Coated stents to prevent restenosis in coronary heart disease

BACKGROUND In-stent-restenosis (ISR) is considered to be an essential limiting factor of stenting in coronary heart disease (CHD). The development of coated stents has raised expectations on substantial lowering restenosis after stenting with decreasing the rate of restenosis and a reduction in the rate of clinical events. OBJECTIVES The present analysis addresses the questions on medical effectiveness and cost-effectiveness of the use of various coated stent types in CHD. METHODS The literature was searched in December 2004 in the most relevant medical and economic databases. The medical evaluation was conducted on the basis of published RCT. The data from the studies regarding various angiographic, sonographic and clinical endpoints were checked for methodical quality and summarised in meta-analyses. Within the scope of economic evaluation the primary studies were analysed and modelling was performed, applying clinical effect estimates from the meta-analyses of the medical evaluation and current estimates of German costs. RESULTS MEDICAL EVALUATION: Ten different stenttypes were used in the included 26 RCT. The results for heparin, silicon-carbide, carbon and PTFE coated stenttypes could not reveal any significant differences between the medical effectiveness of coated and uncoated stents. The application of sirolimus, paclitaxel, everolimus and 7-hexanoyltaxol eluting stents showed a significant lower restenosis at 6-9 months with decrease in the rate of restenosis for polymer-based sirolimus, paclitaxel and 7-hexanoyltaxol eluting stents. In contrast, the use of gold-coated and actinomycin-D eluting stents was associated with a significantly higher restenosis. The polymer-based sirolimus and paclitaxel eluting stents also showed a significant and considerable reduction in the rate of repeated percutaneous revascularisations at 6-12 months (3.5% vs. 19.7%; p<0.0001, RR=0.19 [95%CI: 0.11; 0.33] and 3.5% vs. 12.2%; p<0.0001, RR=0.30 [95%CI: 0.20; 0.43]) and an equivalent reduction in the rate of combined events. The 7-hexanoyltaxol-eluting stents caused, however, a significant increase of stent thrombosis as well as of myocardial infarctions. ECONOMIC EVALUATION: The allocation to polymer-based sirolimus and paclitaxel eluting stents resulted in incremental costs (compared with uncoated stents) of approximately 1,421 € and 1,234 € per patient, taking in account expected revascularisations during the first year after implantation. The mean incremental cost-effectiveness-ratios per avoided revascularisation was 8,881 € and 13,711 €, respectively. The "break-even"-prices for these stenttypes in the used model were 707 € and 551 €, and the "break-even"-risks for ISR after stenting with uncoated stent, was 76% and 65%, respectively. The use of the other evaluated coated stents seems not to be cost-effective. DISCUSSION The absolute effects and cost savings for patient groups with a higher risk of restenosis could be considerably higher than for patient groups with a lower risk of restenosis. The transferability of the results from the present analysis to other (sub)-populations and technology modifications is limited. The direct comparability of the results for sirolimus and paclitaxel eluting stents is also restricted. CONCLUSIONS From a medical point of view the use of polymer-based sirolimus or paclitaxel eluting stents can be recommended. The use of gold coated, 7-hexanoyltaxol and actinomycin-D eluting stents is in contrast not recommendable. From an economical point of view and on the basis of current stent prices the polymer-based eluting sirolimus and paclitaxel stents should primarily be recommended for patients with a higher risk of restenosis.