Background: Ionizing radiation has been shown to reduce neointimal formation after balloon angioplasty in experimental models of restenosis. This study was designed to evaluate the feasibility, safety, and effectiveness of intracoronary radiation therapy (ICRT) after percutaneous transluminal coronary angioplasty (PTCA) for preventing restenosis in human coronary arteries.
Methods and results: Twenty-one patients (22 arteries) with unstable angina underwent standard balloon angioplasty. ICRT was performed with the use of an 192Ir source wire that was hand delivered to the angioplasty site. Angiographic follow-up was performed at 24 hours, between 30 and 60 days, and at 6 months. Angioplasty was successful in 19 of 22 lesions, and insertion of the radioactive source wire was successful at all treated sites. Angiographic study at 24 hours demonstrated early late loss of the luminal diameter from 1.92+/-0.55 to 1.40+/-0.27 mm. Between 30 and 60 days, repeat angiography demonstrated total occlusion in 2 arteries, a new pseudoaneurysm in 1 artery, and significant dilatation at the treatment site in 2 additional vessels. At > or = 6 months' follow-up, all remaining arteries (n=20) maintained patent, with a mean lumen diameter of 1.65+/-0.8 mm. The calculated late lumen loss was 0.27+/-0.56 mm, and the late loss index was 0.19. Clinical events at 1 year included myocardial infarction in 1 patient, repeat angioplasty to the treated site in 3 patients, and persistent angina in 7 patients.
Conclusions: These preliminary results demonstrate that ICRT after coronary intervention is feasible and is associated with an acceptable degree of complications and lower rates of angiographic restenosis indexes.