Thoracic surgeons are routinely involved with patients with superior vena cava obstruction (SVCO) and on occasion are called upon to resect the superior vena cava (SVC) in the course of treatment. This chapter will summarize overall management principles, indications for SVC resection, the proper patient evaluation with coordination of care, intraoperative considerations, and postoperative care principles to ensure a successful outcome.
General Principles and Guidelines
General thoracic surgeons serve the patient with SVCO in three ways. First and most commonly they are involved in the workup and diagnosis of the patient who presents with the spectrum of SVCO symptoms and a chest mass on radiographic studies. Second, a patient with severe symptoms from SVCO will need expedient management of life-threatening symptoms. Similar to approaching the patient with esophageal cancer a “Captain of the Ship” is needed in both above situations which often will require the coordination of care of a multidisciplinary team (oncology, radiation oncology, interventional radiology, pathology) and nonoperative means of treatment will often be utilized (radiation, chemotherapy, stenting, thrombolytic therapy). Last, the thoracic surgeon may be called upon to resect the SVC for benign or malignant disease.
When called upon to evaluate the patient with SVCO the thoracic surgeon should classify the patient by severity of the SVCO symptoms, achieve an expedient tissue diagnosis, coordinate the care of the multidisciplinary team of physicians, and evaluate if there is any role for therapeutic surgical intervention especially if the patient has a diagnosis of non–small-cell lung cancer (NSCLC), thyroid/thymic cancer, or germ cell neoplasm.
Approximately 35% of SVCO patients will be asymptomatic or have only mild symptoms of head and neck edema and cyanosis. Moderate-to-severe symptoms will be seen in 60% of patients manifested by increasing degrees of cerebral edema resulting in visual disturbances, headache, laryngeal edema, and diminished cardiac reserve. Patients will present with life-threatening symptoms 5% of the time.1
See proposed grading system for superior vena cava syndrome (Table 164-1).
|0||Asymptomatic||10||Radiographic superior vena cava obstruction in the absence of symptoms|
|1||Mild||25||Edema in head or neck (vascular distention), cyanosis, plethora|
|2||Moderate||50||Edema in head or neck with functional impairment (mild dysphagia, cough, mild or moderate impairment of head, jaw or eyelid movements, visual disturbances caused by ocular edema)|
|3||Severe||10||Mild or moderate cerebral edema (headache, dizziness) or mild/moderate laryngeal edema or diminished cardiac reserve (syncope after bending)|
|4||Life threatening||5||Significant cerebral edema (confusion, obtundation) or significant laryngeal edema (stridor) or significant hemodynamic compromise (syncope without precipitating factors, hypotension, renal insufficiency)|
As proposed by Detterbeck, patients with grade 4 symptoms require a venogram, urgent stenting, and possible thrombolytics. Patients with grade 1, 2, and 3 symptoms require tissue diagnosis and multidisciplinary discussion to decide on treatment modality based on particular tumor response to a specific modality. Surgery is usually considered for NSCLC, thymoma, thymic carcinoma, or a residual germ cell mass. Chemoradiotherapy is the mainstay of treatment for patients with small-cell lung cancer, lymphoma, or germ cell tumor. Supportive care only may be indicated for patients with treatment refractory tumors or poor performance status.
See treatment algorithm of superior vena cava syndrome (Table 164-2).
Indications: Malignancy is the most common (90%) cause of SVCO usually due to bronchogenic carcinoma (>50% cases) with mediastinal lymphomas or germ cell neoplasms accounting for the rest.2 Occasionally, patients with SVCO of a benign etiology (sarcoidosis, histoplasmosis, fibrosing mediastinitis, iatrogenic thrombosis) may benefit from venous reconstruction to establish flow from the superior venous system to the right atrium.3,4
When approaching the patient with a malignant tumor involving the SVC, complete resection of all diseases should be the goal. Overall, patients should have acceptable ECOG performance status of 0 to 1 because of the potential moderate morbidity associated with surgery. For patients with a diagnosis of lung cancer, acceptable pulmonary functions on the higher end of normal are required because of the extent of resections and possible need for sacrifice of the phrenic nerve.5 Right-sided lung cancers with SVC involvement require a lobectomy at the minimum, and sleeve resection or pneumonectomy is often required.
Goals are to obtain a tissue diagnosis, establish the proper stage of disease, facilitate planning of the vascular reconstruction if needed, and predict the ability to achieve a complete (R0) resection.
Core-needle biopsy (CT or US guided), mediastinoscopy,6,7 mediastinotomy bronchoscopy, EBUS, EUS, and VATS biopsies can all be utilized to confirm the diagnosis and lymph node or other sites of potential metastatic involvement. Fusion PET-CT can focus on areas of potential metastatic sites.
The surgeon must have complete understanding of the venous anatomy involved, in particular the site and extension of venous obstruction, the presence of proximal thrombosis, the degree of venous collateralization (complete or incomplete), and the site where the proximal graft anastomosis can be made. Besides initial workup with plain chest roentography a chest CT scan with contrast, magnetic resonance venography,8 or superior vena cavography (simultaneous injections through both upper limbs)2 can delineate the exact location of venous obstruction, collateralization present, presence of proximal thrombosis, confirm patency of the jugular and axillary veins if needed, and identify sites of proximal graft anastomosis.
ECHO is often useful to assess biventricular function, confirm that there is no thrombosis with extension into the right atrium, and assess for any degree of tricuspid regurgitation. Brain CT or MRI should be done to rule out metastatic disease or any intracranial pathology that may increase brain edema during SVC cross clamping.
When there is no metastatic disease on preoperative staging, an R0 resection is thought possible, and the patient has an acceptable performance status, the patient should be offered resection. A carefully thought-out operation planned in advance will go a long way to insure success and minimize SVC clamp times if needed.
A double-lumen endotracheal tube is useful in obtaining better exposure of the operative field through one-lung ventilation. A Foley catheter is placed to monitor urine output. Electrocardiographic monitoring is standard and especially helpful if inadvertent clamping of the SA node is done. Radial arterial line monitoring is needed to track and manipulate mean arterial pressures to maintain adequate central perfusion. A venous pressure line in the forearm, antecubital fossa, or right internal jugular can monitor the pressure in the cephalic territory and help in assessing the arterial-venous brain parenchymal gradient. In addition to the usual upper extremity vascular access, large bore lower extremity access should also be available if caval clamping is required. Temporary inflow occlusion tolerance will be facilitated by intravascular fluid expansion. Vasoactive agents can also be used once volume status is optimized.
See intraoperative checklist (Table 164-3).
|Double-lumen endotracheal tube|
Arterial line for mean arterial perfusion pressure monitoring
Lower extremity venous access
Intravascular fluid expansion
Cephalic territory venous pressure monitoring
Reverse Trendelenburg position if SVC clamping required
Vasoactive agents to elevate cerebral profusion pressure
Intravenous heparin sodium (50–100 units/kg) 5–10 min before vascular occlusion
Clamp SVC proximal to azygos vein to preserve collateral circulation and reduce cerebral edema if possible
Absolutely avoid clamping at cavo-atrial junction to avoid injury to the SA node
Hyperventilation to reduce vasogenic cerebral edema
Safety briefing with operative team at the beginning and throughout the case concerning procedure steps, equipment and materials needed, cerebral protection issues, and plans to address hemodynamic instability
Surgical approach to the tumor is based on location of the mass in question, involvement of associated structures besides the SVC, and degree of vascular exposure needed. Bronchogenic tumors usually require a right thoracotomy through the fifth intercostal space, which allows access to the right hilum, SVC, and RA. Control of the left brachiocephalic vein can be difficult through this approach unless an extended hemiclamshell incision is added. Patients with an anterior mediastinal mass will be approached through a median sternotomy as this provides access to both brachiocephalic veins, innominate vein, SVC, right atrium, and entire anterior mediastinum. The incision also can be extended into the neck if needed.