Meta-analysis shows benefit of drug-eluting stents below the knee

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A meta-analysis of studies comparing the performance of drug-eluting stents vs. bare metal stents in the treatment of infrapopliteal artery disease has demonstrated favourable one-year results with drug-eluting stents. According to the study, published in the Journal of Endovascular Therapy, patients treated with drug-eluting stents had increased patency rates and freedom from target lesion revascularisation.

The authors, led by George A Antoniou, Department of Vascular and Endovascular Surgery, Manchester Royal Infirmary, Central Manchester University Hospitals, Manchester, UK, noted that “balloon angioplasty alone provides suboptimal results, mainly because of the elastic recoil of heavily diseased infrapopliteal segments and flow-limiting dissection. Balloon-expandable bare metal stents have had limited success; their long-term results are significantly compromised by intimal hyperplasia, in-stent stenosis, and recurrent disease”. They added that “emerging evidence suggests that the combination of stenting and targeted delivery of drugs with antiproliferative properties, aiming to inhibit smooth muscle cell proliferation and intimal hyperplasia, improves the outcomes of endoluminal treatments of distal vessel disease. A small number of series have demonstrated satisfactory performance of drug-eluting stents, as expressed by increased patency and freedom from revascularisation to maintain good clinical results. Controversy exists, however, with regard to the superiority of drug-eluting stents over bare metal stents in terms of the clinical benefit in critical limb ischaemia patients. Our objective was to provide a comprehensive literature review and conduct an analysis of the outcomes of patients with infrapopliteal disease treated with drug-eluting stent and bare metal stents.

The article is a meta-analysis of the results of six studies—four randomised trials (DESTINY, YUKON-BTK, BELOW and Falkowski et al) and two observational studies (Siablis et al and Scheinert el al)—that included 544 patients (287 treated with drug-eluting stents and 257 treated with bare metal stents). Four of the studies used the Cypher sirolimus-eluting stent (Cordis), one used the Xience everolimus-eluting stent (Abbott) and one used the Yukon sirolimus-eluting stent (Translumina). Several different types of bare metal stents were implanted.

The results showed that, at one year, primary patency was achieved in 80% of the patients treated with drug-eluting stent and 49% of patients treated with bare metal stents (p<0.001). Only one study provided data on secondary patency rates. The reported secondary patency rates at one year in the drug-eluting stent and bare metal stent groups were 92% and 71%, respectively (p=0.001).

The freedom from target lesion revascularisation was 89% with drug-eluting stents and 73% with bare metal stents (p<0.001). Clinical improvement, defined as improvement of at least one Rutherford category, was reported in three studies. It was achieved in 61% of the patients treated with drug-eluting stents vs. 52% of the patients treated with bare metal stents.

No significant differences in limb salvage and overall survival at one year were identified between the groups. Sensitivity analyses investigating the potential effects of study design and type of drug-eluting stents on the combined outcome estimates validated the results.

The authors concluded that “emerging evidence exists supporting the safety and efficacy of drug-eluting stents in the treatment of infrapopliteal artery disease”. They added that it remains to be determined whether or not improvement in patency rates and target lesion revascularisation will be reflected in clinical parameters, such as limb salvage and wound healing.

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