I agree with Jugular, although the safety profile is still to be determined. I think we can safely say the procedure itself, on the day that it is done, is showing to be very safe. This fits with what's already known of angioplasty being safe. But with all the travel, patients are not getting appropriate follow-up care. There is always going to be a risk of clotting, even once the right anticoagulation is determined and the right schedule of follow-up dopplers is complied with.
But not having those in place currently makes the risk of clotting much higher than it has to be.
MarkW, drsclafani has said early on in his thread that elastic recoil, which is rebound, and thrombosis are two main causes of restenosis. I too have used angioplasty and venoplasty interchangeably, it is a bit of a fine point there, but you are correct.