{'fraction_non_alphanumeric': 0.07248677248677249, 'fraction_numerical': 0.05291005291005291, 'mean_word_length': 4.097035040431267, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
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.