Table 2.

The most important anatomical factors correlated to LOV insufficiency

- absence, hypoplasia or postthrombotic septations of suprarenal or hepatic segment of IVC

- absence or (partial) hypoplasia of LRV (Figure 4)

- LRV extrinsic entrapment syndrome (“nutcracker phenomenon”) (Figure 5)

- postthrombotic septs or intraluminal webs, channels and spurs in LRV

- extrinsic compression of retroaortic LRV

- ascending course of the LRV (hilar segment below its distal part)

- distended ostium of the LOV draining into the LRV

- lack of an ostial or subostial valve in the LOV trunk

- atypical LOV drainage (the most frequent form draining into the main branch of LRV)

- combined anatomy of the LOV system (e.g., duplication of the main trunk)