ORLANDO, Fla. -- Contradicting earlier research, a Duke University Medical Center study of patients from 57 hospitals indicates that treating a heart attack by unclogging it with a balloon catheter fails in the long run to save substantially more people than therapy with clot-busting drugs.
Not only does the study, the largest of its kind, counter other findings that the catheter method known as direct or primary angioplasty saves significantly more lives, but it changes interpretation of the initial results of the Duke study of 1,138 patients that concluded direct angioplasty patients had a "small-to-moderate" clinical advantage over thrombolytic drug therapy one month after treatment.
Those same patients have now been followed for six months, and the researchers found that advantage has diminished. The rate of death or second heart attack was not statistically different between the two therapies. The new findings were prepared for presentation at the American Heart Association's annual scientific meeting.
While the new study shows a clearer picture of the benefits of the treatments, "we still don't have enough information to definitively say which is better," said Duke cardiologist Dr. Christopher Granger. "Although the truth is not clearly defined yet, it's important to temper enthusiasm for expansion of direct angioplasty into community hospitals."
Many hospitals have not waited for such long-term studies before leaping into direct angioplasty, Granger said. Introduced into general use only about three years ago, now 15 percent of all patients with heart attacks are treated with direct angioplasty.
And this is worrisome, Granger said. "The patients in the study were treated at centers that are very experienced in angioplasty and yet there was, ultimately, no substantial advantage in the treatment," he said. "We are concerned that inexperienced hospitals are rushing to set up direct angioplasty services, forsaking faster, efficient drug therapy to offer perhaps less than optimal intervention.
"Direct angioplasty has excellent results in a place that is extremely experienced with the technique, that can get heart attack victims to the cath lab immediately and into the hands of a skilled operator," he said. "But there are few hospitals like that."
The finding is sure to intensify the already vigorous debate about the benefit of direct angioplasty, a procedure that a growing number of cardiologists love to do, Granger said in an interview. "There seems to be no middle ground in this issue. Most people are on one side or the other -- direct angioplasty or thrombolytic drug therapy."
Direct angioplasty is very satisfying to an interventional cardiologist, Granger said. A patient comes in to the emergency department complaining of chest pain. He is having a heart attack. He's rushed to a "cath lab" where a physician threads a catheter into the dying heart, inflates a balloon, and watches on a monitor as the clog producing the attack is eliminated, and blood rushes in. The patient feels better right away -- and the doctor sees the benefit of his work.
Moreover, by working directly in the heart, physicians can tailor follow-up treatment. The procedure is financially rewarding as well, Granger says.
Contrast that with its decidedly duller cousin, thrombolytic therapy -- the intravenous infusion of clot-busting drugs such as streptokinase and t-PA to relieve heart attacks. Neither the doctor nor the patient knows if, and when, such drug therapy is working. However, intravenous thrombolytic therapy is the standard of care for patients having heart attacks, because of its widespread availability and proven ability to reduce death. More than a million people have received these drugs in the past decade, Granger said.
Direct angioplasty became attractive in 1993 when three small randomized trials concluded the technique saved an estimated 40 lives per 1,000 patients treated, a huge clinical advantage. But these trials were performed at "selected hospitals with a lot of experience, involved few patients, and except in one case, used thrombolytic regimens that are suboptimal by today's standards," Granger said.
The Duke study was designed to study as many patients as possible for a lengthier period of time. It looked at the outcomes of 1,138 heart attack patients who were given either the clot-busting drug t-PA or direct angioplasty in 57 hospitals in nine countries as part of a sub-study of the GUSTO IIb (Global Use of Strategies to Open Occluded Coronary Arteries in Acute Coronary Syndromes) clinical trial. Each participating hospital had to be proficient in the procedure: 85 percent of the hospitals did at least 400 angioplasties yearly.
The researchers looked at the outcome in patients 30 days after treatment and found that direct angioplasty provided a small-to-moderate, short-term clinical advantage. Death occurred in 5.7 percent of the angioplasty patients, compared to 7 percent in patients who received t-PA. Also, 4.5 percent of angioplasty group experienced a second heart attack, compared to 6.5 percent of drug therapy patients. That study was published in the June 5, 1997 issue of The New England Journal of Medicine.
But in the six-month follow-up, they found that the advantage angioplasty patients had after one month diminished six months later. The new results show no statistically significant difference between the two groups. They specifically found that:
- 7.8 percent of patients given angioplasty died, compared to 8.4 percent receiving drug therapy.
- 6.7 percent of angioplasty patients had a second heart attack compared to 7.8 percent in the drug therapy group.
- Death and/or second heart attack together affected 13.3 percent of angioplasty patients compared to 14.8 percent of those treated with drug therapy.
- Death, second heart attack or disabling stroke incident, added together, affected 13.3 percent of angioplasty patients compared to 15.7 percent of drug therapy patients. Pointing out that none of the angioplasty patients had a stroke, Granger said, "A major advantage of direct angioplasty is the low incidence of strokes."
It took an average of two hours to treat patients with direct angioplasty, versus 50 minutes for drug therapy. Time matters when the goal is to save heart muscle, Granger said. "One of the problems with direct angioplasty is that you have to have a ready staff to do the procedure. Not many hospitals are staffed like that." He also said that the time it took to administer thrombolytics was too slow, as well.
Both procedures end up costing the health care system the same, according to an analysis of costs by Duke researchers. Although an angioplasty is more expensive than clot-busting drugs, 36 percent of the drug therapy patients needed to have a follow-up angioplasty, they found.
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Journal
New England Journal of Medicine