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StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-.
Marc T. Seligson ; Scott M. Surowiec .
Last Update: September 26, 2022 .
Superior vena cava (SVC) syndrome is a collection of clinical signs and symptoms resulting from partial or complete obstruction of blood flow through the SVC. This obstruction is most commonly a result of thrombus formation or tumor infiltration of the vessel wall. The superior vena cava is formed by the junction of the left and right innominate (brachiocephalic) veins and is tasked with returning blood from the head, neck, upper extremities, and torso to the heart. Today, this syndrome is most commonly seen secondary to malignancy, although there has been a more recent rise in benign etiologies. This activity describes the causes, pathophysiology, and presentation of superior vena cava syndrome and highlights the role of the interprofessional team in its management.
Evaluate the causes of superior vena cava syndrome. Identify the pathophysiology of superior vena cava syndrome. Assess the treatment options for superior vena cava syndrome.Communicate the importance of improving care coordination among interprofessional team members to improve outcomes for patients affected by superior vena cava syndrome.
Superior vena cava (SVC) syndrome is a collection of clinical signs and symptoms resulting from partial or complete obstruction of blood flow through the SVC. This obstruction is most commonly a result of thrombus formation or tumor infiltration of the vessel wall. The SVC is formed by the junction of the left and right innominate (brachiocephalic) veins and is tasked with returning blood from the head, neck, upper extremities, and torso back to the heart (see Image. Veins and Arteries of the Neck). Today, this syndrƒome is most commonly seen secondary to malignancy, although there has been a recent rise in benign etiologies. The resulting venous congestion produces a clinical scenario of increased upper-body venous pressure. The most common signs and symptoms include face or neck swelling, upper extremity swelling, dyspnea, cough, and dilated chest vein collaterals.[1][2][3]
SVC syndrome saw a dramatic decrease throughout the twentieth century. Today, the majority of SVC syndromes are the result of mediastinal malignancies, primarily among which are small-cell bronchogenic carcinoma. The second most commonly associated malignancy is non-Hodgkins lymphoma, followed by metastatic tumors. In addition, benign or nonmalignant causes of SVC syndrome now comprise at least 40% of cases. Iatrogenic thrombus formation or SVC stenosis is a growing etiology due to pacemaker wires and semipermanent intravascular catheters used for hemodialysis, long-term antibiotics, or chemotherapy.[4][5]
An estimated 15,000 cases of SVC syndrome occur each year in the United States, with studies pointing to increasing frequency due to the concomitant rise in the use of semipermanent intravascular catheters. The incidence of SVC syndrome reported in the literature ranges from 1 in 650 to 1 in 3100 patients.
The SVC is part of the low-pressure venous system containing thin walls susceptible to damage by various pathologic mechanisms. These mechanisms can be divided into 3 categories: compromised vessel anatomy, impaired venous flow, and diminished vessel wall integrity. These mechanisms often coexist in patients presenting with SVC syndrome. Extrinsic compression and obstruction of the SVC by a mass in the mediastinum is the most common cause of SVC syndrome. This is often associated with malignancy; however, a variety of nonmalignant masses and dilation of the overlying aorta can cause compression. A growing proportion of SVC syndromes are now associated with occlusive venous thrombus formation that compromises venous flow back to the heart. The increasing use of indwelling intravascular devices such as catheters, pacemakers, and implantable cardioverter-defibrillator (ICD) leads to this growth. Resultant venous wall inflammation, fibrosis, and eventual thrombus lead to vessel stenosis.[6][7][8]
SVC syndrome diagnosis is largely based on a patient’s history and physical findings, which often develop over days to weeks. This insidious onset results from a collateral vascular network that diverts blood to the lower body, where it is then returned to the heart through the inferior vena cava, azygos vein, and intercostals. The clinical findings in SVC syndrome are closely linked to venous congestion and the resultant elevation in venous pressures seen in the upper body. A careful physical examination is often sufficient to rule out a cardiogenic origin of the patient’s symptoms. The most common presenting symptoms of SVC syndrome are face/neck swelling, distended neck veins, cough, dyspnea, orthopnea, upper extremity swelling, distended chest vein collaterals, and conjunctival suffusion. Other less common symptoms of SVC syndrome include stridor, hoarseness, dysphagia, pleural effusion, head plethora, headache, nausea, lightheadedness, syncope, change in vision, altered mental status, upper body edema, cyanosis, papilledema, stupor, and coma. Some rare but serious clinical consequences reported in SVC syndrome include cerebral edema and upper respiratory compromise secondary to edema of the larynx and pharynx.
Patients with high clinical suspicion for SVC syndrome should undergo imaging of the upper body and vasculature. Ultrasound of the jugular, subclavian, and innominate veins can help to identify a thrombus within the vessel lumen. Radiographic imaging and MRI also play a critical role in providing additional information about the SVC obstruction's location, severity, and etiology. CT of the chest with collateral vessels is associated with a diagnostic sensitivity of 96% and a specificity of 92%. Venography is widely accepted as the gold standard for visualizing and diagnosing a venous obstruction. This modality should be used concomitantly with endovascular intervention for patients with a severe presentation of SVC syndrome.[9][10]
Following a clinical diagnosis, supportive therapy and medical management are commonly initiated. This involves elevating the patient’s head as a simple maneuver to decrease venous pressure. Further management is guided by the patient’s underlying SVC syndrome etiology. For patients with thrombus related to an indwelling intravascular device, removal should be considered along with anticoagulation therapy and catheter-directed thrombolysis. Multidisciplinary treatment planning for those with obstruction due to malignancy is important as tumor type and staging can help to guide appropriate chemotherapy or radiation therapy. Open surgical repair through bypass grafting with spiral saphenous vein, femoral vein, polytetrafluoroethylene (PTFE) graft, or Dacron graft has traditionally been considered to overcome SVC obstruction. However, this is now reserved for cases where recanalization through endovascular repair is either impossible or has previously failed. With expanding treatment options for both benign and malignant etiology, endovascular therapy is now widely considered the first-line treatment for SVC syndrome. Less invasive endovascular management can offer patients immediate relief of symptoms. Acute or subacute thrombus can be managed with catheter-based thrombolysis or thrombectomy before venoplasty and stent placement.[11][12][13]
The differential diagnosis for superior vena cava syndrome includes the following:
