Three-year clinical and angiographic follow-up after intracoronary radiation : results of a randomized clinical trial.
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BACKGROUND: Although several early trials indicate treatment of restenosis with radiation therapy is safe and effective, the long-term impact of this new technology has been questioned. The objective of this report is to document angiographic and clinical outcome 3 years after treatment of restenotic stented coronary arteries with catheter-based (192)Ir. METHODS AND RESULTS: A double-blind, randomized trial compared (192)Ir with placebo sources in patients with previous restenosis after coronary angioplasty. Over a 9-month period, 55 patients were enrolled; 26 were randomized to (192)Ir and 29 to placebo. At 3-year follow-up, target-lesion revascularization was significantly lower in the (192)Ir group (15. 4% versus 48.3%; P<0.01). The dichotomous restenosis rate at 3-year follow-up was also significantly lower in (192)Ir patients (33% versus 64%; P<0.05). In a subgroup of patients with 3-year angiographic follow-up not subjected to target-lesion revascularization by the 6-month angiogram, the mean minimal luminal diameter between 6 months and 3 years decreased from 2.49+/-0.81 to 2.12+/-0.73 mm in (192)Ir patients but was unchanged in placebo patients. CONCLUSIONS: The early clinical benefits observed after treatment of coronary restenosis with (192)Ir appear durable at late follow-up. Angiographic restenosis continues to be significantly reduced in (192)Ir-treated patients, but a small amount of late loss was observed between the 6-month and 3-year follow-up time points. No events occurred in the (192)Ir group to suggest major untoward effects of vascular radiotherapy. At 3-year follow-up, vascular radiotherapy continues to be a promising new treatment for restenosis. (+info)
Localized intracoronary gamma-radiation therapy to inhibit the recurrence of restenosis after stenting.
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BACKGROUND: Although the frequency of restenosis after coronary angioplasty is reduced by stenting, when restenosis develops within a stent, the risk of subsequent restenosis is greater than 50 percent. We report on a multicenter, double-blind, randomized trial of intracoronary radiation therapy for the treatment of in-stent restenosis. METHODS: Of 252 eligible patients in whom in-stent restenosis had developed, 131 were randomly assigned to receive an indwelling intracoronary ribbon containing a sealed source of iridium-192, and 121 were assigned to receive a similar-appearing nonradioactive ribbon (placebo). RESULTS: The primary end point, a composite of death, myocardial infarction, and the need for repeated revascularization of the target lesion during nine months of follow-up, occurred in 53 patients assigned to placebo (43.8 percent) and 37 patients assigned to iridium-192 (28.2 percent, P=0.02). However, the reduction in the incidence of major adverse cardiac events was determined solely by a diminished need for revascularization of the target lesion, not by reductions in the incidence of death or myocardial infarction. Late thrombosis occurred in 5.3 percent of the iridium-192 group, as compared with 0.8 percent of the placebo group (P=0.07), resulting in more late myocardial infarctions in the iridium-192 group (9.9 percent vs. 4.1 percent, P=0.09). Late thrombosis occurred in irradiated patients only after the discontinuation of oral antiplatelet therapy (with ticlopidine or clopidogrel) and only in patients who had received new stents at the time of radiation treatment. CONCLUSIONS: Intracoronary irradiation with iridium-192 resulted in lower rates of clinical and angiographic restenosis, although it was also associated with a higher rate of late thrombosis, resulting in an increased risk of myocardial infarction. If the problem of late thrombosis within the stent can be overcome, intracoronary irradiation with iridium-192 may become a useful approach to the treatment of in-stent restenosis. (+info)
Serial intravascular ultrasound analysis of the impact of lesion length on the efficacy of intracoronary gamma-irradiation for preventing recurrent in-stent restenosis.
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BACKGROUND: The relation between lesion length and effectiveness of brachytherapy is not well studied. METHODS AND RESULTS: We compared serial (postintervention and follow-up) intravascular ultrasound findings in 66 patients with native coronary artery in-stent restenosis (ISR) who were treated with (192)Ir (15 Gy delivered 2 mm away from the radiation source). Patients were enrolled in the Washington Radiation for In-Stent Restenosis Trial (WRIST; ISR length, 10 to 47 mm; n=36) or Long WRIST (ISR length, 36 to 80 mm; n=30). External elastic membrane, stent, lumen, and intimal hyperplasia (IH; stent minus lumen) areas and source-to-target (intravascular ultrasound catheter to external elastic membrane) distances were measured. Postintervention stent areas were larger in WRIST and smaller in Long WRIST patients (P:<0.0001). At follow-up, maximum IH area significantly increased in both WRIST and Long WRIST patients (P:<0.0001 for both), but this increase was greater in Long WRIST patients (P:=0.0006). Similarly, minimum lumen cross-sectional area significantly decreased in both WRIST and Long WRIST patients (P:<0.05 and P:<0.0001, respectively), but this decrease was more pronounced in Long WRIST patients (P:=0.0567). The maximum source-to-target distance was longer in Long WRIST than in WRIST, and it correlated directly with ISR length (r=0.547, P:<0.0001). Overall, the change in minimum lumen area and the change in maximum IH area correlated with the maximum source-to-target distance (r=0.352, P:=0.0038 and r=0.523, P:<0.0001 for WRIST and Long WRIST, respectively). The variability (maximum/minimum) in IH area at follow-up also correlated with the maximum source-to-target distance (r=0.378, P:<0.0001). CONCLUSIONS: Brachytherapy may be less effective in longer ISR lesions because of the greater variability and longer source-to-target distances in diffuse ISR. (+info)
Edge stenosis and geographical miss following intracoronary gamma radiation therapy for in-stent restenosis.
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OBJECTIVES: We sought to determine the relationship between geographical miss (GM) and edge restenosis (ERS) following intracoronary radiation therapy. BACKGROUND: Edge restenosis may be a limitation of intracoronary irradiation to prevent in-stent restenosis (ISR). Inadequate radiation source coverage of the injured segment (GM) has been proposed as a cause of ERS. We studied the relationship between GM and ERS following 192Ir treatment of ISR. METHODS: There were 100 patients with native vessel ISR in WRIST (Washington Radiation for In-Stent Restenosis Trial), in which patients with ISR were first treated with conventional techniques and then randomized to gamma irradiation (192Ir) or placebo. Geographical miss was defined as segments proximal or distal to the treated lesion that were subjected to injury during primary intervention but were not covered by the radiation source. RESULTS: Geographical miss was documented in 56 of 164 edges (34%). Edge restenosis was noted at eight of 80 radiated edges and in four of 84 placebo edges. In the irradiated group, ERS was observed in 21% of edges with GM and in 40% of edges without GM (p = 0.035). In contrast, in the placebo group, ERS was observed in only 7% of edges with GM and in 4% of edges without GM (p = NS). The late edge lumen loss was higher in the irradiated group with GM as compared to placebo with GM (0.74 +/- 0.57 vs. 0.41 +/- 0.50 mm, p = 0.016). CONCLUSIONS: Edge restenosis following gamma irradiation treatment of ISR is related to GM: a mismatch between the segment of artery injured during the primary catheter-based intervention and the length of the radiation source. (+info)
Interstitial brachytherapy using iridium-192 for malignant brain tumors: clinical results.
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OBJECTIVE: To determine the effects and toxicity of interstitial brachytherapy using iridium-192 on brain malignant gliomas. METHODS: Between January 1992 and January 1995, 56 patients with anaplastic astrocytoma and glioblastoma multiforme were treated with stereotactic brachytherapy using temporary high-activity iridium-192 sources. RESULTS: The median survival for patients receiving brachytherapy was 28 months. The survival rates at 1, 2, 3 years were 92.8%, 83.9% and 71.4% respectively. CONCLUSIONS: Brachytherapy may improve the control of local tumor and prolong the survival, when used in deep malignant brain gliomas, by temporary implanted high doses of iridium-192 sources. (+info)
192Ir endovascular irradiation prevents restenosis after balloon angioplasty in rabbit.
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OBJECTIVE: To examine the effect of endovascular irradiation on restenosis after balloon angioplasty in rabbit. METHODS: After the establishment of rabbit iliac atherosclerosis model, balloon angioplasty was performed at the lesion segment of the iliac artery. Rabbits were randomly divided into three groups: control group, 10 Gy irradiated group and 18 Gy irradiated group. Endovascular irradiation was performed for irradiated groups at the dilated sites by introducing the 192Ir radioactive guidewire through a catheter. After four weeks, the animals were killed and the target segments were cut down. Histopathologic and morphometric analyses were carried out. RESULTS: The mean final lumen area in the 18 Gy group was larger than that in the control or 10 Gy group (P < 0.05). The intimal area in the 18 Gy group was smaller (P < 0.05). CONCLUSIONS: 192Ir endovascular irradiation may prevent restenosis after balloon angioplasty. The effect is related to the delivered dose. The mechanism is involved in inhibition of neointimal proliferation. (+info)
Quantitative angiographic methods for appropriate end-point analysis, edge-effect evaluation, and prediction of recurrent restenosis after coronary brachytherapy with gamma irradiation.
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OBJECTIVES: The study was done to investigate the relationship between clinical restenosis and the relative angiographic location of the recurrent restenotic lesion, after treatment of in-stent restenosis with vascular brachytherapy in the Washington Radiation for In-Stent Restenosis Trial (WRIST). BACKGROUND: Intracoronary radiation therapy reduces recurrence of in-stent restenosis. We investigated the above objective in patients enrolled in WRIST. METHODS: The WRIST study randomized 130 patients to double-blinded therapy with gamma irradiation (iridium-192 [(192)Ir]) versus placebo after interventional treatment of diffuse in-stent restenosis. After the intervention and at follow-up, three vessel segments were individually analyzed with quantitative coronary angiography: 1) the "stent," 2) the "radiation ribbon," and 3) the "ribbon+margin" segment (including 5 mm on either end of the injured or radiation-ribbon segment). Receiver operator curves (ROC) were used to assess the value of the follow-up percent diameter stenosis (DS) for each of the three analyzed segments in predicting target vessel revascularization (TVR). RESULTS: (192)Ir reduced recurrent restenosis (23.7% vs. 60.7%, p < 0.001) and the length of recurrent restenosis (8.99 +/- 4.34 mm vs. 17.54 +/- 10.48 mm, p < 0.001) at follow-up compared to placebo. Isolated stent edge (3.4%) and ribbon edge (1.7%) restenoses were infrequent in both groups. The best angiographic surrogate of TVR was the 50% follow-up DS obtained from the ribbon+margin analysis (ROC area 0.806). CONCLUSIONS: In WRIST, not only was (192)Ir therapy effective in reducing restenosis, but it also reduced the lesion length of treatment failures by 50%, and it was not associated with edge proliferation. The restenosis rate obtained from the vessel segment inclusive of the dose fall-off zones was the best correlate of TVR and should become a standard analysis site in all vascular brachytherapy trials. (+info)
High-dose-rate brachytherapy in the treatment of carcinoma of the prostate.
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BACKGROUND: Although radical prostatectomy for localized disease is considered as a standard of care, external-beam radiotherapy and brachytherapy are equally effective. We report on the technique and preliminary results of high-dose-rate (HDR) brachytherapy using a temporary iridium-192 implant technique. METHODS: The authors reviewed the literature on the techniques, treatment protocols, and results of HDR brachytherapy in the treatment of carcinoma of the prostate, and they report their own protocols, technique, and results. RESULTS: The combination of HDR brachytherapy and external irradiation has been well tolerated by all 200 patients in our series, with less than 3% grade 3 late complications and with 95% PSA relapse-free survival with a median follow-up of 24 months. CONCLUSIONS: HDR brachytherapy may be the most conformal type of irradiation in the treatment of carcinoma of the prostate regardless of tumor size, anatomical distortion, and organ mobility. (+info)