Heart failure is one of the biggest killers in the developed world and is commonly caused by blockages to the arteries of the heart. These blockages can result from genetic factors, obesity, or lifestyle factors such as smoking. Surgery can be performed to widen or unblock the blood vessel, at which time a stent, which is a tube-like mesh structure, can be used to hold the artery open and allow unrestricted blood flow. There are two main types of stent used in coronary arteries: drug eluting and bare metal stents. Whereas the bare metal stents do not have a coating, the drug eluting stents slowly release a drug, such as Taxol, that blocks cell proliferation with the aim of preventing blockage of the stent with cells that could impair blood flow. But whether bare metal or drug eluting stents are better for overall survival has been a point of contention for some time. New research published in BMC Medicine provides a comprehensive overview of the evidence. 
Previous observational studies suggest that drug eluting stents give better results in terms of patient outcome than do bare metal stents, but this finding is not replicated in randomized clinical trials. The authors of a research article published today in BMC Medicine explored the reasons for this discrepancy by using multiple statistical methods to compare patient outcomes after coronary intervention with either a drug eluting or bare metal stent. Similar to the results of the randomized clinical trials, the authors found there was no benefit in terms of mortality benefit by using drug eluting stents when compared to bare metal stents. The benefit seen in the observational trials may have been the result of treatment selection bias between the two groups, and so the authors warn that in the presence of such treatment selection, care must be taken when analyzing the data. 
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