Despite their higher cost, and despite recent concerns about late thrombosis, drug-eluting stents now own coronary stenting.
In the final 3 months of 2004, drug-eluting stents were estimated to have been used for 87% of all U.S. interventional coronary procedures, Martin B. Leon, M.D., said last November at the American Heart Association's scientific sessions in New Orleans. Less than 2 years earlier, in the first quarter of 2003, not a single drug-eluting stent had been used outside of a clinical trial. The Food and Drug Administration first approved a drug-eluting stent in April 2003.
“There has never been a technology in the world with this kind of rapid penetration over a short period of time,” said Dr. Leon, associate director of the Center for Interventional Vascular Therapy at Columbia University in New York.
“We have not yet identified any subsets of patients who don't benefit from receiving drug-eluting stents [by having less restenosis] compared with bare metal stents,” said David J. Cohen, M.D., associate director of interventional cardiology at Beth Israel Deaconess Medical Center in Boston. “De facto practice in the United States today is to use drug-eluting stents whenever the available stent lengths and diameters fit. At Beth Israel Deaconess, most of the time when patients [who are undergoing coronary stenting] don't receive drug-eluting stents it's because the vessel is too small or too large to accommodate available stent sizes,” he told this newspaper.
In fact, use of drug-eluting stents has become so widespread that medicolegal concerns may now drive their use even more than purely clinical factors. “When the risk of restenosis is low, operators must balance the need for drug-eluting stents with the medicolegal risk of avoiding what has become the de facto standard of care for all patients,” said Herbert D. Aronow, M.D., director of the cardiac catheterization laboratories at the Veterans Affairs Medical Center in Philadelphia.
According to one study, in 2003, about a third of all sirolimus-eluting (Cypher) stents used in the United States were for off-label, coronary-artery indications (INTERNAL MEDICINE NEWS, Feb. 15, 2005, p. 16).
As of early this year, no cardiology society had issued formal recommendations on the appropriate uses of drug-eluting stents, although these are expected soon. In the meantime, some experts have given their personal opinions.
One set of standards was laid out by Gregg W. Stone, M.D., in a talk at the AHA scientific session. “In workhorse lesions, in patients undergoing elective coronary interventions with de novo lesions up to 46 mm in length and in vessels with reference diameters of 2.5-3.75 mm without acute coronary syndrome or acute myocardial infarction, in general the safety and efficacy of two drug-eluting stents, Cypher and Taxus, has been proved,” said Dr. Stone, an interventional cardiologist at Columbia University in New York. “Using drug-eluting stents over bare metal stents in these lesions is the appropriate thing to do.”
But, he added, “we desperately need more data regarding the safety and efficacy of drug-eluting stents in unapproved and high-risk indications before their use should be considered routine. We must be very circumspect about extending drug-eluting stents to more complex patients and lesions. We are in the midst of stent frenzy, where everyone is putting in drug-eluting stents in every single lesion. You need to be aware of the evidence so you know what you are doing.”
According to Dr. Stone's assessment last November, there are “pretty good grounds” for using a single drug-eluting stent to treat in-stent restenosis within a bare metal stent.
Use of a drug-eluting stent can “probably be recommended” for the following: treating in-stent restenosis in place of brachytherapy when the existing stent was bare metal; bifurcations when the drug-eluting stent is placed in the main branch with angioplasty only for the side branch; aorto-ostial lesions; chronic, total occlusions; patients with multivessel disease instead of bypass surgery if they have only simple, focal lesions; and saphenous vein grafts.
But because of an “absence of sufficient data to warrant routine use,” Dr. Stone cautioned physicians to “think twice” about using drug-eluting stents outside of an investigational setting for these indications: bifurcations when two stents are used; ultralong lesions; unprotected left main disease; in-stent restenosis following failed brachytherapy; and in patients with acute MI. There is even less evidence on using drug-eluting stents for V-stenting of a bifurcation, and it is unclear how cardiologists should manage restenosis within a drug-eluting stent.