Sept. 23, 2010 -- WASHINGTON -- The heart has many moving parts and as humans age many of these parts wear-out or simply fail to work efficiently, and this is especially true of the valves that regulate blood flow into and out of the heart's chambers. For years, surgeons have replaced or repaired those failing valves. But about 30 percent of patients with a condition called aortic stenosis are too old or too sick for surgery, so they struggle along often disabled by chest pain as they struggle for breath.
But that may be changing. Instead of surgery, doctors can successfully implant a new valve into the heart by placing it into an artery in the groin and carefully threading up into the heart.
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Patients who received new valves this way, a technique call transcatheter aortic valve implantation or TAVI (rhymes with have-ee) had a 20 percent lower mortality rate at one year than similar patients who received only medical therapy or who had medical therapy plus a balloon that forced open the valve.
Moreover, the researchers, led by Dr. Martin B. Leon of Columbia University Medical Center/New York-Presbyterian Hospital in New York City, also found that the interventional procedure using a device called the Sapien heart-valve system reduced the combined endpoint of death from any cause or rehospitalization by almost 30 percent compared with standard treatment.
Treating just five patients would prevent one death at one year, and treating three patients would prevent one death or hospitalization.
The one negative note was the rate of stroke/major bleeding at 30 days -- 12 strokes and 30 major bleeds in the TAVI arm versus three strokes and two major bleeding events in the control group, but by one year the difference in the stroke rate was just 5 percent, which Leon said "was much better than expected."
The PARTNER trial results were scheduled for initial unveiling here Thursday at the Transcatheter Cardiovascular Therapeutics (TCT) meeting, but in an unusual move, the New England Journal of Medicine upstaged meeting organizers by publishing the results online today.
One explanation for the "impressive" mortality benefit was that the "patients in the control arm fared much worse than we had predicted. We predicted a one-year mortality of 35 percent," Dr. Michael Mack of Medical City Dallas and a co-author of the PARTNER (Placement of Aortic Transcatheter Valves) trial told MedPage Today/ABC News.
"A 50 percent mortality was much greater than anticipated, and this tells us much more about the natural history of this disease. It is much more lethal than we thought," he said.
Although the mortality results were impressive, the improvement in symptoms and function were also compelling and also favored TAVI with only 25 percent of the TAVI patients still suffering significant disability from heart failure versus almost 60 percent of the standard therapy patients.
"With patients in their 80s and 90s, the issue is often not survival but quality of life," said Dr. Robert Bonow of Northwestern University in Chicago and a past president of the American Heart Association. Bonow, who was not involved in the study, hailed the results and predicted they would advance the cause of TAVI in the United States.
"This is really a just like a plumbing problem -- you fix the broken valve, you get better flow, everything works better," Bonow explained.
The device is approved and has been in use in Europe for several years.
The average age of patients in PARTNER was 83 and more than 80 percent were men.
The results reported here and in the journal represent one cohort in the trial -- 358 patients who were judged unsuitable for surgery because a risk score developed by the Society of Thoracic Surgeons (STS) predicted that their risk of dying within 30 days of surgery was 50 percent.
Another group of high-risk aortic stenosis patients -- those whose chance of dying within 30 days of surgery was closer to 15 percent -- made up cohort A of the PARTNER trial. Patients in that group were randomized to either a surgical valve repair or to TAVI. Results from that cohort are expected to be reported next spring at the American College of Cardiology meeting.
Dr. Richard Shemin, a thoracic surgeon at UCLA, who was not involved in the study, told MedPage Today/ABC News that those anticipated results represent a truly randomized trial -- comparing TAVI with surgery -- and those results are likely to be more helpful in guiding clinical decisions. "But for patients who are not candidates for surgery, this approach appears to be a good option. It's just that this doesn't tell us that percutaneous implant is the way to go for all patients," Shemin said.
The authors agreed that the study was limited by the exclusion of several important subgroups including patients with coronary stenosis and those with severe peripheral vascular disease. Moreover, assessing the durability and long-term safety of the bioprostethic valve will require more than an one-year follow-up.
While warning that the results cannot be extrapolated to other patient groups, the authors concluded that on the basis of "a rate of death from any cause at one year that was 20 percentage points lower with TAVI than with standard therapy, balloon-expandable TAVI should be the new standard of care for patients with aortic stenosis who are not suitable for surgery."