TUESDAY, Jan. 29 (HealthDay News) -- Implanting a stent in a clogged left main coronary artery appeared to give better short-term results than bypass surgery in a Polish study.

But American experts cast some doubt on the clinical value of the finding.

The study, led by cardiologists at the Medical University of Silesia, compared results of surgery versus stenting in 105 patients with serious blockages of the left main coronary artery, which is vital for heart function, because it feeds three other vessels.

There was a significant increase in the heart's blood-pumping ability over the next 12 months in the 52 participants who got the stent implants, but not in the 53 who underwent bypass surgery, said a report in the Feb. 5 issue of the Journal of the American College of Cardiology.

The incidence of major adverse events and the rate of survival was lower in the 30 days following the procedure for stent recipients than for patients who had surgery, the report said, "with a trend toward improved survival" in a two-year follow-up after stent implant.

"One of the limitations of this study is the very small number of patients," said Dr. Edward L. Hannan, assistant dean for research at the State University of New York at Albany, who recently reported at a meeting that surgery tended to be better than stenting for people with blockage of more than one heart artery.

And looking closely at the results, Hannan said he found "no significant difference" between the two methods in the incidence of major adverse events in the longer follow-up.

The Polish results differ from those of one he has done, which he is about to submit to a medical journal for publication, Hannan said. That study, which was not a controlled trial but looked at results reported in clinical practice, found an advantage for surgery over stenting.

But the report has yet to pass the peer review required by medical journals, he cautioned. "No one should trust the results until it has passed peer review," Hannan said.

The surgery-versus-stent question is important for the left main coronary artery, because it is not a blood vessel readily amenable to surgery, Hannan explained. Nevertheless, his research found that surgery "is used much more frequently than angioplasty in current practice, at least 10 times more often. So, we had only a small group of angioplasty patients in our study," he said.

Dr. Howard C. Herrmann, the director of the Interventional Cardiology and Cardiac Catheterization Laboratories at the University of Pennsylvania who has done studies on the subject, found a number of weaknesses in the Polish research, including the small number of patients.

One notable weakness is the relatively short follow-up period, Herrmann explained.

"Their survival time is out to about two years," he said. "Something as important as left main disease might not manifest itself for five years."

Accordingly, older studies that established surgery as the recommended treatment for the condition measured survival at five years or longer, Herrmann noted. "The bottom line from my standpoint is that this study shows that left main stenting is feasible," he said. "I don't think it answers the question about whether it is a better strategy than surgery, which is still considered the standard therapy."

Another report in the same issue of the journal questioned the growing use of a valved stent for aortic stenosis, a condition in which narrowing of a valve reduces the flow of blood from the heart to the aorta and onward to the rest of the body.

The study, by French cardiologists, of 35 cases in which a valved stent was implanted for severe aortic stenosis, found consistent misplacement of the device. "Premature failure of implanted valve stents... might be an important concern in the future," the report warned.

More information

You can learn more about why and how stents are used from the American Heart Association.

SOURCES: Edward L. Hannan, M.D., assistant dean, research, State University of New York at Albany; Howard C. Herrmann, M.D., director, Interventional Cardiology and Cardiac Catheterization Laboratories, and professor, medicine, University of Pennsylvania, Philadelphia; Feb. 5, 2008, Journal of the American College of Cardiology

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