MONDAY, Sept. 10 (HealthDay News) -- Heart valve surgery using only two tiny openings significantly reduces the risk of death for people who have had previous cardiac surgery, Belgian surgeons report.

"We were astonished that the reduction in risk was much more than we expected," said Dr. Filip P. Casselman, a staff surgeon at the OLV Clinic in Aalst and lead author of a report in a cardiovascular surgery supplement of the Sept. 11 issue of Circulation.

The procedure described in that report cannot be used in all heart valve operations and is not widely available in the United States, Casselman noted. But it is an outstanding example of how much safer minimally invasive surgery can be for high-risk patients, he said. In the study, the risk of dying during or immediately after the operation went from 16 percent to 3.8 percent, he noted.

In the procedure, a tiny camera and light are inserted into the chest through an incision a third of an inch long in the right armpit. Miniature surgical instruments are inserted through a two-inch hole below the right nipple. The surgeon sees an image of the heart on a computer screen and uses "joy sticks" to move the instruments.

The procedure can be used for surgery on the mitral and tricuspid valves, Casselman said, but not on the aortic valve. "For that, we have an alternative minimally invasive procedure," he added.

The mitral valve controls flow of blood from the upper left chamber of the heart to the lower left chamber. The tricuspid valve controls blood flow between the two right chambers of the heart. The aortic valve controls blood flow from the left ventricle, the main pumping chamber of the heart.

The report described results of the technique in operations on 80 patients who had at least one previous cardiac operation. Overall survival was 93.6 percent at one year and 85.6 percent at four years.

One major reason for the high success rate is that the minimally invasive technique does not require the removal of scar tissue that almost always forms after cardiac surgery, Casselman said.

People in the United States seeking this particular kind of minimally invasive heart valve surgery might have a long search, he said. "It is known in the United States but not widely available," Casselman said.

Robotic surgery tends to be favored in the United States for mitral valve procedures, he said. "We avoid the extra cost of the robot," Casselman said. "Robotic surgery gives good results but at a much higher cost."

In the United States, "there are multiple approaches to use smaller and smaller incisions for these operations," said Dr. Irving Kron, chairman of the department of surgery at the University of Virginia, and a spokesman for the American Heart Association.

"Many surgeons tend to use robotics right now, but it is not routine in our practice," Kron said. "The robot doesn't give you a direct feeling of what you are doing, and that troubles us."

There is no single guide to the best minimally invasive procedure for a given patient, Kron said. "The surgeon and the patient have to weigh the situation," he said. "A lot has to do with whether the cardiologist has a relationship with someone who knows a surgical technique."

And while minimally invasive surgery generally is preferable for heart operations, its drawback is that the procedure tends to be longer than conventional surgery in which the chest is opened, which means more time on the heart-lung machine, Kron said.

"If the operation can be done quickly, that is the best," he said. "If you spend twice as long on the heart-lung machine, there may be no gain."

More information

A guide to heart valve surgery is provided by the U.S. National Library of Medicine.