Can we bear another bare‐metal stent study?

Confronted with another study comparing bare-metal and drug-eluting stents, the first question that comes to mind is why this issue is still in contention. Aren’t we all using drug-eluting stents by default unless contraindicated? A Medline search for articles with titles containing the words “bare-metal” and “drug-eluting,” together with “versus” or “vs.” yielded 172 articles. Another search for articles with titles containing the words “bare-metal,” “drug-eluting,” and “meta-analysis” yielded 32 articles. Should this issue, which appears to have all the signs and symptoms of “investigative fatigue,” be put to rest? The study by Geng et al. in the current issue of Cardiac Catheterization and Cardiovascular Interventions is a meta-analysis of a select group of six randomized controlled trials investigating the relative efficacy and safety of bare-metal versus drug-eluting stents in coronary arteries with a diameter of 3 mm. This study demonstrated reduced target vessel revascularization with the use of drug-eluting stents, and is unsurprisingly concordant with the results of a previous trial by Kaiser et al., which makes up 50% of the total sample size in this meta-analysis [1]. Living in a consumer-driven society, we strive to provide the latest and most up-to-date products to our patients. Driven by an innate human belief that newer is better, patients will often ask about the type of stents that we plan to implant and are consistently comforted by reassurances that we are using the newest generation stents in the market. This motivation, together with the significantly lower rates of instent restenosis and need for repeat procedures compared to bare-metal stents [2], has led to the widespread adoption of drug-eluting stents by cardiologists worldwide. However, just as when many of us updated our iPhones with iOS 6 without prior knowledge that this would mean the loss of Google Maps, we are not always fully cognizant of the potential downsides of adopting a new technology. There are several disadvantages associated with drug-eluting stents. Apart from the fact that they are more expensive, drug-eluting stents are possibly associated with an increased incidence of late stent thrombosis [1,3], and require patients to be on a longer duration of dual antiplatelet therapy, which is associated with increased risk of bleeding. This has led to attempts at identifying patient groups who are most susceptible to restenosis and who will most benefit from drug-eluting stents [4]. Factors associated with increased risk of restenosis include treating lesions in previously stented segments, ostial lesions, bifurcation lesions, diabetes, longer lesion or stent length, and smaller target vessel or stent diameter [5]. Many of the studies listed as a result of the above mentioned Medline searches compare drugeluting with bare-metal stents in these subpopulations, and the current meta-analysis is one such study making the comparison in large vessels. This particular subset of vessels is worthwhile investigating because reducing restenosis is less beneficial in large vessels compared to small vessels [1], and because stent thrombosis in larger vessels is more likely to be associated with adverse clinical outcome [1]. This study confirms that the superiority of drug-eluting stents extends to use in very large vessels with 4 mm diameter and also when stent length is 15 mm. The benefits were also greater when comparing second-generation drug-eluting stents to bare-metal stents. Even though the results of this study may be slightly biased by the use of routine angiography in two of the trials included in the meta-analysis, which will cause an increase in study endpoints, this study largely vindicates the practice of many of us who are currently using drug-eluting stents routinely in our daily practice regardless of stent size and length [3]. Moreover, this study does not make the comparison in large vessel subpopulations such as in the presence of diabetics,