Aug. 28, 2012— -- The latest salvo in the battle over stents -- the tiny mesh sleeves designed to keep clogged coronary arteries open -- came in the form of a study suggesting that the devices are better for some patients than medicines alone.
In a new multi-center study called FAME II, which examined outcomes of 888 patients with a significant blockage of least one coronary artery, researchers used a new measure -- known as fractional flow reserve, or FFR -- to decide if a patient should get a stent or not.
The study authors suggest that FFR could help doctors figure out whether a patient's coronary artery blockage is going to put them at risk for a heart-related emergency, such as a heart attack or severe chest pain.
The trial was stopped early because it quickly became clear that those who had not received stents required more hospitalizations and emergency procedures and experienced more heart attack symptoms than their stented counterparts. By the time the study was halted, 12.7 percent of patients without stents had experienced one of these cardiac events, while only 4.3 percent of people who received stents had.
The study was published Tuesday in the New England Journal of Medicine to coincide with its presentation at the annual meeting of the European Society of Cardiology in Munich, Germany. The research was supported by St. Jude Medical, a company that manufactures FFR assessment products and other heart-related devices.
"Stable coronary disease is a very common problem, and there is certainly room for improvement, and using FFR appears help guide stent placement," said lead study author Dr. William Fearon, an associate professor of medicine at Stanford University Hospital.
However, the new study is unlikely to end the debate over the use of stents, which has raged since a landmark study in 2007 known as the COURAGE trial. This study looked at all patients who required a coronary artery catheterization for symptoms of heart trouble. What it found was that less-invasive medical therapy -- in other words, using drugs to control heart risk factors -- was better than the more-invasive stent approach.
In 2009, a new trial -- known as FAME I -- reignited the stent debate. Previous trials, such as COURAGE, relied on a long-used diagnostic procedure known as angiography to assess the severity of coronary artery blockages. The researchers behind FAME I said that their findings showed that FFR painted a more accurate picture of who needed stents and who did not. Many criticized this trial, however, because it included patients who were actually having heart attacks -- patients who had been excluded in COURAGE. Additionally, it did not compare stenting to the standard practice of medical therapy.
Fast forward to FAME II -- a study that attempted to exorcise these demons by offering a comparison of FFR to medical therapy.
"I think that, based on COURAGE, many physicians are treating these patients with medical therapy alone," lead author Fearon said. "While it may be appropriate in some, others would benefit from intervention.
"This study shows that we can best identify those patients by FFR and will enable more appropriate care."
Some doctors not involved with the research agreed that FFR could be a very useful tool in determining the severity of a patient's heart disease.
"Fractional flow reserve (FFR) is a powerful, invasive tool that can pick out blockages that, at least at the time at which they are being studied, are sufficiently severe as to be able to prevent a safe and healthy increase of blood flow to the heart and can distinguish them from blockages that are not," said Dr. Brian O'Murchu, associate professor of medicine and associate director of the cardiac catheterization laboratory at Temple University in Philadelphia. "In this way, it gives much the same information as is provided by stress tests that include imaging of the heart."
"Recent pressure based on the COURAGE trial to reduce overall stent usage has made an early revascularization strategy less clear," said Dr. George W. Vetrovec, a professor of medicine in cardiology at Virginia Commonwealth University. "FAME II provides, I believe, an important counter argument in patient management for stable but symptomatic coronary disease."
Yet, some doctors remain cautious about these results.
One of these physicians is Dr. Harlan Krumholz, professor of medicine and investigative medicine at Yale University. Krumholz said that the new study falls short of proving that stents prevent heart attack and death.
"[T]he rates of death and the rates of [heart attack] were similar in the two groups," Krumholz said.
Others agreed. "I do not think that this trial should change practice," said Dr. Raymond Gibbons, professor of medicine at the Mayo Clinic. "Try medical therapy first. If your symptoms don't improve, then discuss the risk and benefits of stents with your physicians. Realize that stents do not reduce the rate of heart attack and death."