It's not known why some people are more susceptible to re-narrowing of arteries after angioplasty or stenting. But scientists at the National Heart, Lung, and Blood Institute of the National Institutes of Health have found that some people prone to restenosis may have a genetic defect involving cytomegalovirus, a member of the herpes virus family. The researchers theorize that this mutation may allow for the uncontrolled growth of new tissue in the artery. They hope the gamma radiation will decrease the need for repeated surgery. The beads deliver the radiation to the cells and kill the ones that are actively forming scar tissue.
Doctors first reopen the narrowed artery segment.
Next, they use dye to determine the size of the area they need to treat, so they know how many radioactive seeds to use. The number ranges from six to 14. A catheter with the seeded wire is then inserted into the blocked area. Once the area has been treated with the Iridium-192, the catheter is removed. During the procedure, the patient is awake, just as in a standard angioplasty.