Radiation Therapy May Help Mend a Broken Heart
Moses and his Lenox Hill colleagues were involved in the Gamma One Trial, a study evaluating the use of coronary gamma-radiation therapy in 131 patients who had renarrowing of the arteries following the implantation of stents. Compared with an equal number of patients with similar symptoms who were not treated with radiation therapy, those receiving gamma radiation had significantly lower rates of artery reclogging. But they also had a higher rate of blood clotting, known as thrombosis, which resulted in more heart attacks. Approximately 10% of the patients who received gamma radiation experienced heart attacks during the follow-up period, compared with 4% of those not given radiation therapy.
Moses says the study group has subsequently solved the blood-clotting problem by implanting fewer stents and treating patients with anticlotting drugs for longer periods. Some 500 radiated patients treated in this manner had late thrombosis rates that were no different from patients who did not receive radiation, he says.
"In retrospect, it is obvious that patients should stay on [anticlotting] therapy, but we certainly didn't know that when we started out," he says. "We believe the strategy we have now is safe and effective. Patients who would have previously faced bypass surgery when stenting failed now have an effective technique to avoid surgery."
In a separate study, conducted at research centers across Europe, the use of beta radiation for the prevention of artery reclogging following angioplasty was evaluated. Again, researchers found a dramatic reduction in arterial renarrowing after beta radiation was given.
Like the U.S. group, the European researchers reported a big increase in blood clotting among patients receiving stents, but they also concluded that this problem could be successfully addressed with an appropriate drug-treatment strategy.
"The concerns we had about late thrombosis in the Gamma One Trial, and in previous studies, have been settled now that we have extended the [anticlotting] therapy and have tried to eliminate the introduction of new stents," Gamma One Trial author Martin D. Leon, MD, tells WebMD. "There are about 150,000 cases of [artery reblocking after stenting] each year in the U.S. alone, so you can imagine that a fair number of patients are now going to get this therapy."