SVC Syndrome

Presentation :

• Most cases of malignant SVC syndrome occur iso non-small cell lung Ca (50%), small cell lung Ca (25-35%) or non-Hodgkin lymphoma (10-15%).
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Pathophysiology :

• Obstruction of blood flow back to the heart via the SVC resulting from either compression by tumor collapsing the vessel (60-85% of cases), stenosis of the vessel, and/or intraluminal thrombus.
• Thrombosis may occur from malignant SVC compression (causing stasis and luminal damage); also may occur from indwelling vascular devices (CVCs, pacemaker/ICDs)
• Alternative non-malignant etiologies of obstruction include post-radiation vascular fibrosis/stenosis, Fibrosing Mediastinitis

Diagnostic Testing:

• CT chest w/ contrast is the primary imaging modality to evaluate both vascular compression and thrombus
• MR venogram may also be considered for those with contrast allergy when available
• US can play a lesser role in evaluating for thrombosis of extremity or neck/veins

Treatment :

• Compressive causes:
  • Malignancy: chemotherapy and radiotherapy may help shrink tumor
  • Endovascular stenting may allow restoration of flow through SVC more
• In cases w/ thrombosis should consider anticoagulation to prevent propagation of thrombosis into other vessels.
  • If thrombosis associated with indwelling device, feasibility of removing the indwelling device should be considered
• Elevate head to promote venous drainage and decrease head/neck venous pressures
• Avoid use of vessicant medications through upper extremity IVs which may have extended vascular dwell times given sluggish flow through venous system
• No strong data to support diuresis as elevated venous pressures are localized and not a result of systemic volume overload

Prognosis:

References: