Infective, or bacterial, endocarditis (IE) is an infection of the heart’s inner lining, most often involving the heart valves. This uncommon, but potentially life-threatening, infection is caused by certain bacteria that normally live in the mouth, in intestinal and urinary tracts, and on the skin. Bacteria that enter the bloodstream (a condition known as bacteremia ) during some dental and surgical procedures could potentially infect the heart in the presence of certain cardiac abnormalities. Guidelines published by the American Heart Association (AHA) in 1997 recommended that patients with high- and moderate-risk heart conditions take oral antibiotics ( prophylactic antibiotics) to prevent IE before a number of routine dental and medical procedures.
But newly updated AHA recommendations, published in the online April 19, 2007 issue of Circulation , state that for most people, the risks of taking prophylactic antibiotics outweigh the benefits. What’s more, they now recommend that only people with underlying heart conditions posing the highest risk of IE infection take prophylactic antibiotics before certain dental procedures. In revising its guidelines, the AHA noted that the vast majority of IE cases caused by bacteria in the mouth result from routine daily activities such as tooth brushing and flossing, rather than from dental procedures.
About the Study
The researchers analyzed medical literature published between 1950-2006 dealing with infective endocarditis, including dental and medical-procedure related bacteremia and IE, prophylactic antibiotics for IE, and other related topics, as a basis to update their guidelines.
The researchers reexamined many previous assumptions and found that: 1) only an “exceedingly small” number of IE cases result from dental procedures, 2) although antibiotic therapy reduces the incidence and duration of bacteremia after dental procedures, there is no evidence that this reduction decreases the risk of IE, 3) even if antibiotic therapy was 100% effective, it might only prevent an “extremely small” number of cases of IE, 4) the “vast majority” of IE cases caused by oral bacteria result from daily activities such as tooth brushing and flossing, and 5) the presence of dental disease may increase the risk of bacteremia associated with these daily activities.
As a result of these observations, the AHA updated their guidelines. Listed here are some of the major changes.
Only patients at the highest risk of adverse outcomes from IE should receive antibiotic prophylaxis before routine dental procedures. Patients considered “highest risk” include those with:
- Artificial heart valves
- Previous infection with IE
- Certain specific, serious congenital heart conditions
- A cardiac transplant that develops a problem in a heart valve
Greater emphasis should be placed on dental care and oral health for patients at “highest risk.”
Prophylactic antibiotics for the prevention of IE should not be routinely used for anyone undergoing a gastrointestinal or genitourinary tract procedure.
How Does This Affect You?
The updated guidelines question the effectiveness of prophylactic antibiotics to prevent IE and recommend restricting their use to people who are at the highest risk for a bad outcome from IE. In most cases, the risks of prophylactic antibiotic use, which include allergic reactions and the emergence of drug-resistant bacteria, outweigh the benefits.
The guideline authors also found that IE cases caused by bacteria in the mouth are much more likely to result from tooth brushing and flossing than from a dental procedure. But before you toss your toothbrush, note that dental disease may increase the risk of bacteremia—which means that good oral health practices and regular visits to the dentist are as important as ever.
- Reviewer: Richard Glickman-Simon, MD
- Review Date: 06/2007 -