(proximal=closer to the heart; distal=further from the heart)
In the one case where there was a reported ccsvi stent migration to the heart (radeck's case), it was the distal stent that migrated.
Specifically the distal stent had been placed first (at the top of the jugular, near the jawline), then the lower stent was placed at the area of the valves. The placement of the lower stent improved the flow so much that the upper portion widened and the upper stent migrated to the heart. In order for the upper portion to widen like that, it is because it was not a true stenosis. This was in 2009.
I think, learning from that situation, it is important to get an accurate measurement of the vein (such as through IVUS) and verify that it is a true stenosis and only place a stent after all other balloonings in the vein are complete.
Really interested in hearing how the covered stent works out. I also like hearing about successful treatments of occluded areas. Just getting them open again is successful, but especially so if the covered stent does the job.