Comparison between drug-eluting stents and beta-radiation for the treatment of diffuse in-stent restenosis: clinical and angiographic outcomes

Radiation therapy for dialysis access stenosis: unfulfilled promise or false expectations

Hemodialysis vascular access dysfunction is a major cause of morbidity and hospitalization in the hemodialysis population at a cost of well over $1 billion per annum. Venous stenosis (due to venous neointimal hyperplasia [VNH]) is the most common cause of polytetrafluroethylene PTFE) dialysis access graft and arteriovenous fistula (AVF) failure. Despite the magnitude of the clinical problem, however, there are currently no effective therapies for this condition. We and others have previously demonstrated that VNH in PTFE dialysis grafts and AVF is composed of smooth muscle cells/myofibroblasts, endothelial cells within neointimal microvessels, and peri-graft macrophages. Radiation therapy blocks the proliferation and activation of all these cell types. The current review will dissect out the available in vitro, experimental, and clinical data on the use of radiation therapy for vascular stenosis in general, and for dialysis access dysfunction in particular. It is important to try and identify whether there is still a role for radiation therapy in this specific clinical setting. We believe that this is a critically important question to answer in view of the huge unmet clinical need that is currently associated with hemodialysis vascular access dysfunction.

Drug-eluting stents vs. intracoronary brachytherapy for in-stent restenosis: a meta-analysis

BACKGROUND

It has been reported that drug-eluting stents (DES) were superior to intracoronary brachytherapy (ICBT) in patients with in-stent restenosis (ISR). However, it is unknown whether there might be differences between DES and ICBT in terms of efficacy and safety in large sample size and long-term follow-up.

HYPOTHESIS

The aim of this study was to determine whether DES implantation remains favorable in large sample size and long-term follow-up when compared with ICBT among patients with ISR.

METHODS

We conducted a search in MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials without language restrictions. A meta-analysis of 1942 cases from 12 controlled trials of DES vs ICBT for ISR was performed.

RESULTS

Drug-eluting stents were significantly more effective in reducing target-vessel revascularization (TVR) (odds ratio [OR]: 0.44, 95% confidence interval [CI]: 0.23-0.81, P = 0.009) and binary restenosis (OR: 0.34, 95% CI: 0.26-0.46, P<0.00001) compared with ICBT at midterm follow-up. There were no significant differences between DES and ICBT in cardiac death, myocardial infarction (MI), and late stent thrombosis at midterm follow-up. A statistical significance has been found between the 2 groups in TVR (OR: 0.61, 95% CI: 0.43-0.86, P = 0.005) at long-term follow-up. There were no significant differences in cardiac death and MI between the 2 groups at long-term follow-up.

CONCLUSIONS

These findings provide evidence that DES is superior to ICBT for the treatment of ISR in TVR and binary restenosis reduction, but not in cardiac death, MI, and late stent thrombosis reduction. © 2011 Wiley Periodicals, Inc. Yong-Guang Lu, MD, and Yan-Mei Chen, MD, contributed equally to this work. The authors have no funding, financial relationships, or conflicts of interest to disclose.

Clinical use of sirolimus-eluting stents

Drug-eluting stents, or intracoronary stents that combine the local delivery of antirestenotic pharmacologic therapies while maintaining the mechanical advantage of bare metal stents over balloon angioplasty alone, are a highly complex technology that have profoundly affected the practice of percutaneous coronary intervention over the last 5 years. These devices were designed specifically to treat the neointimal hyperplasia occurring after conventional bare metal stent placement, and have been remarkably successful in this regard. However, recent concerns have been raised regarding the long-term safety of these devices, particularly when used outside of the specific patient and lesion subsets studied in the pivotal randomized trials that led to device approval by regulatory bodies within the United States and abroad. This review aims to present a brief description of the sirolimus-eluting stent device platform and its mechanism of action, followed by an overview of current data regarding efficacy and safety regarding the clinical use of sirolimus-eluting stent technology.