Echocardiography is important for the diagnosis of infective endocarditis (IE), for which transesophageal echocardiography (TEE) is superior to transthoracic echocardiography (TTE).Methods:
A systematic review and meta-analysis of observational studies was performed with the objective of evaluating diagnostic properties of TTE, with transesophageal findings of IE as the reference standard in patients with suspected IE.Results:
The literature search yielded 377 unique articles, of which 16 met the inclusion criteria. The 16 studies included 2,807 patients, of whom 793 (28%) had vegetations on TEE. For detecting vegetations, harmonic TTE had sensitivity of 61% (95% CI, 45%–75%) and specificity of 94% (95% CI, 85%–98%) with a negative likelihood ratio (NLR) of 0.42 (95% CI, 0.26–0.61). NLR for harmonic TTE can be improved by including only patients without prosthetic valves (NLR = 0.36; 95% CI, 0.22–0.55) or by having strict criteria for conclusively negative results on TTE (NLR = 0.17; 95% CI, 0.10–0.28). In the setting of patients without prosthetic valves, harmonic TTE had likelihood ratios of 0.14 (95% CI, 0.09–0.23) for a conclusively negative result, 0.66 (95% CI, 0.53–0.81) for an indeterminate result, and 14.60 (95% CI, 3.37–70.40) for a positive result.Conclusions:
Modern harmonic TTE still has the potential to miss many vegetations detected on TEE. When limited to patients without prosthetic valves, a conclusively negative TTE under optimal view greatly decreases likelihood of IE. All other transthoracic results are not useful for ruling out IE, and subsequent TEE is almost always required.