Transient bacteremia is usually asymptomatic and thus of little clinical significance in most patients. Individuals with valvular heart disease are a notable exception, because circulating bacteria may lodge on damaged or prosthetic heart valves, resulting in bacterial endocarditis. Transient bacteremia can occur with many medical procedures, and the use of antibiotics to prevent endocarditis in the high-risk patient has become an accepted medical practice. This is based on the premise that microbial seeding of a damaged valve can be prevented by prior administration of antibiotics.1-3
There is no direct evidence for the efficacy of this approach in man; therefore, recommendations must be based on studies using animal models.1,4 The issue may never be completely resolved, because a controlled human study is not feasible. Based on a calculated risk of 0.2%, Durack5 estimated that at least 6,000 patients who have valvular heart disease and are undergoing dental procedures