BETA RADIATION FOR RESTENOSIS: POSITIVE TRENDS CONTINUE, PER FINAL BERT-1 RESULTS

Beta radiation administered to coronary arteries after angioplasty was not associated with poorer outcomes in patients with poorer outcome related to vessel size, reported Emory researchers and colleagues at the 71st Scientific Sessions of the American Heart Association held in November.

"Beta radiation was effective in reducing late loss (a restenosis indicator) following PTCA (i.e. balloon angioplasty) and is associated with a lower than expected rate of restenosis," reports Spencer B. King III, M.D., president of the American College of Cardiology, director of the Gruentzig Cardiovascular Disease Research Center and professor of Medicine (Cardiology) at the Emory University School of Medicine. "Lesions with less than 30 percent residual stenosis and those receiving a minimum of 14 Gy had restenosis rates in the 10 percent range."

"Late loss" is the increase noted in the diameter of the vessel's opening (lumen) several months after angioplasty when compared to the opening just after angioplasty.

The team reports the latest followup findings of the Beta Energy Restenosis Trial (BERT-1), the first Phase I trial of beta radiation for restenosis. The update includes data taken 78 angioplasty patients who received a follow-up angiogram six months after radiation treatment.

"Late loss for the entire group was 0.13 mm and the dichotomous restenosis rate (greater than 50 percent) was 17 percent. This compares with .4 mm and 42 percent for an historical control group (Lovastatin Restenosis Trial) with similar eligibility criteria as the BERT patients," they report.

BERT-1 is the first human trial to test the use of low doses of locally-delivered beta radiation for preventing restenosis that occurs in about one-quarter to one-third of patients who undergo angioplasty.

A phase III clinical trial based on BERT-1 preliminary data is now evaluating the technique in 1,100 patients at 26 medical centers in North America and Europe.

BACKGROUND

During angioplasty, a balloon-tipped catheter is threaded through arteries to sites within those arteries that nourish the heart with oxygen-rich blood. As the balloon expands, it pushes plaque against vessel walls and frees up blood flow.

Unfortunately, that same lifesaving procedure (as well as the use of tiny metal stents to prop open vessels) triggers an inflammatory response in about one-third of patients, putting them at risk for restenosis and further cardiac complications.

About 500,000 coronary angioplasties are performed domestically each year and another 500,000 are performed annually outside the United States; hence, about 300,000 persons each year are at risk for restenosis after angioplasty. In the United States, repeat angioplasties cost in the billions of dollars.