Introduction Echocardiography is central to the diagnosis and management of infective endocarditis. It is generally accepted that transoesophageal echo (TOE) has a much higher sensitivity for the detection of diagnostic features of endocarditis, however the studies on which these findings are based are outdated and generally included small numbers of patients.^1–3 We hypothesised that improvements in ultrasound technology over the last 15 years may have led to an improvement in the diagnostic accuracy of transthoracic echo (TTE).

Methods We retrospectively reviewed clinical records for all patients with a discharge diagnosis of endocarditis over an 18 month period. Only patients in whom the Duke criteria were fulfilled and for whom echo reports were available for review were included for analysis. Patients treated presumptively for endocarditis with no microbiological, pathological or echocardiographic features of endocarditis were excluded.

Results 112 studies (67 TTE and 45 TOE) were carried out in 52 patients. On a per patient basis, the overall sensitivity of TTE was 69.4% (37/49) and of TOE was 94.7% (36/38) for the detection of features of endocarditis. Sensitivity of TTE was lower again for prosthetic valve or pacemaker endocarditis (56.5% [13/23]) compared to TOE (90% [18/20]) and TTE only detected 33% (3/9) of aortic root abscesses. As several patients had more than one study with both positive and negative findings, results were also analysed on a per study basis. Overall sensitivity of TTE was 65.7% (44/67) and of TOE was 93.3% (42/54). Again, sensitivity of TTE for detection of prosthetic and pacemaker endocarditis was much lower (50% [16/32]) compared to TOE (88.5% [23/26]).

Conclusion Despite advances in imaging technology, TOE remains more sensitive than TTE for the detection of features of endocarditis particularly in cases of prosthetic valve and pacemaker infection. Sensitivity is similar to that of studies performed over 20 years ago. This is likely due to intrinsic differences in techniques. Proximity to structures of interest during TOE allows use of higher frequency ultrasound providing improved spatial resolution and more detailed assessment of structures of interest, particularly the aortic valve and aortic root.

References

1. . Shapiro SM, et al. Transesophageal echocardiography in diagnosis of infective endocarditis. Chest 1994;105:377–382.

2. . Shively BK, et al. Diagnostic value of transesophageal compared with ?transthoracic echocardiography in infective endocarditis. J Am Coll Cardiol 1991;18:391–397.

3. . Reynolds HR, et al. Sensitivity of transthoracic versus transesophageal echocardiography for the detection of native valve vegetations in the modern era. J Am Soc Echocardiog2003;16:67–70.