New Study Attempts to Reassure About Drug Eluting Stents

At the American College of Cardiology (ACC) Meetings in Orlando this week, invetstigators from the Duke Clinical Research Institute presented results obtained by analyzing data from the ACC's National Cardiovascular Data Registry, on over 262,000 patients with coronary artery disease over the age of 65 who, received stents between 2004 and 2006. They report that the 83% of patients who received drug-eluting stents (DES) had a significantly reduced chance of subsequent death and heart attacks than did the 17% of patients receiving bare metal stents.

In a subsequent interview with Heartwire, Duke's Dr. Pamela S. Douglas said, "We can now lay to rest concerns about the safety and efficacy of [DES]."

Certainly, this very large study should offer significant reassurance to patients who have DES and who have been worried about reports of sudden occlusion of these devices. But since it was an observational study and not a prospective randomized, controlled study, it actually cannot "lay to rest" all of the questions about DES.

For instance, it is clear that cardiologists adopted DES in a wholesale manner once these devices became available. So, this being the case, what was different about the 17% of patients who received bare metal stents? Why were those individuals selected by their doctors not to receive DES? Could that difference explain some of the difference in outcomes?

More importantly, this study does not address the real issue faced by patients who receive DES, which is, how long do they have to remain on Plavix, and if they should require a surgical procedure after they have a DES, will their cardiologist allow them to stop the Plavix long enough to have the surgery safely?

Finally, the reason DES was developed in the first place was to reduce the problem of re-stenosis after stent placement, and every study to date suggests they have successfully done that. However, in this new study, the subsequent need for revascularization (that is, another stent procedure or bypass surgery) was roughly the same in the DES patients and in the bare metal stent patients. This finding is entirely unexplained.

In summary, this new study is both interesting and important, but cardiologists should not oversell the results. While the study is certainly reassuring, it does not answer all the open questions about DES, and by no means "lays to rest" the controversy surrounding them.

_Sources:

Douglas PS, Brennan JM, Anstrom KJ et al. Clinical effectiveness of coronary stents in elderly persons. J Am Coll Cardiol 2009; DOI: 10.1016/j.jacc.2009.03.005.