Beta Radiation in Lesions Greater Than 15 mm: A START Subgroup
Background: Following conventional treatment of in-stent restenosis, clinical restenosis may be as high as 60% in long lesions. Results of the START (Stents and Radiation Therapy) trial indicate that intracoronary beta radiation yields significant reductions in the incidence of recurrent in-stent restenosis as compared with placebo.
Methods and Results: In a subgroup of the START trial, results in patients with coronary lesions > 15 mm in length (n = 239) were analyzed to assess treatment with a 30 mm, beta radiation source train. Patients received an intracoronary catheter with Strontium/Yttrium (n = 128) or placebo (n = 111). Clinical and angiographic parameters were evaluated at 8 months. Patient demographics and angiographic lesion characteristics were similar between the 2 groups. The mean lesion lengths were comparable in the radiation and placebo groups (21.5 ± 5.2 mm versus 22.1 ± 5.5 mm, respectively; p = 0.3873). A total of 14.1% and 22.5% of patients in the radiation and placebo groups, respectively, received new stents (p = 0.09). At 8 months, radiation therapy yielded significant reductions in major adverse cardiac events (16.4% versus 29.7%; p = 0.014), target vessel revascularization (14.8% versus 28.8%; p = 0.0085) and target lesion revascularization (11.7% versus 27.9%; p = 0.0015). There was no stent thrombosis, and binary restenosis rates were significantly lower in the radiation group compared to placebo.
Conclusion: Intracoronary beta radiation may prevent early recurrent restenosis in long lesions. Additional study is required to determine if the reduction persists throughout mid- to long-term follow-up.
While stents have reduced the risk of restenosis, they induce neointimal hyperplasia, and rates of in-stent restenosis following intervention may be as high as 60%, particularly in long lesions. Studies of gamma-radiation therapy following treatment for in-stent restenosis have demonstrated considerable reduction in the incidence of clinical and angiographic restenosis as compared with placebo. Late thrombosis has been a problem, and while its origin is poorly understood, it appears to be linked to the short duration of ticlopidine therapy, placement of new stents or the use of multiple coronary stents.
Beta-radiation yields less tissue penetration than gamma sources and may offer practical advantages over gamma radiation. Recently, the Stents and Radiation Therapy (START) trial (n = 476) compared the safety and effectiveness of intracoronary beta radiation using a Strontium/Yttrium (Sr/Y) isotope with a 28-year half-life and a placebo control following successful percutaneous intervention in patients with in-stent restenosis. Beta radiation reduced binary stent restenosis by 66% [from 41.2% with placebo to 14.2% in radiation-treated patients (p < 0.001)]. The present analysis describes the results of intervention in a subgroup of the START trial in which patients at higher risk for restenosis with lesions > 15 mm were treated with intracoronary Sr/Y beta radiation or placebo.
Background: Following conventional treatment of in-stent restenosis, clinical restenosis may be as high as 60% in long lesions. Results of the START (Stents and Radiation Therapy) trial indicate that intracoronary beta radiation yields significant reductions in the incidence of recurrent in-stent restenosis as compared with placebo.
Methods and Results: In a subgroup of the START trial, results in patients with coronary lesions > 15 mm in length (n = 239) were analyzed to assess treatment with a 30 mm, beta radiation source train. Patients received an intracoronary catheter with Strontium/Yttrium (n = 128) or placebo (n = 111). Clinical and angiographic parameters were evaluated at 8 months. Patient demographics and angiographic lesion characteristics were similar between the 2 groups. The mean lesion lengths were comparable in the radiation and placebo groups (21.5 ± 5.2 mm versus 22.1 ± 5.5 mm, respectively; p = 0.3873). A total of 14.1% and 22.5% of patients in the radiation and placebo groups, respectively, received new stents (p = 0.09). At 8 months, radiation therapy yielded significant reductions in major adverse cardiac events (16.4% versus 29.7%; p = 0.014), target vessel revascularization (14.8% versus 28.8%; p = 0.0085) and target lesion revascularization (11.7% versus 27.9%; p = 0.0015). There was no stent thrombosis, and binary restenosis rates were significantly lower in the radiation group compared to placebo.
Conclusion: Intracoronary beta radiation may prevent early recurrent restenosis in long lesions. Additional study is required to determine if the reduction persists throughout mid- to long-term follow-up.
While stents have reduced the risk of restenosis, they induce neointimal hyperplasia, and rates of in-stent restenosis following intervention may be as high as 60%, particularly in long lesions. Studies of gamma-radiation therapy following treatment for in-stent restenosis have demonstrated considerable reduction in the incidence of clinical and angiographic restenosis as compared with placebo. Late thrombosis has been a problem, and while its origin is poorly understood, it appears to be linked to the short duration of ticlopidine therapy, placement of new stents or the use of multiple coronary stents.
Beta-radiation yields less tissue penetration than gamma sources and may offer practical advantages over gamma radiation. Recently, the Stents and Radiation Therapy (START) trial (n = 476) compared the safety and effectiveness of intracoronary beta radiation using a Strontium/Yttrium (Sr/Y) isotope with a 28-year half-life and a placebo control following successful percutaneous intervention in patients with in-stent restenosis. Beta radiation reduced binary stent restenosis by 66% [from 41.2% with placebo to 14.2% in radiation-treated patients (p < 0.001)]. The present analysis describes the results of intervention in a subgroup of the START trial in which patients at higher risk for restenosis with lesions > 15 mm were treated with intracoronary Sr/Y beta radiation or placebo.
Source...