Impact of diabetes in long-term outcomes following intravascular brachytherapy for in-stent restenosis

BACKGROUND: In-stent restenosis (ISR) remains a significant clinical challenge after percutaneous coronary intervention (PCI), especially in patients with diabetes mellitus. Intravascular brachytherapy (IVBT) has re-emerged as a treatment for ISR, but data on its effectiveness in patient with diabetes remain limited.

METHODS: This single-center retrospective cohort study with patients undergoing IVBT for ISR. Patients were stratified according to diabetes status. The primary outcome was target lesion revascularization (TLR), with secondary endpoints including MACE, all-cause mortality, myocardial infarction (MI), and heart failure hospitalization (HFH). Statistical analysis was performed using Program R version 4.4.2.

RESULTS: Out of 227 patients, 145 (64 %) had diabetes. Baseline and procedural characteristics were generally comparable between diabetic and non-patient with diabetes. Diabetes was independently associated with higher long-term mortality (HR 3.67, 95 % CI: 1.43-9.40; p = 0.007) but not with TLR, MACE, MI, or HFH. Additional stenting (HR 3.27, p = 0.0038) and female sex (HR 3.33, p = 0.016) were also associated with increased mortality. RMST analysis demonstrated shorter 5-year survival in diabetics (-0.80 years, p < 0.001). Spline modeling revealed a non-linear increase in mortality risk with age, particularly beyond 70 years.

CONCLUSIONS: Among patients undergoing IVBT for ISR, diabetes was independently associated with increased mortality but not with ischemic and heart failure outcomes. Mortality-focused risk stratification and further studies incorporating glycemic and inflammatory markers are needed to optimize outcomes in this high-risk group.