April 20, 2007

CONTACT: Karen Kreeger
(215) 349-5658
karen.kreeger@uphs.upenn.edu


Expert Advisory
New Recommendations on Using Antibiotics Before Dental Procedures to
Prevent Infection of Heart Valves, Lining

Decision Represents Reversal of 50-Year-Old Policy

(PHILADELPHIA) – In the most recent issue of Circulation: Journal of the American Heart Association, the American Heart Association (AHA) reverses its recommendations for the prevention of infective endocarditis (IE), an uncommon but potentially lethal infection of the endocardium, which forms the lining of the heart and heart valves.

In a dramatic reversal of 50 years of policy, the AHA committee now recommends that patients should normally not receive antibiotics before routine dental work.  The only exceptions are those few at the greatest risk of complications should they suffer from IE, such as those who have previously had IE or heart-valve replacement, since they are at the greatest risk of serious adverse outcomes should IE occur.

Brian L. Strom, MD, MPH, Professor of Public Health and Preventive Medicine and Chair of the Department of Biostatistics and Epidemiology at the University of Pennsylvania School of Medicine, and a committee member on this study, comments on the new recommendations: “We questioned the wisdom of these recommendations in the 1970s, but there was no way to generate the needed data to determine whether or not they made sense. Then, in the 1990s, we finally were able to do the needed study, and demonstrated that dental procedures do not place people at higher risk of IE. As such, it makes no sense to give people antibiotics when they have dental procedures.” 

Strom continues, “Further, even if dental work were a risk factor, and even if an antibiotic prevented IE, neither of which has been shown to be true, the amount of disease that would have been prevented is vanishingly low. For that, exposing 10 percent of the population to antibiotics twice a year is not worth the risk.”

Since the bacteria that cause IE live in the mouth and in the intestines, physicians thought that dental or intestinal procedures introduced bacteria into the blood stream, which is how it was proposed to have reached the heart. By looking at 56 years of data on IE and its relationship to dental procedures – from Strom and other groups – the AHA concluded that dental and intestinal procedures were not a factor. People carry chronic infections in their mouths and intestines, so simple activities such as teeth-brushing, eating, and going to the bathroom can introduce the bacteria to the blood stream and can cause IE in a very small portion of the population.

The AHA recommendations were first made in 1955 in Circulation based on what was then thought to be a rational attempt to prevent a life-threatening infection. Since then, and up until 1997, the AHA has continued to change and refine their recommendations.

The review committee has found that the basis for the IE prophylaxis recommendations was not well established and that the quality of evidence was limited to a few case studies. The 1997 recommendations acknowledged that most cases of IE were not attributable to an invasive procedure but instead from randomly occurring bacteria from routine daily activities.

“Giving someone too many antibiotics presents danger to individuals and to society,” says Strom. “We’re becoming more resistant to bacteria as a whole, and over prescribing antibiotics is helping bacteria evolve into organisms that we can’t treat.” It also puts individuals at risk for allergic reactions, nausea and vomiting, and makes them resistant to antibiotics that could be used to help them at another time.

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This release is available online at
http://www.uphs.upenn.edu/news/News_Releases/apr07/infective-endocarditis-recommendations.html