Chapter 33
Endocarditis and Endocarditis Prophylaxis
1. What are believed to be the first steps in the development of infective endocarditis (IE)?
2. How often does routine tooth brushing and flossing cause transient bacteremia?
3. True or false: Prospective randomized placebo-controlled trials have demonstrated that antibiotic prophylaxis before a dental or other procedure reduces the risk of IE?
4. What are the four conditions identified as having the highest risk of adverse outcome from endocarditis for which prophylaxis with dental procedures is still recommended?
Certain cases of congenital heart disease (CHD), such as:
Cardiac transplantation recipients who develop cardiac valvulopathy
5. Which of the above AHA criteria for endocarditis prophylaxis is not recommended for prophylaxis in the 2009 European Society of Cardiology (ESC) guidelines?
Cardiac transplant recipients with valvulopathy. The 2009 ESC guidelines take an approach that is generally similar to that of the 2007 AHA guidelines on which conditions and which procedures should be considered for endocarditis prophylaxis. However, the ESC guidelines do not list cardiac transplant recipients with valvulopathy as a population that should receive prophylaxis, noting that prophylaxis in this group is not supported by strong evidence, and that the probability of IE from dental origin is extremely low in such patients.
6. In the new AHA guidelines, for those patients with conditions listed in Question 4, which dental procedures carry a recommendation of endocarditis prophylaxis?
The guidelines emphasize that all dental procedures that involve the manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa should receive endocarditis prophylaxis. Procedures that do not require prophylaxis include routine anesthetic injections through noninfected tissue, dental radiographs, placement of removable prosthodontic or orthodontic appliances, bleeding from trauma to the lips or oral mucosa, and select other procedures and manipulations. The guidelines emphasize that prophylaxis for the former mentioned procedures “may be reasonable for these patients,” although “its effectiveness is unknown” (and this prophylaxis recommendation is given a class IIb recommendation, with level of evidence C). New changes in the AHA guidelines on IE are summarized in Box 33-1.
7. For those patients with conditions for which antibiotic prophylaxis is recommended, undergoing dental procedures for which prophylaxis is recommended, what regimens are recommended?
Antibiotic treatment should be administered as a single dose before the procedure, with antimicrobial therapy directed against viridians group streptococci. Amoxicillin (2 g orally [PO]), administered 30 to 60 minutes before the procedure, is the first-line recommendation. Those unable to take oral medication can be treated with ampicillin (2 g intramuscularly [IM] or intravenously [IV]) or cefazolin or ceftriaxone (1 g IM or IV). For those allergic to the penicillins or ampicillin, potential agents to use include cephalexin, clindamycin, azithromycin, clarithromycin, cefazolin, and ceftriaxone.
8. For what other procedures may prophylaxis be considered in patients with high-risk lesions?
Invasive procedures of the respiratory tract that involve incision or biopsy of the respiratory mucosa (e.g., tonsillectomy, adenoidectomy)
Bronchoscopy with incision of the respiratory tract mucosa (but not otherwise for bronchoscopy)
Invasive respiratory tract procedures to treat an established infection (e.g., drainage of an abscess or empyema)
Surgical procedures that involve infected skin, skin structures, or musculoskeletal tissue
9. Is endocarditis prophylaxis recommended in patients treated with coronary stents, pacemakers, or defibrillators, those undergoing transesophageal echocardiography (TEE), or those who have undergone coronary artery bypass grafting (CABG) (without valve replacement)?
10. What factors (discussed in detail in the ESC guidelines on endocarditis) should raise the suspicion for endocarditis?