Repeat Radiation for Recurrent In-Stent Restenosis in Patients
Repeat Radiation for Recurrent In-Stent Restenosis in Patients
In-stent restenosis (ISR) is due to neointimal hyperplasia and is shown to be effectively inhibited by vascular brachytherapy (VBT). Despite its efficacy, 20-25% of patients present with recurrent ISR following failed initial VBT. Although conventional percutaneous coronary intervention (PCI) is offered in a majority of patients to treat failed brachytherapy, the requirement for repeat revascularization is about 50%. PCI with repeat radiation to treat this difficult subset of patients is safe and feasible with target lesion revascularization (TLR) rates less than 25%. The lessons learned from randomized trials of brachytherapy, including prevention of edge effect, prolonged antiplatelet therapy and the prescription of a higher mean dose, should be applied to treat these patients with repeat radiation.
Intracoronary stents have revolutionized the treatment of coronary atherosclerosis in the last decade. Serial intravascular ultrasound (IVUS) studies have shown that in-stent restenosis (ISR) after stent implantation in coronary arteries is due to neointimal hyperplasia (NIH). Depending on the distribution of NIH as assessed by angiography, ISR is classified into four varieties: focal (≤ 10 mm), diffuse (> 10 mm but within the stent), proliferative (> 10 mm extending outside the stent) and total occlusion. Percutaneous coronary intervention (PCI) with balloon angioplasty, cutting balloon, repeat stenting, rotational atherectomy, excimer laser angioplasty, directional coronary atherectomy and vascular brachytherapy (VBT) are different modalities to treat patients with ISR. VBT has substantially reduced the rate of recurrent restenosis compared with conventional PCI for ISR in native coronary arteries and saphenous vein grafts with a sustained benefit at 5 years and is currently the only approved method to treat ISR. A meta-analysis reported an estimated 17% reduction of major adverse cardiac events (MACE) in patients undergoing VBT as compared to balloon angioplasty in ISR lesions. However, 20-25% of patients treated with VBT require repeat revascularization to the irradiated site because of stenosis recurrence dependent upon the lesion and patient characteristics. The treatment options for these patients include conventional PCI using balloon angioplasty, cutting balloon and/or stenting, repeat VBT or coronary artery bypass graft surgery (CABG). Although drug-eluting stents are a promising option, their safety and efficacy are not yet established. This article mainly discusses repeat radiation for recurrent ISR in patients who failed initial brachytherapy.
In-stent restenosis (ISR) is due to neointimal hyperplasia and is shown to be effectively inhibited by vascular brachytherapy (VBT). Despite its efficacy, 20-25% of patients present with recurrent ISR following failed initial VBT. Although conventional percutaneous coronary intervention (PCI) is offered in a majority of patients to treat failed brachytherapy, the requirement for repeat revascularization is about 50%. PCI with repeat radiation to treat this difficult subset of patients is safe and feasible with target lesion revascularization (TLR) rates less than 25%. The lessons learned from randomized trials of brachytherapy, including prevention of edge effect, prolonged antiplatelet therapy and the prescription of a higher mean dose, should be applied to treat these patients with repeat radiation.
Intracoronary stents have revolutionized the treatment of coronary atherosclerosis in the last decade. Serial intravascular ultrasound (IVUS) studies have shown that in-stent restenosis (ISR) after stent implantation in coronary arteries is due to neointimal hyperplasia (NIH). Depending on the distribution of NIH as assessed by angiography, ISR is classified into four varieties: focal (≤ 10 mm), diffuse (> 10 mm but within the stent), proliferative (> 10 mm extending outside the stent) and total occlusion. Percutaneous coronary intervention (PCI) with balloon angioplasty, cutting balloon, repeat stenting, rotational atherectomy, excimer laser angioplasty, directional coronary atherectomy and vascular brachytherapy (VBT) are different modalities to treat patients with ISR. VBT has substantially reduced the rate of recurrent restenosis compared with conventional PCI for ISR in native coronary arteries and saphenous vein grafts with a sustained benefit at 5 years and is currently the only approved method to treat ISR. A meta-analysis reported an estimated 17% reduction of major adverse cardiac events (MACE) in patients undergoing VBT as compared to balloon angioplasty in ISR lesions. However, 20-25% of patients treated with VBT require repeat revascularization to the irradiated site because of stenosis recurrence dependent upon the lesion and patient characteristics. The treatment options for these patients include conventional PCI using balloon angioplasty, cutting balloon and/or stenting, repeat VBT or coronary artery bypass graft surgery (CABG). Although drug-eluting stents are a promising option, their safety and efficacy are not yet established. This article mainly discusses repeat radiation for recurrent ISR in patients who failed initial brachytherapy.