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2008 AHA Guidelines: Bacterial Endocarditis Prophylaxis     |  See  sbe2008.pdf  

REF:   J Am Coll Cardiol, 2008; 52:676-685, doi:10.1016/j.jacc.2008.05.008 (Published online 28 July 2008).
 -   http://content.onlinejacc.org/cgi/content/full/52/8/676  

2008 Guidelines updated for infective endocarditis prophylaxis in valvular heart disease

The American College of Cardiology and American Heart Association have updated their joint guidelines for preventing infective endocarditis (IE) in valvular heart disease.

The update, published in the Aug. 19, 2008 Journal of the American College of Cardiology, is based on new evidence that has emerged since the 2006 ACC/AHA Guidelines for the Management of Valvular Heart Disease were published. Major changes include:

* There are now no Class I recommendations for IE prophylaxis in patients with valvular heart disease;

* IE prophylaxis for dental procedures should only be used in patients with underlying cardiac conditions associated with the highest risk for adverse outcomes, such as prosthetic valves or prior IE. In those cases, prophylaxis is reasonable for procedures that involve manipulating gingival tissue or the periapical region of teeth, or perforating oral mucosa.

* Antibiotic IE prophylaxis is no longer indicated in patients with aortic stenosis, mitral stenosis, or symptomatic or asymptomatic mitral valve prolapse. It is also not indicated in adolescents and young adults with native heart valve disease;

* It's not recommended to administer antibiotics solely to prevent IE in patients undergoing a genitourinary (GU) and gastrointestinal (GI) tract procedure. Nor is it recommended solely on the basis of an increased lifetime risk of IE; and

The guidelines were revised for several reasons. IE is more likely to result from frequent exposure to random bacteremias associated with daily activities than from bacteremia caused by a dental, GI tract or GU procedure. As well, the number of IE cases preventable by prophylaxis in patients undergoing those procedures is "exceedingly small," the article said. Also, the risk of adverse effects caused by antibiotics exceeds any benefit from prophylactic antibiotics.

Physicians should be prepared to discuss the updated guidelines with patients as the changes may cause some concern, the article said. Some doctors and patients may still be more comfortable continuing with prophylaxis for IE in certain circumstances; in those cases, the doctor should ensure that the risks associated with antibiotics are minor before prescribing them.

2.3.1 Endocarditis Prophylaxis

Infective endocarditis is a serious illness associated with significant morbidity and mortality. Its prevention by the appropriate administration of antibiotics before a procedure expected to produce bacteremia merits serious consideration. Experimental studies have suggested that endothelial damage leads to platelet and fibrin deposition and the formation of nonbacterial thrombotic endocardial lesions. In the presence of bacteremia, organisms may adhere to these lesions and multiply within the platelet-fibrin complex, leading to an infective vegetation. Valvular and congenital abnormalities, especially those associated with high-velocity jets, can result in endothelial damage, platelet-fibrin deposition, and a predisposition to bacterial colonization. Since 1955, the AHA has made recommendations for prevention of infective endocarditis with antimicrobial prophylaxis before specific dental, gastrointestinal (GI), and genitourinary (GU) procedures in patients at risk for its development. However, many authorities and societies, as well as the conclusions of published studies, have questioned the efficacy of antimicrobial prophylaxis in most situations.

On the basis of these concerns, a writing group was appointed by the AHA for their expertise in prevention and treatment of infective endocarditis, with liaison members representing the American Dental Association, the Infectious Disease Society of America, and the American Academy of Pediatrics. The writing group reviewed the relevant literature regarding procedure-related bacteremia and infective endocarditis, in vitro susceptibility data of the most common organisms that cause infective endocarditis, results of prophylactic studies of animal models of infective endocarditis, and both retrospective and prospective studies of prevention of infective endocarditis. As a result, major changes were made in the recommendations for prophylaxis against infective endocarditis.

The major changes in the updated recommendations included the following:

• The committee concluded that only an extremely small number of cases of infective endocarditis may be prevented by antibiotic prophylaxis for dental procedures even if such prophylactic therapy were 100 percent effective.

• Infective endocarditis prophylaxis for dental procedures is reasonable only for patients with underlying cardiac conditions associated with the highest risk of adverse outcome from infective endocarditis.

• For patients with these underlying cardiac conditions, prophylaxis is reasonable for all dental procedures that involve manipulation of either gingival tissue or the periapical region of teeth or perforation of oral mucosa.

• Prophylaxis is not recommended solely on the basis of an increased lifetime risk of acquisition of infective endocarditis.

• Administration of antibiotics solely to prevent endocarditis is not recommended for patients who undergo a GU or GI tract procedure.

The rationale for these revisions is based on the following:

• Infective endocarditis is more likely to result from frequent exposure to random bacteremias associated with daily activities than from bacteremia caused by a dental, GI tract, or GU procedure.

• Prophylaxis may prevent an exceedingly small number of cases of infective endocarditis (if any) in individuals who undergo a dental, GI tract, or GU procedure.

• The risk of antibiotic-associated adverse effects exceeds the benefit (if any) from prophylactic antibiotic therapy.

• Maintenance of optimal oral health and hygiene may reduce the incidence of bacteremia from daily activities and is more important than prophylactic antibiotics for a dental procedure to reduce the risk of infective endocarditis.

The AHA Prevention of Infective Endocarditis Committee recommended that prophylaxis be given only to a high-risk group of patients before dental procedures that involve manipulation of either gingival tissue or the periapical region of the teeth or perforation of oral mucosa (Tables 2 to 4).GoGo High-risk patients were defined as those patients with underlying cardiac conditions associated with the highest risk of adverse outcome from infective endocarditis, not necessarily those with an increased lifetime risk of acquisition of infective endocarditis. Prophylaxis is no longer recommended for prevention of endocarditis for procedures that involve the respiratory tract unless the procedure is performed in a high-risk patient and involves incision of the respiratory tract mucosa, such as tonsillectomy and adenoidectomy. Prophylaxis is no longer recommended for prevention of infective endocarditis for GI or GU procedures, including diagnostic esophagogastroduodenoscopy or colonoscopy (Table 2). However, in high-risk patients with infections of the GI or GU tract, it is reasonable to administer antibiotic therapy to prevent wound infection or sepsis. For high-risk patients undergoing elective cystoscopy or other urinary tract manipulation who have enterococcal urinary tract infection or colonization, antibiotic therapy to eradicate enterococci from the urine before the procedure is reasonable.

Table 2 Updates to Section 2.3.1. Endocarditis Prophylaxis

2006 Valvular Heart Disease Guideline Recommendations 2008 VHD Focused Update Recommendations Class I Class IIa 1 Prophylaxis against infective endocarditis is recommended for the following patients: • Patients with prosthetic heart valves and patients with a history of infective endocarditis. (Level of Evidence: C) • Patients who have complex cyanotic congenital heart disease (e.g., single-ventricle states, transposition of the great arteries, tetralogy of Fallot). (Level of Evidence: C) • Patients with surgically constructed systemic pulmonary shunts or conduits. (Level of Evidence: C) • Patients with congenital cardiac valve malformations, particularly those with bicuspid aortic valves, and patients with acquired valvular dysfunction (e.g., rheumatic heart disease). (Level of Evidence: C) • Patients who have undergone valve repair. (Level of Evidence: C) • Patients who have hypertrophic cardiomyopathy when there is latent or resting obstruction. (Level of Evidence: C) • Patients with MVP and auscultatory evidence of valvular regurgitation and/or thickened leaflets on echocardiography.* (Level of Evidence: C) 1 Prophylaxis against infective endocarditis is reasonable for the following patients at highest risk for adverse outcomes from infective endocarditis who undergo dental procedures that involve manipulation of either gingival tissue or the periapical region of teeth or perforation of the oral mucosa (4): • Patients with prosthetic cardiac valves or prosthetic material used for cardiac valve repair. (Level of Evidence: B) • Patients with previous infective endocarditis. (Level of Evidence: B) • Patients with CHD. (Level of Evidence: B) • Unrepaired cyanotic CHD, including palliative shunts and conduits. (Level of Evidence: B) • Completely repaired congenital heart defect repaired with prosthetic material or device, whether placed by surgery or by catheter intervention, during the first 6 months after the procedure. (Level of Evidence: B) • Repaired CHD with residual defects at the site or adjacent to the site of a prosthetic patch or prosthetic device (both of which inhibit endothelialization). (Level of Evidence: B) • Cardiac transplant recipients with valve regurgitation due to a structurally abnormal valve. (Level of Evidence: C) * Modified recommendation (changed class of recommendation from I to IIa, changed text). There are no Class I recommendations for infective endocarditis prophylaxis. Class III 1 Prophylaxis against infective endocarditis is not recommended for the following patients: • Patients with isolated secundum atrial septal defect. (Level of Evidence: C) • Patients 6 or more months after successful surgical or percutaneous repair of atrial septal defect, ventricular septal defect, or patent ductus arteriosus. (Level of Evidence: C) • Patients with MVP without MR or thickened leaflets on echocardiography.* (Level of Evidence: C) • Patients with physiological, functional, or innocent heart murmurs, including patients with aortic valve sclerosis as defined by focal areas of increased echogenicity and thickening of the leaflets without restriction of motion and a peak velocity less than 2.0 m per second. (Level of Evidence: C) • Patients with echocardiographic evidence of physiologic MR in the absence of a murmur and with structurally normal valves. (Level of Evidence: C) • Patients with echocardiographic evidence of physiological TR and/or pulmonary regurgitation in the absence of a murmur and with structurally normal valves. (Level of Evidence: C) 1. Prophylaxis against infective endocarditis is not recommended for nondental procedures (such as transesophageal echocardiogram, esophagogastroduodenoscopy, or colonoscopy) in the absence of active infection. (Level of Evidence: B) (4) * This footnote is obsolete. Please see 2006 VHD Guideline (3) for footnote text.

MR indicates mitral regurgitation; MVP, mitral valve prolapse; and TR, tricuspid regurgitation.

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* IE prophylaxis for dental procedures should only be used in patients with underlying cardiac conditions associated with the highest risk for adverse outcomes, such as prosthetic valves or prior IE. In those cases, prophylaxis is reasonable for procedures that involve manipulating gingival tissue or the periapical region of teeth, or perforating oral mucosa.

Dental Procedures and Endocarditis Prophylaxis 2008
Endocarditis prophylaxis recommended	Endocarditis prophylaxis not recommended
Endocarditis prophylaxis is reasonable for patients with the highest risk of adverse outcomes, such as prosthetic valves or prior IE.  who undergo dental procedures that involve manipulation of either gingival tissue or the periapical region of teeth or perforation of the oral mucosa. *Dental extractions *Periodontal procedures including surgery, scaling and root planing, probing, and recall maintenance *Dental implant placement and reimplantation of avulsed teeth *Endodontic (root canal) instrumentation or surgery only beyond the apex *Subgingival placement of antibiotic fibers or strips *Initial placement of orthodontic bands but not brackets *Intraligamentary local anesthetic injections *Prophylactic cleaning of teeth or implants where bleeding is anticipated	Endocarditis prophylaxis is not recommended for: • Routine anesthetic injections through noninfected tissue • Dental radiographs • Placement or removal of prosthodontic or orthodontic appliances • Adjustment of orthodontic appliances • Placement of orthodontic brackets • Shedding of deciduous teeth • Bleeding from trauma to the lips or oral mucosa Endocarditis prophylaxis is not recommended for patients   - with aortic stenosis, mitral stenosis, or symptomatic or asymptomatic mitral valve prolapse. - with native heart valve disease. - undergoing a genitourinary (GU) and gastrointestinal (GI) tract procedure.

Antibiotics Regimens for a Dental Procedure 2008^_*

Table 4: Prophylactic Regimens for Dental, Oral, Respiratory Tract Procedures
Situation	Agent	Regimen1
Oral Med	Amoxicillin	Adults: 2 g; Children: 50 mg/kg orally 1 h before procedure
Unable to take oral medications	Ampicillin	Adults: 2 g IM or IV; Children: 50 mg/kg IM or IV within 30 min before procedure
Allergic to penicillin	Clindamycin or	Adults: 600 mg PO, IM or IV; Children: 20 mg/kg orally 1 h before procedure
	Cephalexin PO or Cefazolin or Ceftriaxone	Adult: Cephalexin 2 gm PO or Cefazolin or Ceftriaxone 1 g IM or IV; Children; 50 mg/kg orally 1 h before procedure
	Azithromycin or clarithromycin	Adults: 500 mg PO; Children: 15 mg/kg orally 1 h before procedure
Allergic to penicillin and unable to take oral medications	Clindamycin or	Adults: 600 mg; Children: 20 mg/kg IV within 30 min before procedure
	Cefazolin2	Adults: 1.0 g; Children: 25 mg/kg IM or IV within 30 min before procedure

1 Total children's dose should not exceed adult dose 2 Cephalosporins should not be used in individuals with immediate-type hypersensitivity reaction (urticaria, angioedema, or anaphylaxis) to penicillins

These changes are a significant departure from the past AHA (7) and European Society of Cardiology (8) recommendations for prevention of infective endocarditis and may violate longstanding expectations in practice patterns of patients and health care providers. However, the writing committee for these updated guidelines consists of experts in the field of infective endocarditis; input was also obtained from experts not affiliated with the writing group. All data to date were reviewed thoroughly, and the current recommendations reflect analysis of all relevant literature. This multidisciplinary team of experts emphasizes that previously published guidelines for the prevention of endocarditis contained ambiguities and inconsistencies and relied more on opinion than on data. The writing committee delineates the reasons with which evolutionary refinement in the approach to infective endocarditis prophylaxis can be justified. In determining which patients receive prophylaxis, there is a clear focus on the risk of adverse outcomes after infective endocarditis rather than the lifetime risk of acquisition of infective endocarditis. The current recommendations result in greater clarity for patients, health care providers, and consulting professionals.

Other international societies have published recommendations and guidelines for the prevention of infective endocarditis. New recommendations from the British Society for Antimicrobial Chemotherapy are similar to the current AHA recommendations for prophylaxis before dental procedures. The British Society for Antimicrobial Chemotherapy did differ in continuing to recommend prophylaxis for high-risk patients before GI or GU procedures associated with bacteremia or endocarditis (9).

Therefore, Class IIa indications for prophylaxis against infective endocarditis are reasonable for VHD patients at highest risk for adverse outcomes from infective endocarditis before dental procedures that involve manipulation of either gingival tissue. This high-risk group includes: 1) patients with a prosthetic heart valve or prosthetic material used for valve repair, 2) patients with a past history of infective endocarditis, and 3) patients with cardiac valvulopathy after cardiac transplantation, as well as 4) specific patients with CHD (Table 2). Patients with innocent murmurs and those patients who have abnormal echocardiographic findings without an audible murmur should definitely not be given prophylaxis for infective endocarditis. Infective endocarditis prophylaxis is not necessary for nondental procedures that do not penetrate the mucosa, such as transesophageal echocardiography, diagnostic bronchoscopy, esophagogastroscopy, or colonoscopy, in the absence of active infection.

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Table 1: Cardiac Conditions Associated With Endocarditis 1999
Endocarditis prophylaxis recommended		Endocarditis prophylaxis NOT recommended: Negligible-risk category (no greater risk than the general population)
High-risk category		*Isolated secundum atrial septal defect Surgical repair of atrial septal defect, ventricular septal defect, or patent ductus arteriosus (without residua beyond 6 mo) *Previous coronary artery bypass graft surgery *Mitral valve prolapse without valvar regurgitation1 *Physiologic, functional, or innocent heart murmur1 *Previous Kawasaki disease without valvar dysfunction *Previous rheumatic fever without valvar dysfunction *Cardiac pacemakers (intravascular and epicardial) and implanted defibrillators
*Prosthetic cardiac valves, including bioprosthetic and homograft valves *Previous bacterial endocarditis *Complex cyanotic congenital heart disease (eg, single ventricle states, transposition of the great arteries, tetralogy of Fallot) *Surgically constructed systemic pulmonary shunts or conduits
Moderate-risk category
*Most other congenital cardiac malformations (other than above and below) *Acquired valvar dysfunction (eg, rheumatic heart disease) *Hypertrophic cardiomyopathy *Mitral valve prolapse with valvar regurgitation and/or thickened leaflets

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* 2008: * It's not recommended to administer antibiotics solely to prevent IE in patients undergoing a genitourinary (GU) and gastrointestinal (GI) tract procedure. Nor is it recommended solely on the basis of an increased lifetime risk of IE;

Table 3: Other Procedures and Endocarditis Prophylaxis 1999
Endocarditis prophylaxis recommended	Endocarditis prophylaxis NOT recommended
Respiratory tract: *Tonsillectomy and/or adenoidectomy *Surgical operations that involve respiratory mucosa *Bronchoscopy with a rigid bronchoscope	Respiratory tract: *Endotracheal intubation *Bronchoscopy with a flexible bronchoscope, with or without biopsy| *Tympanostomy tube insertion
Gastrointestinal tract1: *Sclerotherapy for esophageal varices *Esophageal stricture dilation *Endoscopic retrograde cholangiography with biliary obstruction *Biliary tract surgery *Surgical operations that involve intestinal mucosa	Gastrointestinal tract: *Transesophageal echocardiography| *Endoscopy with or without gastrointestinal biopsy|
Genitourinary tract: *Prostatic surgery *Cystoscopy *Urethral dilation	Genitourinary tract: *Vaginal hysterectomy2 *Vaginal delivery3 *Cesarean section -In uninfected tissue: *Urethral catheterization *Uterine dilatation and curettage *Therapeutic abortion *Sterilization procedures *Insertion or removal of intrauterine devices
	Other: *Cardiac catheterization, including balloon angioplasty *Implanted cardiac pacemakers,implanted defibrillators, and coronary stents *Incision or biopsy of surgically scrubbed skin *Circumcision

1 Prophylaxis is recommended for high-risk patients; it is optional for medium-risk patients. 2 Prophylaxis is optional for high-risk patients 3 Prophylaxis is optional for high-risk patients

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Table 5: Prophylactic Regimens for Genitourinary/Gastrointestinal (Excluding Esophageal) Procedures 1999
Situation	Agents	Regimen1,2
High-risk patients	Ampicillin plus gentamicin	Adults: ampicillin 2.0 g IM or IV plus gentamicin 1.5 mg/kg (not to exceed 120 mg) within 30 min of starting procedure; 6 h later, ampicillin 1 g IM/IV or amoxicillin 1 g orally Children: ampicillin 50 mg/kg IM or IV (not to exceed 2.0 g) plus gentamicin 1.5 mg/kg within 30 min of starting the procedure; 6 h later, ampicillin 25 mg/kg IM/IV or amoxicillin 25 mg/kg orally
High-risk patients allergic to ampicillin/amoxicillin	Vancomycin plus gentamicin	Adults: vancomycin 1.0 g IV over 1-2 h plus gentamicin 1.5 mg/kg IV/IM (not to exceed 120 mg); complete injection/infusion within 30 min of starting procedure Children: vancomycin 20 mg/kg IV over 1-2 h plus gentamicin 1.5 mg/kg IV/IM; complete injection/infusion within 30 min of starting procedure
Moderate-risk patients	Amoxicillin or ampicillin	Adults: amoxicillin 2.0 g orally 1 h before procedure, or ampicillin 2.0 g IM/IV within 30 min of starting procedure Children: amoxicillin 50 mg/kg orally 1 h before procedure, or ampicillin 50 mg/kg IM/IV within 30 min of starting procedure
Moderate-risk patients allergic to ampicillin/amoxicillin	Vancomycin	Adults: vancomycin 1.0 g IV over 1-2 h complete infusion within 30 min of starting procedure Children: vancomycin 20 mg/kg IV over 1-2 h; complete infusion within 30 min of starting procedure

1 Total children's dose should not exceed adult dose 2 No second dose of vancomycin or gentamicin is recommended.

         2008