The role of transthoracic echocardiography in excluding left sided infective endocarditis in Staphylococcus aureus bacteraemia
Introduction
Infective endocarditis (IE) complicates between 8 and 25% of patients with S. aureus bacteraemia (SAB), with an associated mortality rate between 19 and 65%.1, 2, 3 Distinguishing, patients with IE from those with non-IE SAB is essential, but often difficult. Echocardiography is recommended in all patients with SAB to exclude IE. Transoesophageal echocardiography (TOE) is preferred to transthoracic echocardiography (TTE) as the reported sensitivity in detecting vegetations is 93–100% for TOE as compared to 40–80% for TTE.4, 5 However, in the assessment of native valve regurgitation, there is a high level of concordance between TTE and TOE.5
The pathological consequence of IE is valvular regurgitation. Thus, we hypothesised that excluding regurgitation on TTE, in the appropriate clinical context, would be sufficiently reliable to exclude IE. The aim of this retrospective study was to determine the probability of left-sided native valve IE in patients with SAB when the TTE revealed no or trivial regurgitation.
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Patients and methods
The study was conducted at Prince of Wales Hospital, Sydney, Australia (a tertiary care referral centre). Patients were included in this study if they had SAB and had undergone both a TTE and TOE during the period of January 1996 to December 2000.
Consecutive patients (n=808) with at least one positive blood culture bottle for S. aureus (SAB) were identified from the microbiology database and were cross-referenced with the echocardiography database. Patients were excluded if they had no
Results
Of 125 patients, 22 (18%) had IE as per modified Dukes criteria (18 patients had two major criteria while the remaining four patients had one major and three minor criteria).
The patient profiles were not statistically different between the two groups for the majority of variables. However, patients with IE were significantly more likely to have community-acquired SAB (P<0.05), SAB from an unknown source (P<0.05), require SAB related surgery (P<0.001) and have documented embolic phenomena (P
Discussion
In patients with SAB and no embolic phenomena (with a prevalence of IE of 18%), the post-test probability of left-sided native valve IE was less than 2% following a normal TTE. Therefore, patients without embolic phenomena and no or trivial valvular regurgitation on TTE do not require a TOE to exclude S. aureus IE.
Previous clinical profiles have been used to predict patients with SAB of having a high risk of IE. Fowler et al. reported four risk factors (community-acquisition, skin examination
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2020, Infection Prevention in PracticeCitation Excerpt :These rates are consistent with those found in other studies of SAB, including those with much higher published rates of TOE [35–39]. Despite the low rate of utilisation of TOE, the rates of endocarditis diagnosis in this study are consistent with those reported in other case series [9,35–38]. Some authors suggest forgoing TOE if repeat blood cultures are negative and no additional deep foci of infection are identified [38].
Clinical predictors and clinical prediction rules to estimate initial patient risk for infective endocarditis in Staphylococcus aureus bacteraemia: a systematic review and meta-analysis
2017, Clinical Microbiology and InfectionCitation Excerpt :Moreover, most studies did not include consecutive patients. In many studies, a significant proportion of SAB patients who did not receive echocardiograms were excluded [4,6,26–28,30,34,41,45,46]. This exclusion introduces potential selection bias and makes the study results less applicable to all SAB patients.
An Approach to Improve the Negative Predictive Value and Clinical Utility of Transthoracic Echocardiography in Suspected Native Valve Infective Endocarditis
2016, Journal of the American Society of EchocardiographyUse of transthoracic echocardiography in the management of low-risk Staphylococcus aureus bacteremia: Results from a retrospective multicenter cohort study
2015, JACC: Cardiovascular ImagingCitation Excerpt :Few studies using modern echocardiography have examined a model with clinical and TTE criteria (19). All were small or single-center studies, and none used separate derivation and validation cohorts (17,18,24). In a 2009 to 2010 study, Rasmussen et al. (17) concluded that TTE may be an adequate screening tool in patients at low risk for IE; however, criteria were complex and based on many variables, which introduces model instability.
Diagnosis and treatment of bacteremia and endocarditis due to Staphylococcus aureus. A clinical guideline from the Spanish Society of Clinical Microbiology and Infectious Diseases (SEIMC)
2015, Enfermedades Infecciosas y Microbiologia Clinica