What’s a Heart Patient to Do?

Are drug-eluting stents good or bad medicine? The question has been hotly debated since 2006, when a Swedish study indicated that the devices might be too risky to use in patients with complex coronary artery disease. Now a new pair of studies in the New England Journal of Medicine suggests another, more nuanced answer: the stents can be either good or bad, depending on the patient's needs. One of the studies, the first of its kind, pits drug-eluting stents against coronary artery bypass graft (CABG) operations and finds that the devices are not as effective as the surgery. (They are, however, equally safe in the long run.) The other study suggests that drug-eluting stents do have an advantage over another therapy: simpler, older "bare metal" stents. Together the studies suggest that doctors are closing in on an agreement for how and when drug-eluting stents should be used—a position that may put to rest the biggest cardiology controversy in recent years.

Stents are mesh tubes that hold coronary arteries open and improve blood flow to the heart muscle. Drug-eluting stents, which release heart medications, have been popular since their introduction in 2003, when the FDA approved them for use in a select group of patients: the "plain vanilla" ones, according to Dr. Donald Baim, medical director of Boston Scientific, a major manufacturer of the devices. Patients in the first trials of drug-eluting stents were relatively healthy. Some had only one narrowed artery, and generally the blockages in those arteries were small. The FDA's approval came with the caveat that the stents were appropriate only for these patients.

But doctors quickly and widely adopted the devices for "off-label" use in sicker patients, too. "They made the assumption that if the stents worked in the first group of patients, they'd work in others," says Dr. Oscar Marroquin, a cardiologist at the University of Pittsburgh and the lead author of one of the new studies. By 2005 somewhere between 50 and 70 percent of all stents were being used off-label in patients with multiple arterial blockages.

There was little reason at the time to think that was a bad thing. Before 2006 there were no studies to suggest that drug-eluting stents were inappropriate for treating serious disease. The devices were also appealing to patients in the current age of minimally invasive surgery. "Drug-eluting stents are much less invasive than CABG, so people who didn't want to be cut open and laid up for a long time favored them," says Edward Hannan, a health policy analyst at SUNY Albany and the lead researcher on the other new study. "There's also the fact that the gatekeeper—the physician who speaks with the patient about his options—was usually a cardiologist. Those are the doctors who put in stents. So cardiologists were in the position of advising the patient to undergo either the procedure they do or the procedure someone else does. It was a funny situation."

Then in March 2006 came the Swedish study—and with it what Baim likens to a "panic on Wall Street." The study showed that the long-term risk of death in patients with drug-eluting stents was 18 percent higher than the risk in patients treated with older stents, ones not coated in drugs that keep the vessels clear and open. It also suggested that drug-eluting stents might be causing potentially fatal clots in patients with complex arterial disease. Patients and doctors reacted with fear. Nationwide, enthusiasm for drug-eluting stents waned, a trend dramatically documented in the medical registries of New York state, which provided the data used in the new studies. Between early 2006 and early 2007 the number of patients in the New York databases treated with stents of any kind dropped by 12.5 percent, and the proportion of those stents that were drug-coated also dropped steeply, from 93.5 percent to 73.5 percent.

What was lost in the hubbub over the Swedish study was a simple, and in retrospect obvious, fact: the off-label patients in the study had always been sicker than the on-label ones. If they did worse with drug-eluting stents than the on-label patients, it could have been because they were worse off to begin with—not because of anything to do with the stents. The real question, says Marroquin, was whether the stents were "causing more problems than an alternative therapy." The Swedish study couldn't provide an answer to that.