Bypass 'Off-Pump' Boosts Women's Outcomes

TUESDAY, Sept. 11 (HealthDay News) -- Performing coronary bypass procedures without using the heart-lung machine can shrink the gender gap in survival and boost women's outcomes after these procedures, a new study finds.

The bypass results are "good news for women," said Dr. John D. Puskas, the lead author of the study that reviewed more than 11,000 bypass surgeries on men and women at Emory University Heart Center un Atlanta, conducted over more than eight years.

The isolated bypass surgeries studied involved bypass grafts alone rather than multiple types of heart procedures, the researchers noted.

And, in another step forward for women's cardiac care, a new study finds that vitamin E supplements reduces a woman's risk of deep vein and pulmonary thrombosis, according research from Brigham and Women's Hospital, Boston.

Both studies were published Sept. 10 in the online edition of Circulation.

When surgeons operate off-pump, the heart continues to beat, and it's a "little bit like changing the spark plugs when the engine is running," said Puskas, an associate chief of cardiothoracic surgery at the Atlanta center. It's a newer technique that's not as frequently used elsewhere as it is at Emory, especially among older surgeons who may have developed their expertise using the traditional heart-pump approach, he added.

"We find there are other benefits" to the off-pump surgery such as "lower transfusion requirements, quicker times out of intensive care, quicker times out of the hospital, lower risk of kidney problems," Puskas said.

In the study, women who had bypass surgery at Emory using the traditional heart-lung machine had a 2.5 times greater likelihood of dying than in the "off-pump" mode, Puskas said.

Men also did better with the off-pump technique, but their benefit was of a smaller degree than that seen in women, he said.

Bypass surgeries already have a good record for safety and effectiveness, but if the mortality rate is reduced "by one-third to one-half, we're trying to make something that is very good even better," Puskas said. "Off-pump is a way to do that, especially for women."

The better results for off-pump surgery were not due only to lowered risk factors, Puskas added, because higher risk patients were also done off-pump.

Researchers for years have been trying to figure out why women tend to fare worse after heart surgery compared to men. One explanation was that female patients tended to be older, and their arteries were smaller in size.

The Emory study gets no further at explaining why off-pump surgery made such an improvement, Puskas added.

Last year, a University of Michigan study reported that 96 percent of the gender gap in mortality rates for women and men within 100 days of coronary artery bypass surgery might be explained by higher infection rates in women.

Puskas, however, said that infection rates did not play a role in results of the Emory study.

If the Emory results are replicated in additional studies, "they will change the practice patterns for women going for bypass, so these are highly significant findings," said Dr. Elizabeth Jackson, a cardiologist and assistant professor of medicine at Michigan. The Emory study now raises questions about "what kind of procedures benefit women more than men and vice-versa." added Jackson, who did not play a role in the Michigan infection study.

Another expert believes that women should be careful not to pressure their heart surgeons to do off-pump procedures.

"The surgeon's comfortability comes into play. I think, down the road, more off-pump surgeries will be done on women, but, ultimately, it will be the choice of the surgeon," said Dr. Suzanne Steinbaum, director of Women and Heart Disease at Lenox Hill Hospital in New York City.

The difference between cardiovascular disease in women and men also affects venous thromboembolism (blood clots in the veins), said Steinbaum, because women have smaller arteries that can raise bigger problems in terms of blood clots and stroke.

But the new vitamin E study, which comes from an analysis of Women's Health Study data, suggests the supplement might reduce the risk of deep vein or pulmonary blood clots, particularly for women with a prior history or who have genetic mutations that predispose them to these events. The study looked at a decade's worth of data from almost 27,000 U.S. women.

Robert J. Glynn, the study's lead author and an associate professor of medicine at Harvard Medical School, said his team was "somewhat surprised to find this result" after prior findings that vitamin E did not lower risks for either cardiovascular disease or cancer in the same research subjects.

Jackson said that, pending further research, women at higher risk should not replace current therapies with vitamin E.

More information

There's more on women's heart health at the American Heart Association.

SOURCES: John D. Puskas, M.D., associate chief, cardiothoracic surgery, Emory University, Atlanta; Robert J. Glynn, Ph.D., Sc.D., associate professor, medicine (biostatistics), Harvard Medical School, Boston; Elizabeth Jackson, M.D., assistant professor, medicine, University of Michigan School of Medicine, Ann Arbor; Suzanne Steinbaum, D.O., director, women and heart disease, Lenox Hill Hospital, New York City; Sept. 10, 2007, online edition, Circulation