Risk of endocarditis in transesophageal echocardiography.

The risk of endocarditis associated with transesophageal echocardiography was studied in 101 patients. To evaluate possible bacteremia, blood cultures were performed on samples from consecutive patients who did not have clinical or laboratory evidence of infection. The broth blood culture Signal system was used in all patients, and additionally, the lysis-centrifugation technique was performed in a subgroup of 40 patients to further ameliorate recovery of rapidly phagocytosed germs. Comprehensive criteria for differentiation between true bacteremia and possible contamination were provided by means of simultaneous blood sampling from two separate venipuncture sites and skin specimens from the venipuncture area. Oropharyngeal specimens were cultured for evaluation of possible association of oropharyngeal flora with positive blood culture findings. They revealed facultative pathogenic isolates, as well as physiologic residental flora, in 15 patients. All blood isolates that were recovered simultaneously 6 minutes after the procedure were found to be sterile. Correspondingly, clinical follow-up for 2 weeks was uneventful with regard to episodes of infection. These results indicate that the risk of bacteremia associated with transesophageal echocardiography is extremely low. Thus endocarditis prophylaxis is not required for this procedure.