Prevention of infective endocarditis: new US Guidelines

Prevention of infective endocarditis: new US Guidelines bring major changes for at-risk patients

Infective endocarditis (IE) is a life-threatening disease associated with a high mortality rate. To avoid its severe complications, several recommendations have been published during the past 20 years about the best use of antimicrobial prophylaxis to prevent IE in patients who undergo a dental, gastrointestinal (GI) or genitourinary (GU) tract procedures. However, efficacy of such prophylaxis has been questioned and several authorities have suggested that guidelines need to be revised and simplified.

The new American guidelines for prevention of infective endocarditis

The main changes in the updated American recommendations are as follows:

1. IE prophylaxis for dental procedures should be recommended only for patients with underlying cardiac conditions associated with the highest risk of adverse outcome from IE.

2. For patients with these underlying cardiac conditions, 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.

3. Prophylaxis is not recommended based solely on an increased lifetime risk of acquiring IE.

4. Administration of antibiotics solely to prevent endocarditis is not recommended for patients who undergo a genitourinary or gastrointestinal tract procedure.

A considerable change for patients with cardiac disease


These represent a considerable change and limitation in the current use of endocarditis prophylaxis for Americans with cardiac disease; for instance:

• patients at risk: only those with the highest risk of adverse outcome in case of IE are considered for prophylaxis, including prosthetic cardiac valves, previous endocarditis, unrepaired congenital heart disease, and cardiac transplants who develop cardiac valvulopathy.
Most patients with valvular heart disease are no longer considered candidates for antibiotic prophylaxis;

• the dental procedures for which IE prophylaxis is recommended: all procedures involving manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa are considered at risk and need prophylaxis when performed in at-risk patients;

• the GU or GI tract procedures: antibiotic prophylaxis is no longer recommended in these procedures

Limits to applying American guidelines in Europe

Before applying the American guidelines in Europe, we need to consider their limitations.

First, the new guidelines are not based on randomised studies.

Second, such radical modifications may be difficult to accept and understand by both patients and practitioners, and much effort will be required to explain them carefully, particularly so that patients understand the shift from focus on dental procedures towards a greater access to dental care and oral health for those with cardiac disease associated with the worst outcome after IE.

Third, these guidelines probably will be followed by a reduction in the number of antibiotic prescriptions for preventing IE in the USA. It will be important to monitor the consequences on the epidemiologic profile of IE in the USA.

Finally, prospective placebo-controlled double-blinded studied of antibiotic prophylaxis of IE in patients at risk of IE remain necessary, as well as additional prospective case-control studies.The ESC is developing a new version of the 2004 IE guidelines. These will focus on prevention, diagnosis and treatment of IE and are expected by 2009.

Revised AHA Guidelines for Prevention of Endocarditis

Revised AHA Guidelines for Prevention of Endocarditis

Allan S. Brett, MD

Journal Watch. 2007;6(6) ©2007 Massachusetts Medical Society
Posted 07/25/2007

Major changes include a narrowed list of cardiac conditions that warrant prophylaxis, and the elimination of gastrointestinal and genitourinary indications for prophylaxis.

Summary

The complex 1997 American Heart Association (AHA) recommendations for preventing infective endocarditis have guided practice during the past decade. However, experts have long acknowledged that the evidence to support the effectiveness of endocarditis prophylaxis is not compelling. For example, cumulative exposure to bacteremia from daily oral activities (e.g., chewing, brushing, flossing) is thousands of times greater than exposure from a few dental visits yearly. Thus, prophylaxis for dental procedures is likely to prevent only a tiny proportion of cases of endocarditis, at best.

In view of the limited evidence, the AHA has published a new guideline with the following key elements:

1. Prophylaxis is now recommended only for patients with these four conditions:

prosthetic cardiac valve
previous infective endocarditis
certain types of congenital heart disease (see guideline for details)
cardiac transplantation with valvulopathy

2. For patients with the conditions listed above, prophylaxis should be given only before:
dental procedures that involve manipulation of gingival tissue or the periapical region of teeth, or perforation of oral mucosa (see guideline for dental procedures that do not require prophylaxis)

incision or biopsy of respiratory tract mucosa
procedures on infected skin or musculoskeletal structures

3. Prophylaxis is no longer recommended for gastrointestinal or genitourinary procedures. However, if urine is colonized by enterococcus, eradication before invasive urinary procedures is reasonable.

4. A single 2-g dose of amoxicillin, given 30 to 60 minutes before the procedure, remains the regimen of choice (see guideline for alternatives in cases of penicillin allergy or inability to take oral medication).

Comment

This new guideline will substantially reduce the number of people who receive endocarditis prophylaxis. Conspicuous changes from the previous guideline include the elimination of acquired valvular dysfunction (including mitral valve prolapse) from the list of cardiac conditions warranting prophylaxis, and the elimination of gastrointestinal and genitourinary indications for prophylaxis. In my view, primary care clinicians should read the full guideline so that they can knowledgeably advise patients and dentists who might resist these changes.