Prolonged Antiplatelet Therapy to Prevent Late Thrombosis After Intracoronary γ-Radiation in Patients With In-Stent Restenosis

Publisher Website
Google Scholar
Abstract
Background —Intracoronary γ-radiation reduces recurrent in-stent restenosis. Late thrombosis (>30 days after radiation therapy) is identified as a serious complication. The Washington Radiation for In-Stent Restenosis Trial (WRIST) PLUS, which involved 6 months of treatment with clopidogrel and aspirin, was designed to examine the efficacy and safety of prolonged antiplatelet therapy for the prevention of late thrombosis. Methods and Results —A total of 120 consecutive patients with diffuse in-stent restenosis in native coronary arteries and vein grafts with lesions 192 Ir seeds was positioned to cover the treated site, and a dose of 14 Gy to 2 mm was prescribed. Patients were discharged with clopidogrel and aspirin for 6 months and followed angiographically and clinically. All patients but one tolerated the clopidogrel. The late occlusion and thrombosis rates were compared with the γ-radiation–treated (n=125) and the placebo patients (n=126) from the WRIST and LONG WRIST studies (which involved only 1 month of antiplatelet therapy). At 6 months, the group receiving prolonged antiplatelet therapy had total occlusion and late thrombosis rates of 5.8% and 2.5%, respectively; these rates were lower than those in the active γ-radiation group and similar to those in the placebo historical control group. Conclusions —Six months of clopidogrel and aspirin and a reduction in re-stenting for patients with in-stent restenosis treated with γ-radiation is well tolerated and associated with a reduction in the late thrombosis rate compared with a similar cohort treated with only 1 month of clopidogrel and aspirin.