Prolonged antiplatelet therapy to prevent late thrombosis after intracoronary gamma-radiation in patients with in-stent restenosis - Washington Radiation for In-Stent Restenosis Trial PLUS 6 months of clopidogrel (WRIST PLUS)

Background-Intracoronary gamma -radiation reduces recurrent in-stent resten osis. Late thrombosis (> 30 days after radiation therapy) is identified as a serious complication. The Washington Radiation for In-Stent Restenosis Tr ial (WRIST) PLUS, which involved 6 months of treatment with clopidogrel and aspirin, was designed to examine the efficacy and safety of prolonged anti platelet therapy for the prevention of late thrombosis. Methods and Results-A total of 120 consecutive patients with diffuse in-ste nt restenosis in native coronary arteries and vein grafts with lesions < 80 mm underwent percutaneous coronary transluminal angioplasty, laser ablatio n, and/or rotational atherectomy. Additional stents were placed in 34 patie nts (28,3%). After the intervention, a closed-end lumen catheter was introd uced into the artery, a ribbon with different trains of radioactive Ir-192 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 co mpared with the gamma -radiation-treated (n = 125) and the placebo patients (n = 126) from the WRIST and LONG WRIST studies (which involved only 1 mon th of antiplatelet therapy). At 6 months, the group receiving prolonged ant iplatelet therapy had total occlusion and late thrombosis rates of 5.8% and 2.5%, respectively; these rates were lower than those in the active gamma -radiation group and similar to those in the placebo historical control gro up. Conclusions-Six months of clopidogrel and aspirin and a reduction in re-ste nting for patients with in-stent restenosis treated with gamma -radiation i s well tolerated and associated with a reduction in the late thrombosis rat e compared with a similar cohort treated with only 1 month of clopidogrel a nd aspirin.