Millions of people with coronary artery disease are alive today because one or more stents are holding their coronary arteries open.
But these devices, which have enabled millions of people to avoid bypass surgery, have some problems of their own. Plaque tends to grow inside stents made of bare metal during the first year after they are implanted, reproducing the problem that led to the need for the stent in the first place. This process is called restenosis.
Coating stents with one of two drugs that trickle out into the bloodstream over time can prevent restenosis, but these stents aren’t risk-free either. Drug-eluting stents (DES) appear to slightly increase the risk of heart attack-causing clots. Patients take clopidogrel (Plavix®, an antiplatelet medication, for six to 12 months to prevent this from occurring, and all patients should take aspirin for life. But a small number of patients with DES are experiencing clots months or years later — a phenomenon known as late-stent thrombosis. Does this mean stents are unsafe?
“There are many benefits of drug-eluting stents, and there may be some hazards. Late-stent thrombosis occurs in less than one-half percent of patients,” says Steven Nissen, M.D., Chairman of Cardiovascular Medicine.
The problem appears not to lie so much in the devices themselves, but in whom they are being used. Stents have been approved by the U.S. Food and Drug Administration for the treatment of simple blockages in the coronary arteries of a certain diameter (“on-label use”). However, less than 50 percent of patients in this country who receive stents meet these criteria. In other patients, multiple overlapping stents are implanted end to end to cover a long blockage. Sometimes DES are inserted inside bare-metal stents, implanted in coronary bypass grafts or used in other unapproved ways (“off-label use”). Some of these patients may be better suited for medical therapy or bypass surgery, although the best treatment remains uncertain.
A series of studies published in a recent issue of the New England Journal of Medicine illustrates various views on which type of stent is better and why. According to Dr. Nissen, one of these trials is worrisome — a Swedish study conducted by independent interventionalists in 20,000 patients that represent the typical patients seen in catheterization labs today. It showed that during the first six months after implantation, DES have a modest advantage. After six months, the outcome was better with bare-metal stents.
“In some patients, we may have traded a short-term advantage in preventing restenosis for a long-term disadvantage,” says Dr. Nissen. “Drug-eluting stents were approved based on short-term clinical trials in low-risk patients, but those in whom they are commonly used are not necessarily identical.
“We need a large study to evaluate the risks and benefits of DES for patients with conditions now considered off-label,” Dr. Nissen suggests. He advises they be used more cautiously in patients who do not meet the FDA-approval criteria for DES.
Already have a stent?
If you already have a drug-eluting stent, Dr. Steven Nissen strongly recommends you follow your doctor’s advice, and stay on antiplatelet medications for as long as your doctor prescribes.
If you are facing revascularization and don’t know how to make a decision, he stresses the need to make an informed decision.
Talk with your doctor about whether you might benefit most from medical therapy, angioplasty and stenting or bypass surgery.
“What’s right for one patient may not be right for another,” he says.
WEB EXTRA! SOS Heart Problems – You may remember it as a line in a song, “How do you mend a broken heart?” Cleveland Clinic researchers say they may have found a new, unique way to do just that. This discovery could potentially help the millions of people who suffer from heart failure. View or download this video podcast by clicking here.
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 5/1/2007…#13547
