A new study shows that the use of beta radiation may prevent repeat blockages in heart vessels following angioplasty. The University of Maryland Medical Center was part of a multi-center study to evaluate the safety and effectiveness of using beta radiation to treat and prevent new blockages inside of stents. The study found that beta radiation reduced the frequency of repeat blockages by as much as 66 percent in the patients treated.
This is encouraging news for patients with coronary artery disease who are at risk of repeat blockage within a stent after an angioplasty to open the vessel. A stent is a small tube that is inserted into the vessel to help keep it open after balloon angioplasty is performed.
More than 75 percent of all patients who undergo balloon angioplasty for coronary artery disease - about 700,000 people per year in the United States, receive stents in an effort to keep the arteries open longer. However, approximately 25 percent of the patients with stents later suffer from "in-stent restenosis," a condition where the stent becomes clogged with new tissue growth. When this happens, cardiologists have to repeat the angioplasty procedure to unclog the stent.
"The early results from this study are very encouraging," says Warren Laskey, M.D., associate director of Cardiology at the University of Maryland Medical Center and professor of medicine at the University of Maryland School of Medicine. "In addition to having a great benefit for our patients, this therapy could potentially save hundreds of thousands of dollars a year." Several thousand repeat balloon angioplasties are performed each year, at an average cost of $20,000 per case, according to Dr. Laskey.
In the study, patients were treated with "radiation seeds" (small pellets that emit radiation) immediately after angioplasty to open their blocked stents. The seeds were delivered through a catheter temporarily placed inside the patient's artery and then withdrawn after a few minutes. The patients were randomized to receive either a placebo or active radiation seeds. Patients returned for follow-up examinations eight months after the therapy. Eighty-six percent of patients treated with radiation seeds had no recurrent blockage after eight months.
"Beta radiation is a highly localized form of radiation. The treatment, which is called brachytherapy, takes very little time with minimal radiation exposure to healthy tissues in the patient," says Mohan Sunthalaringam, M.D., vice chair of the Department of Radiation Oncology at the University of Maryland Medical Center and assistant professor of Radiation Oncology at the University of Maryland School of Medicine. "It also exposes the medical team to significantly less radiation than the x-ray imaging associated with angioplasty procedures."
The study, called the START trial, enrolled 476 patients at 50 medical centers in North America and Europe. The START trial is the first randomized, multi-center, placebo-controlled study to evaluate the safety and effectiveness of beta radiation in treating in-stent restenosis.
Dr. Laskey and Dr. Sunthalaringam were principal investigators of the study at the University of Maryland Medical Center. Dr. Laskey presented results from this study at the 49th Annual Scientific Sessions of the American College of Cardiology on March 12, 2000.
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