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Journal of the American College of Cardiology Vol. 52, No. 6, 2008© 2008 by the American College of Cardiology Foundation ISSN 0735-1097/08/$34.00Published by Elsevier Inc. doi:10.1016/j.jacc.2008.07.004

ACC NEWS

resident’s Page: Antimicrobial Prophylaxiso Prevent Infective Endocarditis:

hy Did the Recommendations Change?

W. Douglas Weaver,

MD, FACC

ACC President,

Rick A. Nishimura,

MD, FACC

Carole A. Warnes,

MD, FACC

A final impetus for

change was that

the guidelines

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the prophylaxis.

t has been more than 50 years since the American Heart Association (AHA) firstmade recommendations for the use of antimicrobial agents to prevent infective en-docarditis (IE). The first AHA document on this subject was published in 1955

nd has been followed by 9 revisions outlining which patients, which procedures, andhat antibiotics should be used to prevent IE. Since that time, there have been extensive

fforts by physicians, dentists, and patients to ensure that everyone at risk for developingndocarditis would follow these guidelines and receive the proper regimen of antibioticsrior to selected dental or surgical procedures.However, in 2007 the AHA issued guidance for IE prophylaxis that greatly simplified

he recommendations and proposed substantive changes—changes that would affectundreds of thousands of patients in the U.S. alone (1). Since then, we, and most likelyll of you, have been barraged by our surgical and dental colleagues and patients withnquiries—“Are you sure this is the right thing to do? Would you mind putting the rec-mmendation in writing before I proceed?”

hat Evidence for Change?

hy were these significant changes introduced, and why wasn’t there a heads up thatuch a dramatic change was coming? It helps to remember that the prior rationale forsing antimicrobial prophylaxis was that antibiotics would control bacteremia at theime of the procedure and thus prevent IE. However, this treatment rationale wasased primarily on expert opinion and support from a few case-controlled and de-criptive studies. There has never been a controlled, randomized study that evaluatedhis strategy.

In contrast, some have noted the lack of consistent association between having annterventional procedure and the development of IE, and they have questioned thelinical effectiveness of antibiotic prophylaxis. Some have asked whether the risk ofiving antibiotics outweighed the small, perhaps nonexistent benefit. It has eveneen suggested that the risk of a serious allergic reaction to amoxicillin is greaterhan the risk of contracting IE.

A report from the Cochrane Collaboration in 2004 concluded, “There is no evi-ence about whether penicillin prophylaxis is effective or ineffective against IE ineople at risk who are about to undergo an invasive dental procedure. There is lackf evidence to support published guidelines in this area, and it is not clear whetherhe potential harm and costs of penicillin administration outweigh any beneficial ef-ect” (2).

Evidence is now moving from “procedure-related bacteremia” toward “cumulativeacteremia” as the more likely cause of most cases of IE. For instance, daily activi-ies such as tooth brushing are estimated to produce bacteremia 6 million timesigher than a single tooth extraction. Thus, continued episodic bacteremia due tooor dentition may pose a much greater risk for the development of IE than a single

ental procedure.

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496 Weaver et al. JACC Vol. 52, No. 6, 2008President’s Page August 5, 2008:495–7

A final impetus for change was that the guidelineshemselves had become more complicated with each revi-ion, with ambiguous recommendations for which specificatient and which particular procedure required the pro-hylaxis.

ecommendations Shift Emphasis

n the basis of these controversies, the AHA Rheumaticever, Endocarditis, and Kawasaki Disease Committeeonvened a group of national and international experts inhe field, including cardiologists, infectious disease spe-ialists, pediatricians, and dentists. This writing groupnalyzed relevant literature regarding procedural-relatedacteremia and IE, in vitro susceptibility data of the or-anisms causing IE, and results of prophylactic studiesnd animal models of experimental IE, as well as any ret-ospective or prospective studies in the prevention of IE.fter several years of discussion and debate within theriting group combined with input from experts fromther learned societies, the new recommendations wereeleased. The recommendations were clear, simple, ando the point:

Infective endocarditis prophylaxis should be given only to ahigh-risk subgroup of patients prior to dental proceduresthat involve manipulation in gingival tissue or periapicalregion of the teeth or perforation of the oral mucosa.High-risk patients include only those with a: 1) prostheticcardiac valve; 2) previous infective endocarditis; 3) com-plex congenital heart disease; and 4) valvulopathy follow-ing cardiac transplantation.Infective endocarditis prophylaxis is not recommended priorto gastrointestinal or genitourinary procedures.

These recommendations represented a major departurerom the traditional practice of IE prophylaxis. The com-ittee wanted to shift emphasis away from a focus on

ntibiotic prophylaxis prior to a single procedure to rec-mmendations that place a much greater emphasis onmproved access to dental care and oral health in patientsith underlying cardiac conditions. “High-risk” patientsere defined not on the basis of an increased risk for IE,ut rather on an increased risk of an adverse outcomehould they develop endocarditis.

The new guideline, which generated considerable con-roversy among physicians, dentists, and patients, repre-ented a paradigm shift from traditional dogma and wasased on expert consensus rather than on any compellingew data or evidence. In fact, one might argue that it waseally a consensus document—and not an evidence-baseduideline.

Health care providers have been reluctant to stop aractice that they had been taught was necessary to pre-ent a devastating event and that they have ingrained inheir patients who have underlying structural heart dis-

ase. Even the experts in this practice area have been un- a

ble to reach agreement or comfort with these new rec-mmendations. Other societies, such as the Britishociety for Antimicrobial Chemotherapy, have also rec-mmended simplified guidelines, although not at theagnitude of change suggested by the AHA (3).The American College of Cardiology (ACC)/AHA

ask Force on Practice Guidelines is providing an updaten IE prophylaxis for the 2006 ACC/AHA Guidelinesor the Management of Patients with Valvular Heart Dis-ase (VHD) (4), and we should probably anticipate thathe soon to-be-published Adult Congenital Heart Diseaseuidelines will also include some sort of update. TheCC/AHA VHD Guidelines, as well as several others,ave always referenced the AHA IE Prophylaxis Guide-

ine. The writing committees for the VHD Focused Up-ate and Guidelines, which comprise physicians selectedor their expertise in VHD, were asked to comment onhe new IE recommendations released by the AHA.ased on their review of the initial 2007 AHA document,

he AHA published an errata document in April 2008hat changed some of the language in order to clarify theecommendations. The ACC/AHA Focused Update,hich will be published in JACC and Circulation soon,

ddresses the recommendations as they apply to the man-gement of VHD.

ontroversy or Different Expectations?

mong many physicians and experts, controversy contin-es over these changes. Some firmly believe that the newecommendations should clearly be followed without ex-eption. However, others argue that for antibiotic prophy-axis “the lack of evidence of benefit is not necessarily theame as lack of benefit” and that insufficient new evidencexists to justify such a radical change in policy. It haseen argued that there is an illogicality of the fudge inontinuing to recommend prophylaxis for very high riskatients, as endocarditis is always dangerous. If antibioticrophylaxis is ineffective, why select only a high-riskroup for prophylaxis?

Despite the controversy and angst that these new rec-mmendations have generated, there have been someeneficial outcomes. The document has raised awarenesshat meticulous oral hygiene and routine preventive carey dentists are of utmost importance in preventing IEn patients at increased risk. Other sources of contin-ed bacteremia, such as nail biting, intrauterine de-ices, acne, and body piercing, are now being recog-ized and addressed.The situation we face revolves in part around our ex-

ectations about what represents a guideline. We haveecome less comfortable in endorsing consensus as a guide-

ine and have come to expect evidence-based data to guideur clinical decision-making. Thus, there is no correctecommendation, and a state of equipoise currently exists

round this question, which begs for a properly designed

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497JACC Vol. 52, No. 6, 2008 Weaver et al.August 5, 2008:495–7 President’s Page

linical trial. Perhaps, the AHA and our own committeeshould have eliminated the “guideline,” simply explainedhe issues, and recommended that you and your patientsake the final decision regarding treatment while we

wait real evidence.

ddress correspondence to:

. Douglas Weaver, MD, FACCmerican College of Cardiology400 N Street NW

ashington, DC 20037

EFERENCES

. Wilson W, Taubert KA, Gewitz M, et al. Prevention of infective

endocarditis. Guidelines from the American Heart Association. Aguideline from the American Heart Association Rheumatic Fever,

Endocarditis, and Kawasaki Disease Committee, Council on Cardio-vascular Disease in the Young, and the Council on Clinical Cardiology,Council on Cardiovascular Surgery and Anesthesia, and the Quality ofCare and Outcomes Research Interdisciplinary Working Group. Cir-culation 2007;116;1736–54.

. Oliver R, Roberts GJ, Hooper L. Penicillins for the prophylaxis ofbacterial endocarditis in dentistry. Cochrane Database Syst Rev 2004;2:CD003813.

. Gould FK, Elliott TS, Foweraker J, et al. Guidelines for the prevention ofendocarditis: report of the Working Party of the British Society forAntimicrobial Chemotherapy. J Antimicrob Chemother 2006;57:1035–42.

. Bonow RO, Carabello BA, Chatterjee K, et al. ACC/AHA 2006guidelines for the management of patients with valvular heart disease: areport of the American College of Cardiology/American Heart Asso-ciation Task Force on Practice Guidelines (Writing Committee toRevise the 1998 Guidelines for the Management of Patients WithValvular Heart Disease): developed in collaboration with the Society ofCardiovascular Anesthesiologists endorsed by the Society for Cardio-vascular Angiography and Interventions and the Society of Thoracic

Surgeons. J Am Coll Cardiol 2006;48:e1–148.