WEDNESDAY, Sept. 22 (HealthDay News) -- For patients who are too sick to withstand surgery to treat a narrowed aortic valve, a new and less invasive heart procedure might keep them alive, researchers say.

As many as 300,000 Americans suffer from aortic stenosis, a condition that prevents the heart's aortic valve from fully opening and sending blood back into the heart. Because of age or poor health, about 30 percent of those with aortic stenosis can't undergo surgery, the researchers say.

"Aortic stenosis is a high prevalence disease in the elderly, and with an aging population it's becoming more frequent," said lead researcher Dr. Martin B. Leon, director of the Center for Interventional Vascular Therapy at New York-Presbyterian Hospital and Columbia University Medical Center in New York City.

"This is truly a lifesaving procedure for those patients who cannot have surgery and who have this terrible disease," Leon said.

Without a valve replacement, which requires surgery to open up the chest, about 50 percent of patients with aortic stenosis die within two or three years of diagnosis.

For the study, published in the Sept. 23 issue of the New England Journal of Medicine, 358 patients with severe aortic stenosis who could not undergo replacement-valve surgery were randomly assigned to either standard therapy or a new procedure. The patients' average age was 83, and 20 percent were 90 or older, Leon said.

Standard therapy included medication and a procedure called balloon aortic valvuloplasty, which provides some relief but does not alter long-term outcomes.

The new procedure -- transcatheter aortic-valve implantation (TAVI) -- involves routing a large catheter through the femoral artery in the patient's groin into the heart. When the catheter reaches the aortic valve, a balloon inflates and opens the valve. Doctors then implant a cow's heart valve, Leon explained.

The procedure takes less than an hour, and patients leave the hospital after a day or two, he said. Open-heart surgery, on the other hand, can last four to six hours, and recovery may take three months, he noted.

After a year, patients who underwent TAVI had a significantly lower rate of death from any cause compared with patients who got standard therapy (30.7 percent vs. 50.7 percent).

TAVI patients also had a reduced rate of death or re-hospitalization compared with those receiving standard care (42.5 percent versus 71.6 percent respectively), the researchers report.

TAVI patients reported greater reduction in symptoms than the other group, and no valve deterioration was noted during the year after the procedure.

"It's not just the fact they are living longer, they are feeling dramatically better," Leon said.

However, more patients who underwent TAVI had a major stroke (5 percent) in the 30 days after the procedure than those in the standard therapy group (1.1 percent), the researchers note.

Efforts are under way to reduce complications, Leon said.

Another trial is assessing the procedure in high-risk patients who could undergo surgery. "In the future we will be looking at lower-risk patients as well," he said.

Previously, no effective treatments were available for patients with severe aortic stenosis who were not candidates for aortic valve surgery, said Dr. Gregg Fonarow, an American Heart Association spokesman and a cardiology professor at the University of California, Los Angeles. These patients "faced a very high risk of mortality," he added.

"As a result of this impressive new trial and pending FDA approval, transcatheter aortic-valve implantation represents an important therapeutic advance and a new standard of care for this important patient population," Fonarow said.

Dr. William O'Neill, executive dean for clinical affairs at the University of Miami Miller School of Medicine, added that this is one of the top studies of the decade. "I think it's going to be looked at as a true landmark study," he said.

"This will totally change practice," O'Neill added. "If the valves are durable, they will eliminate the need for patients to have open-heart surgery to replace the valves."

More information

For more information on aortic stenosis, visit the U.S. National Library of Medicine.