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A. Overview

  1. A variety of invasive procedures cause transient bacteria
  2. In most cases, these bacteremias are easily cleared from the circulation
  3. Adherance of organisms to cardiac valves occurs in certain populations
  4. Most conditions predisposing to endocarditis are cardiac valve abnormalities
  5. Failure to clear organisms from valves leads ot endocarditis
  6. Various cardiac repair operations, particularly for congenital disease, require prophylaxis [6]
  7. Recommendations for prophylaxis now significantly reduced to high risk conditions [3,4]

B. Situations Where Prophylaxis Recommended [3,4]

  1. Many dental and periodontal procedures [1,7]
  2. Tonsillectomy or adenoidectomy
  3. Rigid bronchoscopy
  4. Surgery involving upper respiratory mucosa
  5. Esophageal sclerotherapy and dilatation
  6. Gallbladder surgery
  7. Catheterization in setting of urinary tract infection
  8. Incision and drainage of infected tissues
  9. Vaginal delivery with infection present
  10. Any invasive procedure in patients with significant heart valve lesions [7]

C. Situations Where Prophylaxis Not Usually Recommended

  1. Intraoral injection of local anesthetic
  2. Shedding of primary teeth
  3. Tympanostomy-tube insertion
  4. Endotracheal tube insertion
  5. Bronchoscopy with flexible bronchoscope
  6. Transesophageal Echocardiography
  7. Cardiac catheterization
  8. Cesarean Section (give antibiotics only if infection is present)
  9. Gastrointestinal endoscopy, with or without biopsy (prophylaxis for high risk patients)
  10. Genitourinary procedures with no infection present (except those above)
  11. Circumcision

D. High Risk Predisposing Conditions

  1. Should generally receive prophylaxis, particularly with dental conditions
  2. Previous bacterial endocarditis
  3. Prosthetic heart values
  4. Unrepaired cyanotic congenital heart disease such as tetralogy of Fallot
  5. Surgically constructed palliative shunts or conduits
  6. Within 6 months of crrection of congenital heart defects with prosthetic material / device
  7. Congential heart defect with residual defect or adjacent to prosthetic patch or device 8 Cardiac valvulopathy after cardiac transplant

E. Moderate Risk Predisposing Conditions

  1. Congenital cardiac diseases except those in High Risk (D) and Low Risk (F)
  2. Acquired Valvular Dysfunction
    1. Rheumatic Heart Disease
    2. Libman-Sacks Valve
    3. Antiphospholipid Syndrome Associated Valve Disease
  3. Hypertrophic Cardiomyopathy
  4. Complicated Mitral Valve Prolapse (MVP):
    1. MVP with Valvular Regurgitation
    2. MVP with thickened valve leaflets
    3. MVP without clinical findings (uncomplicated) does not require echocardiography [5]
  5. Dental procedures may not confer increased risk in patients with normal valves [7]

F. Negligible Risk Predisposing Conditions

  1. Isolated Atrial Septal Defect, Secundum Type
  2. Surgically Repaired Cardiac Defects >6 months
    1. Atrial Septal Defect (ASD)
    2. Ventricular Septal Defect (VSD)
    3. Patent Ductus Arteriosus (PDA)
  3. Heart Murmers with normal echocardiogram (physiologic or functional, flow murmers)
  4. Systemic diseases without residual cardiac valve anomalies
    1. Kawasaki Disease - normal echocardiogram only
    2. Rheumatic Heart Disease - normal echocardiogram only
  5. Cardiac Pacemakers and Implantable Defibrillators

G. Antibiotics [1,3,4]

  1. Situations above the Diaphragm (Dental, Oral, Esophageal, Respiratory)
    1. Amoxicillin 2-3gm po (or ampicillin 2-3gm iv) 1 hour before procedure
    2. Need for post-procedure antibiotics unclear: amoxicillin 1.5gm at 6 hours
    3. Pencillin Allergy: clindamycin (Cleocin®), cephelexin (Keflex®), cefadroxil (Duricef®), clarithromycin (Biaxin®) or azithromycin (Zithromax®)
    4. An aminoglycoside can be added in high risk patients
  2. Situations below the Diaphragm (Genitourinary, Gastrointestinal except Esophagus)
    1. High Risk: ampicillin (2gm IV) ± gentamicin (1.5mg/kg) <30 minutes pre-procedure
    2. High Risk with Pencillin Allergy: vancomycin 1.0gm IV ± gentamicin
    3. Generally give additional ampicillin (not vancomycin) 6 hours following procedure
    4. Moderate Risk: ampicillin or vancomycin as above (usually without aminoglycoside)
    5. Amoxicillin po may be used (2gm given one hour before) in lower risk situations
  3. Efficacy
    1. Prevention may be in range of 50-90% although studies are difficult
    2. Use of platelet inhibitors, fibrin blockers, is also under investigation

References

  1. Dajani AS, Taubert KA, Wilson W, et al. 1997. JAMA. 277(22):1794 abstract
  2. Antibacterial Prophylaxis. 2005. Med Let. 47(1213):59 abstract
  3. Prevention of Bacterial Endocarditis. 2007. Med Let. 49(1275):99 abstract
  4. Wilson W, Taubert KA, Gewitz M, et al. 2007. Circulation. 116:1736 abstract
  5. Heidenreich PA, Bear J, Browner W, Foster E. 1997. Am J Med. 102(4):337 abstract
  6. Morris CD, Reller MD, Menashe VD. 1998. JAMA. 279(8):599 abstract
  7. Strom BL, Abrutyn E, Berlin JA, et al. 1998. Ann Intern Med. 129(10):761 abstract