. Squamous (epidermoid) carcinoma accounts for 22% to 27% of cases and appears to be relatively consistent across reports. Small-cell carcinoma is the most variable (18%-46%), although its etiologic role appears to be increasing. Lymphoma is the second most frequent cause of SVC obstruction, accounting for 5% to 15% of cases. These malignancies are located in the anterior mediastinum and produce obstruction by external compression from the front. Thoracic metastasis from extrathoracic malignancies, particularly breast and testicle, accounts for a small number of SVC obstructions.
Malignancy is also the most common cause of SVC obstruction in children. In contrast to adults, however, non-Hodgkin lymphoma is the leading etiology.
Clinical Features And Diagnostic Criteria
Superior Vena Cava Syndrome
Because extrinsic compression usually produces obstruction gradually, collateral circulation develops, the obstruction is usually well tolerated, and the patient has few if any signs and symptoms. If obstruction develops rapidly, as in malignant tumor invasion and in infants and children with central venous catheters, collateral circulation may not have time to develop and adequately decompress upper body veins. The most severe syndrome develops in cases of SVC thrombosis in which obstruction is sudden and collateral venous channels have no time to develop. Thrombosis may involve major caval tributaries as well and thus eliminate major collateral pathways. Thrombosis often accompanies SVC obstruction from any cause and compounds the problem because (1) subsequent fibrotic organization of the clot results in permanent SVC stenosis or closure, and (2) thrombosis does not respond to treatment directed at the primary disease process that resulted in the SVC obstruction.
Thoracic lymphatic ducts drain into the subclavian veins and are affected by venous hypertension associated with SVC obstruction. Pulmonary lymphatics may also be secondarily affected, leading to increased lung water and dyspnea. Respiratory insufficiency is frequently associated with acute SVC obstruction and may be difficult to manage. Chylous pleural effusion may result from thoracic lymphatic obstruction.
Symptoms
Patients with SVC obstruction usually present with a well-established syndrome that is easily recognized and unmistakable. Only rarely does complete SVC obstruction occur without noticeable signs or symptoms. The typical syndrome consists of swelling of face, neck, and arms; shortness of breath; orthopnea; and cough. Patients may notice tightness of a shirt collar and that their face is flushed and swollen, especially around the eyes. Other symptoms include hoarseness, stridor, tongue swelling, nasal congestion, epistaxis, dysphagia, headache, dizziness, syncope, lethargy, and chest pain. Symptoms are aggravated by bending forward, stooping, or lying down. Many patients become dyspneic when recumbent and must sleep in a chair.
Signs
The most common signs are dilatation and tortuosity of upper body veins, plethora or cyanosis of the face, and swelling of face, neck, or arms. Other signs include proptosis, glossal edema, rhinorrhea, laryngeal edema, mentation changes, elevated venous and cerebrospinal fluid pressures, and chylous pleural effusion. Signs and symptoms suggesting cerebral or laryngeal edema were shown to be of prognostic importance by Lochridge and colleagues. Headache, vertigo, visual disturbances, decreased mentation, stupor, somnolence, and convulsions indicate cerebral edema ; hoarseness and stridor suggest laryngeal edema.
Diagnosis
Clinical diagnosis is usually obvious. Location, degree, and cause of SVC obstruction should be characterized in every case. There is some controversy about how specific this characterization should be, because more than 90% of cases are due to malignancy. Some believe that palliation of the intrathoracic malignancy should proceed without delay. Others argue that SVC syndrome is seldom a medical emergency and should be characterized as completely as possible in an orderly fashion so that treatment can be specific. Although tissue diagnosis by biopsy can usually be obtained, in some cases it may be difficult and even hazardous to do so. Patients seek relief of symptoms of SVC and seldom complain of symptoms related to the etiologic cause of the obstruction. Treatment of SVC syndrome should be accompanied by diagnostic measures and therapy directed at the causative primary disease.
Chest Radiography
Chest radiography is helpful but not specific in diagnosing SVC obstruction. Because bronchogenic carcinoma is the most common cause of SVC syndrome, the chest radiograph often shows a right-sided hilar mass. An anterior mediastinal mass suggests lymphoma.
Venography
The most useful diagnostic procedure is bilateral arm contrast venography ( Fig. 28-2 ). It establishes:
- ▪
Location of SVC obstruction
- ▪
Degree of obstruction
- ▪
Degree of involvement of caval tributaries
- ▪
Extent of collateral venous pathways
- ▪
Extrinsic compression vs. intrinsic SVC obstruction
Identifying retrograde propagation of thrombosis that involves caval tributaries may indicate that caval obstructive symptoms are not likely to respond to nonoperative therapy.
Using venography in 36 patients, Stanford and Doty defined four patterns of venous circulation useful in planning therapy ( Box 28-2 ).
Box 28-2
Type of Superior Vena Cava Obstruction According to Venographic Pattern
Type I
-
Partial obstruction (up to 90% stenosis) of the superior vena cava (SVC) with patency of the azygos–right atrial pathway
Type II
-
Near-complete to complete obstruction (90%-100%) of the SVC with patency and antegrade flow in the azygos–right atrial pathway
Type III
-
Near-complete to complete obstruction (90%-100%) of the SVC with reversal of azygos blood flow
Type IV
-
Complete obstruction of the SVC and one or more of the major caval tributaries, including the azygos systems
Digital Contrast Angiography, Venous Phase
Digital contrast angiography in the venous phase is also helpful in assessing collateral circulation ( Fig. 28-3 ).
Two-Dimensional Echocardiography
Masses in the SVC are imaged with great clarity by two-dimensional echocardiography ( Fig. 28-4 ). The image is dynamic, so movement of obstructing lesions may be detected. It is useful in evaluating clot formation on central venous catheters and other devices.
Computed Tomography
Computed tomography (CT) provides an effective noninvasive means of analyzing the SVC and its tributaries. It has increasing importance in evaluating SVC syndrome and masses in the right atrium and IVC ( Fig. 28-5 ). Its advantages are outlined by Moncada and colleagues :
- ▪
Caval anatomy can be related to surrounding mediastinal structures.
- ▪
Mediastinal masses or lymph node pathology relative to the SVC can be located.
- ▪
Directed needle biopsy of mediastinal masses is facilitated.
- ▪
Patency of the internal jugular veins in the neck can be assessed despite extensive occlusion of tributaries of the SVC.
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