CONGENITAL VENOUS ANOMALIES

CONGENITAL VENOUS ANOMALIES

There are four main types of anomaly: /uni25CF aplasia; /uni25CF hypoplasia; /uni25CF duplication; /uni25CF persistence of vestigial vessels. Aplasia is most commonly seen in the inferior vena cava and has a similar presentation to the post-thrombotic limb. Membranous occlusion of the left common iliac vein (May– Thurner syndrome) often develops where the v ein passes behind the right common iliac artery (iliac vein compression syndrome). This leads to an iliac vein thrombosis, which most commonly a ff ects the left common and external iliac veins. Membranes may also narrow the hepatic veins, which can become totally occluded, leading to a Budd–Chiari syndrome. Hypoplasia results in a narrow vein, which frequently o ff ers little significant venous function and amounts to a functional venous occlusion, being circumvented by enlarged collateral venous tributaries. Duplications are quite common, with dou b le vena cava, femoral and renal veins; they often present as an incidental finding.