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At least 793 records · Page 44Linked to original sources
PubMed2000

Beta-radiation for coronary in-stent restenosis.

To determine the feasibility and safety of an intracoronary beta-radiation device in preventing the recurrence of in-stent restenosis (ISR) after successful angioplasty, we studied 37 patients treated with beta-radiation (30-mm strontium-90 source) after angioplasty. The mean reference diameter was 2.9 +/- 0.5 mm, and 62% of lesions were diffuse, including four total occlusions. Beta-radiation was successfully delivered in 36 of 37 (97%) cases. Over the course of 7.1 +/- 4.5 mo follow-up, there were no myocardial infarctions and three deaths: one from preexisting malignancy, one from progressive cardiac failure, and one from sudden cardiac death. Target vessel revascularization (TVR) was performed in seven of 36 (19%) patients. Thirty patients underwent angiography at 6 mo; three (10%) experienced restenosis (diameter stenosis > 50%) at the target site, four (13%) had edge stenoses, and two (7%) had late (> 1 mo) thrombotic occlusions. Beta-radiation for ISR is associated with encouragingly low rates of target lesion restenosis and TVR. Further improvements are needed to solve the limitations of the edge effect and late occlusion.

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PubMed1982

Correlation between growth rate and cytochemistry in Morris hepatomas.

The correlation between the cytochemistry (glycoprotein, glycogen, glucose-6-phosphatase, catalase, alkaline phosphatase) and the growth rate of the fast-growing Morris hepatoma 3924A and the slow-growing Morris hepatoma 9618A was studied by utracytochemical techniques. By the chromic acid-phosphotungstic acid technique, acid glycoprotein is stained in glycocalyx, Golgi saccules and vesicles, and secretory granules of the tumor cells of both hepatomas. However, the hepatoma 3924A cells contain thicker glycocalyx and more numerous glycoprotein-rich granules than hepatoma 9618A cells. Abundant alpha and beta glycogen particles are found in hepatoma 3924A. Moderate glucose-6-phosphatase activity is observed in the cisternae of endoplasmic reticulum and nuclear envelope of hepatoma 9618A, but it is totally absent in hepatoma 3924A. High catalase activity is present in numerous peroxisomes of hepatoma 9618A. Hepatoma 3924A contains only a few catalase-positive microperoxisomes. Weak to moderate alkaline phosphatase is present in the plasma membrane and nuclear envelope of hepatoma 9618A cells, while hepatoma 3924A shows no activity of the enzyme. All the cytochemical parameters except glycoprotein show an inverse relationship with the growth rate of the hepatomas. The higher intracellular glycoprotein content of hepatoma 3924A may be related to differences in cell coat secretion (composition and activity) from the slower-growing hepatoma 9618A

Alkaline Phosphatase↗
PubMed2002

Repeated intracoronary beta radiation for recurrent in-stent restenosis.

More than 70% of percutaneous coronary interventions are followed by a stent implantation. In-stent restenosis still occurs in 20-30% of patients and remains a therapeutic challenge. At present only vascular brachytherapy has been shown to be an effective treatment option. We report here one case of recurrent in-stent restenosis after vascular brachytherapy that was successfully treated by a second beta radiation treatment.

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PubMed2002

Intracoronary brachytherapy.

Patients presenting with in-stent restenosis have an increased risk of need for repeat intervention. Intracoronary brachytherapy is indicated for these patients to prevent recurrent in-stent restenosis. Three intravascular brachytherapy systems are currently FDA-approved for use in patients: one utilizing gamma-radiation (Cordis) and two using beta-radiation (Novoste and Guidant). Current evidence and labeling do not support using intracoronary brachytherapy for prevention of restenosis in de novo lesions. Brachytherapy is absolutely contraindicated in patients unable to take prolonged combination antiplatelet drugs. Aspirin and a thienopyridine should be taken for 6 months if no new stent is placed and 12 months if a new stent is placed. If possible, new stent implementation should be avoided.

Beta Particles↗
PubMed2002

Combined cutting balloon angioplasty and intracoronary beta radiation for treatment of in-stent restenosis: clinical outcomes and effect of pullback radiation for long lesions.

Intracoronary beta (beta) radiation decreases the incidence of target lesion revascularization after percutaneous intervention (PCI) for in-stent restenosis (ISR). Cutting balloon (CB) angioplasty may also be superior to other percutaneous techniques for the treatment of ISR. We sought to study the outcomes of patients with ISR who underwent both CB angioplasty and intracoronay beta radiation and compare them to patients with ISR who underwent other PCI techniques without concomitant radiation. We also sought to evaluate the safety and efficacy of pullback intracoronary beta radiation for the treatment of long ISR lesions. Between January 2001 and November 2001, 102 patients (mean age = 55 +/- 13 years) with ISR underwent both CB angioplasty and intracoronay beta radiation. beta radiation was delivered using the Beta Cath (Novoste) 30 mm system, and pullback radiation was performed in 41 patients. A comparison group included a total of 393 patients with ISR who underwent other PCI techniques without concomitant intracoronary radiation therapy. Follow-up was obtained in 99 patients (97%) in the CB angioplasty with intracoronary radiation group and 377 patients (96%) in the comparison group. At follow-up, both target vessel revascularization (TVR) and major adverse cardiovascular events (MACE) occurred significantly less in the CB angioplasty with intracoronary radiation group than in the comparison group (7% vs. 18% for TVR, and 14% vs. 24% for MACE; P < 0.05 for both). In the pullback radiation group, TVR was performed in five patients (12%), and MACE occurred in eight patients (20%). A combination of CB angioplasty and intracoronay beta radiation for ISR seems to yield low rates of subsequent target vessel revascularization and adverse cardiac events. In addition, pullback beta radiation using the Beta Cath (Novoste) 30 mm system is safe and can be used to treat long ISR lesions effectively. Further randomized trials are needed to confirm these findings.

Angina Pectoris↗
PubMed2003

Intracoronary beta-brachytherapy in chronic total occlusions: a subgroup analysis from the RENO registry.

Conventional interventional therapy has been less rewarding in chronic total occlusion (CTO). Brachytherapy by its antiproliferative and positive remodeling effect may be more efficacious. Forty-six centers registered 1,098 consecutive patients undergoing brachytherapy with the BetaCath system. Of these, 78 patients had 82 lesions (CTO) at presentation-the study population. With 67% in-stent CTO, 8% graft CTO, 4% recurrent CTO, long lesions (27.6 +/- 20.9 mm), and 31% diabetes, the cohort had high risk for recurrence. The in-hospital event rate was 1.3%. Six-month follow-up revealed 1.3% death, 5.1% myocardial infarction, 21.8% target vessel revascularization, 77.8% improved angina, 34.5% binary restenosis, 12.7% reocclusion, and 10.3% late thrombosis. The results were comparable to all other patients in the registry, although late thrombosis rate was higher in the CTO group (10.3% vs. 5.0%; P = 0.047). In the in-stent CTO subgroup (n = 52; 66.7%), there was no in-hospital event, no follow-up death or myocardial infarction, restenosis in 35.1%, and reocclusion in 10.8% of patients. In comparison, death or myocardial infarction was significantly higher in de novo CTO subgroup (P = 0.005). Compared to all other in-stent restenosis patients in the registry, the patients with in-stent CTO had similar clinical and angiographic event rate. Thus, beta-brachytherapy was safe, feasible, and effective in this broad population of high-risk patients with CTO presenting in day-to-day practice. It was particularly effective in in-stent CTO, where conventional interventional strategies are disappointing.

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PubMed2003

Debulking does not benefit patients undergoing intracoronary beta-radiation therapy for in-stent restenosis: insights from the START trial.

Intracoronary brachytherapy has become the current treatment of choice for patients with in-stent restenosis (ISR). The aim of the present study was to determine whether plaque extraction using debulking techniques prior to brachytherapy would improve the outcomes of patients with ISR. Patients enrolled into the START (n = 476) and START-40 (n = 205) trials were divided into four subgroups according to their treatment assignments: debulking-radiation, debulking-placebo, balloon angioplasty (BA) radiation, and BA placebo. Patients were further divided according to their ISR lesion length: all lesions, > 15 mm, and > 19 mm. Restenosis rates were higher in placebo, nonradiated lesions undergoing debulking (52.7%) vs. BA alone (38.5%; P = 0.04). Postprocedural minimal lumen diameter (MLD) was similar among the subgroups. Outcomes were similar between debulking and BA within each therapeutic arm. MLD after debulking radiation was greater in patients with ISR > 15 mm (post-MLD was 1.9 vs. 1.7 mm; P = 0.06) but not in the placebo. Debulking radiation patients had greater MLD at follow-up, but restenosis (23.5% after debulking vs. 32.7% BA alone) and late loss (0.3 mm in both subgroups) were not statistically different. There was a trend toward higher mortality among debulked patients (3.7%) compared to BA alone (0.8%). In patients with ISR > 19 mm, four patients died following debulking radiation as compared to no death after BA (P = 0.05). Our results do not support the strategy of plaque extraction prior to intracoronary beta-radiation for ISR.

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PubMed2003

Correlates of failure following treatment with Sr-90 beta irradiation for in-stent restenosis.

We sought to determine the correlates of failure following intracoronary radiation therapy (IRT) with Sr-90 using the Novoste Beta-Cath system for the treatment of in-stent restenosis (ISR) in a broad range of patients. IRT has been shown to be more efficacious compared to placebo for the treatment of ISR in large randomized trials. However, even in patients treated with IRT, major adverse cardiac events occur in approximately 20% of cases on follow-up. This trial sought to elucidate the correlates of failure following successful IRT for ISR. To determine the correlates of IRT failure, we retrospectively compared the demographics, lesion characteristics, and clinical outcomes of 102 consecutive patients with ISR treated with Sr-90 from September 1998 to July 2001. IRT failure was defined as death, myocardial infarction (MI), or target vessel revascularization (TVR) due to repeat ISR on follow-up. A comparison of the clinical and angiographic profile of IRT failures (n = 16) vs. IRT successes (n = 86) revealed that a history of smoking (75% vs. 40%; P = 0.012), current use of calcium channel blockers (84% vs. 45%; P = 0.013), ostial location of target lesion (44% vs. 16%; P = 0.020), and mean posttreatment minimal luminal diameter (MLD; 1.64 +/- 0.19 vs. 2.21 +/- 0.29 mm; P < 0.001), respectively, were correlated with failure using univariate analysis. After multivariate regression analysis, the correlates of failure that remained significant were treatment of an ostial lesion (OR = 31.2; 95% CI = 2.6-382.7; P = 0.007) and final posttreatment MLD (P < 0.001). Ostial location of target lesion and smaller posttreatment MLD are correlated with subsequent death, MI, and TVR following therapy with Sr-90 for ISR.

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PubMed2003

Catheter-based 32P beta-radiation after stent implantation in porcine coronary arteries: role of source-centering and geographical miss.

The present study examined the role of source-centering and geographical miss in vascular brachytherapy. After implantation of 13 mm long stents, 38 coronary arteries in 13 pigs were randomly assigned to centered brachytherapy (n = 13), eccentric brachytherapy (n = 13), or no radiation (n = 12). Geographical miss was avoided by careful placement of a 27 mm (32)P beta-radiation source. Restenosis was quantified by angiography, histomorphometry, and intravascular ultrasound at 28 days. Source-centering led to a significant (P < 0.001) reduction of in-stent area stenosis (centered radiation, 12% +/- 5%; eccentric radiation, 37% +/- 21%; control arteries, 41% +/- 13%). Despite 7 mm coverage of the edge segments, radiation was found to induce edge stenosis due to neointima formation and constrictive vascular remodeling. We conclude that centered radiation was superior to eccentric radiation in reducing in-stent luminal narrowing while radiation-induced edge stenosis was still observed despite extension of the radiation zone to 7 mm beyond the stent edges.

Animals↗
PubMed2004

Intravascular ultrasound study of the effect of beta-emitting ((55)Co) stents on vascular remodeling and intimal proliferation.

The aim of this study was to evaluate vessel remodeling after implantation of high-activity (mean, 41.1 +/- 1.2 microCi) beta-emitting ((55)Co) stents. Proton bombarding in cyclotron has brought the radioactivity. Intravascular ultrasound (IVUS) investigation has been completed in 10 patients. The angiographies performed at 6 months revealed restenosis > 50% in five cases (50%). IVUS analysis demonstrated an absence of remodeling behind the stent, with no changes in total vessel volume (TVV; 353.6 +/- 126.3 and 343.9 +/- 90.6 mm(3)) or plaque + media volume (PMV; 171.7 +/- 57.4 and 166.8 +/- 42.6 mm(3)). On the other hand, lumen volume (LV) within the stent decreased significantly from 181.9 +/- 80.2 to 154.6 +/- 45.2 mm(3) (P < 0.02). This was due to presence of neointimal hyperplasia (NIH) at both extremities of implanted stents. No chronic recoil of the implanted stents was found. The analysis of edges (5 mm distally and proximally to the last stent struts) showed no significant changes in TVV (187.3 +/- 62.60 and 176.9 +/- 53.5 mm(3)), but PMV increase significantly from 61.9 +/- 31.2 to 82.2 +/- 43.4 mm(3) (P < 0.04) and LV decreased from 125.2 +/- 40.7 to 94.7 +/- 22.0 mm(3) (P < 0.02). In conclusion, single (55)Co radioactive beta-emitting stents with high initial activity are effective in reducing neointimal hyperplasia only within the stent body, as measured by IVUS, and they do not solve the problem of restenosis at the stent extremities as well as at the stent edges. Edge restenosis in this high radioactive stents was mainly (from 66%) due to neointimal proliferation.

Beta Particles↗
PubMed2001

Intravascular ultrasound analysis of beta radiation therapy for diffuse in-stent restenosis to inhibit intimal hyperplasia.

We evaluated the efficacy of beta-radiation therapy ((188)Re-MAG(3)) to inhibit intimal hyperplasia (IH) in diffuse in-stent restenosis by intravascular ultrasound (IVUS) analysis in 50 patients. Nine patients who did not agree with radiation therapy, and therefore underwent rotational atherectomy and balloon angioplasty for diffuse in-stent restenosis in the same study period, were selected for control groups. Serial IVUS comparisons were available in 44 of 50 patients with radiation therapy and 7 of 9 control patients. At 6-month follow-up, there was less significant increase of IH area in patients with radiation therapy than in control patients (Delta IH area = 0.1 +/- 0.8 mm(2) vs. 2.6 +/- 1.8 mm(2), P > 0.001 in mean values, and 0.6 +/- 1.4 mm(2) vs. 2.9 +/- 2.1 mm(2), P = 0.026 in values of follow-up lesion site, respectively). In conclusion, beta-radiation therapy might be an effective treatment modality to inhibit intimal hyperplasia in patients with diffuse in-stent restenosis.

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