Inferior vena cava syndrome (IVCS) is a result of obstruction of the inferior vena cava. It can be caused by invasion or compression by a pathological process or by thrombosis in the vein itself.
Epidemiological data is elusive owing to the wide variety of clinical presentation. In the U.S., incidence is estimated to be at 5–10 cases per 100'000 per year.
IVCS presents with a wide variety of signs and symptoms, making it difficult to diagnose clinically.