My daughter read this in the Austin American Statesman newspaper on Sunday and sent it to me.
Nina
Research questions value of artery-opening operations
New model of heart disease indicates such aggressive measures might not be
as effective as old-fashioned advice
By Gina Kolata
THE NEW YORK TIMES
Sunday, March 21, 2004
A new and emerging understanding of how heart attacks occur indicates that
increasingly popular aggressive treatments may be doing little or nothing to
prevent them.
Artery-opening methods such as bypass surgery and stents -- the widely used
wire cages that hold plaque against an artery wall -- can open obstructed
blood vessels and alleviate crushing chest pain. Stents also can rescue
someone in the midst of a heart attack by destroying an obstruction and
holding the closed artery open.
But the new model of heart disease shows that a vast majority of heart
attacks do not originate with obstructions that narrow arteries.
Instead, recent and continuing studies show that a more powerful way to
prevent heart attacks in patients at high risk is to adhere rigorously to
what can seem like boring old advice: give up smoking, for example, and take
drugs to control blood pressure, lower cholesterol levels and prevent blood
clotting.
Researchers estimate that just one of those tactics -- lowering cholesterol
to what guidelines suggest -- can reduce the risk of heart attacks by a
third, but is followed by only 20 percent of heart patients.
"It's amazing, and it's completely backward in terms of prioritization,"
said Dr. David Brown, an interventional cardiologist at Beth Israel Medical
Center in New York.
Heart experts say they understand why the disconnect occurred: They, too, at
first found it hard to believe what research was telling them. For years,
they were wedded to the wrong model of heart disease.
"There has been a culture in cardiology that the narrowings were the problem
and that if you fix them the patient does better," said Dr. David Waters, a
cardiologist at the University of California at San Francisco.
The old idea was this: Coronary disease is akin to sludge building up in a
pipe. Plaque accumulates slowly, over decades, and once it is there it is
pretty much there for good.
Every year, the narrowing grows more severe until one day no blood can get
through and the patient has a heart attack. Bypass surgery or angioplasty --
opening arteries by pushing plaque back with a tiny balloon and then, often,
holding it there with a stent -- can open an artery before it closes
completely.
But, researchers say, most heart attacks do not occur because an artery is
narrowed by plaque. Instead, they say, heart attacks occur when an area of
plaque bursts, a clot forms over the area and blood flow is abruptly
blocked. In 75 percent to 80 percent of cases, the plaque that erupts was
not obstructing an artery and would not be stented or bypassed. The
dangerous plaque is soft and fragile, produces no symptoms and would not be
seen as an obstruction to blood flow.
That is why so many heart attacks are unexpected, heart experts say. A
person will be out jogging one day, feeling fine, and struck with a heart
attack the next. If a narrowed artery had been the culprit, exercise would
have caused severe chest pain.
Heart patients have hundreds of vulnerable areas with plaque, so preventing
heart attacks means going after all their arteries, not one narrowed
section, by attacking the disease itself. That is what happens when patients
take drugs to aggressively lower their cholesterol levels, to control their
blood pressure and to prevent blood clots.
Yet, researchers say, old notions persist.
"There is just this embedded belief that fixing an artery is a good thing,"
said Dr. Eric Topol, an interventional cardiologist at the Cleveland Clinic.
In particular, he said, more people are getting stents. According to an
analysis by Merrill Lynch, based on sales figures, more than a million stent
operations will be performed this year, nearly double the number performed
five years ago.
Some doctors still adhere to the old model. Others say they know it no
longer holds but that they sometimes end up opening blocked arteries anyway,
even when patients have no other symptoms.
Dr. David Hillis, an interventional cardiologist at the University of Texas
Southwestern Medical Center in Dallas, explained: "If you're an invasive
cardiologist and Joe Smith, the local internist, is sending you patients,
and if you tell them they don't need the procedure, pretty soon Joe Smith
doesn't send patients anymore. Sometimes you can talk yourself into doing it
even though in your heart of hearts you don't think it's right."
Hillis said he has tried to explain the evidence to patients, to little
avail.
"You end up reaching a level of frustration," he said. "I think they have
talked to someone along the line who convinced them that this procedure will
save their life. They are told if you don't have it done you are, quote, a
walking time bomb."