Elsevier

Journal of Infection

Volume 51, Issue 3, October 2005, Pages 218-221
Journal of Infection

The role of transthoracic echocardiography in excluding left sided infective endocarditis in Staphylococcus aureus bacteraemia

https://doi.org/10.1016/j.jinf.2005.01.011Get rights and content

Abstract

In all patients with Staphylococcus aureus bacteraemia a transoesophageal echocardiogram is recommended to exclude infective endocarditis.

We determined that a finding of normal to trivial valvular regurgitation on transthoracic echocardiogram in these patients significantly reduced the probability of infective endocarditis. Furthermore, in the absence of embolic phenomena the likelihood of infective endocarditis was less than 2%. This probability could be further reduced if the echocardiogram was performed greater than 5 days after the bacteraemia. Therefore, in the assessment of patients with S. aureus bacteraemia a transoesophageal echocardiogram is not always required to exclude infective endocarditis.

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.

Section snippets

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

References (13)

There are more references available in the full text version of this article.

Cited by (43)

  • Assessing the impact of a ‘bundle of care’ approach to Staphylococcus aureus bacteraemia in a tertiary hospital

    2020, Infection Prevention in Practice
    Citation 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 Infection
    Citation 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.

  • Use of transthoracic echocardiography in the management of low-risk Staphylococcus aureus bacteremia: Results from a retrospective multicenter cohort study

    2015, JACC: Cardiovascular Imaging
    Citation 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.

View all citing articles on Scopus
View full text