Drug-coated stents overused in heart patients, study finds

By Deborah Kotz, Globe Staff

Cardiologists are routinely over-using drug-coated stents to prop open blocked arteries in the heart rather than using bare-metal stents for patients at low-risk of another blockage, according to a study conducted by researchers at Massachusetts General Hospital and other institutions.

While drug-coated stents release medication to help prevent the artery from closing again -- which would necessitate insertion of a second stent -- they cost about $1,000 to $2,000 more than the bare-metal ones. What’s more, they require patients to take anti-clotting drugs for at least a year, increasing the risk of internal bleeding and burdening patients with out-of-pocket costs.

The study, published online Monday in the Archives of Internal Medicine, analyzed more than 1.5 million stent procedures performed along with angioplasties -- in which a tiny balloon is inflated to reopen closed arteries -- from 2004 through 2010. Nearly 74 percent of patients at low risk for a re-blockage received a drug-coated stent -- also called a drug-eluting stent -- compared with 83 percent of those at the highest risk, based on factors such as diabetes, the length of the blockage, and the diameter of the blood vessel.

The paper underscores the broader problem of cardiologists performing too many angioplasties and stent procedures in patients with stable heart disease; many of the procedures examined in the study were performed on patients who elected to get treated to relieve chronic symptoms such as chest pain and fatigue even though the latest research suggests that medications work just as well. A study published last year in the Journal of the American Medical Association found that 12 percent of elective stent procedures performed in heart disease patients were unnecessary and that an additional 38 percent were of “uncertain’’ benefit.

“A lot of clinicians want to give what they perceive to be best technology to their patients, and drug-eluting stents are the latest technology,” said study co-author Dr. Robert Yeh, a cardiologist at Massachusetts General Hospital. In patients at low-risk, however, about 50 need to be treated with drug-eluting stents, compared with bare stents, to prevent a single re-blockage, which Yeh said is too small a benefit to warrant the use of such stents in these patients.

Besides the added costs, patients who receive drug-coated stents must take a combination of blood thinner drugs such as aspirin and Plavix (clopidogrel) for about a year after their angioplasty to avoid an increased risk of heart attack associated with these stents. While Plavix is now generic, a month’s supply of the 75-milligram dose can cost anywhere from $15 at several Costco pharmacies to $175 or more at others including CVS, according to a May survey conducted by Consumer Reports.

Plavix, aspirin, and other anti-platelet therapies also raise the risk of internal bleeding and bruising, and the drugs must be stopped before surgery.

In an editorial that accompanied the study, Dr. Peter Groeneveld, a professor of medicine at the University of Pennsylvania School of Medicine, wrote that fewer than half of British patients who receive stents got a drug-eluting type in 2007 compared with 70 percent of American patients, yet “there is little evidence to suggest that British patients with coronary artery disease were treated suboptimally by their physicians, but it is likely that on average they were treated more inexpensively.”

Considering that drug-coated stents have risen in popularity since then, researchers estimate that about 75 to 85 percent of American angioplasty patients now get them over the bare stents.

Yeh and his colleagues calculated that reducing the unnecessary use of drug-coated stents by half would save $205 million in US health care costs each year and lead to an increase of stent failures in only 5 out of every 1,000 patients treated.

That goal could be achieved, Yeh said, if cardiologists agree to adopt risk prediction calculators such as one that he and his colleagues recently posted on massdac.org, but he added that changes have been slow to be implemented even at his own institution. “We’re working at Mass. General now to implement these risk prediction models at the bedside, so patients and physicians can make a more informed decision about which stent to use on the day of the procedure.”

The hospital may launch a pilot program to test the model by the end of this summer, but at the moment, its use of drug-eluting stents in low-risk patients is only “a little bit better” than the national average, said Yeh.

But Dr. Carey D. Kimmelstiel, director of the Interventional Cardiology Center at Tufts Medical Center, said doctors don’t need a risk calculator and can help patients come to a decision on their own about which stent to use based on a variety of factors including how likely patients are to remain on anti-clotting medications and whether they can afford them. He estimates that about 65 to 70 percent of angioplasty patients treated at Tufts get drug-coated stents over bare metal ones.