Current guidelines recommend echocardiography for all patients with Staphylococcus aureus bacteraemia (SAB) regardless of baseline risk, as the diagnosis of infective endocarditis (IE) determines duration of treatment and prognosis. However the benefit of routine screening in cancer patients without complicated SAB has not been established.
The primary aim of the study was to describe the incidence of infective endocarditis detected on echocardiography in cancer patients with confirmed SAB. We retrospectively identified 95 cases of SAB in cancer patients from Jan 2007-Mar 2016. Echocardiography was ordered at the discretion of the treating team, and positive findings were defined according to the Modified Dukes Criteria. Complicated bacteraemia was defined by prolonged bacteraemia, presence of intracardiac device/prosthetic valve, or signs of metastatic infection on clinical examination.
Major predisposing risk factors for IE (intracardiac device, prosthetic valve, valvular disease, diabetes mellitus, renal dialysis) were present in 27% of cases. 51/95 (54%) had a central venous catheter and 17 (18%) patients had complicated bacteraemia. Echocardiography was performed in 75/95 (79%) episodes, with transthoracic echocardiography (TTE) alone in 56, transoesophageal echocardiography (TOE) alone in 4 and both in 15. Echocardiography was diagnostic for IE in 2 patients (1 TTE, 1 TOE), including one result that led to the diagnosis of IE in a clinically unsuspected case. Four further cases of IE were diagnosed on clinical findings, resulting in an overall rate of IE of 6% (6/95). Five of these cases occurred in patients with complicated bacteraemia or >1 risk factor for IE. No patient was readmitted due to IE.
IE is infrequent in cancer patients with uncomplicated SAB and no risk factors for IE. Performing echocardiography routinely in all cancer patients with SAB rarely alters diagnosis or affects antibiotic management and therefore should be reserved for patients with specific risk factors.