Blood thinner shown to help heart patients

Research: Clopidogrel, a 'super aspirin,' reduces the likelihood of heart attack and stroke in many patients with existing heart conditions.

Health & Fitness

April 15, 2001|By Thomas H. Maugh II | Thomas H. Maugh II,LOS ANGELES TIMES

A relatively inexpensive drug already on the market could prevent as many as 100,000 heart attacks in the United States each year, researchers reported recently.

The drug is clopidogrel, a blood thinner now used to stave off clotting in patients undergoing angioplasty. For people who suffer mild heart attacks or ominous chest pain, it could be the biggest advance in heart care since the widespread introduction of prophylactic aspirin therapy, authorities said.

"This is a breakthrough," said Dr. Valentin Fuster of the Mount Sinai School of Medicine in New York, a past president of the American Heart Association. "It will change the practice of medicine."

The research was reported at a meeting of the American College of Cardiology, in Orlando, Fla. Several other promising studies and at least one negative one were also presented at the meeting.

As many as 2 million Americans are hospitalized with mild heart attacks and bad chest pain every year -- a condition often called acute coronary syndrome, unstable angina, or non-q-wave myocardial infarction -- and a significant percentage of them go on to suffer more serious heart attacks or strokes when clots form in their bloodstream.

If every one of these patients received clopidogrel as part of a regimen of heart drugs, the drug would prevent 50,000 to 100,000 heart attacks and strokes and save 5,000 to 10,000 lives, Dr. Salim Yusuf of McMaster University in Hamilton, Canada, said. Worldwide, it could prevent 250,000 to 500,000 cardiac events if used on just one-fifth of those who might benefit, he added.

Yusuf led a team that studied 12,562 patients at 482 hospitals in 28 countries, all with acute coronary syndrome. All of the patients received standard treatment for the condition, including aspirin. In addition, half got clopidogrel; half got a placebo.

Yusuf said that 11.47 percent of those receiving standard therapy alone suffered an additional heart attack or stroke or died, compared with 9.28 percent of those receiving clopidogrel -- a 20 percent reduction.

"This is really a super aspirin that lives up to its name," said Dr. Christopher P. Cannon of Brigham and Women's Hospital in Boston.

The principal side effect of the treatment was increased bleeding, Yusuf said. About six of every 1,000 patients receiving the drug needed a transfusion, he said -- about the same rate observed for aspirin.

Clopidogrel costs about $2 to $3 a day. The $50-million study was paid for by Sanofi-Synthelabo, which sells the drug as Plavix, and Bristol-Myers Squibb, which markets it as Iscover. The study was conducted independently of the companies, however.

Among the other presentations at the meeting was a report that looked at secondary effects of the family of cholesterol-lowering drugs called statins.

Statins have proved highly effective in warding off heart attacks and strokes, and a new study suggests that the drug may be combating inflammation of blood vessels, an immune response triggered by infections that is increasingly recognized as an important contributor to heart disease.

Another study demonstrated that a new kind of pacemaker can improve the care of patients with congestive heart failure, in which the heart does not pump effectively, producing fatigue, shortness of breath and accumulation of fluids in the lungs and limbs.

Pacemakers are generally used to treat hearts that beat erratically. Electrical stimulation prods the organ into a regular rhythm. Some types of congestive heart failure also arise, at least in part, because different segments of the heart are not all beating in unison. The new pacemakers use three electrodes to stimulate each of these areas simultaneously so that they march to the same beat.

Between 2 million and 3 million Americans suffer from congestive heart failure, with 400,000 new cases diagnosed each year. It causes 39,000 deaths annually and contributes to 225,000 more. Between 25 percent and 50 percent of the victims suffer from poor synchronization between the right and left ventricles of the heart, reducing pumping efficiency.

A team led by Dr. William Abraham of the University of Kentucky studied 266 patients with the problem. They implanted a quarter-sized device called InSync into the chest of each. Half the implants were left turned off for the first six months, however.

Abraham reported that 63 percent of those whose devices were turned on improved substantially, compared with only 38 percent of those in which it was left turned off. (Those were turned on after six months.)

The devices cost between $10,000 and $12,000, about the same as a good standard pacemaker. Abraham estimated that 750,000 to 1.25 million Americans might be good candidates for them.

Also reported in the meeting were the results of the first controlled study of chelation therapy, in which a chemical called EDTA is reputed to reduce heart disease by removing heavy metals from the blood. The treatment is widely touted on the Internet but is not generally recognized as effective and is rarely paid for by insurance.

Working with proponents of chelation, Dr. D. George Wyse of the University of Calgary studied 84 heart disease patients who were randomly assigned to receive either chelation therapy or a dummy procedure. They got two treatments a week for 15 weeks, followed by monthly treatments for three months.

After six months, Wyse said, "there was absolutely no difference between the two groups."

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