Five-year clinical follow up after intracoronary radiation for the prevention of in-stent restenosis

Intracoronary radiation therapy (IRT), utilizing both gamma- and beta-emitting radiation sources, is considered to be a safe and effective treatment for in-stent restenosis (ISR). Although no longer in clinical use, a significant number of patients were treated in the past with IRT, and their long-term outcomes have not been well documented. The aim of the present analysis was to document the long-term outcomes of all patients who underwent IRT at our institution for the prevention of recurrence of ISR. Data were collected from 132 patients (148 irradiated lesions) treated with IRT at our institution between March 1999 and January 2004. Clinical and angiographic data were collected over a 5-year period. Patients were divided into 2 groups: those with failed IRT (n ≤ 65), defined as a procedure that resulted in a major adverse cardiac event: death, myocardial infarction, target lesion revascularization, target vessel revascularization or coronary artery bypass graft surgery at any time during the follow-up period, and patients with successful IRT (n ≤ 67). Both groups were identical regarding baseline clinical and angiographic characteristics, with the exception of a higher percentage of multivessel disease and diffuse restenosis in patients who failed IRT (p ≤ 0.01). At 1-year follow up, slightly less than half (43%) of those patients in the failure group experienced a major adverse cardiac event. During the long-term follow up period, half of all patients who underwent IRT at our institution experienced a major adverse cardiac event, 61 patients (46%) either died or underwent a revascularization procedure, 16 patients (24%) had a myocardial infarction or died, and 55 patients (42%) required repeat coronary revascularization. The average time to develop a major adverse cardiac event was 14.6 ± 15 months. Therefore, during long-term follow up following IRT for the prevention of ISR, half of all patients developed a major cardiovascular event, mainly due to the need for repeat revascularization procedures.