Sense and nonsense of bare metal stents below the knee

Critical limb ischemia (CLI) is increasingly present in daily practice, and diabetes is responsible for a preferential below the knee (BTK) localization of the disease. The objective was to determine if there is still a sense to BTK implantation of bare metal stents (BMSs) in CLI patients in the era of drug eluting strategies.

An extensive review of the literature was carried out over the last 15 years on the use of BMSs in BTK revascularization based on a PubMed (Medline), EMBASE and PubMed Central search.

The Chromis Deep® (Invatec, Roncadelle, Italy) was the first dedicated stent in BTK lesions, followed by passive coated BMSs developed in an attempt to inhibit platelets deposition. Comparative results showed no advantage of primary BMS implantation over peripheral transluminal angioplasty (PTA) in improving primary patency rates, Rutherford classification or wound healing and the place of BMSs was restricted to bailout spot stenting. The fear of patency loss in connection with possible stent fractures led to an interest towards nitinol stents, but results were disappointing, especially in patients with severely calcified lesions. Drug-eluting stents (DESs) were then developed and showed better long-term primary patency, restenosis and freedom from target lesion revascularization (TLR) rates, even in long calcified lesions against BMS or drug eluting balloons (DEB). However, limb salvage and wound healing rates were not significantly improved.

Primary BMS implantation showed no advantage over PTA and as of today DES trials have not shown enough clinical or economic benefit. Thus, BMSs are recommended over DESs, and only as a bailout strategy in case of flow limiting dissection or recoil. Quality trials assessing long-term clinically relevant outcomes, evolution in stents designs and vessel preparation could lead to a change in those recommendations.