Judicious use of transthoracic echocardiography in infective endocarditis screening.
BACKGROUND
Patients with a very low probability of infective endocarditis (IE) do not benefit from transthoracic echocardiography (TTE). Because the term 'very low probability' has not yet been defined, the present prospective study sought to identify the population with a 'very low probability'.


METHODS
TTE was performed between July 2005 and October 2006 in consecutive patients clinically suspected of having IE. Clinical parameters suggestive of IE and presence of infectious focus were recorded.


RESULTS
Twenty-four (15.5%) of 155 patients studied had positive findings on TTE. Significant positive predictors were embolic events, intravenous drug use, the presence of a prosthetic valve, positive blood cultures and immunological phenomena. The significant negative predictor was confirmed infection sites other than endocardium. Sixty-three (40.6%) of 155 patients without positive predictors were found to have no vegetation. Thus, the collective absence of these predictors indicated a zero probability of TTE showing evidence of IE. A significant negative predictor was a definite etiology of infection other than IE. Only one in 76 patients was diagnosed with both IE and infection at another site.


CONCLUSIONS
The absence of positive predictors or the presence of a negative predictor indicate a near-zero probability of IE being detected by TTE. Use of clinical parameters may avoid up to 41% of unnecessary TTE examinations, increasing the likelihood that such a diagnosis will be correct.
Liu
Yen-Wen
YW
Department of Internal Medicine, National Cheng Kung University Medical Center, Tainan, Taiwan.
Tsai
Wei-Chuan
WC
Hsu
Chih-Hsin
CH
Lin
Li-Jen
LJ
Li
Wei-Ting
WT
Chen
Chun-Hsiu
CH
Chen
Jyh-Hong
JH
D000368:Aged; D004452:Echocardiography; D004696:Endocarditis / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity