Analysis of venacavograms in 27 patients with superior vena caval obstruction revealed the following four patterns of venous collateral return: type I, partial obstruction (up to 90% stenosis) of the superior vena cave with patency of the azygos vein; type II, near-complete to complete obstruction (90-100%) of the superior vena cava with patency and antegrade flow through the azygos vein and into the right atrium; type Ill, near-complete to complete obstruction (90-100%) of the superior vena cava with reversal of azygos blood flow; type IV, complete obstruction of the superior vena cave and one or more of the major caval tributaries, including the azygos system. These patterns correlate well with the patients’ clinical courses and can be used to identify patients who are at risk of developing cerebral and airway compromise and therefore would benefit from superior vena cava bypass surgery.
This paper is on the superior vena cava which is the next level down stream toward the heart from the veins we are talking about, it goes directly into the heart at the right atrium from there to be recirculated.
Note that the development of collateral veins is a key diagnostic that leads the clinican to decide that treatment is needed, and in these terminal patients it was done to give them some symptom relief.
but notice that cerebral symptoms including acute confusion were the reason it was done..........
most of them had a tumor pressing on the vena cava.
You could argue that this is a more acute aggressive version of what we have, our refux and blockage is not so close to the heart but one level back closer to the brain so it is less dramatic. I suspect brain plasticity may play a role in making it more benign as well. I also think it develops more slowly so there is no dramatic "she could talk and think last week" thing going on; with MS it is more like "she could talk and think 20 years ago". Note these people are too sick to live long at all. They do not get MS diagnoses, though I wonder if they were left in that situation they might develop typical MS type lesions if they lived long enough.
here's another paper where stents were used to open the VC in the same type of situation.
http://radiology.rsnajnls.org/cgi/conte ... /176/3/665
so there is another situation similar to Jeff Sharon and I wherein the stent is placed inside the vein to keep it open in the face of pressure from outside structures (vs a plaque inside the vein).