Despite all the advances in cardiology, Americans are still having heart attacks at the rate of more than one million each year. Usually, these are caused by a blockage (most often a blood clot) that dramatically diminishes blood flow to a section of the heart, sometimes cutting it off completely. Without blood and oxygen, heart tissue quickly dies. Without immediate medical intervention, sadly, some patients die, too.

While heart attacks can be fatal, modern medicine has developed effective tools that often save lives. People having a heart attack are currently treated with an immediate combination of clot-dissolving drug therapy, balloon angioplasty (to open the blocked artery) and stenting (to ensure the artery remains open). It would seem obvious that if unblocking an artery saves the life of a person having a heart attack, doing so in individuals with clogged (or nearly clogged) arteries whose lives are not currently hanging in balance should be helpful in preventing a heart attack (or having another one). However, an important new study finds otherwise — and the president of the American Heart Association has said… he expects it will change the way doctors handle such cases in the future. Additionally, a recent article in The New York Times even went so far as to question if bypass surgeries were “poised for a comeback,” especially for the sickest heart patients, for whom the less invasive stenting procedure turns out to be perhaps more dangerous in some.

A Care-Changing Finding
First, a primer on the stenting process. Time is of the essence in treating heart attack victims. Preferably within two hours of the onset of symptoms, an interventional cardiologist threads a catheter through the artery, to the blockage. A small balloon at the tip of the catheter is then inflated to re-open the artery, and a small metal-mesh tube surrounding the balloon is pressed into the artery wall. The stent remains in place in order to re-establish blood flow to the heart muscle, keeping the vessel open, and the balloon is deflated and removed.

Both angioplasty and stenting are life-saving procedures, but there are many questions about their safety and efficacy. Loads of research has demonstrated that angioplasty performed immediately (called “primary” or “emergency” angioplasty) reduces the likelihood of death or recurrence of a heart attack affecting that portion of the heart. What’s now been called into question by the new study is whether this is helpful in preventing further problems for patients who’ve already survived their heart attack without having had the artery opened up. When it comes to the hotly debated question of whether drug-coated stents are better than plain metal ones, well, that controversy goes on and on and on.

Published in the December 7, 2006 issue of The New England Journal of Medicine, this latest study has cardiologists reconsidering their long-held belief that clogged arteries should always be opened. Led by Judith S. Hochman, MD, director of the Cardiovascular Clinical Research Center at New York University School of Medicine, this startling study divided 2,166 patients — patients who were stable, but who still had 100% blockage three to 28 days after their initial heart attacks — into two groups. One group received drug therapy plus angioplasty and stenting, and the other group received only drug therapy. The researchers were surprised by the results: After three years, there was no significant difference between the groups in mortality, recurrent heart attack or heart failure. There was a trend for the angioplasty group to have a slightly higher risk for another heart attack (7%, compared with 5.3% for the drug therapy group) and between the two groups the mortality rates were similar — 9.1% for the angioplasty group versus 9.4% for the group receiving drug therapy alone.

Along with highlighting the value and effectiveness of drug therapy alone (such as beta blockers, angiotensin-converting enzyme, or ACE inhibitors, aspirin, and statins) — even with their possibly risky side effects — the study results bring to mind the importance of questioning conventional wisdom.

You can’t get any more “blocked” than 100%, points out Dr. Hochman. “Understanding that helps us interpret, at least somewhat, the results we saw,” she explains. “If you’re totally blocked, you’re not very likely to have another heart attack in that vessel (5% did at three years). If you re-open it, you can block it yet again. It is important to understand that for the research we selected for survivors of the early heart attack period. Most of our patients had collateral blood flow — some blood flow through new small vessels to the area of the blocked artery which was keeping some of the heart muscle in that area alive,” said Dr. Hochman.

“Early angioplasty interrupts the progression of heart muscle death. Prior evidence had suggested that there would be less heart failure and death with an open artery, even established late after the heart attack, due to less progressive enlargement of the heart. We confirmed a modest benefit for prevention of enlargement of the heart in our sub-study, but it did not translate to less heart failure or death.”

Raymond J. Gibbons, MD, president of the American Heart Association said, “This is a good example of a negative study that will improve the efficiency of health care in this country.”

Drug-Coated Stents: Complicating the Equation Futher
As for drug-coated stents (the ones with a special polymer coating that slowly releases medication to suppress the reclogging of arteries), keeping track of the back-and-forth study findings is a little like watching a tennis match. Several studies published in a variety of publications over the last few years have suggested that drug-coated or “drug-eluting” stents may raise the risk of blood clots in the long run, even years after the angioplasty that installed them… but those studies also show they reduce the risk of a new blockage or heart attack. And as researchers try to establish whether the benefits outweigh the risks for patients who meet the FDA criteria for stent use, a growing body suggests that the not uncommon “off label” use (representing 60% of drug-eluting stent procedures) for weaker, sicker patients, could be more problematic.

The volley of studies and strong opinions has prompted governmental action. A congressional committee is looking into the practice and safety of the use of stents, even though an FDA advisory committee had already issued its findings — concluding in December that the benefits of the devices outweighed the risks of thrombosis compared with bare metal stents when implanted “within limits of their approved indication of use.” Still, in early January 2007, the Society for Cardiovascular Angiography and Interventions (SCAI), a professional association for invasive and interventional cardiologists, issued a clinical alert advising physicians how to carefully monitor patients who receive the drug-coated stents, and reduce thrombosis risk — for example, having those patients receive anti-clotting medications for up to 12 months or more. Because, while the drug-eluting stents can reduce the likelihood of re-narrowing the artery by up to 60%, the risk of clotting is about 0.2% more than with bare metal stents — tiny, but nonetheless there.

Later that winter, The New England Journal of Medicine posted early publication of five stent studies and two commentaries on its Web site. While the studies had various conclusions on risk of death, thrombosis and long-term survival, one study noted that drug-coated stents reduce the need for repeat procedures by more than half. However, more research (likely to take several years) is required before a consensus can be achieved on their use in patients who do not meet FDA-approved criteria for device use.

And Then…
The NEJM studies were followed by an article in the New York Times quoting one leading cardiologist who said, “We as cardiologists have probably pressed forward on stent technology a little faster than we should have.” In addition, it was revealed that patients often requested stenting instead of surgery, presumably to avoid major surgery… that interventional cardiologists may earn more money when their patients receive stents (because often they can do the implants themselves, rather than referring the work to a surgeon)… and that evidence is mounting that suggests that though angioplasty is less invasive, bypass surgery may buy more time for the sickest heart patients.

What Do You Need To Know?
These fluctuations in interpreting the research are frustrating. By definition, however, “state of the art” thinking is only based on the latest knowledge and is not infallible. There is still much to learn. We’ll need to watch closely as further research and analysis on the risks and benefits of bare-metal and drug-coated stents plays out. For now, know that none of these decisions are simple, even if your doctor tells you it’s the way he’s done it for years. Do all you can to minimize your risk of heart attack with healthy diet and exercise. Just as important, be aware of the signs of heart attack — and if you think you might be having one, get immediately to the hospital. (For symptoms of heart attack, go to the National Heart Lung and Blood Institute’s Web site at www.nhlbi.nih.gov/actintime/haws/haws.htm.) According to Dr. Hochman, “around 25% of heart attack victims don’t seek help immediately. Maybe it’s denial, and maybe they’re hoping the symptoms will go away. But, for whatever reason, they wait. And they shouldn’t.”

Source(s):

Judith S. Hochman, Director of the Cardiovascular Clinical Research Center, New York University School of Medicine, New York City.

The Society for Cardiovascular Angiography and Interventions

The New England Journal of Medicine

Food and Drug Administration

The New York Times, February 25, 2007.

(This article is from a newletter from Bottom Line’s Daily Health News)