Stanford and Doty classified the venographic pattern seen in patients with superior vena cava obstruction. The pattern correlates with a number of clinical features such as cerebral symptoms. The authors are from the University of Iowa.
Parameters:
(1) percent occlusion of the superior vena cava
(2) flow through the azygous vein
(3) obstruction of major collateral veins
Percent Occlusion
Flow in Azygous Vein
Obstruction of Collaterals
Type
< 90%
NA
NA
I
90 - 99%
antegrade into right atrium
NA
II
90 - 99%
retrograde into iliac veins
none
III
100%
NA
>= 1 obstructed
IV
where:
• Collaterals include the azygous vein, accessory hemiazygous vein and the connecting veins between them.
• Alimi et al have nice diagrams illustrating the flows in Figure 1, pages 288-289.
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