Intravascular Brachytherapy for In-Stent Restenosis in Patients With Chronic Kidney Disease.

Background: In-stent restenosis (ISR) remains a significant challenge in coronary intervention, particularly among patients with chronic kidney disease (CKD) who exhibit altered inflammatory responses and accelerated vascular calcification. Vascular brachytherapy has reemerged as a potential treatment modality for recurrent ISR. This study evaluates the clinical outcomes of vascular brachytherapy for ISR in patients with and without CKD. Methods: We conducted a retrospective analysis of 227 patients (54 in CKD and 173 in non-CKD groups) who underwent vascular brachytherapy for coronary ISR between June 2016 and January 2024 at the Houston Methodist Hospital. Patients were stratified based on the presence of CKD, defined as an estimated glomerular filtration rate of <60 mL/min/1.73 m2 for at least 3 months. The primary end point was target lesion revascularization (TLR). Secondary end points included major adverse cardiovascular events, its components and all-cause mortality at 1 year. Results: Baseline demographic characteristics and procedural characteristics were similar between groups, except for a significantly higher prevalence of diabetes in the CKD group (83.3% vs 57.8%; P = .001). At 1-year follow-up, major adverse cardiovascular events (MACE) rates were significantly higher in patients with CKD than those in patients without CKD (63.0% vs 32.9%; P = .0003), primarily driven by higher TLR rates (31.5% vs 17.9%; P = .038). Bleeding complications occurred exclusively in the CKD group (5.6% vs 0%; P = .013). In multivariable analysis, male sex was associated with a significantly lower risk of TLR in patients with CKD (hazard ratio, 0.15; 95% CI, 0.04-0.64; P = .010). Conclusions: Despite similar procedural characteristics, patients with CKD experience significantly higher rates of adverse events following vascular brachytherapy for ISR than those without CKD patients. The nearly doubled rate of MACE and higher TLR rates suggest that the inflammatory milieu associated with CKD may overcome the antiproliferative effects of radiation therapy. These findings highlight the need for refined interventional strategies and comprehensive cardiovascular risk management in this high-risk population with MACE.