The AHA Guidelines on Prevention of Infective Endocarditis: Implications for At-Risk Patients Who Undergo GI Endoscopic Procedures

David A. Johnson, MD, FACG, FACP


July 06, 2007

Prevention of Infective Endocarditis. Guidelines From the American Heart Association. A Guideline From the American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group

Wilson W, Taubert KA, Gewitz M, et al
Circulation. 2007; April 19; [Epub ahead of print]

Although infective endocarditis is an uncommon disease, this infection has potentially life-threatening consequences. Obviously, the primary goal would be prevention. As such, for more than 50 years, the American Heart Association (AHA) has recommended that patients deemed at "cardiac risk" for infective endocarditis should receive prophylactic antibiotics. As relevant to the gastroenterology setting, this has been the standard of care for at-risk patients who undergo endoscopic procedures. Despite this "standard," there has been little evidence to support these long-standing AHA recommendations. The present task force of experts from the AHA committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease -- along with an international group of experts -- reviewed data on the effectiveness of prophylaxis in preventing infective endocarditis in patients who undergo a dental, gastrointestinal, or genitourinary procedure.

There was consensus that the development of infective endocarditis occurs as a result of a complex interaction between the bloodstream pathogen with matrix molecules and platelets at sites of endocardial cell damage. All cases of infective endocarditis develop from a common sequence that involves formation of a nonbacterial thrombus, bacteremia, adherence of the bacteria to the nonbacterial thrombus, and then proliferation of the bacteria within a vegetation.

Data were supportive to warrant a new recommendation for gastrointestinal and genitourinary procedures. On the basis of analyses of the relevant literature in regard to procedure-related bacteremia and infective endocarditis, the administration of antibiotics solely to prevent infective endocarditis was not recommended, and specifically is not recommended for patients who undergo endoscopy or colonoscopy. The committee concluded that the bacteremia risks associated with daily activities (eg, toothbrushing, defecation) were more likely to cause bacteremia than were the endoscopic procedures. In fact, they cited the transient bacteremia that is associated with routine daily activities: toothbrushing and flossing (20% to 68%), use of a wooden toothpick (20% to 68%), use of water irrigation devices (7% to 50%), and chewing food (7% to 51%). For dental procedures, the committee recommended prophylaxis, although the identification of "high-risk" patients was refined and limited to include those with prosthetic cardiac valves, previous infective endocarditis, and congenital heart disease (selected and limited new definitions), and cardiac transplant patients with cardiac valvulopathy. Of note is that the committee reported that there was no evidence to support the need for antibiotic prophylaxis in patients who have had recent coronary bypass surgery or coronary stent placement. The use of antibiotics for the prevention of infection of prosthetic joints or for prevention of bacterial peritonitis (in patients with ascites) was beyond the scope of this report.

These updated recommendations are a welcome addition and will help define a new standard of care. The recommendations made for gastrointestinal practice were classified as Class III, Level of Evidence B. This means that for this condition (infective endocarditis), there is evidence and/or general agreement that the treatment (antibiotic prophylaxis for gastrointestinal procedures) is not useful/effective, and in some cases may be harmful. The data to support this recommendation has Grade B support, meaning that the data are derived from nonrandomized studies.

There has been a tremendous increase in the frequency of antibiotic-resistant strains of pathogens, particularly with respect to Enterococcus strains resistant to penicillins, vancomycin, and aminoglycosides: All of these agents have been recommended as prophylactic antibiotics in prior AHA guidelines. It will understandably take time for cardiologists to recognize these new guidelines, and perhaps even more so, for patients to feel comfortable with the major changes. However, gastroenterologists should heed these new recommendations -- antiobiotic prophylaxis solely to prevent infective endocarditis is not recommended for patients undergoing gastrointestinal procedures -- and incorporate the changes immediately into their endoscopic practice.



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