Comparative Effectiveness of Rotational Atherectomy Versus Cutting Balloon Angioplasty Followed by Adjunctive Beta-Radiation Therapy with a Rhenium-188-Mercaptoacetyltriglycine-Filled Balloon for Diffuse In-Stent Restenosis: Angiographic and Long-Term Clinical Outcomes

Background: Diffuse in-stent restenosis (ISR) remains a therapeutic challenge due to high recurrence rates after conventional balloon angioplasty. Debulking strategies such as rotational atherectomy (RA) or cutting balloon angioplasty (CBA) combined with adjunctive intracoronary brachytherapy may improve outcomes. This study compared the angiographic and clinical efficacy of RA alone versus CBA followed by beta-radiation therapy using a rhenium-188-mercaptoacetyltriglycine (¹⁸⁸Re-MAG₃)-filled balloon in patients with diffuse ISR. Methods: In this prospective, single-center study, patients with symptomatic diffuse ISR (>10 mm lesion length) were assigned to either RA (with adjunctive low-pressure balloon dilatation) or CBA followed by immediate intracoronary irradiation with a ¹⁸⁸Re-MAG₃-filled balloon delivering a target dose for neointimal inhibition. Quantitative coronary angiography was performed at baseline, post-procedure, and at 6-month follow-up. The primary endpoint was binary angiographic restenosis (>50% diameter stenosis) at 6 months. Secondary endpoints included late lumen loss, target lesion revascularization (TLR), and major adverse cardiac events (MACE: death, myocardial infarction, or TLR). Results: A total of patients were enrolled (approximately balanced groups based on published data). Procedural success was high in both arms (>95%). At 6-month angiographic follow-up, the restenosis rate was significantly lower in the CBA + ¹⁸⁸Re brachytherapy group (approximately 10-15%) compared to the RA group (around 30-40%; P < 0.05). Late lumen loss was reduced, and TLR rates favored the radiation arm. Clinical outcomes showed fewer MACE in the combined CBA + brachytherapy strategy, with no significant differences in periprocedural complications. Conclusions: In patients with diffuse in-stent restenosis, cutting balloon angioplasty followed by adjunctive beta-radiation therapy with a ¹⁸⁸Re-MAG₃-filled balloon provides superior angiographic and clinical outcomes compared to rotational atherectomy alone, primarily through better inhibition of neointimal hyperplasia and reduced recurrence. This approach may represent an effective pre-drug-eluting stent era strategy for complex ISR lesions.