Failure patterns after intravascular brachytherapy for in‐stent coronary restenosis

One strategy to improve the effectiveness of intravascular brachytherapy (IVBT) is to study its failures. Previous investigations described mostly discrete, focal recurrences, typically at the proximal or distal edges of the irradiated segment after plain angioplasty or bare metal stents. We reviewed failure patterns of 30 unselected drug-eluting stent (DES) patients who had follow-up angiograms for recurrence within their IVBT-treated vessel.Records of 53 unselected IVBT patients treated between 2016 and 2021 were reviewed. Thirty of the 53 patients had at least one subsequent percutaneous intervention (PCI) for in-stent restenosis (ISR) after IVBT. Angiographic findings of those 30 patients with ISR within their previously irradiated vessel are reported here.Of the 30 patients, 21 (70%) developed recurrent ISR within the irradiated segment. Six of the 21 patients who failed within the irradiated segment also experienced ISR proximal or distal to the irradiated segment. Only 15 patients (50%) failed exclusively within the irradiated segment. In nine patients (30%), restenosis occurred proximally and/or distally to the irradiated segment, but not inside of the irradiated segment itself.We have shown here that 50% of failures after coronary IVBT for DES ISR occur exclusively within the irradiated segment. An additional 20% of patients had failure within and outside of the irradiated segment. These percentages suggest that a higher radiation dose might improve the long-term patency rates, a conclusion that should be tempered by the lack of universal follow-up.