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Studies Clarify Best Practices for Heart Care

November 14, 2006 at 6:02 PM EDT
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GWEN IFILL:  Two major findings presented at an American Heart Association meeting in Chicago this week could make a difference in how heart attack patients are treated.

Opening clogged arteries by balloon angioplasty is still the recommended response, but only one-third of heart attack victims get them as quickly as they should, within 90 minutes of their arrival at the hospital. And getting an angioplasty more than three days after a heart attack does not reduce the risk of having another one.

For more, we turn to Dr. Elizabeth Nabel, the director of the National Heart, Lung, and Blood Institute, which is part of the National Institutes of Health.

Welcome, Dr. Nabel.

ELIZABETH NABEL, Director, National Heart, Lung and Blood Institute: Good evening.

GWEN IFILL: Are we saying now that angioplasties, which we have always taken to be the gold standard, that they’re being overused?

ELIZABETH NABEL: Well, let’s first remember that angioplasties are a very effective treatment for heart attack victims during the first 12 hours of the heart attack. We know that opening up the blocked artery during the first 12 hours will save lives, and it will improve the functioning of the heart muscle.

What this new study has taught us is that opening up the blocked artery days, weeks and months later is not that beneficial over and above standard medical treatment.

The study randomized individuals between angioplasty and stents, plus medical therapy, versus medical therapy alone, and then followed individuals for a standard of four years to see if they developed recurrent heart attacks, heart failure, or died. And what we learned is that the angioplasty and stent did not benefit patients in terms of heart attack, heart failure or death.

GWEN IFILL: So the stent, which is that little metal mesh opening, which is threaded up through the thigh and into the heart and is supposed to prop open these veins, even if that happens after the fact — you’re saying three days after the fact — it seems counterintuitive that that wouldn’t keep it from clogging again.

ELIZABETH NABEL: You’re right, Gwen. And cardiologists for many years have thought that having an opened artery would benefit patients, but we never tested it in an objective, randomized clinical trial. And that’s what this study did.

Now, the results were surprising. We didn’t anticipate this. We hypothesized that opening the artery would benefit patients, but, lo and behold, the findings are what they are.

Clinical trials

GWEN IFILL: Is this something that doctors have resisted coming up with these conclusions? I read that it took five years to get enough volunteers, patients, to take part in this study.

ELIZABETH NABEL: Well, that's right, because many physicians thought opening up the artery must be good, so why would I allow my patient to be randomized in this study? But that's why we do randomized clinical trials; that's why we need to test these hypotheses in a very objective manner.

Now, we anticipate that the results from this study will change clinical practice. We are hopeful that the results will form the evidence that then is used in what we call evidence-based guidelines that will then guide physicians on how to treat heart attack patients.

GWEN IFILL: But I guess I'm still curious about how we got to this point. Is this something that -- is there a financial incentive, for instance, for doing this kind of surgery, rather than treating and saying, "Take some aspirin, and call me in the morning"?

ELIZABETH NABEL: Sure. Well, look, there were several lines of evidence that got us to the open artery hypothesis. There were a number of animal studies that had been done over a number of years. In addition, we had looked at observational studies, retrospective studies, small studies that seemed to suggest that an open artery was better.

But our gold standard in providing evidence for medical practice is a randomized clinical trial. The NHLBI-NIH funded such a trial, and these are now the results.

Alternatives to angioplasty

GWEN IFILL: So what are the alternatives, if your doctor says to you, "OK, I think it's too late for you to bother with an angioplasty. I don't think it's going to give you any long-term improvement"? What will the doctor tell you instead?

ELIZABETH NABEL: Sure. If you come to the hospital late after your heart attack, you're not having any further chest pain, you're very stable, you're doing well, there's no need to undergo a heart catheterization or an angioplasty.

On the other hand, if you come to the hospital late and you're continuing to have chest pain, it suggests that you may benefit from opening the artery. Remember, this study looked at people who were very stable after their heart attacks. So if you've had a heart attack and you're not stable, there may be still an indication for you to have the angioplasty and stent procedure.

GWEN IFILL: So when they say drug therapy instead, what does that mean?

ELIZABETH NABEL: Well, the standard medical therapy would be a series of medications that are given to all heart attack patients. And those are aspirin, medicines that we call a beta-blocker, an ACE inhibitor, clopidogrel, and others.

GWEN IFILL: Now, we've also heard in recent weeks that the stents, the drug-coated stents which prop these arteries open, are apparently not necessarily as effective as we had first been led to believe.

ELIZABETH NABEL: Well, we embraced these new stents, these drug-eluting stents with open arms. And just to remind you, the stent is the metal apparatus. It's like a chicken wire mesh that props open and keeps the artery open.

And the drug-eluting stents then have a polymer coating around the outside of the stent. And there is a drug embedded in the polymer. And after the stent is implanted against the blood vessel wall, the drug slowly eludes from the polymer into the blood vessel to prevent the blockage from occurring.

Now, we are very hopeful that this would be used to prevent a recurrence of the blockage. And for the vast majority of people who receive drug-eluting stents, they are benefited tremendously.

GWEN IFILL: But for some people, there are some clots?

ELIZABETH NABEL: However, that's exactly right. There is a growing concern of an increased risk of blood clots occurring within the stents several years after placement of the stent.

Now, the incidence is anywhere from .5 percent to 2 percent to 3 percent of patients receiving the stent per year, so it's still a very small number, but we're very concerned about it. And you will likely see a number of clinical studies following up on this observation to really tease out, what do we need to do next?

The future of treatment

GWEN IFILL: You mentioned earlier that this is actually changing the way some doctors behave, the way some treatments are prescribed. For instance, when it just comes to the angioplasty piece of this as opposed to the stents, how is this changing behavior?

ELIZABETH NABEL: Well, we know that there are about 1.3 million angioplasty stent procedures performed in this country each year. Most of these are performed for individuals who have blocked arteries but are not in the throes of a heart attack.

We know that, as a result of the study that's just being published today, that there probably are about 50,000 individuals a year with a heart attack who present to the hospital late who have had the angioplasty stent procedure. So that's really the group of individuals that we're talking about that will be affected by today's findings.

GWEN IFILL: And what about those people who get to the hospital in time but they don't get treated in time?

ELIZABETH NABEL: Well, that's part of what we're really encouraging hospitals around the country to think seriously about. We know that opening up the blocked artery within 12 hours after the onset of the heart attack, either using the angioplasty stent procedure or the clot-busting drug procedure, is very, very effective.

One of the other major findings that was announced at the American Heart Association meetings today was a study that's called "door-to-balloon." And what it's looking at is the length of time it takes for an individual with a heart attack, once they arrive in the emergency room, to get to the heart catheterization laboratory and have that balloon inserted in their artery and open it up.

We're recommending that the door-to-balloon time be less than 90 minutes, although that's very difficult to achieve. Only about 20 percent of hospitals in this country achieve that at the present time.

GWEN IFILL: OK, so a whole new set of questions apparently.

ELIZABETH NABEL: Absolutely, but some answers, as well.

GWEN IFILL: Some answers, as well. Dr. Nabel, thank you very much for helping us.

ELIZABETH NABEL: My pleasure. Thank you.