TUESDAY, Nov. 22 (HealthDay News) -- For patients with a condition called infective endocarditis, coupled with heart failure, heart valve surgery can reduce the risk of dying by nearly two-thirds, a new study suggests.

Infective endocarditis, an infection of the lining of the heart that often includes the heart valves, has been associated with a high risk of death. Previous studies have found that in-hospital mortality can be as high as 20 percent and death after a year can reach 40 percent.

"Cardiac surgery during hospitalization for infective endocarditis is associated with significantly lower in-hospital and one-year mortality, compared to medical therapy [drug therapy] alone, even for heart failure which is mild or moderate in severity," said lead researcher Dr. Andrew Wang, a cardiologist and associate professor of medicine at Duke University.

About one-third of patients with endocarditis experience heart failure as a complication, which is typically advanced or severe in degree and due to an acute heart valve problem, he said.

"Nearly two-thirds of patients with this complication undergo surgery during the initial hospitalization, and surgery is associated with lower mortality at one year," Wang added.

Patients with endocarditis and mild heart failure should be evaluated by a team of specialists for possible cardiac surgery, he noted. "Increased use of cardiac surgery for patients with this complication may lower the mortality rate in endocarditis," Wang said.

The study was published in the Nov. 23/30 issue of the Journal of the American Medical Association.

For the study, Wang's team looked at data from more than 4,000 patients with endocarditis of a heart valve from June 2000 to December 2006, in 61 hospitals in 28 countries.

Among patients with chest X-rays available, 33 percent had heart failure and 67 percent of these patients had heart failure so severe it limited their activities.

More than 800 of these heart failure patients underwent heart valve surgery.

Wang's group found that nearly 30 percent of the heart failure patients died in the hospital, and those who had surgery were at lower risk (20.6 percent) compared with patients treated with drug therapy alone (44.8 percent).

After one year, 29 percent of the patients who had surgery died, compared with 58 percent of the patients who were on drug therapy alone, the researchers found.

Factors connected with dying in the year after treatment included older age, diabetes, an infection contracted in the hospital, other infections, stroke and complications from the surgery, the study authors noted.

In the United States, there are about 15,000 new cases of infective endocarditis each year, according to background information in the study.

Wang noted that the average Medicare payment to hospitals for heart valve replacement surgery ranges from $25,000 to $45,000.

"In our study, surgery for patients with heart failure as a complication of endocarditis was associated with a 50 percent lower mortality, compared to medical treatment alone, so was more effective than medical therapy," he said.

Commenting on the study, Dr. Gregg Fonarow, a professor of cardiology at the University of California, Los Angeles, and a spokesman for the American Heart Association, said that "infective endocarditis results in very substantial morbidity and mortality."

The risks these patients face are even higher if the infective endocarditis results in heart failure. In these patients, the benefits of valvular heart surgery generally outweigh the risk, he said.

"Current guidelines from the American Heart Association and American College of Cardiology recommend surgery in patients with endocarditis complicated by heart failure, even in older patients with multiple comorbid [pre-existing] conditions," Fonarow said.

"These findings suggest that there are further opportunities to improve the care of patients with infective endocarditis, both in identifying appropriate patients for surgery and improving outcomes for those treated surgically," he added.

More information

For more on endocarditis, visit the U.S. National Library of Medicine.