Stents May Not Increase Patient Survival
Study: Tiny Tubes Don't Extend Life After Angioplasty Operation
Nov. 8, 2004 -- Stents cut a patient's risk of having a repeat balloon angioplasty to clear a clogged artery. But patients who get stents don't survive any longer than those who don't get them.
The finding comes from a study of patients who underwent balloon angioplasty between 1990 and 2002. It's the largest study of its kind, say Duke University's David Kandzari, MD, and colleagues. It may help doctors decide whether to treat patients with balloon angioplasty or with much more invasive heart bypass surgery.
Stents are tiny wire tubes that prop open an artery after balloon angioplasty is used to clear a clog.
Out of some 12,000 patient records from 1990-2002, Kandzari and colleagues found 644 pairs of closely matched balloon angioplasty patients. One member of each patient pair received a stent during the balloon angioplasty; the other -- treated before the 1994 advent of stents -- didn't.
What happened? Patients who got stents had fewer repeat angioplasties. But after seven years of follow-up, those who got stents didn't survive any longer than those who did not get them.
"While stenting was associated with significant reduction in the need for [repeat procedures], it made absolutely no difference in long-term mortality," Kandzari tells WebMD. "In both groups there was about 20% mortality over seven years. This reminds us that stents, as used in the real world, are not associated with a survival advantage."
Kandzari presented the findings at this week's meeting of the American Heart Association in New Orleans.
Use of stents began in 1994 and is now routine. Newer stents, called drug-eluding stents, are coated with drugs that help prevent reclogging. They likely will cut the risk of repeat angioplasties even further than seen in the Kandzari study. They're also more likely to provide better symptom relief. But they aren't likely to keep patients alive any longer than the old stents, Kandzari says.
Why? People with clogged arteries don't just have plaque buildup in one place. There are many plaque deposits in the lining of their blood vessels, notes Prediman K. Shah, MD. Shah heads the atherosclerosis research center at Cedars-Sinai Medical Center in Los Angeles and is professor of cardiology at UCLA.
"Heart attacks are caused by plaques bursting, leading to blood clot formation and [blocking] of the artery at sites other than those treated by angioplasty or stents," Shah says.
There's one exception. Stents save the lives of heart-attack or unstable-angina patients when they're used to open the blockage causing acute problems.
Balloon Angioplasty With Stents, Bypass Surgery, or Risk Reduction?
For some patients, Shah says, bypass surgery may offer a survival advantage over balloon angioplasty with stents. However, balloon angioplasty is far less risky for some patients with heart disease and less invasive than bypass surgery.
"Bypass surgery -- in selected subgroups of patients -- does reduce mortality because bypassing ... creates an alternate source of blood flow," Shah says.
Kandzari makes a similar point.
"In this era of stent mania -- where more and more challenging patients with more and more complex problems are being treated with balloon angioplasty and stents -- we should be reminded that bypass surgery may still have a role," he says.
Stents offer meaningful benefits to patients, Kandzari stresses. But patients need more.
"Doctors often exclude other therapies in favor of stents alone," he says. "There is more to patient treatment than just getting them stents."
Aggressive medical treatment -- use of cholesterol-lowering drugs, tight diabetes control, and lifestyle changes -- are vastly important to patient survival, Kandzari and Shah agree.
Both Kandzari and Shah predict that better medical treatments -- and better heart-disease prevention -- will reduce the need for both balloon angioplasty and heart bypass surgery.