In the hands of cardiologists, tiny balloons on the ends of hair-like wires open blocked coronary arteries of more than 1 million Americans each year. Cardiologists tried to significantly reduce restensosis rates by using tiny flexible girders called stents inserted into the arteries to hold them open after angioplasty. Stents reduced the rate of restenosis, but one-fifth of the arteries still clogged again. Cardiologists now believe that a new approach, using radiation either with or without stents, can reduce the restenosis rate even more. Based on studies on a small group of patients, minute doses of radiation administered for as little as five minutes at the time of angioplasty show such promise.
Radiation has the same potential for making a huge impact on angioplasty as stents have done.
In angioplasty, a tiny balloon is threaded through the arteries to the site of blockage, where it is inflated, pushing the atherosclerotic plaque to the side. While this process opens a larger channel for blood to flow through, it also stimulates the abnormal growth of new endothelial cells, which can then re-block the treated artery. This process is called neointimal hyperplasia. Researchers believe that radiation, when delivered at the same time the artery is re-opened, interferes with the endothelial cells proliferative response. While this effect was shown in a very small number of patients, the results are promising, and exciting.