The High-Tech Heart: Radiation Therapy to Prevent New Blockages after Angioplasty
Balloon angioplasty is a common procedure that’s performed when heart arteries are clogged with plaque. During the procedure, a catheter carrying a deflated balloon on its tip is inserted into the clogged artery. The balloon is then inflated. It opens up the artery, widening the passage for blood flow and improving circulation. Angioplasty can give highly successful results, but sometimes, even when the angioplasty was initially successful, arteries can become re-blocked. Re-blockage can be caused by additional cholesterol and fatty deposits, clot formation or thickening of the artery wall, which can result after the wall is stretched during angioplasty. This re-blockage is called restenosis.
To prevent restenosis, cardiac surgeons sometimes insert what’s called a “stent” into the artery during the angioplasty. Stents are small mesh tubes that can help prop the arterial passage open and keep it open. The trouble is, in some people, the stents themselves can create scar tissue that causes restenosis.
Radiation prevents cell growth
It’s normal for a thin layer of cell tissue to form around the stent. But when the cell growth continues unchecked, tissue fills the entire stent itself, making another angioplasty necessary.
Researchers have discovered that injecting a small dose of radiation into the stent can stop the excessive cell growth. This process is called radiation therapy. You’re probably more familiar with the idea of using radiation for cancer patients, who frequently undergo radiation therapy to stop the growth of cancer cells. The concept is the same for overgrowth of cells in the scar tissue in and around the stent.
Some of the complications you may associate with radiation therapy for cancer, such as making tissue sensitive and causing extreme fatigue, are not side affects of radiation that prevents restenosis. Radiation therapy for heart patients is highly targeted to a specific segment of the artery and doesn’t affect other parts of the body.
Not necessary for all patients
Radiation therapy isn’t necessary for everybody who has angioplasty with stents. About 85 to 90 percent of the people who have the stents placed don’t have trouble afterwards. But many cardiac surgeons do use the radiation therapy the first time around with people who have diabetes, because diabetics have a 30 to 40 percent rate of restenosis with stents.
Recovery time is the same
Patients who have radiation therapy with their stents don’t take any longer to recover. The procedure itself takes about 15 minutes longer, and they have to take anti-clotting drugs longer than people who don’t have radiation.
The American Heart Institute; The National Heart, Lung, and Blood Institute; Texas Heart Institute, Heart Owner’s Handbook. Johan Wiley and Sons, New York, New York, 1996.