Antibiotic prophylaxis. Part II: recommendations of the American Heart Association and related committees.

ABSTRACT

The American Heart Association's (AHA) Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee; the Council on Cardiovascular Disease in the Young; and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and Quality of Care and Outcomes Research Interdisciplinary Working Group recently published guidelines for antibiotic prophylaxis prior to dental procedures, respiratory tract procedures and gastrointestinal (GI) or genitourinary (GU) tract procedures. The groups of committees were instructed to use the systematic review process to develop new guidelines to assist oral-health and other health professionals. Major changes include (1) cardiac conditions indicated for prophylaxis pertain only to those that carry the highest risk of developing infective endocarditis (EI); (2) dental procedures requiring prophylaxis in these conditions include any procedure requiring tooth manipulation rather than procedures that are associated with significant bleeding; and (3) timing of the antibiotic is to administer a single dose 30 to 60 minutes prior to the dental procedure rather than the previous 60-minute requirement. The recommendation for a pre-procedural antimicrobial rinse was eliminated. The antibiotics recommended for prophylaxis were not changed.

RESUME

Le Rheumatic Fever, Endocarditis and Kawasaki Disease Committee, le Council on Cardiovascular Disease in the Young, le Council on Clinical Cardiology, le Council on Cardiovascular Surgery and Anesthesia et le Quality of Care and Outcomes Research Interdisciplinary Working Group de l'American Heart Association (AHA) ont publie dernierement des directives sur l'antibioprophylaxie prealable aux interventions dentaires et aux interventions touchant les voies respiratoires, le tractus gastro-intestinal et l'appareil genitourinaire. Les groupes de comites devaient appliquer un mecanisme de revision systematique pour elaborer de nouvelles directives d'aide aux professionnels de la sante dentaire et autres professionnels de la sante. Les principaux changements sont, notamment : 1) les troubles cardiaques indiques pour la prophylaxie sont uniquement ceux qui presentent le risque le plus eleve de developper une endocardite infectieuse; 2) les interventions dentaires necessitant une prophylaxie dans ces conditions incluent toute intervention exigeant une manipulation dentaire plutot que les interventions associees a un saignement abondant; 3) l'antibiotique doit etre administre sous forme de dose unique entre 30 et 60 minutes avant les interventions dentaires au lieu de 60 minutes, comme auparavant. Le rincage antimicrobien pre-intervention qui etait recommande a ete elimine. Les antibiotiques recommandes pour la prophylaxie demeurent les memes.

INTRODUCTION

THE AMERICAN HEART ASSOCIATION'S (AHA) Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee; the Council on Cardiovascular Disease in the Young; and the Council on Clinical Cardiology, Council on Cardiovascular surgery and Anesthesia, and Quality of Care and Outcomes Research Interdisciplinary Working Group recently published new guidelines to assist oral-health and other health professionals in the use of antibiotic prophylaxis prior to dental, respiratory tract and gastrointestinal (GI) or genitourinary (GU) tract procedures. (1) The British Antimicrobial Society (BAS) updated their recommendations in 2006. Both the BAS and the AHA, which are equivalent authorities in their respective countries, used the systematic review process to develop the new guidelines. Antibiotic Prophylaxis, Part 1: Recommendations of the British Society for Antimicrobial Chemotherapy Working Party, published in the May-June 2007 issue of this journal, reviewed relevant scientific evidence and clinical studies used by the Working Party of the BAS to establish recommendations for dental-health professionals when making judgments related to antibiotic prophylaxis to prevent infective endocarditis (IE). The AHA's recommendations for using antibiotic prophylaxis are discussed in this article, representing Part II of the issue. As well, this article discusses the differences between the two professional recommendations. The writing group of the AHA Committee reported the recent changes are intended to define more clearly those situations when endocarditis prophylaxis is or is not recommended and to provide more uniform and consistent global recommendations.

SYSTEMATIC REVIEW LEVELS OF EVIDENCE

The AHA Committee, Councils and Working Group were charged with the task of assessing the evidence and giving a classification of recommendations and a level of evidence (LOE) to each recommendation. The group used the American College of Cardiology/American Heart Association classification system (Boxl) (1) and determined their recommendations over the past 50 years to be Class IIb, LOE C.

HISTORY OF AHA RECOMMENDATIONS FOR PREVENTION OF IE

The AHA has made recommendations for the prevention of IE for more than 50 years, beginning with the first guidelines in 1955. (2) The recommendations for the use of antibiotic prophylaxis prior to dental treatment were made based on the significant morbidity and mortality of IE and the finding that microorganisms found in high numbers in the oral cavity (viridans group streptococci) were the most common microorganisms cultured from early cases. (2) The 1965 guidelines recognized for the first time the role of enterococci in bacteremias following GI- or GU-tract procedures. (3) Recommendations published in 1972 were endorsed for the first time by the American Dental Association (ADA) and emphasized the importance of maintaining good oral hygiene. (4) Subsequent recommendations attempted to simplify prophylactic regimens and address the growing problem with antibiotic resistance until the 1997 recommendations stratified cardiac conditions into high-, moderate-, and low-risk categories, advising not to provide antibiotic prophylaxis for low-risk cardiac conditions and to limit pre-procedure dosing to a single dose. (5) The fundamental principles that led to the formulation of the AHA's new guidelines and the nine previous sets of guidelines are that (1) IE is an uncommon but life-threatening disease and prevention is preferable to treatment of an established infection; (2) certain underlying cardiac conditions predispose to IE; (3) bacteremia with organisms known to cause IE occurs commonly in association with invasive dental, GI- or GU-tract procedures; (4) antimicrobial prophylaxis has proven to be effective in preventing experimental IE in animals; and (5) antimicrobial prophylaxis is thought to be effective in humans for prevention of IE associated with dental, GI- or GU-tract procedures. (1) The 2007 guidelines are based on the results of a large body of evidence published in numerous studies over the past two decades. The guidelines are intended to be in the best interest of clients and care providers, are considered to be reasonable and prudent and represent the collective wisdom of many experts on IE and relevant national and international societies.

RATIONALE FOR REVISING THE 1997 GUIDELINES

The AHA Committee explained that the 1997 guidelines were based largely on expert opinion and what seemed to be a rational and prudent attempt to prevent a life-threatening infection. They report the basis for former recommendations for endocarditis prophylaxis was not well established and the quality of evidence was limited to a few case-control studies or was based on clinical experience and descriptive studies that utilized surrogate measures of risk. (1) Although many dental and dental-hygiene professionals believed that (based on AHA guidelines) antibiotic prophylaxis prior to dental procedures was effective to prevent endocarditis, research published prior to and following the 1997 guidelines questioned the effectiveness of the then-recommended regimen to prevent IE associated with oral procedures and dental treatment. (6,7,8,9) The primary reasons for the current revision of guidelines for antibiotic prophylaxis to prevent IE are that (1) IE is much more likely to result from frequent exposure to random bacteremias associated with daily activities than from bacteremia caused by a dental, GI- or GU-tract procedure; (2) only a small number of cases of IE, if any, would be prevented with prophylaxis prior to a dental, GI- or GU-tract procedure; (3) the risk of antibiotic-associated adverse events exceeds the benefit, if any, from prophylactic antibiotic therapy; and (4) maintenance of oral health and hygiene may reduce the incidence of bacteremia from daily activities and is more important than prophylactic antibiotics prior to a dental procedure to reduce the risk of IE.

ROLE OF ORAL HEALTH AND HYGIENE

Oral health and the absence of periodontal inflammation and bleeding have been considered important to reduce bacteremias from the oral cavity. The AHA Committee noted that this presumed relationship is controversial, (10,11,12,13) however available evidence supports an emphasis on maintaining good oral hygiene and eradicating dental disease to decrease the frequency of bacteremia from routine daily activities. (14,15,16,17) Because study results vary, the AHA Committee concluded that a precise determination of the relative risk of bacteremia that result from a specific dental procedure in clients with or without dental disease is probably not possible. (18,19,20).

PRE-PROCEDURAL RINSE

Results are contradictory with regard to the efficacy of the use of topical antiseptics in reducing the frequency of bacteremia associated with dental procedures, but the preponderance of evidence suggests there is no clear benefit. (6,21,22,23) The collective published data suggests that the vast majority of dental treatments result in some degree of bacteremia; however, there is no evidence-based method to decide which procedures should require prophylaxis, because no data shows that the incidence, magnitude or duration of bacteremia from any dental procedure increase the risk of IE. In past regimens a pre-procedural use of chlorhexidine was recommended, but the current regimen does not recommend an antiseptic rinse because there is no evidence that demonstrates the practice will prevent IE.

POTENTIAL CONSEQUENCES OF CHANGES IN GUIDELINES

The AHA Committee's writing group recognized that changes in the new guidelines could be confusing to both practitioner and client, because they might violate longstanding expectations and practice patterns. The changes would likely cause concern among clients who previously received antibiotic prophylaxis before dental or other procedures and would now be advised that such prophylaxis is unnecessary. The Committee agrees that for 50 years, since the publication of the first AHA guidelines on the prevention of IE, clients and health-care providers assumed that antibiotics administered in association with a bacteremia-producing procedure effectively prevented IE in clients with underlying cardiac risk factors. Receiving antibiotic prophylaxis may have given clients with underlying cardiac defects a sense of reassurance and comfort that IE would be prevented. Oral health-care providers need to understand the reasons for the changes and communicate this information to those clients who are affected.

CLIENT INFORMATION

Part 1 of the discussion on antibiotic prophylaxis included a sample information sheet, which the BAS proposed to provide to clients, explaining the changes in the new recommendations. The AHA also has a client information sheet that can be printed and provided to clients explaining the changes in the new guidelines and identifying those clients who should have antibiotic prophylaxis prior to dental procedures (http://www.americanheart.org/presenter.jhtml?identifier=11086).

RECOMMENDED GUIDELINES FOR ANTIBIOTIC PROPHYLAXIS (1)

The cardiac conditions recommended for antibiotic prophylaxis prior to dental procedures include those that carry the highest risk of an adverse outcome from IE (Box 2). Although it has been reported that IV-drug users represent a group who are very likely to develop IE, the AHA Committee did not include this group in their 2007 recommendations. The AHA Committee recommendation is to be applied to "community-acquired" IE and endocarditis resulting from IV-drug use is not in this category. In the high-risk cardiac conditions identified by the new guidelines, dental procedures that require prophylaxis include all procedures that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa. The appropriate antibiotic should be administered in a single dose 30 minutes to one hour before the procedure. If the dose is inadvertently not taken before the dental appointment it may be administered up to two hours after the procedure. This should only be considered if the client failed to take the antibiotic prior to the appointment. Table 1 illustrates the antibiotics recommended for prophylaxis and alterations to the oral-dose regimen for individuals who cannot swallow oral-dose forms. Amoxicillin is the preferred choice for oral therapy because it is well absorbed from the GI tract and provides a rapid and sustained serum concentration of antibiotic. For situations in which the client is currently taking amoxicillin an alternate drug from a different class in Table 1 should be selected for prophylaxis. The current regimen does not discuss situations in which multiple dental appointments are needed, however the AHA Committee states that waiting 10 days after an antibiotic has been taken may allow sufficient time for the usual oral flora to be reestablished. Applying this principle to multiple dental appointments for the individual at high risk of IE, spacing appointments 10 days apart can be considered, as well as selecting an antibiotic from a different class. For example, when treatment needs to be completed within a two-week time period and four quadrants of periodontal therapy are required (and no allergy to antibiotics is reported in the health history), amoxicillin is the drug of first choice for the initial appointment, followed by clindamycin for the second appointment of less than 10 days later, followed by a macrolide for the third appointment of less than 10 days later, and so on.

Other special situations addressed in the updated recommendations include avoiding intramuscular injections for IE prophylaxis when anticoagulant medication is being taken (Class I, LOE A). In addition, clients who are scheduled to undergo cardiac surgery should have a careful preoperative dental evaluation and the recommended treatment should be completed, whenever possible, before cardiac valve surgery or replacement or repair of coronary heart disease (CHD). There is no evidence that coronary artery bypass graft surgery is associated with a long-term risk of infection, therefore, antibiotic prophylaxis for dental procedures is not necessary in clients who have undergone this surgery. As well, antibiotic prophylaxis prior to dental procedures is not recommended for clients with coronary artery stents (Class III, LOE C). However, endocarditis in a client with a heart transplant is associated with a high risk of adverse outcome, (24) so antibiotic prophylaxis is recommended for clients who develop valvular dysfunction after transplantation.

CONCLUSIONS

The Committees concluded major changes in the updated guidelines that include the following: (1) only an extremely small number of cases of IE might be prevented by antibiotic prophylaxis prior to dental procedures even if such prophylactic therapy were 100-percent effective; (2) IE prophylaxis for dental procedures should be recommended only for clients with underlying cardiac conditions associated with the highest risk of adverse outcome from IE; (3) when these underlying cardiac conditions are present, antibiotic prophylaxis is recommended for all dental procedures that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa; (4) prophylaxis is not recommended based solely on an increased lifetime risk of acquisition of IE; (5) bacteremia resulting from daily activities is much more likely to cause IE than bacteremia associated with a dental procedure; and (6) administration of antibiotics solely to prevent endocarditis is not recommended for clients who undergo genitourinary- or gastrointestinal-tract procedures. The Committees reaffirmed those procedures noted in the 1997 prophylaxis guidelines for which endocarditis prophylaxis is not recommended and extended this prohibition to other common procedures, including ear and body piercing, tattooing, and vaginal delivery and hysterectomy. In former recommendations the AHA Committee used the term "bacterial endocarditis" because the antibiotic regimen only covered bacteria, not fungi or nonbacterial cardiac infections. For the first time, the 2007 guidelines terminology was changed to "infective endocarditis" as this is a currently accepted term for the condition.

DIFFERENCES FROM THE BRITISH ANTIMICROBIAL SOCIETY RECOMMENDATIONS

The AHA and BAS regimens are very similar. The cardiac conditions recommended for prophylaxis are similar in both sets of guidelines, however the BAS does not include congenital cardiac conditions nor the heart-transplant client who develops valvular dysfunction. The AHA continues to recommend a two-gram single dose of amoxicillin, whereas the BAS now recommends a three-gram single dose. The AHA does not address multiple dental visits, while the BAS recommends a regimen when multiple dental visits are needed. The AHA does recommend spacing dental appointments 10 days apart to avoid antibiotic resistance and to select an antibiotic from another class when the client is currently taking an antibiotic in the regimen. The AHA does not include a pre-procedure antiseptic mouthrinse in their new guidelines, whereas the BAS recommends this practice. Both sets of guidelines stress the importance of oral health and that clients with cardiac disease should be educated to maintain periodontal and dental health to reduce the risk of IE.

SUMMARY

In the past, it was assumed that taking an antibiotic prior to dental procedures would reduce the formation of a bacteremia and reduce the risk for IE, however no evidence-based studies have verified this assumption. The collective published evidence suggests that antibiotic prophylaxis, if it is effective, would reduce the condition in only a very few cases. The majority of IE cases caused by oral microflora likely develop from routine daily activities, such as chewing, toothbrushing, flossing and using toothpicks. Dental and periodontal disease may increase the risk of bacteremia and maintaining good oral health is felt to be important to reduce IE. The AHA Committee recognizes a shift is needed away from antibiotic prophylaxis and toward a greater emphasis on improved access to dental care in order to eliminate oral infection and on maintaining good periodontal health in individuals with underlying cardiac conditions associated with the highest risk of IE.

REFERENCES

1. Wilson W, Taubert KA, Gewitz M, Lockhart PB, Baddour LM, Levison M, Bolger A, Cabell, CH, Takahashi M, Baltimore RS, Newburger JW, Strom BL, Tani LY, Gerber M, Bonow RO, Pallasch T, Shulman ST, Rowley AH, Burns JC, Ferrieri P, Gardner T, Goff D, Durack DT. 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. J Am Dent Assoc 2007;138(6):739-60.

2. Jones TD, Baumgartner L, Bellow MT, Breese BB, Kuttner AG, McCarty M, Rammelkamp CH (Committee on Prevention of Rheumatic Fever and Bacterial Endocarditis, American Heart Association). Prevention of rheumatic fever and bacterial endocarditis through control of streptococcal infections. Circulation 1955;11:317-20.

3. Wannamaker LW, Denny FW, Diehl A, Jawetz E, Kirby WMM, Markowitz M, McCarty M, Mortimer EA, Paterson PY, Perry W, Rammelkamp CH Jr, Stollerman GH (Committee on Prevention of Rheumatic Fever and Bacterial Endocarditis, American Heart Association). Prevention of bacterial endocarditis. Circulation 1965;31:953-54.

4. Rheumatic Fever Committee and the Committee on Congenital Cardiac Defects, American Heart Association. Prevention of bacterial endocarditis. Circulation 1972;46:S3-S6.

5. Dajani AS, Taubert KA, Wilson W, Bolger AF, Bayer A, Ferrieri P, Gewitz MH, Shulman ST, Nouri S, Newburger JW, Hutto C, Pallasch TJ, Gage TW, Levison ME, Peter G, Zuccaro G Jr. Prevention of bacterial endocarditis: recommendations by the American Heart Association. JAMA 1997;277:1794-1801.

6. Oliver R, Roberts GJ, Hooper L. Penicillins for the prophylaxis of bacterial endocarditis in dentistry. Cochrane Database Syst Rev 2006, issue 1.

7. Strom BL, Abrutyn E, Berlin JA et al. Dental and cardiac risk factors for infective endocarditis: a population-based, casecontrol study. Ann Intern Med 1998;129(10):761-69.

8. van der Meer JTM, van Wijk W, Thompson J, Vandenbroucke JP. Efficacy of antibiotic prophylaxis for prevention of nativevalve endocarditis. Lancet 1992;339:135-39.

9. Morris AM. Coming clean with antibiotic prophylaxis. Arch Intern Med 2007;167:330-34.

10. Sconyers JR, Crawford JJ, Moriarty JD. Relationship of bacteremia to toothbrushing in patients with periodontitis. J Am Dent Assoc 1973;87:616-22.

11. Forner L, Larsen T, Kilian M, Holmstrup P. Incidence of bacteremia after chewing, tooth brushing and scaling in individuals with periodontal inflammation. J Clin Periodontol 2006;33:401-7.

12. Lockhart PB, Schmidtke MA. Antibiotic considerations in medically compromised patients. Dent Clin North Am 1994;38:381-402.

13. Conner HD, Haberman S, Collings CK, Winford TE. Bacteremias following periodontal scaling in patients with healthy appearing gingiva. J Periodontol 1967;38:466-72.

14. Roberts GJ. Dentists are innocent! "Everyday" bacteremia is the real culprit: a review and assessment of the evidence that dental surgical procedures are a principal cause of bacterial endocarditis in children. Pediatr Cardiol 1999;20:317-25.

15. Hockett RN, Loesche WJ, Sodeman TM. Bacteraemia in symptomatic human subjects. Arch Oral Biol 1977;22:91-98.

16. McEntegart MG, Porterfield JS. Bacteraemia following dental extractions. Lancet. 1949:2:596-98.

17. Robinson L, Kraus FW, Lazansky JP, Wheeler RE, Gordon S, Johnson V. Bacteremias of dental origin, II: a study of the factors influencing occurrence and detection. Oral Surg Oral Med Oral Pathol 1950;3:923-36.

18. Lockhart BP. The risk for endocarditis in dental practice. Periodontol 2000. 2000;23:127-35.

19. Barco CT. Prevention of infective endocarditis: a review of the medical and dental literature. J Periodontol 1991;62:510-23.

20. Bayliss R, Clarke C, Oakley C, Somerville W. Whitfield AG. The teeth and infective endocarditis. Br Heart J. 1983;50:506-12.

21. MacFarlane TW, Ferguson MM, Mulgrew CJ. Post-extraction bacteremia: role of antiseptics and antibiotics. Br Dent J 1984;156:179-81.

22. Lockhart BP. An analysis of bacteremias during dental extractions: a double-blind, placebo-controlled study of chlorhexidine. Arch Intern Med 1996;156:513-20.

23. Cherry M, Daly CG, Mitchell D, Highfield J. Effect of rinsing with povidone-iodine on bacteraemia due to scaling: a randomized-controlled trial. J Clin Periodontol 2007;34(2):148-55.

24. Sherman-Weber S, Axelrod P, Suh B, Rubin S, Beltramo D, Manacchio J, Furukawa S, Weber T, Eisen H, Samuel R. Infective endocarditis following orthotopic heart transplantation: 10 cases and a review of the literature. Transpl Infect Dis 2004;6:165-70.

By Frieda Pickett, RDH, MS

Class 1:    Conditions for which there is evidence and/or general
            agreement that a given procedure or treatment is beneficial,
            useful and effective.
Class II:   Conditions for which there is conflicting evidence and/or a
            divergence of opinion about the usefulness/efficacy of a
            procedure or treatment.
            Class lla:  Weight of evidence/opinion is in favor of
                        usefulness/efficacy.
            Class llb:  Usefulness/efficacy is less well established by
                        evidence/opinion.
Class III:  Conditions for which there is evidence and/or general
            agreement that a procedure/treatment is not useful/effective
            and in some cases may be harmful.
Level of Evidence (LOE):
            LOE A:  Data derived from multiple randomized clinical
                    trials or meta-analyses.
            LOE B:  Data derived from a single randomized trial or
                    nonrandomized studies.
            LOE C:  Only consensus opinion of experts, case studies, or
                    standard of care.

Source: Wilson W et al. J Am Dent Assoc 2007; 1 38(6):740

Box 1. ACC/AHA classification of recommendations and levels of evidence

Prosthetic cardiac valve
Previous history of IE
Congenital heart disease (CHD)
  * Unrepaired cyanotic CHD, including palliative shunts and conduits
  * Completely repaired congenital heart defect with prosthetic material
    or device, whether placed by surgery or by catheter intervention,
    during the first six months after the procedure
  * Repaired CHD with residual defects at the site or adjacent to the
    site of a prosthetic patch or prosthetic device (which inhibit
    epithelialization)
Cardiac transplantation recipients who develop cardiac valvulopathy

Source: Wilson et al. Prevention of Infective Endocarditis. Circulation
May 8, 2007:10.

Box 2. High-risk cardiac conditions for which prophylaxis prior to
dental procedures is recommended

Situation          Antibiotic       Adult dose*      Child dose*

Able to take oral  amoxicillin      2 g              50 mg/kg
  med
Unable to take     Ampicillin       2 g IM or IV     50 mg/kg IM or IV
  oral med         Cefazolin or     1 g IM or IV     50 mg/kg IM or IV
                   ceftriaxone
Allergic to        Clindamycin or   600 mg           20 mg/kg
  penicillin--     Azithromycin or  500 mg           15 mg/kg
  able to take     clarithromycin   2 g              50 mg/kg
  oral med         Cephalexin+
Allergic to        Clindamycin or   600 mg IM or     20 mg/kg IM or
penicillin and     Cefazolin or     IV 1 g IM or IV  IV 50 mg/kg IM or
unable to take     ceftriaxone+                      IV
oral med

e*taken 30 to 60 min before dental procedure
+ do not use cephalosporin if individual has history of anaphylaxis,
angioedema or urticaria with penicillin on thIM = intramuscular; IV =
intravenous
Source: Wilson et al. Prevention of Infective Endocarditis. Circulation.
May 8, 2007:12.

Table 1. Antibiotic Regimens for Dental Procedure in those at high-risk
for IE