Long-term outcomes after treatment of diffuse in-stent restenosis with rotational atherectomy followed by beta-radiation therapy with a 188Re-MAG3-filled balloon

Background: Intracoronary radiation therapy for in-stent restenosis has been demonstrated to reduce restenosis and major adverse cardiac events. However, long-term angiographic and clinical outcomes after beta radiation therapy have not been sufficiently evaluated. Methods: We evaluated the long-term angiographic and clinical outcomes of 50 consecutive patients who had received beta-radiation therapy with a 188Re-MAG3-filled balloon after rotational atherectomy for diffuse in-stent restenosis (lesion length>10 mm) in native coronary arteries. The radiation dose was 15 Gy at a depth of 1.0 mm into the vessel wall. Results: The mean lesion length was 25.6±12.7 mm. Radiation was delivered successfully to all patients without any procedural or in-hospital complications. At the 6-month angiogram, the restenosis rates was 10% (5/50). There were no major adverse cardiac events (MACE), such as death, myocardial infarction, and target lesion revascularization (TLR) by 6-month follow-up. Long-term clinical follow-up data were obtained in all patients during 30.1±4.5 months. No myocardial infarction and one noncardiac death occurred during follow-up. Two-year follow-up angiogram was performed in 26 (58%) of 45 patients who showed a patent radiation segment at the 6-month angiogram. Significant narrowing of diameter stenosis of more than 50% occurred in 6 (23%) of 26 patients between 6 and 24 months after beta-radiation. Late TLR was performed in 6 patients. The rate of 30-month death-free survival and MACE-free survival were 98.0±2.0% and 86.9±5.0%. Conclusion: Beta-radiation using a 188Re-MAG3-filled balloon after rotational atherectomy is associated with favorable long-term angiographic and clinical outcomes.