Review of intracoronary radiation for in-stent restenosis.

Vascular Brachytherapy using beta and gamma radiation is the standard care for patients with in-stent restenosis (ISR). The reported incidence of ISR varies from 7-37% of patients who undergo bare metal stent implantation and is dependent on patient characteristics, lesion morphology, and procedural technique. The recurrence rate after treatment for ISR varies among reported series but remains high, ranging from 35-85%, regardless of treatment modalities, including balloon angioplasty, rotational or directional atherectomy, excimer laser ablation, re-stenting and cutting balloon. The diffuse pattern of ISR (> 10 mm) is associated with even higher rates of recurrence and presents a therapeutic challenge. Serial intravascular ultrasound (IVUS) studies have demonstrated that ISR results primarily from neointimal tissue hyperplasia distributed either focally or diffusely over the entire length of the stent. Recently, new stent designs and the use of drug-eluting stents have shown promise in decreasing the overall incidence of in-stent restenosis. Yet even for the Sirolimus eluting stent, the reported restenosis in diabetes, small vessel, and long lesions range from 1518%. ISR continues to be a clinical problem. This review summarizes the clinical trials in vascular brachytherapy using beta or gamma radiation for the treatment of ISR with an emphasis on lessons learned from these trials and its role in the era of drug-eluting stents.