Improved diagnostic value of echocardiography in patients with infective endocarditis by transoesophageal approach. A prospective study

Abstract

In a prospective study, the clinical value of transoesophageal two-dimensional echocardiography (TOE) as compared with transthoracic two-dimensional echocardiography (TTE) was determined in patients with suspected infective endocarditis. Ninety-six patients were studied consecutively with an electronic sector scanner using 2.25 and 3.5 MHz probes for TTE and a 3.5 MHz probe embedded in tip of a flexible 12 mm gastroscope for TOE. Results of surgery and autopsy were available for 20 of the 96 patients with infective endocarditis and echocardiographically demonstrated vegetations and 70 control patients with valvular heart disease without infective endocarditis and no signs of vegetations, who were studied preoperatively with TTE and TOE. For TTE and TOE, the measured sensitivity was 63% and 100%, specificity 98% and 98%, positive predictive accuracy 92% and 95%, and negative predictive accuracy 91% and 100%, respectively. In 39 patients who had positive blood cultures, vegetations were found by TOE in 32 patients (82%), but in only 27 patients (69%) by TTE. Image quality was the main factor contributing to the superiority of TOE over TTE: it was reduced in 11/20 patients (55%) in whom vegetations were not detected by TTE. Another important factor was the size of vegetations. Only 6/24 vegetations (25%) of less than 5 mm but 9/13 vegetations of 6-10 mm, and 14/14 vegetations of greater than 11 mm detected by TOE were also observed with TTE. The clinical importance of detecting vegetations was demonstrated by the rate of embolism. In patients with vegetations embolism was 25% when blood cultures were positive and 21% when they were negative. In patients without echocardiographically detectable vegetations signs of embolism were seen in no patient with positive and 7% of the patients with negative blood cultures. Evidence of vegetations was found on the aortic valve in 14 patients and on the mitral valve in seven patients in whom valvular incompetence was not present, indicating that the valve had not yet been damaged significantly. TOE is superior to TTE in detecting vegetations in suspected infective endocarditis because of better image quality, particularly when vegetations are small. TOE seems to be indicated in patients with suspected endocarditis and reduced image quality or negative TTE results. Early detection of vegetations on valves may help confirm the diagnosis of infective endocarditis at an early stage and hopefully lead to an improved prognosis by reducing delay in instituting appropriate therapy.

Diagnosis and Management of Infective Endocarditis and Its Complications

“…23 Another prospective TEE study, however, found no clear correlation of vegetation size with embolization. 95 Overall, these data are compatible with previous observations that in general, mitral vegetations, regardless of size, are associated with higher rates of embolization (25%) than aortic vegetations (10%). Of interest, the highest embolic rate (37%) has been seen in the subset of patients with mitral vegetations attached to the anterior rather than the posterior mitral leaflet.…”

“…The number of vegetations, the number of valves involved, and vegetation characteristics (eg, lack of calcification) predicted embolic complications in one study. 95 Vegetation mobility has not been shown to be an independent risk factor for embolic events, probably because it is strongly correlated with vegetation size. 23 Embolic events do appear to be predicted by an increase in vegetation size by TEE over 4 to 8 weeks of therapy.…”

Changing Trends of Infective Endocarditis in India: A South Indian Experience

“…[4][5][6] The sensitivity of TTE varies from 40-63%, and for TEE between 90-100%, while the specificity for both is greater than 95%. [14][15][16] The diagnostic yield of echocardiography reported by Chaudhury et al (64%) was lower, probably due to lack of TEE at that time. 6 The culture positivity of 83.8% of IE in our study is higher than that reported by Math (41%), Chaudhury et al (47%) and Garg et al (67.6%).…”

Judicious use of transthoracic echocardiography in infective endocarditis screening

“…Therefore, the current European Society of Cardiology and American Heart Association guidelines (3,9) recommend that any patients suspected of having native valve endocarditis by clinical criteria should be screened by TTE. Furthermore, TTE is rapid and noninvasive, and has excellent specificity for vegetations (4,10). TTE is therefore widely used in IE surveillance.…”