Scripps Coronary Radiation to Inhibit Proliferation Post Stenting II - SCRIPPS II
Randomized safety and efficacy trial of gamma irradiation using Ir-192 source
Gamma radiation using Ir-192 can reduce restenosis rates after angioplasty for diffuse in-stent restenosis
Patients Enrolled: 100
Mean Follow Up: 9 months
Mean Patient Age: 62 years (mean)
restenotic lesion in native coronary or vein graft reference vessel 3.0-3.5 mm lesion length <65 mm
Patients post intervention are randomized to treatment with Ir-192 gamma emitter versus placebo
At nine-month follow-up, 20 patients (41.7 percent) had undergone TVR, a 33 percent reduction compared with placebo. Intracoronary ultrasound was used to prescribe dosimetry so that the target furthest from the source would receive 800 cGy while the target closest to the source would not receive more than 3000 cGy. The mean radiation dose delivered at 2 mm from the source was 1397 + 229 cGy (range 888 to 2295). Target vessel revascularization decreased significantly as radiation dose increased. A dose of <1200 cGy at 2 mm from the source was associated with a TVR probability of 66 percent while a dose of >1500 cGy resulted in a TVR probability of 25 percent. For every increase in dose of 100 cGy, the odds of TVR decreased by 26 percent.
For the treatment of in-stent restenosis, gamma radiation using Ir-192 was associated with a reduced rate of target vessel revascularization. There was a suggestion that higher radiation doses were associated with lower restenosis rates. However, SCRIPPS II was not designed to be a dose-finding study and the number of patients receiving Iridium-192 was rather small.
Clinical Topics: Invasive Cardiovascular Angiography and Intervention
Keywords: Follow-Up Studies, Coronary Disease, Probability, Angioplasty, Iridium Radioisotopes, Gamma Rays, Stents
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