Intracoronary brachytherapy, a safe, feasible option for drug-eluting stent restenosis

Many existing studies of intracoronary brachytherapy include mostly bare metal stent (BMS) in-stent restenosis or single drug-eluting stent ISR, or they need to report the number of stent layers. Data is required for this population because DES is now the predominant strategy for treating stable and unstable coronary lesions. Considering this, Stephen Ellis from Heart, Vascular, and Thoracic Institute in Cleveland Clinic, Cleveland, Ohio, and colleagues aimed to report outcomes of intracoronary brachytherapy in treating drug-eluting stent in-stent restenosis and identify correlated factors.

For this purpose, the researchers included patients who underwent ICBT for DES ISR from 2010 to 2021 in the single-institution retrospective PCI registry. Patients were treated with laser atherectomy, balloon angioplasty, and rotational atherectomy followed by ICBT at a dose of 18.4-25 Gy delivered at the ISR site with a dose estimated by the reference vessel size.

A 3-year target lesion failure rate was determined (primary outcomes). Secondary endpoints included 1-year r target lesion failure rate (TLF), all-cause mortality, target lesion revascularization (TLR), and cardiac mortality.

The study revealed the following findings:

• In total, 330 consecutive patients presented with 345 treated lesions; 70% were male, their age was 66 ± 11 years, 62% underwent previous bypass surgery, 55% were diabetic patients, and 89% were placed with at least two stent layers at the treated site.
• The rate of TLF was 18% at one year and 46% at three years.
• All-cause and cardiac mortality rates were 19.8% and 12.3% at three years.
• The number of stent layers was associated with 3-year TLF (1 layer, 33.3%; 2 layers, 47.0%, > three layers, 60.2%).
• Diabetes, repeat ICBT, final percent stenosis, lesion length, and intravascular imaging use were not correlated with the primary outcome.
• Lower ICBT dose and restenosis <1 year from the previous percutaneous coronary intervention were correlated with early (1-year) TLF.

To conclude, intracoronary brachytherapy for recurrent DES ISR provided a low recurrence rate at one year, substantially increasing by three years. Outcomes most closely corresponded with stent layers, but lower ICBT dose and early restenosis adversely impacted early TLF.

"Future work should include prospective double-blinded randomized control studies comparing intracoronary brachytherapy with a drug-coated balloon in multilayer in-stent restenosis, which holds promise in this population," the researchers wrote, testing of combination therapies, and evaluating the utility of higher dose or repeat brachytherapy dosing at set time intervals on outcomes in ISR treated with brachytherapy."

Reference:

Ho, E., Denby, K., Cherian, S., Ciezki, J., Kolar, M., Wilkinson, D., Wagener, J., Young, L., Essa, A., & Ellis, S. (2023). Intracoronary Brachytherapy for Drug-Eluting Stent Restenosis: Outcomes and Clinical Correlates. Journal of the Society for Cardiovascular Angiography & Interventions, 100550. https://doi.org/10.1016/j.jscai.2022.100550