Uncertainty Remains about Effectiveness of Antibiotic Prophylaxis for Bacterial Endocarditis

A 2013 Cochrane Review¹ found there is little scientific evidence to support the effectiveness of antibiotic prophylaxis for patients at risk of developing bacterial endocarditis who are about to undergo invasive dental treatment. The review authors found few primary studies that evaluated the effectiveness of antibiotic prophylaxis and they were generally of low quality. Only one case-control study met the inclusion criteria for the review.

Clarification of CDA position on antibiotic prophlylaxis to prevent infective endocarditis

The CDA Position on the Prevention of Infective Endocarditis (approved in 2007 and reaffirmed in 2013 by the CDA Board of Directors) is aligned with the American Heart Association’s (AHA) 2007 guidelines for antibiotic prophylaxis prior to dental procedures to prevent infective endocarditis.

Recently, the AHA published “Corrections” to its 2007 guidelines that clarified language in the guideline. In particular, a change was made to the list of cardiac conditions for which antibiotic prophlylaxis with dental procedures is reasonable—those conditions associated with the highest risk of an adverse outcome from infective endocarditis. The cardiac condition “artificial heart valve” was replaced with “prosthetic cardiac valve or prosthetic material used for cardiac valve repair.”

CDA’s Clinical and Scientific Affairs Committee contacted the AHA to get more information about the rationale for the change. Based on the answer received from the AHA, the committee confirmed that the change was editorial in nature. However, in their medical questionnaire, dentists should ask patients if they have had cardiac valve repairs—if they have not already done so.

In terms of implications for practice, the study authors conclude that “...practitioners need to discuss the potential benefits and harms of preventive antibiotic treatment with their patients before a decision is made about prescribing it.”

CDA’s position statement on prevention of infective endocarditis² supports the American Heart Association’s (AHA) 2007 guidelines³, which suggest that short-term preventive antibiotic therapy before certain dental and medical procedures are reasonable for patients at greatest risk of developing infective endocarditis.

“The AHA guidelines recognize that the effectiveness of antibiotic prophylaxis for high risk patients is unknown, which is consistent with this most recent Cochrane Review,” says Dr. Susan Sutherland, chair of CDA’s Clinical and Scientific Affairs Committee. “The uncertainty surrounding the effectiveness of antibiotic prophylaxis for these high risk patients makes it all the more important for dentists to discuss the benefits and risks of antibiotic prophylaxis with these patients before a decision is made to prescribe antibiotics.”

Use of prophylactic antibiotic therapy to prevent mortality, serious illness or incidence of bacterial endocarditis is controversial because the adverse effects of antibiotics may outweigh the potential benefits. Many countries recommend giving antibiotics prophylactically to patients at high risk for developing bacterial endocarditis, such as patients with previous endocarditis and prosthetic heart valves. For example, European, American, and Australian guidelines recommend giving antibiotics only to those patients deemed to be at high risk. However, in England and Wales, guidelines published by the National Institute for Health and Care Excellence (NICE) indicate that patients at risk of developing infective endocarditis do not require antibiotics for any interventional procedure—dental or surgical.

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To read the CDA position statement on prevention of infective endocarditis, go to cda-adc.ca/_files/position_statements/infectiousEndocarditis.pdf. For information on the impact of the NICE guidelines in the 2 years after they were introduced, see: http://www.jcda.ca/article/jcda_express_issue_6_2011.