I had one of those machines and used mine about 1 week after I had Cardiac Ablation done... that was a bit uncomfortable in the beginning but I believe the fibration is great for blood circulation! just made me itch all over, but not to bad :)
I would say that you are safe. Just people with pacemakers have been adviced not to use it! maybe it is due to electro's? not sure. But I can also concur with "ED" that the stent will stay in position.
Have fun :)
I can't think of anything which would cause a stent to actually move. They are inflated into position with quite high pressure. If they are unable to get the stent to inflate and push the artery into the dilated position, they will have injected nitro to achieve this.