What is the role of a double or duplicated inferior vena cava in the etiology of deep venous thrombosis (DVT)?

Updated: Jun 05, 2019
  • Author: Kaushal (Kevin) Patel, MD; Chief Editor: Barry E Brenner, MD, PhD, FACEP  more...
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Answer

A double or duplicated inferior vena cava results from lack of atrophy in part of the left supracardinal vein, resulting in a duplicate structure to the left of the aorta. The common form is a partial paired inferior vena cava that connects the left common iliac and left renal veins. When caval interruption, such as placement of a filter, is planned, these alternate pathways must be considered. As an alternative, the inferior vena cava may not develop. The most common alternate route for blood flow is through the azygous vein, which enlarges to compensate. If a venous stenosis is present at the communication of iliac veins and azygous vein, back pressure can result in insufficiency, stasis, or thrombosis. [64]

In rare cases, neither the inferior vena cava nor the azygous vein develops, and the iliac veins drain through internal iliac collaterals to the hemorrhoidal veins and superior mesenteric vein to the portal system of the liver. Hepatic venous drainage to the atrium is patent. Because this pathway involves small hemorrhoidal vessels, thrombosis of these veins can cause severe acute swelling of the legs.


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