Intracoronary brachytherapy. Treatment of in-stent restenosis with the Beta-Cath system. Initial experience in Latin America.

OBJECTIVE: To assess the safety and efficacy of intracoronary brachytherapy using the Beta-Cath system for preventing recurrence of in-stent restenosis (ISR), by analyzing clinical, angiographic, and intracoronary ultrasound (ICUS) results. METHODS: This study assessed 30 patients with ISR in native coronary arteries who underwent balloon catheter angioplasty followed by intracoronary beta radiation with the Beta-Cath system (90Sr/Y). RESULTS: The study comprised complex, extensive (18.66 +/- 4.15 mm) restenotic lesions, 77% of which were of the diffuse-proliferative type. Brachytherapy was successful in 100% of the cases. The mean radiation dose used was 20.7 +/- 2.3 Gy, released for a mean period of 3.8 +/- 2.1 minutes. On late follow-up, the in-stent minimum luminal diameter (MLD) slightly decreased (from 1.98 +/- 0.30 mm to 1.84 +/- 0.39 mm at 6 months; P=0.13), with a late loss of 0.14 +/- 0.18 mm. The intrasegmentary MLD was significantly smaller than the in-stent diameter (1.55 +/- 0.40 mm vs 1.84 +/- 0.39 mm; P=0.008), and was associated with a more significant late loss (0.40 +/- 0.29 mm vs 0.14 +/- 0.18 mm; P=0.0001). On ICUS, a mild increase of 6.8 +/- 14.3 mm3 in the neointimal tissue was observed at 6 months (P=0.19), and the percentage of volumetric obstruction increased by 4.7 +/- 7.5%. Binary restenosis and revascularization of the target vessel recurred in 17% of the cases; late occlusion associated with myocardial infarction occurred in 1 case (3%). Event-free survival was 80%. CONCLUSION: The management of in-stent restenosis with intracoronary beta radiation proved to be a safe and effective procedure, with a high rate of immediate success, representing a therapeutic option for inhibiting neointimal hyperplasia.