Effects of intracoronary beta-radiation therapy after coronary angioplasty- An intravascular ultrasound study

Background-Endovascular radiation is emerging as a potential solution for t he prevention and treatment of restenosis, Its effects on the morphology of unstented vessels cannot be determined by angiography and therefore requir e the use of intravascular ultrasound, Methods and Results-Through a 5F noncentered catheter for delivery of a Sr- 90/Y source train, 12, 14, or 16 Gy at 2 mm was delivered to native coronar y arteries after successful balloon angioplasty in 30 patients, Four patien ts required stent deployment in the first week. Quantitative coronary angio graphy and IVUS were performed during the initial procedure and at 6-month follow-up. Binary angiographic restenosis was present in 3 of 30 patients, with target lesion and vessel revascularization performed in 3 and 5 patien ts, respectively. Angiographic late loss was -0.02+/-0.60 mm, with a -0.09/-0.46 loss index, IVUS demonstrated no significant reduction in lumen area (from 5.69+/-1.72 mm(2) after treatment to 6.04+/-2.63 mm(2) at follow-up) , with no significant change in external elastic membrane area (13.71+/-4.5 4 to 14.22+/-4.71 mm(2)) over die 6-month follow-up, Wall area was 8.01+/-3 .85 mm(2) after radiation therapy and 8.19+/-3.44 mm(2) at follow-up (P=NS) . No significant differences were noted between the different dose groups. Conclusions-beta-Radiation therapy resulted in a low restenosis rate with n egligible late loss by angiography. By IVUS, beta-radiation was shown to in hibit neointima formation, with no reduction of total vessel area at 6-mont h follow-up.