I dont know the answer either (well it is a forum!) but the CAUSE seems to me to be the big issue, followed by the extent of the thrombus and any secondary damage.
And no, sitting in front of a computer is not the same! The reason for thrombembolic phenomena is multifactorial but includes the effect of depressuriasation. It is a real issue. We now have a faily precise protocol to advise patients.
The big mystery is why pilots dont get so many DVTs........