Outcomes of Intracoronary Brachytherapy for In-Stent Restenosis.

Because of limited alternative options, intracoronary brachytherapy (ICBT) continues to be used for treating in-stent restenosis (ISR). We examined the indications, characteristics, and outcomes of ICBT in consecutive patients who underwent ICBT for ISR between January 2014 and December 2023 at a tertiary care center. During the study period 343 patients underwent ICBT of 502 lesions. The median patient age was 67 [60, 74] years, 73.4% of the patients were men, 77.3% had prior myocardial infarction, and 49.4% had prior coronary artery bypass graft surgery. The most common target vessel was the right coronary artery (38.7%) and 7.37% of lesions were in bypass grafts (33 saphenous vein grafts, 4 arterial grafts). A diffuse ISR pattern was found in 76.2% of lesions. Among the study lesions, 58.0% had 2 stent layers and 20.6% had 3 or more stent layers. Technical success was achieved in 96.1% of lesions. Follow-up was available for all patients with a mean follow-up of 701.5 days. The 3-year incidence of target lesion failure (TLF), target vessel myocardial infarction, and major adverse cardiac events were 36.4%, 17.2%, and 45.6%, respectively. In multivariable analysis, higher brachytherapy radiation dose was associated with a lower risk for TLF (aHR per 10 Gy: 0.73; 95% CI 0.54-0.93; p = 0.048). Repeat ICBT procedures had a higher incidence of TLF over 3 years compared with lesions treated with ICBT for the first time (log-rank test: p = 0.008). In conclusion, the 3-year incidence of TLF after ICBT is 36.4% and was lower with higher radiation dose and higher in lesions retreated with ICBT.