Intracoronary brachytherapy (ICBT) is an effective treatment for restenosis (ISR) of bare metal stents, but its utilization has waned due to the advent of drug eluting stents (DES). The purpose of this study is to evaluate the predictors of ICBT in preventing ISR in DES.
A retrospective analysis was performed on 211 consecutive patients treated on an IRB approved protocol using ICBT for DES ISR for the last 5 years. All patients received ICBT, after balloon angioplasty, using Sr-90 with a centering balloon and an automated delivery device. A dose of 18.4Gy or 23Gy at 2mm depth was delivered based upon the diameter of the injured vessel. The patients were also divided into 2 groups based on the presence (Group A) or absence (Group B) of clinic restenosis (ISR) post ICBT, and the two groups were compared for baseline characteristics. All patients were followed for MACE for 2 years.
The mean age of patients was 66.7 years. At 1 and 2 years post ICBT, clinical ISR occurred in 17.3% and 25.5% of all patients. At 2 years, cumulative MACE incidence was 31.4% with a TVR of 15.2%. Lesion length and vessel diameter were found to be significantly higher in group A patients (Table 1). All-cause mortality at 1[2.7% vs. 3.4% p=0.549] and 2[2.3% vs. 3.5% p=0.551] years was not significantly different between group A and B patients. Prior CABG was found to be associated with a lower incidence of DES ISR post ICBT (p=0.006,multivariate analysis).
ICBT is a safe and effective therapy for DES ISR. We propose that it should be utilized as first-line therapy. Presence of pre-existing CABG may be a negative predictor for DES ISR post ICBT. This may be due to the larger collateral presence. This study represents the largest single center ICBT registry for DES ISR to date, however more prospective data will be needed to determine the optimal patient for treatment.