antibiotic prophylaxis for bacterial endocarditis

Introduction

Guidelines 2007 recommend prophylaxis only in patients at highest risk for an adverse outcome from endocarditis.

Indications

• patients with prosthetic cardiac valves*
  • bioprosthetic valves
  • mechanical valves
• heart transplant recipients who develop cardiac valvulopathy
• history of infective endocarditis
  • choice of prophylactic antibiotic independent of organism associated with prior endocarditis
• some patients with congenital heart disease (CHD)
  • unrepaired cyanotic CHD
    • persistent murmur &/or low oxygen saturation breathing room air in adulthood indicates incomplete repair
  • up to 6 months after a repair with prosthetic material or device
  • repaired CHD with residual defects
• prosthetic material used for cardiac valve repair (annuloplasty rings, chords)

antibiotic prophylaxis also recommended for patients with aortic prosthesis (endovascular graft)

* possible link between invasive dental procedures & infective endocarditis (risk ~5%), but no clear benefit from prophylaxis

In these patients, the guidelines recommend prophylaxis before:

• dental procedures involving the gingival tissue or the periapical region of the teeth or that perforate the oral mucosa
• procedures on the respiratory tract
  • tonsillectomy &/or adenoidectomy
  • surgical operations that involve the respiratory mucosa
  • bronchoscopy with a rigid bronchoscope
• procedures on infected skin, skin structures, or musculoskeletal tissue

no increase in endocarditis incidence after invasive dental procedures, even among high-risk patients

Contraindications

Antibiotic prophylaxis is NOT recommended for:

• genitourinary procedures
• gastrointestinal tract procedures
  • including transesophageal echocardiography
• endotracheal intubation or bronchoscopy
• cardiac catheterization
• incision of clean skin
• the following cardiac conditions
  • isolated secundum atrial septal defect
  • repaired atrial septal defect
  • repaired ventricular septal defect
  • repaired persistent patent ductus arteriosus
  • previous CABG
  • mitral valve prolapse without regurgitation or lealet thickening; mitral valve prolapse.
  • cardiac pacemakers & implanted defibrillators
  • native valvular heart disease without a history of endocarditis
  • hypertrophic cardiomyopathy
  • aortic valvular stenosis
  • bicuspid aortic valve
• cosmetic implants

Procedure

Antibiotics 1 hour prior to procedure (one dose)

• amoxicillin 2 g PO
• clarithromycin 500 PO
• azithromycin 500 mg PO
• Ceftriaxone 1 g IM or IV
• Cefazolin 1 g IM or IV
• clindamycin* 600 mg PO, IM or IV

* AHA guidelines suggest clindamycinis no longer an alternative to amoxicillin because it is associated with more frequent occurrence of C difficile colitis

AHA recommends a single dose of antibiotic for skin surgery patients at high risk for severe adverse endocarditis events, only if the tissue is clearly infected at the time of surgery.

Coverage for:

• Staphylococcus aureus
• beta-hemolytic streptococcus

Antibiotics given once 30-60 minutes prior to the procedure

• dicloxacillin 500 mg PO
• clindamycin 600 mg PO or IV

Reductions in antibiotic use for dental prophylaxis in the US & France have not resulted in an increase in mouth-flora related endocarditis

if antibiotic prophylaxis is inadvertantly not administered before the procedure, it may be give up to 2 hours after the procedure

Notes

Implementation of 2007 guidelines have not increased incidence of endocarditis

• have increased incidence of endocarditis

Prior evidence supporting prophylaxis was anecdotal; consensus was that it seemed like a good idea.

New emphasis on oral hygiene.

It is the primary care responsibility to determine if patient has one of above 4 qualifying conditions for antibiotic prophylaxis.

It is the dentist's responsibility, not the primary care physician's responsibility to determine whether the upcoming dental procedure warrants prophylaxis.

More general terms

• antibiotic prophylaxis