I think it depends on the size of the clot, and how long it has been "firmed up". My stent was full of a hard clot, The Dr. was not concerned that this clot would migrate as He couldn't get thru it. They had to come from the top of the clot and stent to work on it. They did get thru, it was a long procedure. I am very thankful that the Dr. did not give up. Currently on blood thinners to keep the stent open, and I feel good.