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Which patients should be given antibiotics to prevent infective endocarditis?
Summary of the ACC/AHA 2008 guidelines
Introduction
The American College of Cardiology (ACC) and the American Heart Association (AHA) Task Force on Practice Guidelines issued a 2008 guideline update on valvular heart disease (VHD) focused on infective endocarditis (IE). Guidelines for the management of patients with VHD were published in 2006. Only recommendations related to infective endocarditis were revised in the 2008 update.1 A summary of the changes are provided below. Clinicians are encouraged to review the full update at http://circ.ahajournals.org/cgi/content/full/118/8/887.
Rationale for changes
These changes are reflective of the evidence and recommendations presented in the 2007 AHA guidelines for the prevention of IE.1,2 The committee concluded that if antibiotic prophylactic treatment prior to dental procedures was 100% effective, only a very small number of cases of IE would be prevented.2 Furthermore, exposure to bacteremia is greater during the patients’ daily activities than during dental procedures, and the risks of adverse effects associated with antibiotic therapy outweigh the benefits (if any) of prophylactic therapy. Instead of antibiotic prophylaxis, optimal oral hygiene is recommended to possibly reduce the risk of IE and bacteremia exposure during daily activities.
The guidelines utilize a grading system to classify recommendations as the following: Class I (recommendation that procedure/treatment is useful/effective/beneficial), Class IIa (recommendation that procedure/treatment can be useful/effective), Class IIb (recommendation that procedure/treatment usefulness/effectiveness is uncertain or not well established), Class III (recommendation that procedure/treatment is not useful/effective/beneficial and may be harmful).1 The levels of evidence are classified as the following: Level A (data derived from multiple randomized clinical trials or meta-analyses), Level B (data derived from a single randomized trial or nonrandomized studies), Level C (data derived from consensus opinion of experts, case studies, or standard of care).
ACC/AHA 2008 guidelines on VHD: focused update on infective endocarditis
Significant changes have been made to the VHD guidelines with regards to IE.1,2 As a result, fewer patients are eligible for antibiotic treatment for the prevention of IE. The 2006 VHD guidelines had Class I recommendations for IE prevention; however, the following 2008 recommendations are Class IIa.1,3
Prophylaxis is given before dental procedures involving manipulation of either gingival tissue or the periapical region of teeth or perforation of the oral mucosa and is limited to patients with the following conditions, who are associated with the highest risk of adverse outcomes from IE1:
- Prosthetic cardiac valves or prosthetic material used for cardiac valve repair
- Previous IE
- Congenital heart disease (CHD)
- Unrepaired cyanotic CHD, including palliative shunts and conduits
- Completely repaired congenital heart defect repaired with prosthetic material or device during the first 6 months after the procedure
- Repaired CHD with residual defects at the site or adjacent to the site of a prosthetic patch or prosthetic device
- Cardiac transplant recipients with valve regurgitation due to a structurally abnormal valve
Antibiotic prophylaxis for IE is no longer recommended for patients (without an active infection) undergoing GI and GU procedures, transesophageal echocardiograms, and respiratory tract procedures (unless there is an incision of the mucosa).1
The committee recognized that some clinicians may elect to continue antibiotic prophylaxis for IE in patients with bicuspid aortic valve or coarctation of the aorta, severe mitral valve prolapse, or hypertrophic obstructive cardiomyopathy.1 In these conditions, the risks associated with antibiotic therapy should be low and clinicians should evaluate these risks before initiating therapy. The treatment regimens for dental procedures are the same as those listed in the 2006 ACC/AHA guidelines for the management of VHD (see table 1).1,3 Doses should be administered 30 to 60 minutes prior to the procedure, and no dose is indicated after the procedure.
Table 1. Antibiotic regimens for dental procedures.1,3
| Situation |
Agent |
Adults |
Children |
| Oral |
Amoxicillin |
2 g |
50 mg/kg |
| Unable to take oral medication |
Ampicillin
OR
Cefazolin or ceftriaxone |
2 g IM or IV
1 g IM or IV |
50 mg/kg IM or IV
50 mg/kg IM or IV |
| Allergic to penicillins or ampicillin (oral regimens) |
Cephalexin*†
OR
Clindamycin
OR
Azithromycin or clarithromycin |
2 g
600 mg
500 mg |
50 mg/kg
20 mg/kg
15 mg/kg |
| Allergic to penicillins or ampicillin (parenteral regimens) |
Cefazolin or
ceftriaxone†
OR
Clindamycin |
1 g IM or IV
600 mg IM or IV |
50 mg/kg IM or IV
20 mg/kg IM or IV |
| min=minutes; IM=intramuscular; IV=intravenous
*Can use other first- or second-generation oral cephalosporins.
†Cephalosporins should not be used in an individual with a history of anaphylaxis, angioedema, or urticaria with penicillin or ampicillin. |
Summary
The focused update from ACC/AHA represents a dramatic shift in practice, and as such implementation will be challenging. Antibiotic prophylaxis is now only recommended for patients at high risk for adverse outcomes if they were to get IE, and the number of procedures for which prophylaxis is warranted has been substantially reduced. Pharmacists are in a unique position to educate prescribers about the new guidelines when processing orders or filling prescriptions for the prophylactic antibiotic regimens listed in table 1.
References
- Nishimura RA, Carabello BA, Faxon DP, et al. ACC/AHA 2008 guideline update on valvular heart disease: focused update on infective endocarditis: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines: endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. Circulation. 2008;118(8):887-896.
- Wilson W, Taubert KA, Gewitz M, et al. 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. Circulation. 2007;116(15):1736-1754.
- Bonow RO, Carabello BA, Chatterjee K, et al. ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to revise the 1998 guidelines for the management of patients with valvular heart disease) developed in collaboration with the Society of Cardiovascular Anesthesiologists endorsed by the Society for Cardiovascular Angiography and Interventions and the Society of Thoracic Surgeons. J Am Coll Cardiol. 2006;48(3):e1-148.
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