Public Release: 

New American Heart Association Guidelines Clarify Need For Antibiotics To Prevent Bacterial Endocarditis

American Heart Association

NR 97- 4533 (Bact)
American Heart Association report:

DALLAS, June 10 - To reduce the risk of bacterial endocarditis, a rare but potentially fatal infection, antibiotics should be given to certain heart patients before they undergo some dental and surgical procedures, according to updated recommendations from the American Heart Association.

Bacterial endocarditis causes inflammation of the heart's valves or inner lining, which results in abscesses that deform the heart and can lead to irreversible damage.

The infection can arise after invasive procedures, such as dental surgery, when bacteria from the mouth enter the bloodstream.

Lead author of the recommendations, Adnan Dajani, M.D., professor of pediatrics at Wayne State University in Detroit, says that the new version defines more clearly when antibiotics to prevent infection should or should not be considered. The recommendations should reduce treatment costs and potential side effects of antibiotics.

The recommendations will be published in the June 11 issue of The Journal of the American Medical Association, and subsequently in the July 1 issue of Circulation and the Journal of the American Dental Association.

The recommendations, which incorporate new data collected since they last were published in 1990, were developed by the association's volunteer Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease of the Council on Cardiovascular Disease in the Young.

The use of antibiotics to prevent endocarditis among individuals who have mitral valve prolapse has been controversial, says Ann Bolger, M.D., associate professor of cardiovascular medicine at Stanford University in Palo Alto, Calif., and another author of the guidelines.

"The large number of people with mitral valve prolapse makes treatment a costly issue in terms of drug expenses, patient inconvenience and side effects," she says. "Many people will not benefit from taking the drugs, when the only abnormality is the excess motion -- without leakage or thickening there is no increase risk of endocarditis."

Antibiotics are not required for most individuals with mitral valve prolapse, a common condition in which the mitral valve is slightly oversized for the heart and has extra range of motion as a result.

Antibiotics are indicated for individuals with valve leakage (mitral regurgitation), detected as a heart murmur or by ultrasound examination, or those with significantly thickened valve tissues.

"It is not the abnormal valve motion, but the jet of mitral insufficiency that creates shear forces and flow abnormalities that increase the likelihood of bacterial adherence on the valve," says Bolger.

Kathryn A. Taubert, Ph.D., a senior science consultant with the American Heart Association and co-author of the recommendations, says the guidelines, primarily directed to physicians, dentists and other health-care professionals, also apply to anyone who is at high risk due to a heart condition or who has previously had endocarditis. A "wallet card" is available for members of the general public who may be at risk and for health-care professionals. The card may be obtained through the local American Heart Association offices or by calling 1-800-AHA-USA1.

Certain heart conditions are more often associated with endocarditis than others. Antibiotics to prevent infection are recommended for individuals considered at higher risk for developing endocarditis than the general population. Antibiotics are particularly important for individuals in whom endocardial infection is likely to lead to serious complications, including death, says Taubert.

At-risk individuals include anyone with an artificial heart valve, certain congenital heart malformations, heart valve damage or dysfunction, or who has already had endocarditis. Other conditions include hypertrophic cardiomyopathy, or previous heart valve reconstruction.

Antibiotics are not recommended for individuals with isolated atrial septal defects, previous coronary bypass surgery, innocent heart murmurs, previous Kawasaki or rheumatic heart disease without valvular dysfunction, or cardiac pacemakers.

For high or moderate risk individuals, the American Heart Association recommends antibiotics before dental procedures if bleeding is anticipated. These include dental extraction and other periodontal procedures including surgery, scaling, root planing, probing, recall maintenance, dental implants, and reimplantation of teeth.

Antibiotics are not recommended for local anesthetic injection, placement of rubber dams, suture removal, taking of oral impressions, fluoride treatment or orthodontic appliance adjustment.

In addition to dental work, antibiotics for at-risk patients are indicated for certain surgical procedures that involve the mouth and oral cavity, the upper respiratory tract and the gastrointestinal and genitourinary system. Some of the procedures include tonsillectomy, adenoidectomy, billary tract surgery, and other surgical operations that involve the intestinal mucosa.

Antibiotics are not recommended for vaginal hysterectomy, vaginal delivery or Cesarean section. Cardiac catheterization, balloon angioplasty, implanted pacemakers or defibrillators, or coronary stents also do not require antibiotics.

The new recommendations have changed antibiotic regimens. For oral/dental procedures, the initial amoxicillin dose has been reduced to 2 grams as a single dose; a follow up dose is no longer recommended. Erythromycin is no longer recommended for penicillin-allergic individuals; but clarithromycin and other alternatives are offered.

Dajani, Taubert and Bolger's colleagues in drafting the new recommendations were Walter Wilson, M.D.; Arnold Bayer, M.D., Patricia Ferrieri, M.D., Michael H. Gewitz, M.D., Standford T. Shulman, M.D., Soraya Nouri, M.D., Jane W. Newburger, M.D., Cecelia Hutto, M.D., Thomas J. Pallasch, D.D.S, M.S. (liaison, American Dental Association); Tommy W. Gage, D.D.S., Ph.D. (liaison, American Dental Association); Matthew E. Levison, M.D. (liaison, Infectious Diseases Society of America); Georges Peter, M.D. (liaison, American Academy of Pediatrics); Gregory Zuccaro, M.D. (liaison, American Society for Gastrointestinal Endoscopy).

Media advisory: Dr. Taubert can be reached at (214) 706-1455. (Please do not publish telephone numbers.)

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