Technique That Measures Blood Flow Aids Stent Placement
By Charlene Laino
WebMD Health News
Reviewed by Louise Chang, MD
Aug. 28, 2012 (Munich, Germany) -- A technique that measures blood flow through clogged arteries can better tell which heart patients need angioplasty and stenting to open clogged heart arteries, researchers say.
The technique is called fractional flow reserve, or FFR. It involves inserting a wire into the artery to measure blood flow. In a large study, patients for whom FFR revealed restricted blood flow through clogged heart arteries fared better if they had angioplasty plus stenting than patients who took medication.
For people with clogged heart arteries whose blood flow was not restricted on FFR, however, medication was just as effective as stenting, says researcher Bernard De Bruyne, MD, PhD, of the Cardiovascular Center Onze-Lieve-Vrouw Kliniek in Aalst, Belgium.
The main advantage to this test is that some people may have buildup in their arteries, but their blood flow is still fine. In these circumstances, medication is effective, and there is no need for the additional risk that can come from inserting a stent.
FAME vs. COURAGE
The idea for the study grew out of the landmark COURAGE trial, published in 2007. The trial showed that people with stable heart disease who got drug treatment were no more likely to die or to have a heart attack than those who also underwent angioplasty with stents.
COURAGE relied solely on traditional testing to determine if patients had heart disease.
For the new trial, patients also underwent FFR to determine if blood flow to the clogged vessel was restricted.
"We hypothesized that there is a significant proportion of patients who would benefit from stenting compared to receiving only medication -- namely people with severely compromised blood flow to the vessel on FFR," De Bruyne says. And that proved to be the case.
The study, called FAME2, involved 888 patients with at least one narrowed artery causing dangerously restricted blood flow on FFR. They received medication alone or medication plus stenting and were followed for an average of seven months.
Results showed that people who had the artery-opening stents were much less likely to be rehospitalized on an emergency basis (for either another stent or bypass surgery) than those given drug treatment: less than 1% vs. nearly 10%, respectively.
There was no difference in the rates of heart attack or death between the two groups. But the need for emergency procedures was so great in the medication group that the study was stopped early so people taking the drugs could be offered stents, De Bruyne says.
The findings were published online Aug. 28 in The New England Journal of Medicine and presented here at the annual meeting of European Society of Cardiology.
More Centers Offering FFR
Fractional flow reserve is available at most medical centers. And It's being used more and more to help determine the best course of treatment for opening narrowed arteries, says American College of Cardiology immediate past president David Holmes, MD. He is a heart doctor at the Mayo Clinic in Rochester, Minn.
Robert Bonow, MD, is a professor of cardiology at Northwestern University's Feinberg School of Medicine in Chicago. He says he has some reservations about the technique.
While an accurate diagnostic tool, "the cost could be significant in hospitals desperately trying to maintain their bottom line," he tells WebMD.
But De Bruyne says the cost is low, about $750, and studies show that its use is cost-effective -- that more savings are gained through correct choice of patients for stenting than are spent on the test.
The FAME 2 trial was funded by St. Jude Medical, for which De Bruyne consults.
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