Study Finds Angioplasty Safer Than Bypass Surgery : Health: Results apply to patients with mild heart ailment. But cardiovascular surgeons say the research is misleading and based on outdated figures.

Patients with a mild form of clogged arteries are twice as likely to die from bypass surgery as they are from angioplasty, in which a balloon is inflated inside the arteries to open them, according to the first major study to directly compare the two procedures.

While cardiovascular surgeons charged that the research is misleading and based on outdated figures, the study’s authors say it appears to raise serious questions about the use of bypass surgery in such low-risk patients.

They added that the difference in the risk of the two procedures is probably even greater now because the study involved patients treated during 1985, when angioplasty was first widely used. The death rate for angioplasty has fallen since then, while that for bypass surgery has remained stable, according to Dr. Arthur J. Hartz, a clinical epidemiologist at the Medical College of Wisconsin and primary author of the study published in the most recent issue of the American Journal of Cardiology.

For patients with a more severe form of clogged arteries, the study showed, the two procedures have about equal risk.

“This is an enormously important study,” said Dr. David B. Pryor, a cardiologist at the Duke University Medical Center and another of the study’s authors. “We shouldn’t assume that all patients are the same” in selecting the proper form of treatment.

The study also showed that where a procedure is performed may be crucial to its effectiveness and safety. The angioplasty death rate in the study, in which data was collected from a broad spectrum of hospitals, was higher than that in previous published studies of angioplasty conducted in large university medical centers. The effectiveness of medical procedures in the “real world” may not be as good it is in the university medical centers where they were developed, Pryor said.

While it would be “premature” to make any recommendations based on this study, “it is a useful set of data that will generate some interesting discussions,” said Dr. George Sopko, a cardiologist at the National Heart, Lung and Blood Institute. “It will provide further impetus to the study of these types of coronary revascularization.”

In fact, five major studies comparing the two procedures are under way in the United States and Europe. Results will not be available until the mid-1990s, however, so the current study is the only one to date that offers a clear comparison between the two approaches.

But the new study is an unfair comparison because the researchers were not able to get all the information they needed to make a more accurate assessment of risks, said Dr. Gerald M. Pohost, a cardiologist at the University of Alabama at Birmingham and chairman of the American Heart Assn.’s Council on Clinical Cardiology.

Pohost and others say a much larger number of such low-risk patients are directed to angioplasty than was the case when the study results were collected. He noted that bypass surgery is more often used on patients with more serious disease who are thus more likely to die in the year after surgery.

Furthermore, the patients involved in the study were all over 65 and thus at a higher risk of dying from surgery of any kind, said Dr. Lawrence Cohn, chief of cardiac surgery at Brigham & Women’s Hospital in Boston. “At first blush, it sounds like a problem, but in the light of day, the risks are almost equivalent,” Cohn said. Clogged arteries create the crushing pain known as angina. More than 2.4 million Americans suffer from angina and an additional 300,000 new cases are diagnosed each year, according to the American Heart Assn. Even if the condition does not produce a heart attack, it can be severely crippling, interfering dramatically with daily life.

More than 370,000 patients have bypass surgery each year and 250,000 have angioplasty. Because of the large numbers of patients involved, it is crucial to know which of the two procedures is better and safer. That information has not been available.

Hartz and his colleagues based their study on data collected by the Health Care Financing Administration, which administers Medicare. They studied records for all 96,666 Medicare patients who had bypass surgery or angioplasty in 1985.

When the researchers took the severity of the angina and other complications into account, they found that patients with milder angina who underwent bypass surgery had a the risk of dying 2.15 times greater than patients who underwent angioplasty. Among sicker patients, however, the risk was the same for both procedures.

Previous studies of angioplasty conducted at large medical centers have reported 30-day mortality rates between 0.1% and 1.2%, well below the 3.8% observed in the current study. Part of the difference may reflect the fact that the Medicare patients were older and poorer than those in the university studies, Sopko said.

But it also reflects the fact that surgeons in public hospitals generally may not perform as well as those in university medical centers, Pryor said. “It appears, as best we can tell, that performance in angioplasty from the best medical centers is superior to the experience for the country as a whole,” he said.

The primary limitation with the study is that the data is seven years old, while the technology for opening clogged arteries has been continually evolving. Furthermore, angioplasty is being used much more routinely on low-risk patients such as those described in the study.

“Angioplasty is now the first procedure of choice,” Pohost said. “Most patients and doctors feel that it is worth a try to start with it.”

The Health Care Financing Administration is attempting to develop ways to obtain information from its data banks on a more timely basis, said Dr. Henry Krakauer of the agency.

“We need mechanisms to keep teaching us what works and what works well,” Krakauer said. “We need to continually evaluate the quality of the product so that we can make rational choices that are then, by definition, cost effective.”